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Soluble guanylate cyclase (sGC) modulation has been scrutinized in several disease states including heart failure (HF). Recently, it was shown that an sGC modulator improved HF-related hospitalization significantly, though, there was no benefit related to mortality. Herein, a comprehensive meta-analysis of randomized controlled trials (RCTs) for sGC modulation in HF patients was provided in agreement with the PRISMA statement. A total of 10 RCTs yielding 12 papers were included. There were 7526 patients with heart failure of each phenotype, 4253 in the sGC modulator group and 3273 in the placebo group. Use of sGC modulators in HF patients yielded no significant difference in the risk of all-cause mortality compared to placebo (RR = 0.97, 95% CI 0.88–1.08, p = 0.62). The use of sGC modulators was associated with a trend toward a considerable but non-significant increase in the incidence of SAEs (RR = 1.10, 95% CI 0.99–1.22, p = 0.07), as well as an increased incidence of hypotension and anemia. There was an overall neutral effect of sGC modulation on NT-proBNP levels, 6MWD and mortality, at a cost of slight increase in hypotension and anemia. Of note, the improvement in EQ-5D-based quality of life was significant. Hence, the benefit seems to be driven by distinctive domains of quality of life. [ABSTRACT FROM AUTHOR]

Existing video object segmentation (VOS) methods based on matching techniques commonly employ a reference set comprising historical segmented frames, referred to as 'memory frames', to facilitate the segmentation process. However, these methods suffer from the following limitations: (i) Inherent segmentation errors in memory frames can propagate and accumulate errors when utilized as templates for subsequent segmentation. (ii) The non-local matching technique employed in top-leading solutions often fails to incorporate positional information, potentially leading to incorrect matching. In this paper, we introduce the Modulated Memory Network (MMN) for VOS. Our MMN enhances matching-based VOS methods in the following ways: (i) Introducing an Importance Modulator, which adjusts memory frames using adaptive weight maps generated based on the segmentation confidence associated with each frame. (ii) Incorporating a Position Modulator that encodes spatial and temporal positional information for both memory frames and the current frame. The proposed modulator improves matching accuracy by embedding positional information. Meanwhile, the Importance Modulator mitigates error propagation and accumulation by incorporating confidence-based modulation. Through extensive experimentation, we demonstrate the effectiveness of our proposed MMN, which also achieves promising performance on VOS benchmarks. [ABSTRACT FROM AUTHOR]

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High data rate coverage, security, and energy efficiency will play a key role in the continued performance scaling of next-generation mobile systems. Dense, small mobile cells based on a novel network architecture are part of the answer. Motivated by the recent mounting interest in free-space optical (FSO) technologies, this paper addresses a novel mobile fronthaul network architecture based on FSO, spread spectrum codes, and graphene modulators for the creation of dense small cells. The network uses an energy-efficient graphene modulator to send data bits to be coded with spread codes for achieving higher security before their transmission to remote units via high-speed FSO transmitters. Analytical results show the new fronthaul mobile network can accommodate up to 32 remote antennas under error-free transmissions with forward error correction. Furthermore, the modulator is optimized to provide maximum efficiency in terms of energy consumption per bit. The optimization procedure is carried out by optimizing both the amount of graphene used on the ring resonator and the modulator's design. The optimized graphene modulator is used in the new fronthaul network and requires as low as 4.6 fJ/bit while enabling high-speed performance up to 42.6 GHz and remarkably using one-quarter of graphene only. [ABSTRACT FROM AUTHOR]

With the working frequency of wireless communication systems moving to a higher terahertz (THz) band, the design of high-performance THz wave modulators has become a pivotal issue to be tackled urgently in THz communication. In this paper, we design a high-performance dual-channel photonic crystal modulator to enable ON–OFF regulation of the THz wave based on the defect mode disappearance of combined microcavities. The modulator introduces Y-type line defects into silicon rod photonic crystals as a dual-channel waveguide and the point defects and ring resonator form a combined microcavity. Due to the refractive index of the ring resonator filler, gallium arsenide, it is tunable with pump light excitation, and the defect mode frequency of the combined microcavity can be dynamically changed. Under pump excitation with a wavelength of 810 nm and an intensity of 0.4 μJ/cm2, 1.34 THz and 1.83 THz dual-channel waves can be OFF due to the defect mode disappearance of the combined microcavity. This is simulated by the time-domain steady-state response and steady-state THz wave field intensity distribution of the modulator by the finite-difference time-domain method. The results indicate that the dual-channel modulator has large modulation depths of 100% and 99.7%, high modulation rates of 4.05 GHz and 4.17 GHz, and low insertion losses of 0.31 dB and 0.18 dB, which lays foundation for the development of high-speed and low-loss THz communication technology. [ABSTRACT FROM AUTHOR]

In this paper, we propose an optically controlling broadband terahertz modulator of a layer-dependent PtSe2 nanofilm based on a high-resistance silicon substrate. Through optical pump and terahertz probe system, the results show that compared with 6-, 10-, and 20-layer films, a 3-layer PtSe2 nanofilm has better surface photoconductivity in the terahertz band and has a higher plasma frequency ωp of 0.23 THz and a lower scattering time τs of 70 fs by Drude–Smith fitting. By the terahertz time-domain spectroscopy system, the broadband amplitude modulation of a 3-layer PtSe2 film in the range of 0.1–1.6 THz was obtained, and the modulation depth reached 50.9% at a pump density of 2.5 W/cm2. This work proves that PtSe2 nanofilm devices are suitable for terahertz modulators. [ABSTRACT FROM AUTHOR]

In this paper, we present an electro-optical modulator based on graphene absorption. In this structure, graphene is placed on aluminum oxide, the structure of which is repeated alternately. This alternating structure of graphene on aluminum oxide is located inside a semi-cylindrical cavity in a 1-dimensional photonic crystal nanobeam cavity. Unlike previous articles, which consisted of cylinder holes and different areas in the nanobeam cavity is formed by changing the radius of the holes, in this structure, semi-cylinder holes have been used and, different areas are formed by rotating these semi-cylinders. This type of crystal photonics has a high quality factor. Also, this type of modulator requires little space after construction, so they are a very good option for integrated circuits. In this paper, three-dimensional finite-difference time-domain method is used for analysis. In this modulator, it is observed that by changing the bias voltage, the amount of absorption peak and also its resonance wavelength are changed. As a result of these changes, we achieve a modulation depth of about 7dB. Our proposed structure can have potential applications in integrated optical circuits, especially in telecommunication frequencies.

The external unit of small telemetry system for animals uses inductive link to transmit both data and power to a small implant. In this work, firstly, we have presented a wideband frequency shift keying (FSK) transmitter, which is a class E power amplifier (PA) switches between two load networks that make the PA tuned correctly at tow input clock frequencies. Carrier frequencies used for data modulation are 5MHz/10MHz, the data rate of the proposed link is 2.5 Mbps. On the other hand, the analog circuits of the internal unit are designed in this paper. Internal unit has a demodulator circuit to derive directly a frequency clock from the FSK carrier and to sample the binary data stream. It also has a low power generator circuit to generate the supply voltage to the other blocks. The low power generator is composed of a high efficiency, low power rectifier, and a low power voltage regulator. To minimize the quiescent current of the regulator, we propose a control section which is a two-stage error amplifier to control the gate voltage of the PMOS transistors used in the differential pair of the voltage regulator and thus stabilize the direct current (DC) level at its output signal (Vreg). The output voltage of the proposed generator circuit is regulated at 1V, the quiescent current simulated is about 9.9μA and the line regulation performance is only 8mV/V. All circuits proposed in this paper were designed and simulated using Cadence in 180 nm CMOS technology. [ABSTRACT FROM AUTHOR]

Image super-resolution reconstruction is a research hotspot in the field of computer vision. Traditional image super-resolution reconstruction methods based on deep learning mostly up-sample low-resolution images ignoring categories and instances, which will cause some problems such as unrealistic texture in the reconstructed images or sawtooth phenomenon on the edge of instance. In this manuscript, we propose an image super-resolution reconstruction method based on instance spatial feature modulation and feedback mechanism. First, the prior knowledge of instance spatial features is introduced in the reconstruction process. Instance spatial features of low-resolution images are extracted to modulate super-resolution reconstruction features. Then, based on the feedback mechanism, the modulated low-resolution image features are iteratively optimized for the reconstruction results, so that the model can finally learn instance-level reconstruction ability. Experiments on COCO-2017 show that, compared with traditional deep learning-based image super-resolution reconstruction methods, the proposed method can obtain better image reconstruction results, and the reconstructed images have more realistic instance textures. [ABSTRACT FROM AUTHOR]

In this paper, a dynamically tunable triple plasmon-induced transparency (PIT) is numerically investigated in a simple monolayer graphene- patterned structure. The structure is composed of five graphene strips and a silicon substrate. Electric field distributions show that the triple PIT effect is originated from the strong destructive interference between three bright modes and one dark mode, coupled mode theory (CMT) is utilized to confirm the finite-difference-time-domain (FDTD) simulation. Results show the maximum figure of merit (FOM) and sensitivity can reach 15.88 and 0.91 THz/RIU. A on-to-off electro-optical modulator is realized by tuning the Fermi levels of the graphene, the modulation degrees of amplitude are 79.3 %, 87.1 %, 70.5 %, 79.2 %, and 84.3 %, corresponding to 2.35 terahertz (THz), 3.12THz, 3.58 THz, 3.91THz, and 4.31 THz, respectively. In addition, the effect of polarized angle on the transmission spectra was studied in detail. A multi-frequency polarization modulator can also be realized with modulation degrees of amplitude (MDA) of 77.6 %, 85.9 %, and 93.7 % at 2.09 THz, 2.82 THz, and 3.59 THz, respectively, and the corresponding polarization extinction ratio (PER) are 6.5 dB, 8.5 dB, and 12.1 dB, respectively. Therefore, the results of the paper are significant to the design of multi-frequency, terahertz sensors, slow light, and modulators. [Display omitted] • Multi frequency electro-optic modulator and polarization modulator can be realized. • Compared with three-layer graphene PIT structure , the present structure is simpler. • The RI sensitivity, modulation degrees of amplitude, extinction ratio are excellent. [ABSTRACT FROM AUTHOR]

The external unit of small telemetry system for animals uses inductive link to transmit both data and power to a small implant. In this work, firstly, we have presented a wideband frequency shift keying (FSK) transmitter, which is a class E power amplifier (PA) switches between two load networks that make the PA tuned correctly at tow input clock frequencies. Carrier frequencies used for data modulation are 5MHz/10MHz, the data rate of the proposed link is 2.5 Mbps. On the other hand, the analog circuits of the internal unit are designed in this paper. Internal unit has a demodulator circuit to derive directly a frequency clock from the FSK carrier and to sample the binary data stream. It also has a low power generator circuit to generate the supply voltage to the other blocks. The low power generator is composed of a high efficiency, low power rectifier, and a low power voltage regulator. To minimize the quiescent current of the regulator, we propose a control section which is a two-stage error amplifier to control the gate voltage of the PMOS transistors used in the differential pair of the voltage regulator and thus stabilize the direct current (DC) level at its output signal (Vreg). The output voltage of the proposed generator circuit is regulated at 1V, the quiescent current simulated is about 9.9μA and the line regulation performance is only 8mV/V. All circuits proposed in this paper were designed and simulated using Cadence in 180 nm CMOS technology.

Abstract Soluble guanylate cyclase (sGC) modulation has been scrutinized in several disease states including heart failure (HF). Recently, it was shown that an sGC modulator improved HF-related hospitalization significantly, though, there was no benefit related to mortality. Herein, a comprehensive meta-analysis of randomized controlled trials (RCTs) for sGC modulation in HF patients was provided in agreement with the PRISMA statement. A total of 10 RCTs yielding 12 papers were included. There were 7526 patients with heart failure of each phenotype, 4253 in the sGC modulator group and 3273 in the placebo group. Use of sGC modulators in HF patients yielded no significant difference in the risk of all-cause mortality compared to placebo (RR = 0.97, 95% CI 0.88–1.08, p = 0.62). The use of sGC modulators was associated with a trend toward a considerable but non-significant increase in the incidence of SAEs (RR = 1.10, 95% CI 0.99–1.22, p = 0.07), as well as an increased incidence of hypotension and anemia. There was an overall neutral effect of sGC modulation on NT-proBNP levels, 6MWD and mortality, at a cost of slight increase in hypotension and anemia. Of note, the improvement in EQ-5D-based quality of life was significant. Hence, the benefit seems to be driven by distinctive domains of quality of life.

Sirtuins (SIRTs) represent a class of nicotinamide adenine dinucleotide (NAD+)-dependent protein deacetylases that exert a crucial role in cellular signal transduction and various biological processes. The mammalian sirtuins family encompasses SIRT1 to SIRT7, exhibiting therapeutic potential in counteracting cellular aging, modulating metabolism, responding to oxidative stress, inhibiting tumors, and improving cellular microenvironment. These enzymes are intricately linked to the occurrence and treatment of diverse pathological conditions, including cancer, autoimmune diseases, and cardiovascular disorders. Given the significance of histone modification in gene expression and chromatin structure, maintaining the equilibrium of the sirtuins family is imperative for disease prevention and health restoration. Mounting evidence suggests that modulators of SIRTs play a crucial role in treating various diseases and maintaining physiological balance. This review delves into the molecular structure and regulatory functions of the sirtuins family, reviews the classification and historical evolution of SIRTs modulators, offers a systematic overview of existing SIRTs modulation strategies, and elucidates the regulatory mechanisms of SIRTs modulators (agonists and inhibitors) and their clinical applications. The article concludes by summarizing the challenges encountered in SIRTs modulator research and offering insights into future research directions. [Display omitted] • Sirtuins (SIRTs), as key regulatory factors in cellular processes, are deeply involved in many life processes. • SIRTs modulators have shown great potential in treating various diseases and maintaining physiological balance. • The field of SIRTs and its modulators is developing very rapidly. This paper fills the gap in the research summary of SIRTs modulators in time, and provides valuable insights into the challenges encountered in the research field. [ABSTRACT FROM AUTHOR]

Fatty acid binding proteins (Fabps) are small soluble proteins that are abundant in the cytosol. These proteins are known to bind a myriad of small hydrophobic molecules and have been postulated to serve a variety of roles, yet their precise functions have remained an enigma over half a century of study. Here, we consider recent findings, along with the cumulative findings contributed by many laboratories working on Fabps over the last half century, to synthesize a new outlook for what functions Fabps serve in cells and organisms. Collectively, the findings illustrate that Fabps function as versatile multi‐purpose devices serving as sensors, conveyors and modulators to enable cells to detect and handle a specific class of metabolites, and to adjust their metabolic capacity and efficiency. [ABSTRACT FROM AUTHOR]

The reversible insulating-to-conducting phase transition (ICPT) of vanadium dioxide (VO2) makes it a versatile candidate for the implementation of integrated optical devices. In this paper, a bi-functional in-line optical device based on a four-layer stack of PMMA/graphene/VO2/graphene deposited on a side-polished fiber (SPF) is proposed. The structure can be employed as an ultra-compact TE modulator or a TM-pass polarizer, operating at 1.55 μm. We show that the ICPT characteristic can be used for polarization-selective mode shaping (PSMS) to manipulate orthogonal modes separately. On the one hand, as an optical modulator, the PSMS is used to modify mode profiles so that the TE mode attenuation is maximized in the off-state (and IL is minimized in the on-state), while the power carried by the TM mode remains unchanged. As a result, a TE modulator with an ultrahigh extinction ratio (ER) of about ER = 165 dB/mm and a very low insertion loss (IL) of IL = 2.3 dB/mm is achieved. On the other hand, the structure can act as a TM-pass polarizer featuring an extremely high polarization extinction ratio (PER) of about PER = 164 dB/mm and a low TM insertion of IL = 3.86 dB/mm. The three-dimensional heat transfer calculation for the ICPT process reveals that the response time of the modulator is in the order of few nanoseconds. Moreover, the required bias voltage of the proposed device is calculated to be as low as 1.1 V. The presented results are promising a key step towards the realization of an integrated high-performance in-line modulator/polarizer. [ABSTRACT FROM AUTHOR]

In this paper, cam profile dynamic modeling and analysis of the cam slider modulator are presented. The nonlinear dynamic model is derived for the modulator equation with consideration of the flexible effect. The fourth order Runge-Kutta method is employed to for response solving. The lumped parameter and Monte Carlo simulation methods are also utilized. Modulator roller vibration with regard to the cam profile machining errors are analyzed. In order to analyze the vibrational response at different speeds, VB.net simulation is performed. The results demonstrate that the disturbed cam profile vibrates smoothly and randomly when the dobby speed is less than 400 r/min. Furthermore, it is observed that the operating dobby speed should not exceed 900 r/min. For disturbed cam profile system, when the speed of the dobby is less than 400 r/min, small follower vibration response is observed. When dobby speed is greater than 200 r/min, significant impact on the follower vibration response is observed. [ABSTRACT FROM AUTHOR]

Bonding technology can be an important component of packaging for photonic chips, such as electro-optic (EO) modulators and other active function devices. In general, an EO modulator chip can achieve a broader 3 dB EO bandwidth than its packaging device, as the packaging design and structure can technically limit modulation performance. Recently, bump bonding has been shown to be a good candidate for the EO interconnection technique, which has a higher transmission bandwidth than wire bonding. In this article, we propose a design for radio frequency (RF) interconnection of bump bonding with a dislocation packaging (BBDP) structure. Through simulation calculations and analysis, the proposed BBDP structure shows a 3 dB transmission bandwidth of approximately 145 GHz, which is 52.6% better than one using optimized wire-bonding structures (95 GHz). The proposed packaging structure presents an important alternative method for ultrahigh speed optical modulation applications. [ABSTRACT FROM AUTHOR]

Existing video object segmentation (VOS) methods based on matching techniques commonly employ a reference set comprising historical segmented frames, referred to as ‘memory frames’, to facilitate the segmentation process. However, these methods suffer from the following limitations: (i) Inherent segmentation errors in memory frames can propagate and accumulate errors when utilized as templates for subsequent segmentation. (ii) The non-local matching technique employed in top-leading solutions often fails to incorporate positional information, potentially leading to incorrect matching. In this paper, we introduce the Modulated Memory Network (MMN) for VOS. Our MMN enhances matching-based VOS methods in the following ways: (i) Introducing an Importance Modulator, which adjusts memory frames using adaptive weight maps generated based on the segmentation confidence associated with each frame. (ii) Incorporating a Position Modulator that encodes spatial and temporal positional information for both memory frames and the current frame. The proposed modulator improves matching accuracy by embedding positional information. Meanwhile, the Importance Modulator mitigates error propagation and accumulation by incorporating confidence-based modulation. Through extensive experimentation, we demonstrate the effectiveness of our proposed MMN, which also achieves promising performance on VOS benchmarks.

With the increase in the modulation rate of thin-film lithium niobate ( L i N b O 3 , LN) modulators, the multi-physical field coupling effect between microwaves, light, and heat becomes more significant. In this study, we developed a thin-film LN modulator model using undoped pure LN thin film and T-shaped slow-wave electrodes. Furthermore, we utilized this model to simulate the microwave heating and light heating situations of the modulator. The temperature of the LN modulator was analyzed over time and with different signal frequencies. We also studied the influence of temperature rise on microwave and light signals, and we analyzed the change of S parameters and the Phase Shift of the light signal caused by temperature rise. Finally, we improved the thermodynamic characteristics of the modulator by adding a diamond heat dissipation layer. The diamond was obtained through the Chemical Vapor Deposition (CVD) technique and was a polycrystalline diamond. After adding the diamond heat dissipation layer, the temperature rise of the modulator was significantly improved, and the adverse effects of temperature rise on microwave signals were also significantly reduced. [ABSTRACT FROM AUTHOR]

From the various aspects of spintronics the review highlights the area devoted to the creation of new functional materials based on magnetic semiconductors and demonstrates both the main physical phenomena involved and the technical possibilities of creating various devices: maser, p-n diode with colossal magnetoresistance, spin valve, magnetic lens, optical modulators, spin wave amplifier, etc. Particular attention is paid to promising research directions such as ultrafast spin transport and THz spectroscopy of magnetic semiconductors. Special care has been taken to include a brief theoretical background and experimental results for the new spintronics approach employing magnetostrictive semiconductors—strain-magnetooptics. Finally, it presents top-down approaches for magnetic semiconductors. The mechano-physical methods of obtaining and features of the physical properties of high-density nanoceramics based on complex magnetic oxides are considered. The potential possibility of using these nanoceramics as an absorber of solar energy, as well as in modulators of electromagnetic radiation, is shown. [ABSTRACT FROM AUTHOR]

A high data rate RF-DAC and a power detector (PD) are designed and fabricated in a 250 nm indium phosphide (InP) double heterojunction bipolar transistor (DHBT) technology. A communication link using the Tx-Rx over polymer microwave fiber (PMF) is measured. The link consists of a pulse amplitude modulation (PAM) modulator and a PD as a demodulator, as well as a one-meter-long dielectric waveguide. The working frequency range of the complete link is verified to be 110–150 GHz. The peak output power of the PAM modulator is 5 dBm, and it has a −3 dB bandwidth of 43 GHz. The PD consists of a parallel connected common emitter configured transistor and a common base configured transistor to suppress the odd-order harmonics at the PD's output, as well as a stacked transistor to amplify the output signal. Tx and Rx chips, including pads, occupy a total area of only 0.83 mm2. The PMF link can support a PAM-4 signal with 22 Gbps data transmission, and a PAM-2 signal with 30 Gbps data transmission, with a bit error rate (BER) of <10−12, with demodulation performed in real time. Furthermore, the energy efficiency for the link (Tx + Rx) is 4.1 pJ/bit, using digital data input and receiving PAM-2 output (5.6 pJ/bit for PAM-4). [ABSTRACT FROM AUTHOR]

The key advantage of silicon photonics comes from its potential for large scale integration, in a low-cost and scalable fashion. This has sustained the growth in the area despite disadvantages such as the lack of a monolithic light source, or the absence of a second order non-linear response (χ(2)). Thus far, the work in the field has focused on reporting individual devices from a single die, with excellent performances. Wafer-level results, an area which has not been addressed sufficiently, is a critical aspect of silicon photonics and will provide the community with information regarding scalability and variation, which will be the key differentiating advantage of silicon photonics over other photonic platforms. In this work, we report the development of a low-loss, high-bandwidth C-band silicon photonic platform on a 200 mm CMOS-compatible process line, demonstrating wafer-level performance in the process. Ultra-low waveguide propagation loss with median values as low as 0.43 dB/cm has been achieved. Silicon Mach-Zehnder and microring modulators with median bandwidth of 38.5 and 43 GHz respectively are presented. Finally, germanium waveguide-integrated photodetectors with median bandwidth of 43 GHz are reported. The results reported in this work are comparable to prior demonstrations concerning individual devices. The baseline designs on this platform presented in this work can be accessed commercially from CompoundTek. [ABSTRACT FROM AUTHOR]

This article is aiming to unify the modeling methods for various ripple-based control schemes. It is divided into two parts, and the first part presents a sampled-data modeling method for the peak/valley current mode (PCM/VCM) control and the peak/valley voltage mode (PVM/VVM) control. It is pointed out that due to the high bandwidth of the dc–dc converter under PCM/VCM or PVM/VVM control, the sideband effect cannot be ignored in the modeling process. Meanwhile, with the small-signal assumption, the feedback perturbation signal has a discontinuity of the first kind at each sampling instant, so the perturbation value at this instant should be obtained according to the Dirichlet conditions, which is equal to half of the sum of the limit values on the left and right sides of the signal. Then, by using Shannon's sampling theorem, the transfer functions of the modulator and the loop gain are derived, and they are used to analyze the influence of the sideband components on the converter stability. Finally, the experimental results from a PCM controlled buck converter validate the proposed modeling technique. [ABSTRACT FROM AUTHOR]

This part is the second part of this article and mainly presents the sampled-data modeling method for the dc–dc converters with the constant on-time (COT) and constant off-time (COFT) controls. Compared with the constant frequency control in the first part, the duty cycle perturbation signal in the COT/COFT control is found to have two sets of narrow pulse signals in each switching period. Then, by establishing the relationship between the two sets of signals and using Shannon's sampling theorem, the transfer functions of the modulator and the loop gain are derived. Based on the theoretical results, the phenomenon that a current-mode constant on/off time controlled buck converter is stable at any duty cycle, and the instability of a voltage-mode constant on/off-time controlled buck converter with the smaller time constant of the output capacitor could be predicted. Moreover, the sampled-data modeling method is further extended to the digital control by taking a digitally current-mode controlled buck converter as an example. Simulation results are provided to confirm the validity of the proposed modeling method. [ABSTRACT FROM AUTHOR]

G-protein-coupled receptors (GPCRs), among various cell surface proteins, are essential targets in the fields of basic science and drug discovery. The discovery and development of modulators for the receptors have provided deep insights into the mechanism of action of receptors and have led to a new therapeutic option for human diseases. Although various modulators against GPCRs have been developed to date, the identification of new modulators for GPCRs remains a challenge due to several technical problems and limitations. To overcome this situation, a variety of strategies have been developed by several modalities, including nucleic acid aptamers, which are emerging as unique molecules isolated by a repetitive selection process against various types of targets from an enormous combinatorial library. This review summarized the achievements in the development of aptamers targeting GPCRs, and discussed their isolation methods and the diverse functional features of aptamers against GPCRs. [ABSTRACT FROM AUTHOR]

The reversible insulating-to-conducting phase transition (ICPT) of vanadium dioxide (VO2) makes it a versatile candidate for the implementation of integrated optical devices. In this paper, a bi-functional in-line optical device based on a four-layer stack of PMMA/graphene/VO2/graphene deposited on a side-polished fiber (SPF) is proposed. The structure can be employed as an ultra-compact TE modulator or a TM-pass polarizer, operating at 1.55 μm. We show that the ICPT characteristic can be used for polarization-selective mode shaping (PSMS) to manipulate orthogonal modes separately. On the one hand, as an optical modulator, the PSMS is used to modify mode profiles so that the TE mode attenuation is maximized in the off-state (and IL is minimized in the on-state), while the power carried by the TM mode remains unchanged. As a result, a TE modulator with an ultrahigh extinction ratio (ER) of about ER = 165 dB/mm and a very low insertion loss (IL) of IL = 2.3 dB/mm is achieved. On the other hand, the structure can act as a TM-pass polarizer featuring an extremely high polarization extinction ratio (PER) of about PER = 164 dB/mm and a low TM insertion of IL = 3.86 dB/mm. The three-dimensional heat transfer calculation for the ICPT process reveals that the response time of the modulator is in the order of few nanoseconds. Moreover, the required bias voltage of the proposed device is calculated to be as low as 1.1 V. The presented results are promising a key step towards the realization of an integrated high-performance in-line modulator/polarizer.

High data rate coverage, security, and energy efficiency will play a key role in the continued performance scaling of next-generation mobile systems. Dense, small mobile cells based on a novel network architecture are part of the answer. Motivated by the recent mounting interest in free-space optical (FSO) technologies, this paper addresses a novel mobile fronthaul network architecture based on FSO, spread spectrum codes, and graphene modulators for the creation of dense small cells. The network uses an energy-efficient graphene modulator to send data bits to be coded with spread codes for achieving higher security before their transmission to remote units via high-speed FSO transmitters. Analytical results show the new fronthaul mobile network can accommodate up to 32 remote antennas under error-free transmissions with forward error correction. Furthermore, the modulator is optimized to provide maximum efficiency in terms of energy consumption per bit. The optimization procedure is carried out by optimizing both the amount of graphene used on the ring resonator and the modulator’s design. The optimized graphene modulator is used in the new fronthaul network and requires as low as 4.6 fJ/bit while enabling high-speed performance up to 42.6 GHz and remarkably using one-quarter of graphene only.

With the working frequency of wireless communication systems moving to a higher terahertz (THz) band, the design of high-performance THz wave modulators has become a pivotal issue to be tackled urgently in THz communication. In this paper, we design a high-performance dual-channel photonic crystal modulator to enable ON–OFF regulation of the THz wave based on the defect mode disappearance of combined microcavities. The modulator introduces Y-type line defects into silicon rod photonic crystals as a dual-channel waveguide and the point defects and ring resonator form a combined microcavity. Due to the refractive index of the ring resonator filler, gallium arsenide, it is tunable with pump light excitation, and the defect mode frequency of the combined microcavity can be dynamically changed. Under pump excitation with a wavelength of 810 nm and an intensity of 0.4 μJ/cm2, 1.34 THz and 1.83 THz dual-channel waves can be OFF due to the defect mode disappearance of the combined microcavity. This is simulated by the time-domain steady-state response and steady-state THz wave field intensity distribution of the modulator by the finite-difference time-domain method. The results indicate that the dual-channel modulator has large modulation depths of 100% and 99.7%, high modulation rates of 4.05 GHz and 4.17 GHz, and low insertion losses of 0.31 dB and 0.18 dB, which lays foundation for the development of high-speed and low-loss THz communication technology.

In this paper, we propose an optically controlling broadband terahertz modulator of a layer-dependent PtSe2 nanofilm based on a high-resistance silicon substrate. Through optical pump and terahertz probe system, the results show that compared with 6-, 10-, and 20-layer films, a 3-layer PtSe2 nanofilm has better surface photoconductivity in the terahertz band and has a higher plasma frequency ωp of 0.23 THz and a lower scattering time τs of 70 fs by Drude–Smith fitting. By the terahertz time-domain spectroscopy system, the broadband amplitude modulation of a 3-layer PtSe2 film in the range of 0.1–1.6 THz was obtained, and the modulation depth reached 50.9% at a pump density of 2.5 W/cm2. This work proves that PtSe2 nanofilm devices are suitable for terahertz modulators.

The effort to confine the electromagnetic field by silicon passive metadevices has made the design of an on-chip wideband sub-terahertz (sub-THz) I/O redriver feasible, paving a new way toward energy-efficient and crosstalk-immune ON–OFF keying (OOK) communications. Two metadevices, namely spoof surface plasmon polaritons (SPPs) metawaveguide and split-ring resonator (SRR), are exploited to build the sub-THz low-crosstalk silicon channel and high-ON–OFF-ratio modulator, respectively. A sub-THz signal source combining the merit of spoof SPPs and SRR is introduced. A 140-GHz dual-channel redriver composed of these metadevices is fully integrated in a 65-nm CMOS technology. The redriver realizes both 27–1 and 231–1 13.5 Gb/s/lane for dual-channel OOK modulation. The measured energy efficiency is 2.6 pJ/bit/lane and the bit error rate (BER) is ≤10−12, demonstrating a crosstalk-immune sub-THz I/O system. The power consumption is 35.1 mW/lane and the active area of the redriver is 0.23 mm2. [ABSTRACT FROM AUTHOR]

This article presents the kinematic modeling and analysis of cam profiles of two different types of modulator: a cam-link and a cam-slider modulators. Kinematic and dynamic models of the two different modulators were established based on the motion curves of the main shaft of the rotary dobby. Simulations were carried out in Simulink to analyze the vibration responses under different rotary speeds, and vibration responses of the two mechanisms were compared. The results show that the cam-link modulator vibrates smoothly at speeds of <700 rpm, and theoretically, the speed should not exceed 1,400 rpm. The cam-slider modulator vibrates smoothly at speeds of <500 rpm, and theoretically, the speed should not exceed 1,000 rpm. The cam-slider modulator is more suitable for use at low speeds, whereas the cam-link modulator is more appropriate for high speeds. When both the cam-slider and cam-link modulators operate at high speeds, vibration distortion occurs, leading to bifurcation and chaotic vibration. Further knowledge of the complex behaviors associated with detachment of the follower from the cam can support the design of more sophisticated controllers aimed at avoiding follower detachment. [ABSTRACT FROM AUTHOR]

This work is devoted to the study of the pyroelectric effect on the properties of optical waveguides formed in a lithium niobate crystal by proton exchange. In the present work, we studied the cessation effect of the radiation channeling during thermocycling of Y-splitters samples. We examined the spectral dependence of optical losses on the wavelength using an optical spectrum analyzer. The results demonstrate that in the range of 1530–1570 nm, all wavelengths are suppressed equally. The optical frequency domain reflectometry shows that the increase of optical losses is observed along the entire waveguide, but not only at the Y-splitting point, as supposed earlier. [ABSTRACT FROM AUTHOR]

The article below presents a review of current research on silicon photonics. Herein, an overview of current silicon modulator types and modern integration approaches is presented including direct bonding methods and micro-transfer printing. An analysis of current state of the art silicon modulators is also given. Finally, new prospects for III–V-silicon integration are explored and the prospects of an integrated modulator compatible with current CMOS processing is investigated. [ABSTRACT FROM AUTHOR]