REVIEW | doi:10.20944/preprints202101.0409.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: GPCRs; cholesterol; allosteric modulation
Online: 21 January 2021 (09:10:59 CET)
G-protein coupled receptors (GPCRs) are membrane proteins that convey extracellular signals to the cellular milieu. They represent a target for more than 30 % of currently marketed drugs. Here we review the effects of membrane cholesterol on the function of GPCRs of Class A. We review both the specific effects of cholesterol mediated via its direct high-affinity binding to the receptor and non-specific effects mediated by cholesterol-induced changes in the properties of the membrane. Cholesterol binds to many GPCRs at both canonical and non-canonical binding sites. It allosterically affects ligand binding to and activation of GPCRs. Also, it changes the oligomerization state of GPCRs. In this review, we consider a perspective of the potential for the development of new therapies that are targeted at manipulating the level of membrane cholesterol or modulating cholesterol binding sites on to GPCRs.
ARTICLE | doi:10.20944/preprints202005.0356.v1
Subject: Computer Science And Mathematics, Artificial Intelligence And Machine Learning Keywords: Supervised Learning; Time Series Classification; Jamming Detection; Automatic Modulation Classification; Feature Selection; Genetic Algorithm; Principal Component Analysis; QPSK modulation; APSK modulation
Online: 23 May 2020 (05:10:36 CEST)
Satellite communication (Satcom) is an artificial geostationary satellite that facilitates a wide range of telecommunications. Considering its quality of service (QoS) and security is crucial in government/military applications. The most challenging situation for efficient Satcom is radio frequency interference (RFI) environment. Thus, it is necessary to ensure that transmissions are incorruptible or at least sense the quality of its spectrum. This paper presents a new method to recognize received signal characteristics using a hierarchical classification in a multi-layer perceptron neural network. We consider signal modulation and the type of RFI as the characteristics of a real-time video stream transmitted in the direct broadcast satellite. Four different modulation types are investigated in this study. Moreover, the combination of the communication signal with various kinds of interference and their effects on the classification method widely have been analyzed. Besides, two robust feature selection techniques have been developed to reduce the data-set dimensional, which leads to optimizing the classification process. The results show that the Genetic Algorithm (GA) slightly outperforms Principal Component Analysis (PCA) for feature selection. Furthermore, the robustness of the proposed techniques is assessed to detect unknown signals at different signal to noise ratios.
ARTICLE | doi:10.20944/preprints202308.1779.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: Cumulants; Modulation Classification; Machine Learning.
Online: 25 August 2023 (07:26:05 CEST)
This paper presents a novel method for automatic modulation classification (AMC) for cognitive radio (CR) networks based on a simple classifier that is trained with high-order cumulant. The proposed method focuses on the statistical behavior of modulated signals and includes analog modulation and digital schemes, which received less attention in the literature. The effectiveness of the proposed method is demonstrated through simulation results using high-quality generated signals under different signal-to-noise ratios (SNRs) and channel conditions. The classification performance achieved by the proposed method is superior to that of the more complex deep learning methods, making it well-suited for deployment in end units of CR networks, particularly in military and emergency service applications. The proposed method offers a cost-effective, high-quality solution for AMC that meets the stringent requirements of these critical applications.
ARTICLE | doi:10.20944/preprints202110.0430.v1
Subject: Physical Sciences, Optics And Photonics Keywords: Graphene; metasurface; phase modulation; terahertz
Online: 28 October 2021 (10:06:28 CEST)
Dynamic phase modulation is vital for tunable focusing, beaming, polarization conversion and holography. However, it remains challenging to achieve full 360∘ dynamic phase modulation while maintaining high reflectance or transmittance based on metamaterials or metasurfaces in the terahertz regime. Here we propose a doubly resonant graphene-metal hybrid metasurface to address this challenge. Simulation results show that by varying the graphene Fermi energy, the proposed metasurface with two shifting resonances is capable to provide dynamic phase modulation covering a range of 361∘ while maintaining relatively high reflectance above 20% at 1.05 THz. Based on the phase profile design, dynamically tunable beam steering and focusing are numerically demonstrated. We expect this work will advance the engineering of graphene metasurfaces for the dynamic manipulation of terahertz waves.
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: acetylcholine; muscarinic receptors; allosteric modulation
Online: 18 January 2020 (10:25:54 CET)
Allosteric modulators are ligands that bind to a site on the receptor that is spatially separated from the orthosteric binding site for the endogenous neurotransmitter. Allosteric modulators modulate the binding affinity, potency and efficacy of orthosteric ligands. Muscarinic acetylcholine receptors are prototypical allosterically-modulated G-protein-coupled receptors. They are a potential therapeutic target for the treatment of psychiatric, neurologic and internal diseases like schizophrenia, Alzheimer’s disease, Huntington disease, type 2 diabetes or chronic pulmonary obstruction. Here we review progress made during the last decade in our understanding of their mechanisms of binding, allosteric modulation and in vivo actions of in order to understand the translational impact of studying this important class of pharmacological agents. We overview newly developed allosteric modulators of muscarinic receptors as well as new spin-off ideas like bitopic ligands combining allosteric and orthosteric moieties and photo-switchable ligands based on bitopic agents.
ARTICLE | doi:10.20944/preprints202207.0431.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: split ring resonator; superconductor; modulation; THz
Online: 28 July 2022 (07:28:04 CEST)
Superconducting split ring resonator arrays allow to overcome two main limitations affecting metallic metamaterial resonating in the Terahertz (THz) range: Ohmic losses and tunability of their optical response. In this work, we design and experimentally realize direct and complementary square arrays of superconducting YBa2Cu3O7 (YBCO) split ring resonators working in the THz spectral range. The main purpose of this paper is to show how the metamaterial resonances can be tuned by temperature (T) when crossing the superconducting transition temperature Tc of YBCO. The tuning property can be quantified by describing the THz transmittance of the patterned YBCO films vs. T through a model of coupled resonators. This model allows us to estimate the THz resonances of split-ring arrays and their interaction, showing how the kinetic inductance Lk in the superconducting state is the main parameter affecting the metamaterial properties.
ARTICLE | doi:10.20944/preprints202108.0547.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: wireless sensor network; compressive sensing; short word-length; sensor tracking; delta modulation; sigma-delta modulation; communication energy efficiency.
Online: 30 August 2021 (14:24:44 CEST)
This work combines compressive sensing and short word-length techniques to achieve localization and target tracking in wireless sensor networks with energy-efficient communication between the network anchors and the fusion center. Gradient descent localization is performed using time-of-arrival (TOA) data which are indicative of the distance between anchors and the target thereby achieving range-based localization. The short word-length techniques considered are delta modulation and sigma-delta modulation. The energy efficiency is due to the reduction of the data volume transmitted from anchors to the fusion center by employing any of the two delta modulation variants with compressive sensing techniques. Delta modulation allows the transmission of one bit per TOA sample. The communication energy efficiency is increased by RⱮ, R≥1, where R is the sample reduction ratio of compressive sensing and Ɱ is the number of bits originally present in a TOA-sample word. It is found that the localization system involving sigma-delta modulation has a superior performance to that using delta-modulation or pure compressive sampling alone, in terms of both energy efficiency and localization error in the presence of TOA measurement noise, owing to the noise shaping property of sigma-delta modulation.
ARTICLE | doi:10.20944/preprints202107.0290.v1
Subject: Engineering, Automotive Engineering Keywords: permanent magnet synchronous motor; sideband harmonic component; space vector pulse-width modulation; carrier frequency modulation; vibro-acoustic responses.
Online: 13 July 2021 (10:45:49 CEST)
In the permanent magnet synchronous motor (PMSM) drive system, the unwilling and ear-piercing vibro-acoustics caused by high-frequency sideband harmonics becomes unacceptable in the electric vehicle application. In this paper, a modified space vector pulse-width modulation (SVPWM) technique implemented with hybrid carrier frequency modulation (HCFM) is provided to reduce the sideband current harmonic components and vibro-acoustic responses. The principle and implementation of the proposed HCFM technique are firstly presented, in which the fixed carrier frequency is improved with the sawtooth and random signal-based coupling modulation based on the rotor position. For verification, the experiment tests are carried out on a prototype 12/10 PMSM and microcontroller unit. The effectiveness of the HCFM technique can hence be confirmed, in which the sideband vibro-acoustics reduction shows more effectively than that in conventional random PWM. The proposed approach may provide a new route in noise-cancelling and electromagnetic compatibility for the electric drive powertrain.
REVIEW | doi:10.20944/preprints202307.1969.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Shrimps; Disease management; Epigenetics; Epigenetic modulation; Future applications
Online: 28 July 2023 (10:21:05 CEST)
Aquaculture assumes a pivotal role in meeting the escalating global food demand, and shrimp farming, in particular, holds indispensable significance for the global economy and food security, providing a rich source of nutrients for human consumption. Nonetheless, the industry faces formidable challenges, primarily attributed to disease outbreaks, and the diminishing efficacy of conventional disease management approaches, such as antibiotic usage. Consequently, there is an urgent imperative to explore alternative strategies to ensure the sustainability of the industry. In this context, the burgeoning field of epigenetics emerges as a promising avenue for combating infectious diseases in shrimp aquaculture. Epigenetic modulations entail chemical alterations in DNA and proteins, orchestrating gene expression patterns without modifying the underlying DNA sequence by utilizing DNA methylation, histone modifications, and non-coding RNA molecules. Exploiting epigenetic mechanisms presents an opportunity to enhance immune gene expression and bolster disease resistance in shrimp, thus revolutionizing disease management strategies and optimizing shrimp health and productivity. Additionally, the concept of epigenetic inheritability in marine animals holds immense potential for the future of the shrimp farming industry. To this end, this comprehensive review thoroughly explores the dynamics of epigenetic modulations in shrimp aquaculture, with a particular emphasis on its pivotal role in disease management. It accentuates the significance of harnessing advantageous epigenetic changes to ensure the long-term viability of shrimp farming while deliberating on the potential consequences of these interventions. Overall, this appraisal highlights the promising trajectory of epigenetic applications, propelling the field toward strengthening sustainability in shrimp aquaculture.
ARTICLE | doi:10.20944/preprints202306.1497.v1
Subject: Physical Sciences, Applied Physics Keywords: porous silicon; photoactive yellow protein; photocycle; optical modulation
Online: 21 June 2023 (07:46:41 CEST)
We successfully created a composite photonic structure out of porous silicon (PSi) microcavities doped by the photochromic protein, photoactive yellow protein (PYP). Massive incorporation of the protein molecules into the pores was substantiated by a 30-nm shift of the resonance dip upon functionalization, and light-induced reflectance changes of the device due to the protein photocycle were recorded. Model calculations for the photonic properties of the device were consistent with earlier results on the nonlinear optical properties of the protein, whose degree of incorporation into the PSi structure was also estimated. The successful proof-of-concept results are discussed in light of possible practical applications in the future.
ARTICLE | doi:10.20944/preprints202201.0052.v1
Subject: Chemistry And Materials Science, Metals, Alloys And Metallurgy Keywords: metal-ceramic; microwave sintering; susceptor; phase modulation; nanostructures
Online: 6 January 2022 (09:42:02 CET)
This study provides a novel method to prepare metal-ceramic composites from magnetically selected iron ore using microwave heating. By introducing three different microwave susceptors (Activated Carbon, SiC, and a mixture of Activated Carbon and SiC) during the microwave process, effective control of the ratio of metallic and ceramic phases has been achieved easily. The effects of the three susceptors on the microstructure of the metal-ceramics and the related reaction mechanisms were also investigated in detail. The results show that the metal phase (Fe) and ceramic phase (Fe2SiO4, FeAl2O4) can be maintained, but the metal phase to ceramic phase changed significantly. In particular, the microstructures appeared as well-distributed nanosheet structures with diameters of ~400 nm and thicknesses of ~20 nm when SiC was used as the microwave susceptor.
ARTICLE | doi:10.20944/preprints202102.0320.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: Telecommunications Education; Active Learning; Educational Escape Rooms; Modulation
Online: 16 February 2021 (13:17:35 CET)
Traditional education, particularly at a university level isn’t necessarily very engaging1 or strong at building teamwork skills. Educational escape rooms are a recent game based learning2 approach which combines team based problem solving with a story-line and cryptic clues. In this3 paper we apply the concept of educational escape rooms to the telecommunications engineering4 classroombycreatingaseriesoftwoseparatescenarios,eachcontainingthreepuzzles. Ourevaluation5 is based on beta tester survey results which suggest that this will be an engaging and challenging6 tool for teaching telecommunications engineering. Although educational escape rooms are rapidly7 being deployed in education, these are the ﬁrst educational escape rooms that speciﬁcally addresses8 the ﬁeld of telecommunications engineering.
ARTICLE | doi:10.20944/preprints201705.0073.v1
Subject: Medicine And Pharmacology, Obstetrics And Gynaecology Keywords: Hochu-ekki-to; immune modulation; polycystic ovarian syndrome
Online: 9 May 2017 (04:11:56 CEST)
The traditional herbal medicine, Hochu-ekki-to, has been shown to have preventive effects on viral infection and stress. This study aimed to evaluate the clinical effects of Hochu-ekki-to on two stress-related rat models of polycystic ovarian syndrome. Female Sprague-Dawley rats were divided into control and treatment groups, the latter of which were subjected to stress induced by exposure to adrenocorticotropic hormone (ACTH) or cold temperatures. After these stress inductions, rats were orally treated with dissolved Hochu-ekki-to once per day for 7 days. Rats subjected to the two different stressors exhibited upregulation of steroid hormone receptors (in ovaries) and reproductive hormones (in blood), and consequent stimulation of abnormal follicle development accompanied by elevation of Hsp 90 expression (in ovaries). Treatment with Hochu-ekki-to for 7 days after stress induction increased immune functions, reduced the stress-induced activation of Hsp 90, and normalized the levels of the tested steroid hormone receptors and reproductive hormones. Our findings suggest that stress stimulations may promote the activation of Hsp 90 via the dysregulation of steroid hormone receptors and reproductive hormones, but that post-stress treatment with Hochu-ekki-to improves reproductive and immune functions in the ovaries of stressed rats.
ARTICLE | doi:10.20944/preprints202307.0364.v1
Subject: Physical Sciences, Atomic And Molecular Physics Keywords: magnetometer; optically pumped magnetometer; dead zone; heading error; intensity modulation; amplitude modulation; light shift; nonlinear Zeeman effect; atomic magnetic sensor
Online: 6 July 2023 (07:13:47 CEST)
In mobile applications such as geomagnetic surveying, two major effects hamper the use of optically pumped magnetometers: dead zones, sensor orientations where the sensors signal amplitude drops; and heading errors, a dependence of the measured magnetic field value on the sensor orientation. We present a concept for an omnidirectional magnetometer to overcome both these effects. The sensor uses two cesium vapor cells, interrogated by circularly-polarized amplitude-modulated laser light split into two beams running perpendicular to each other. This configuration is experimentally investigated using a setup wherein the laser beam and magnetic field direction can be freely adjusted relative to each other within a magnetically shielded environment. We demonstrate that a dead-zone free magnetometer can be realized with nearly isotropic magnetic-field sensitivity. While in the current configuration we observe heading errors emerging from light shifts and due to the nonlinear Zeeman effect, we introduce a straightforward approach to suppress these systematic effects in an advanced sensor realisation.
ARTICLE | doi:10.20944/preprints201811.0273.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: optical communications; optical spatial modulation; free-space optical communication; multiple-input-multiple-output (MIMO) systems; pulse position modulation; atmospheric turbulence
Online: 12 November 2018 (09:26:34 CET)
In this paper, spatial pulse position modulation (SPPM) is used as a case study to investigate the performance of the optical spatial modulation (SM) technique in outdoor atmospheric turbulence (AT). A closed-form expression for the upper bound on the asymptotic symbol error rate (SER) of SPPM in AT is derived and validated by closely-matching simulation results. The error performance is evaluated in weak to strong AT conditions. As the AT strength increases from the weak to strong, the channel fading coefficients become more dispersed and differentiable. Thus, a better error performance is observed under moderate-to-strong AT compared to weak AT. The performance in weak AT can be improved by applying unequal power allocation to make FSO links more distinguishable at the receiver. Receive diversity is considered to mitigate irradiance fluctuation and improve the robustness of the system to turbulence-induced channel fading. The diversity order is computed as half of the number of detectors. Performance comparisons, in terms of energy and spectral efficiencies, are drawn between the SPPM scheme and conventional MIMO schemes such as repetition coding and spatial multiplexing.
ARTICLE | doi:10.20944/preprints201805.0284.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: dual two-level voltage source inverter; common-mode voltage; discontinuous space vector modulation schemes; centralizing pulse width modulation; open-end load
Online: 22 May 2018 (05:11:06 CEST)
The popular motor drive systems with a single two-level voltage source inverter (VSI) have one main problem that is the occurrence of the common-mode voltage (CMV), which is an effect of the electromagnetic interference, shaft voltage, bearing currents, leakage current. These cause the high stress, increasung temperature and early mechanical failure in machine. To overcome this problem, the technology of the dual two-level VSI fed open-end three-phase ac loads is now available to eliminate the CMV at the ac/induction motor load with the 120-degree modulation technique for controlling each inverter. In this paper, the discontinuous space vector modulation (DSVM) schemes are proposed and applied for the dual two-level VSI fed open-end load. It is based on the 120-degree modulation technique by using only 12 active voltage vectors and the 10 zero voltage vectors from the total 64 voltage vectors along with the different five-segment swicthing sequence designs with centralizing pulse width modulation technqiue in order to not only cancel the CMV in the ac load, but also reduce the switching number/switching loss of the conversion system. Among the various DSVM schemes, their performances are compared in this paper, such as the number of the switching, the step and peak value of the CMV in each inverter, and the quality of the output waveform, etc. The details of the verfication and comparison are carried out by simulation using Matlab/Simulink software.
ARTICLE | doi:10.20944/preprints202301.0202.v1
Subject: Medicine And Pharmacology, Clinical Medicine Keywords: Alpha synchronisation; Working memory; Auditory processing; Modulation detection threshold
Online: 12 January 2023 (01:48:00 CET)
Background: Despite hearing aids adequately compensate for hearing loss, a substantial proportion of the population leave their hearing difficulties untreated. Even though this is a well-known clinical issue, the optimal approach to address this issue during the hearing rehabilitation process is still unclear. Purpose: The present study aims to characterise behavioural and neurophysiological auditory and cognitive processing skills in experienced hearing aid users versus those with normal hearing, aimed at providing clinicians with the evidence required to adequately manage the expectations of their clients, thus indirectly reinforcing hearing-aid adoption within the adult population with hearing loss. Research design: Behavioural tests included auditory, cognitive, and speech-in-noise tasks; and neurophysiological testing included cortical auditory evoked potentials evoked by a /da/ stimulus presented at 65 dB SPL. The tests were selected based on previous literature supporting specific speech-understanding skills. Study sample: Ten participants (7 female, 21—68 years) with bilateral, mild-moderate to moderately-severe sensorineural hearing loss (HL), and 10 with clinically normal hearing (NH, 8 female, 19—62 years) participated in the study. Data collection and analysis: Behavioural data was analysed using multivariate analysis of variance (MANOVA) and neurophysiological analysis used measurements such as independent t-test, time-frequency analysis and inter-trial phase coherence. Results: The NH and HL groups presented similar scores in all the behavioural tasks. Time-frequency analysis revealed a statistically significantly reduction in alpha (8–12 Hz) synchronisation at the centro-frontal electrodes in the HL group – a brain activity pattern that has been associated with listening effort, inhibition and selective attention. Conclusions and significance: Results support the conclusion that hearing aids are effective in compensating for the audibility of their users, enabling them to perform at similar levels than their normal-hearing peers. However, the reduced alpha synchronisation observed in the HL population indicates that adequate audibility does not extend to improved neural responses. Future studies need to investigate the induced activity in speech understanding paradigms to explore the auditory processing differences at cortical level. The results are only from a small sample size but the findings have the potential to support clinicians in managing adequately the expectations of their clients in regards the benefits of hearing aid technologies.
ARTICLE | doi:10.20944/preprints202204.0046.v1
Subject: Physical Sciences, Optics And Photonics Keywords: Nonlinear optics; integrated waveguides; self-phase modulation; graphene oxide
Online: 6 April 2022 (11:44:56 CEST)
We experimentally demonstrate enhanced self-phase modulation (SPM) in silicon nitride (Si3N4) waveguides integrated with 2D graphene oxide (GO) films. GO films are integrated onto Si3N4 waveguides using a solution-based, transfer-free coating method that enables precise control of the film thickness. Detailed SPM measurements are carried out using both picosecond and femtosecond optical pulses. Owing to the high Kerr nonlinearity of GO, the hybrid waveguides show significantly improved spectral broadening compared to the uncoated waveguide, achieving a broadening factor of up to ~3.4 for a device with 2 layers of GO. By fitting the experimental results with theory, we obtain an improvement in the waveguide nonlinear parameter by a factor of up to 18.4 and a Kerr coefficient (n2) of GO that is about 5 orders of magnitude higher than Si3N4. Finally, we provide a theoretical analysis for the influence of GO film length, coating position, and its saturable absorption on the SPM performance. These results verify the effectiveness of on-chip integrating 2D GO films to enhance the nonlinear optical performance of Si3N4 devices.
ARTICLE | doi:10.20944/preprints202012.0152.v1
Subject: Engineering, Automotive Engineering Keywords: Wind farm noise; Amplitude modulation; Random Forest; AM detection
Online: 7 December 2020 (12:51:54 CET)
Amplitude modulation (AM) is a characteristic feature of wind farm noise and has the potential to contribute to annoyance and sleep disturbance. This study aimed to develop an AM detection method using a random forest approach. The method was developed and validated on 6,000 10-second samples of wind farm noise manually classified by a scorer via a listening experiment. Comparison between the random forest method and other widely-used methods showed that the proposed method consistently demonstrated superior performance. This study also found that a combination of low-frequency content features and other unique characteristics of wind farm noise play an important role in enhancing AM detection performance. Taken together, these findings support that using machine learning-based detection of AM is well suited and effective for in-depth exploration of large wind farm noise data sets for potential legislative and research purposes.
ARTICLE | doi:10.20944/preprints202308.1447.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: Silage additives; Condensed tannin; Fermentative quality; Bacterial modulation; silage quality
Online: 22 August 2023 (03:44:48 CEST)
Maize silage is produced to alleviate forage shortage on dairy animals, particularly during the dry season. Microorganisms play a significant role in silage fermentation and thus determine the silage quality. Therefore, modulation of microorganisms in silage may help prohibit undesired bacteria and improve silage quality. Hence, this study evaluated the effects of tannin extract as an additive on fermentative quality, aerobic stability and microbial composition of maize silage. Therefore, a mini-silo experiment of maize with five treatments was conducted for 75 days. The results showed that additives modulate silage microorganisms. In addition, tannin extract reduced certain silage bacteria while promoting others. However, this is without affecting the silage’s fermentative quality and aerobic stability. All silage fermented well with a pH below 4.2. Tannin extract improved dry matter recovery of silage while reducing silage weight loss. Furthermore, tannin extract suppressed the establishment of undesired bacteria, such as genera Dysgonomonas, Gluconacetobacter and Clostridium, while promoting desirable bacteria, such as genera Lactobacillus and Weissella, which attributed to silage quality. Therefore, it is concluded that tannins can be strategically used as silage additives to modulate microbial composition of silage and improve silage quality by promoting the dominance of desirable bacteria in silage.
ARTICLE | doi:10.20944/preprints202209.0372.v1
Subject: Physical Sciences, Optics And Photonics Keywords: magnetic fluid; thermotropic nematic liquid crystals; terahertz modulation; microfluidic chip
Online: 23 September 2022 (10:27:05 CEST)
In recent years, solid state terahertz (THz) modulators have obtained rapid progress with the widespread use of two-dimensional (2D) materials in the field of THz; however, challenges remain in preparing flexible THz modulators. In this study, flexible ferromagnetic nematic materials were prepared by doping thermotropic nematic liquid crystals 5CB into magnetic fluids, and the influence of hydrogen bonding in water was reduced by a self-made cyclic olefin copolymer (COC) microfluidic chip. THz modulation characteristics of magnetic fluid and ferromagnetic nematic liquid crystal (FNLC) under the induction of external magnetic field were compared using a THz time domain spectroscopy system. Under the action of a 91 mT magnetic field, the magnetic fluid has a maximum modulation depth (MD) of 54%. Under the same magnetic field, the maximum MD of the ferromagnetic nematic liquid crystal materials increase to 78% because of the rearrangement of Fe3O4 nanoparticles induced by the topological defect of the liquid crystal. We demonstrate that the magneto-optical effect is significantly enhanced in the ferromagnetic nematic liquid crystal hybrid system. This strategy of doping thermotropic nematic liquid crystals to enhance the magneto-optical effect has great potential for THz filtering, modulation, and sensing applications.
REVIEW | doi:10.20944/preprints202202.0278.v1
Subject: Biology And Life Sciences, Insect Science Keywords: nociception; pain; modulation of nociception; insects; descending control of nociception
Online: 22 February 2022 (14:24:24 CET)
Modulation of nociception allows animals to prioritise their survival by adapting their behaviour in different contexts. In mammals, this is executed by neurons from the brain, and is referred to as the descending control of nociception. Whether insects have this control, or have the neural circuits underpinning it, has not been clarified. Here, we review evidence supporting descending control of nociception control in insects, and consider which neuronal sub-types and brain areas may be involved.
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Adiponectin; Adiponectin modulation inducer; C-reactive protein; Metabolic marker; Sujiaonori.
Online: 20 July 2021 (14:46:08 CEST)
Unhealthy diet can lead to the development of metabolic disorders, and studies have shown strong associations between those conditions, c-reactive protein (CRP) and adiponectin. We report on associations between targeted metabolic markers and active nutrients from diet and Sujiaonori algal supplement (SBM), a natural adiponectin modulation inducer (NAMI) containing 60% of bioactive ulvan-rich fiber, in Japanese women. The study comprised dietary survey and intervention conducted in Kochi, Japan (2016-2017), involving 31 women who completed a dietary survey and provided biospecimen for CRP and adiponectin measurement using ELISA. Sixteen women received 3g SBM daily for one month and 15 others (controls) received 3g of corn starch. In SBM group, mean age was 23.06 (2.21) years [vs. 23.06 (1.55)], BMI was 21.11 (0.59) kg/m2 [vs. 21.43 (0.60) in controls], and daily intake of n3-PUFA [3.83 (0.24) vs. 2.21 (0.33) mg/day; p=0.042] and total fiber [364.12 (2.45) vs. 48.13 (1.57) mg/day in controls; p=0.000] were markedly higher. Furthermore, CRP was inversely associated with total fiber, total n3-PUFA, SBM-n3PUFA, vitamin D and vitamin B6, whereas adiponectin was strongly and positively associated with SBM-fiber and total n3-PUFA. Thus ulvan-rich SBM supplement, which contains ulvan-rich fiber and n3-PUFA, might be beneficial in reducing metabolic risk.
ARTICLE | doi:10.20944/preprints202107.0415.v1
Subject: Medicine And Pharmacology, Endocrinology And Metabolism Keywords: Adiponectin; Adiponectin modulation inducer; C-reactive protein; Metabolic marker; Sujiaonori.
Online: 19 July 2021 (14:28:52 CEST)
Unhealthy diet can lead to the development of metabolic disorders, and studies have shown strong associations between those conditions and biomarkers, such as c-reactive protein (CRP) and adiponectin. Recently, marine algal biomaterials have been investigated extensively due to their health benefits. We report on associations between metabolic markers and bioactive nutrients from diet and Sujiaonori algal biomaterial (SBM), a natural adiponectin modulation inducer (NAMI) containing 60% of ulvan-rich fiber, in a sample of Japanese women. The study comprised dietary survey and intervention conducted in Kochi, Japan (2016-2017), involving 31 women who completed a dietary survey and provided biospecimen for CRP and adiponectin measurement using ELISA. Sixteen women received 3g SBM daily for one month and 15 others (controls) received 3g of corn starch. In SBM group, mean age was 23.06 (2.21) years [vs. 23.06 (1.55)], BMI was 21.11 (0.59) kg/m2 [vs. 21.43 (0.60) in controls], and daily intake of n3-PUFA [3.83 (0.24) vs. 2.21 (0.33) mg/day; p=0.042] and total fiber [364.12 (2.45) vs. 48.13 (1.57) mg/day in controls; p=0.000] were markedly higher. Furthermore, CRP was inversely associated with total fiber, total n3-PUFA, SBM-n3PUFA, vitamin D and vitamin B6, whereas adiponectin was strongly and positively associated with SBM-fiber and total n3-PUFA. Thus ulvan-rich SBM supplement, which contains ulvan-rich fiber and n3-PUFA, might be beneficial in reducing metabolic risk.
Subject: Physical Sciences, Acoustics Keywords: Photonic crystal waveguide; Pulse acceleration; Self-steepening; Self-phase modulation
Online: 28 June 2021 (11:44:55 CEST)
Based on the sensitive sum frequency generation cross-correlation frequency-resolved optical gating (SFG-XFROG) measurement setup, besides the pulse broadening, blue shift, red shift and obvious pulse acceleration, we observed the soliton evolution when the low energy soliton pulse with wavelength of 1555nm transmit through the Si photonic crystal waveguide. The measurements were nicely matched with the simulation results, which are achieved with an optimized nonlinear Schrödinger equation (NLSE) modeling. The effects of various parameters of the silicon photonic crystal waveguides and the incident pulses on the pulse transmission were also analyzed, including the nonlinear effects and dispersion such as the self-phase modulation (SPM), self-steepening (SS) and intra-pulse Raman scattering(IRS). The results help us understand further the ultra-fast nonlinear dynamics of soliton in silicon-based waveguides, and even open a novel way for soliton-based functional elements in CMOS-compatible platforms.
ARTICLE | doi:10.20944/preprints201910.0368.v2
Subject: Engineering, Electrical And Electronic Engineering Keywords: directional modulation; physical layer security; polarization sensitive array; multi-beam
Online: 5 December 2019 (11:59:29 CET)
Directional modulation (DM), as an emerging promising physical layer security (PLS) technique at the transmitter side with the help of an antenna array, has developed rapidly over decades. In this study, a DM technique using a polarization sensitive array (PSA) to produce the modulation with different polarization states (PSs) at different directions is investigated. A PSA, as a vector sensor, can be employed for more effective DM for an additional degree of freedom (DOF) provided in the polarization domain. The polarization information can be exploited to transmit different data streams simultaneously at the same directions, same frequency, but with different PSs in the desired directions to increase the channel capacity, and with random PSs off the desired directions to enhance PLS. The proposed method has the capability of concurrently projecting independent signals into different speciﬁed spatial directions while simultaneously distorting signal constellation in all other directions. The symbol error rate (SER), secrecy rate, and the robustness of the proposed DM scheme are analyzed. Design examples for single- and multi-beam DM systems are also presented. Simulations corroborate that 1) the proposed method is more effective for PLS; 2) the proposed DM scheme is more power-efﬁcient than the traditional artiﬁcial noise aided DM schemes; and 3) the channel capacity is signiﬁcantly improved compared with conventional scalar antenna arrays.
ARTICLE | doi:10.20944/preprints201905.0047.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: young interferometer; depolarization measurement; modulation of depolarization; liquid crystal device
Online: 6 May 2019 (10:22:05 CEST)
In a depolarizing instrument, such as a broadband imaging spectrometer, the depolarizers are placed on the system for stabilization the optical signal. They are also used to reduce measurements offsets due to strong polarization dependence, which produce drastic deterioration of the signal to noise ratio. Dynamic depolarizer with a controllable degree of polarization is also required to study the effect of noise on quantum information. The article described a new instrument for characterization the variable depolarizer with features which make it different from a polarimetric system. The analysing system based on the simple structural design and has good stability for real-time measurement. A practical application of the described interferometer system for variable depolarizer characterization is also presented.
ARTICLE | doi:10.20944/preprints201804.0287.v1
Subject: Environmental And Earth Sciences, Oceanography Keywords: Radar; ocean; backscatter; Doppler shift; wave groups; non-linearity; modulation
Online: 23 April 2018 (11:46:21 CEST)
Observed sea surface Ka-band normalized radar backscatter cross section (NRCS) and Doppler velocity (DV) exhibit energy at low frequencies (LF) below the surface wave range. It is shown that non-linearity in NRCS-wave slope Modulation Transfer Function (MTF) and inherent NRCS averaging within the footprint account for the NRCS and DV LF variance with the exception of VV NRCS for which almost half of the LF variance is attributable to wind fluctuations. Although the distribution of radar DV is quasi-Gaussian suggesting virtually little impact of non-linearity, the LF DV variations arise due to footprint averaging of correlated local DV and non-linear NRCS. Numerical simulations demonstrate that MTF non-linearity weakly affects traditional linear MTF estimate (less than 10% for |MTF|< 20). Thus the linear MTF is a good approximation to evaluate the DV averaged over large footprints typical of satellite observations.
ARTICLE | doi:10.20944/preprints201710.0086.v2
Subject: Engineering, Electrical And Electronic Engineering Keywords: cluster head; dead node; random; vicinity; modulation; index; survival; overhead
Online: 23 October 2017 (08:06:47 CEST)
As Heterogeneous Wireless Sensor Network (HWSN) fulfill the requirements of researchers in the design of real life application to resolve the issues of unattended problem. But, the main constraint face by researchers is energy source available with sensor nodes. To prolong the life of sensor nodes and hence HWSN, it is necessary to design energy efficient operational schemes. One of the most suitable routing scheme is clustering approach, which improves stability and hence enhances performance parameters of HWSN. A novel solution proposed in this article is to design energy efficient clustering protocol for HWSN, to enhance performance parameters by EECPEP-HWSN. Propose protocol is designed with three level nodes namely normal, advance and super node respectively. In clustering process, for selection of cluster head we consider three parameters available with sensor node at run time, i.e., initial energy, hop count and residual energy. This protocol enhance the energy efficiency of HWSN, it improves performance parameters in the form of enhance energy remain in the network, force to enhance stability period, prolong lifetime and hence higher throughput. It is been found that proposed protocol outperforms than LEACH, DEEC and SEP with about 188, 150 and 141 percent respectively.
ARTICLE | doi:10.20944/preprints202309.0234.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: Multi-Task Learning; Convolutional Neural Network; Automatic modulation recognition; Feature Fusion
Online: 6 September 2023 (15:08:47 CEST)
Recently, deep learning models have been widely applied to modulation recognition, which have become a hot topic due to their excellent end-to-end learning capabilities. However, current methods are mostly based on uni-modal inputs, which suffer from incomplete information and local optimization. To complement the advantages of different modalities, we focus on the multi-modal fusion method. Therefore, we introduce an iterative dual-scale attentional fusion (iDAF) method to integrate multimodal data. Firstly, two feature maps with different receptive field sizes are constructed using local and global embedding layers. Secondly, the feature inputs are iterated into the Iterative Dual Scale Attention Module (iDCAM), where the two branches capture the details of high-level features and the global weights of each modal channel, respectively. The iDAF not only extracts the recognition characteristics of each specific domains, but also complements the strengths of different modalities to obtain a fruitful view. Our iDAF achieves a recognition accuracy of 93.5\% at 10dB and 0.6232 at full SNR. The comparative experiments and ablation studies effectively demonstrate the effectiveness and superiority of the iDAF.
ARTICLE | doi:10.20944/preprints202305.1153.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: power line communication; modulation; spread spectrum; dc-dc converter; emi mitigation
Online: 16 May 2023 (10:38:05 CEST)
Interference on Power Line Communication (PLC), which is a wired communication technology that provides communication and data transmission over the existing electrical network, is examined in this paper. Many applications employ PLC technologies, which have the benefit of leveraging existing power connections for both power and data transfer, reducing cost and complexity. These interactions may be observed in contemporary smart grids and automobile power networks, where lengthy cables, switching power supplies, and communication links all work together but exacerbate electromagnetic interference problems. This research examines the effects of Spread Spectrum methods used to reduce EMI from power converters on PLC systems. Spread spectrum modulation and its three variants Sine, Random and Triangle are frequently employed to meet the requirements of electromagnetic compatibility, however there are some repercussions, that might be detrimental to the converter or the rest of the electrical network. These outcomes occur for various modulation algorithm settings and at various frequencies. Measurements are made utilising the Frame Error Rate value provided by the PLC link system to ascertain the interference produced by a SiC-based DC-DC converter in order to investigate these concerns and standardise an assessment approach.
REVIEW | doi:10.20944/preprints202302.0307.v1
Subject: Chemistry And Materials Science, Applied Chemistry Keywords: carbon; anode; lithium-ion batteries; electronic modulation; structural engineering; low temperature
Online: 17 February 2023 (08:49:24 CET)
Lithium-ion batteries (LIBs) have become the preferred battery system for portable electronic devices and transportation equipment because of their high specific energy, good cycling performance, low self-discharge and no memory effect. However, too low ambient temperature will seriously affect the performance of LIBs, almost cannot discharge at -40~-60 ℃. There are many factors affecting the low temperature performance of LIBs, among which the electrode material is an important factor. Thus it is urgent to develop electrode materials or modify existing materials with excellent low temperature LIBs performance. Carbon-based anode is a kind of LIBs candidate. In recent years, it has been found that the diffusion coefficient of lithium ion in graphite anode decreases more obviously at low temperature, which is one of the important bottlenecks limiting its low temperature performance. However, the structure of amorphous carbon materials is complex, amorphous carbon materials have good ionic diffusion properties, and its grain size, specific surface area, layer spacing, structural defects, surface functional groups and doping elements may have a greater impact on the low temperature performance of the material. In this work, the low temperature performance of LIBs is obtained by modifying the carbon-based material from the perspective of electronic modulation and structural engineering.
REVIEW | doi:10.20944/preprints202202.0011.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: Rotavirus; off-target effects; neonatal; live attenuated; RV3-BB; epigenetic modulation
Online: 1 February 2022 (12:34:07 CET)
Following the introduction of live-attenuated rotavirus vaccines in many countries, a notable reduction in deaths and hospitalizations associated with diarrhoea in children <5 years of age has been reported. There is growing evidence to suggest that live-attenuated vaccines also provide protection against other infections beyond the vaccine-targeted pathogens. These so called off-target effects of vaccination have been associated with the tuberculosis vaccine Bacille Calmette Guérin (BCG), measles, oral polio and recently salmonella vaccines, and are thought to be mediated by modified innate and possibly adaptive immunity. Indeed, rotavirus vaccines have been reported to provide greater than expected reductions in acute gastroenteritis caused by other enteropathogens, that have mostly been attributed to herd protection and prior underestimation of rotavirus disease. Whether rotavirus vaccines also alter the immune system to reduce non targeted gastrointestinal infections has not been studied directly. Here we review the current understanding of the mechanisms underlying off-target effects of vaccines and propose a mechanism by which the live-attenuated neonatal rotavirus vaccine, RV3-BB, could promote protection beyond the targeted pathogen. Finally, we consider how vaccine developers may leverage these properties to improve health outcomes in children, particularly those in low-income countries where disease burden and mortality is disproportionately high relative to developed countries.
ARTICLE | doi:10.20944/preprints202111.0042.v1
Subject: Physical Sciences, Mathematical Physics Keywords: Wind wave; Ice cover; Vortex sheet; Negative energy wave; Modulation instability
Online: 2 November 2021 (10:53:15 CET)
An interesting physical phenomenon was recently observed when a fresh-water basin is covered by a thin ice film that has properties similar to that of a rubber membrane. Surface waves can be generated under the action of wind on the air-water interface that contains an ice film. The modulation property of hydro-elastic waves (HEWs) in deep water covered by thin ice film blown by the wind with a uniform vertical profile is studied here in terms of the air-flow velocity versus a wavenumber. The modulation instability of HEWs is studied through the analysis of coefficients of the nonlinear Schrödinger (NLS) equation with the help of the Lighthill criterion. The NLS equation is derived using the multiple scale method in the presence of airflow. It is demonstrated that the potentially unstable hydro-elastic waves with negative energy appear for relatively small wind speeds, whereas the Kelvin–Helmholtz instability arises when the wind speed becomes fairly strong. Estimates of parameters of modulated waves for the typical conditions are given.
ARTICLE | doi:10.20944/preprints202102.0051.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Metal-Organic Framework; Photocatalysis; Band-Gap modulation; Strain Engineering; Catalyst Selectivity.
Online: 1 February 2021 (15:00:06 CET)
In recent years, the class of metal-organic framework (MOF) materials emerged. These materials' unique properties can be assigned to their structure, containing inorganic nodes connected with organic linkers. Due to their porosity and flexibility, MOFs have become suitable for various energy-related applications, including gas storage, hydrogen production and heterogeneous catalysis, and photocatalysis. Using DFT+U calculations, we show that the substitution of metal centers in inorganic nodes and the strain engineering of UiO-66 alters the electronic and optical properties of this material. We show that applying mechanical strain on UiO-66 enables the control of absorption coefficient in the UV-Vis spectrum and the photocatalytic processes' selectivity when reactants for several photocatalytic processes are present. The presented findings could lead to general strategies for designing novel MOFs for sustainable energy conversion applications.
ARTICLE | doi:10.20944/preprints202009.0224.v1
Subject: Physical Sciences, Optics And Photonics Keywords: photon catalyzing; discrete modulation; dontinuous-variable; quantum key distribution; quantum communications
Online: 10 September 2020 (06:01:48 CEST)
Establishing global high-rate secure communications is a potential application of continuous-variable quantum key distribution (CVQKD) but also challenging for long-distance transmissions in metropolitan areas. The discrete modulation(DM) can make up for the shortage of transmission distance that has a unique advantage against all side-channel attacks, however its further performance improvement requires source preparation in the presence of noise and loss. Here, we consider the effects of photon catalysis (PC) on the DM-involved source preparation for lengthening the maximal transmission distance of the CVQKD system. We address a zero-photon catalysis (ZPC)-based source preparation for enhancing the DM-CVQKD system. The statistical fluctuation due to the finite length of data is taken into account for the practical security analysis. Numerical simulations show that the ZPC-based DM-CVQKD system can not only achieve the extended maximal transmission distance, but also contributes to the reasonable increase of the secret key rate. This approach enables the DM-CVQKD to tolerate lower reconciliation efficiency, which may promote the practical implementation solutions compatible with classical optical communications using state-of-the-art technology.
ARTICLE | doi:10.20944/preprints201811.0304.v1
Subject: Physical Sciences, Theoretical Physics Keywords: quasi-monochromatic waves; group velocity; dispersion relation; longitudinal modulation; coherence time
Online: 13 November 2018 (09:24:07 CET)
The wave packet consisting of two harmonic plane waves with the same frequencies, but with different wave vectors is considered. The dispersion relation of a packet is structurally similar to the dispersion relation of a relativistic particle with a nonzero rest mass. The possibility of controlling the group velocity of a quasi-monochromatic wave packet by varying the angle between the wave vectors of its constituent waves is discussed.
ARTICLE | doi:10.20944/preprints201804.0013.v2
Subject: Engineering, Electrical And Electronic Engineering Keywords: temperature modulation; gas sensors; volatile organic compounds; electronic nose; conditioning circuit
Online: 23 April 2018 (11:47:33 CEST)
This paper consists of the design and implementation of a simple conditioning circuit to optimize the electronic nose performance, where a temperature modulation method was applied to the heating resistor to study the sensor’s response and confirm whether they are able to make the discrimination when exposed to different volatile organic compounds (VOC’s). This study was based on determining the efficiency of the gas sensors with the aim to perform an electronic nose, improving the sensitivity, selectivity and repeatability of the measuring system, selecting the type of modulation (e.g., pulse width modulation) for the analytes detection (i.e., Moscatel wine samples (2% of alcohol) and ethyl alcohol (70%)). The results demonstrated that by using temperature modulation technique to the heating resistors, it is possible to realize the discrimination of VOC’s in fast and easy way through a chemical sensors array. Therefore, a discrimination model based on principal component analysis (PCA) was implemented to each sensor, with data responses obtaining a variance of 94.5% and accuracy of 100%.
ARTICLE | doi:10.20944/preprints202309.2092.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: Ageing; Fiber Optic Sensor; Transformer Oil; Refractive Index; Evanescent Field; Intensity Modulation
Online: 3 October 2023 (03:18:58 CEST)
In the realm of power delivery to end-users, transformers are indispensable, with their malfunctions leading to substantial economic, safety, and environmental repercussions. The need for persistent surveillance is accentuated for in-situ oil-filled transformers, given the potential degradation of oil and the emergence of related ageing by-products. As the focus tilts towards online detection methodologies for transformer oil ageing, bypassing challenges associated with traditional offline methods such as sample contamination and misinterpretation, fiber optic sensors are gaining trac-tion due to their compact nature, cost-effectiveness, and resilience to electromagnetic disturbances typical in high-voltage environments. This work delves into the sensitivity analysis of intensi-ty-modulated plastic optical fiber sensors. The investigation encompasses key determinants such as the influence of optical source wavelengths, noise response dynamics, ramifications of varying sensing lengths, and repeatability assessments. Findings underscore that elongating the sensing length detrimentally affects both the linearity response and repeatability, largely attributed to the diminished resistance to external noise. Additionally, the choice of the optical source wavelength proved to be a critical variable in assessing sensor sensitivity.
ARTICLE | doi:10.20944/preprints202307.0597.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: Terahertz wave; phase stabilization; photomixing; optical frequency comb; phase modulator; phase modulation
Online: 10 July 2023 (10:03:28 CEST)
As a high-frequency carrier, the Terahertz (THz) wave is essential for achieving high-data-rate wireless transmission due to its ultra-wide bandwidth. Phase stabilization becomes crucial to enable phase-shift-based multilevel modulation for high-speed data transmission. We developed a Mach-Zehnder interferometric phase stabilization technique for photomixing, which has proved a promising method for phase-stable continuous THz-wave generation. However, this method faces inefficiencies in generating phase-modulated THz waves due to the impact of the phase modulator on the phase stabilization system. By photomixing, which is one of the promising methods for generating THz waves, the phase of the generated THz waves can be controlled in the optical domain so that the stability of the generated THz wave can be controlled by photonics technologies. Thus, we have devised a new phase stabilization approach using backward-directional lightwave, which is overlapped with the THz wave generation system. This study presents a conceptual and experimental framework for stabilizing the phase differences of optical carrier signals. We compare the optical domain and transmission performances between forward-directional and backward-directional phase stabilization methods. Remarkably, our results demonstrate error-free transmission at a modulation frequency of 3 Gbit/s and higher.
ARTICLE | doi:10.20944/preprints202305.0003.v1
Subject: Computer Science And Mathematics, Artificial Intelligence And Machine Learning Keywords: Categorical emotion recognition; Auditory signal processing; Modulation-filtered cochleagram; Multi-level attention
Online: 1 May 2023 (03:06:38 CEST)
Speech emotion recognition is a critical component for achieving natural human-robot interaction. The modulation-filtered cochleagram is a feature based on auditory modulation perception, which contains multi-dimensional spectral-temporal modulation representation. In this study, we propose an emotion recognition framework that utilizes a multi-level attention network to recognize emotions from the modulation-filtered cochleagram. The channel-level attention and spatial-level attention modules are used to capture emotional saliency maps of channel and spatial feature representations from the 3D convolution feature maps, respectively. Furthermore, the temporal-level attention module captures significant emotional regions from the concatenated feature sequence of the emotional saliency maps. Our experiments on the IEMOCAP dataset demonstrate that the modulation-filtered cochleagram significantly improves the prediction performance of categorical emotion compared to other evaluated features. Moreover, our emotion recognition framework achieves a better unweighted accuracy of 71% in categorical emotion recognition than several existing approaches in the experiments. In summary, our study demonstrates the effectiveness of the modulation-filtered cochleagram in speech emotion recognition, and our proposed multi-level attention framework provides a promising direction for future research in this field.
ARTICLE | doi:10.20944/preprints202204.0221.v1
Subject: Physical Sciences, Optics And Photonics Keywords: Nonlinear optics; silicon photonics; graphene oxide; femtosecond optical pulses; self-phase modulation
Online: 25 April 2022 (07:37:12 CEST)
We experimentally demonstrate enhanced spectral broadening of femtosecond optical pulses after propagation through silicon-on-insulator (SOI) nanowire waveguides integrated with two-dimensional (2D) graphene oxide (GO) films. Owing to the strong mode overlap between the SOI nanowires and the GO films with a high Kerr nonlinearity, the self-phase modulation (SPM) process in the hybrid waveguides is significantly enhanced, resulting in greatly improved spectral broadening of the femtosecond optical pulses. A solution-based, transfer-free coating method is used to integrate GO films onto the SOI nanowires with precise control of the film thickness. Detailed SPM measurements using femtosecond optical pulses are carried out, achieving a broadening factor of up to ~4.3 for a device with 0.4-mm-long, 2 layers of GO. By fitting the experimental results with theory, we obtain an improvement in the waveguide nonlinear parameter by a factor of ~3.5 and the effective nonlinear figure of merit (FOM) by a factor of ~3.8, relative to the uncoated waveguide. Finally, we discuss the influence of GO film length on the spectral broadening and compare the nonlinear optical performance of different integrated waveguides coated with GO films. These results confirm the improved nonlinear optical performance for silicon devices integrated with 2D GO films.
ARTICLE | doi:10.20944/preprints202203.0123.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Depression; psychoimmune resilience; tricyclic antidepressants; serotonin; modulation of inflammatory response; infectious diseases
Online: 8 March 2022 (11:04:46 CET)
Brucellosis infection induces fever, chills, sweats, headache, myalgia, arthralgia, anorexia, fa-tigue, and mood disorders. In mice, it causes a rise in IL-6, TNF-, and IFN-; and reduces sero-tonin and dopamine levels in hippocampus. There is loss in muscle strength and equilibrium and increased anxiety and hopelessness. Imipramine (ImiP) is a tricyclic antidepressant that increases the capacity of macrophages to destroy intracellular microorganisms in vivo. The effect of ImiP was evaluated in Balb/c mice infected with Brucella abortus 2308. Serum levels were determined in IFN-, IL-6, TNF-, IL-12, MCP-1, and IL-10 by FACS; the bacterial count in the spleen, by CFU; the serotonin concentration in the hippocampus, by HPLC; and strength, equilibrium, and mood by behavioral tests. Our results showed that infected vs. control mice had a significant rise in lev-els of IFN-, IL-6, TNF-, and IL-12 with a low IFN-/IL-6 ratio, elevated bacterial-counts, alter-ations in serotonin concentration at hippocampus, and decreased muscular strength, equilibrium, and mood. Infected mice treated with ImiP vs. infected mice showed: 1) improved mood; 2) in-creased hippocampal serotonin availability, splenic dendritic cells, and macrophage phagocytic activity; and 3) upturn inflammation and reduced CFU ability. Our results support that ImiP fa-vors positive outcomes in subjects handling Brucella infections likely by improving psychoim-mune resilience.
ARTICLE | doi:10.20944/preprints202002.0426.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: IEEE 802.15.4g, Smart Utility Networks; Low-Power; Wireless; Modulation Diversity; Reliability; Availability
Online: 28 February 2020 (12:08:40 CET)
The IEEE 802.15.4-2015 standard includes the SUN (Smart Utility Networks) modulations, i.e., SUN-FSK, SUN-OQPSK and SUN-OFDM, which provide long range communications and allow to trade data rate, occupied bandwidth and reliability. However, given the constraints of low-power devices and the challenges of the wireless channel, communication reliability cannot still meet the PDR (Packet Delivery Ratio) requirements of industrial applications, i.e., PDR>99%. Hence, in this paper we evaluate the benefits of improving communication reliability by combining packet transmissions with modulation diversity using multiple IEEE 802.15.4g SUN modulations. The results derived from a real-world deployment show that going from 1 to 3 packet transmissions with the same SUN modulation can increase PDR from 85.0/84.6/71.3% to 94.2/94.1/86.0% using SUN-FSK, SUN-OQPSK and SUN-OFDM, respectively. Combining the same number of packet transmissions with modulation diversity allows to further increase the average PDR to 97.1%, indicating its potential as a tool to help meeting the reliability requirements of industrial applications.
ARTICLE | doi:10.20944/preprints201901.0119.v1
Subject: Social Sciences, Behavior Sciences Keywords: embodied language, grip force modulation, intraparietal sulcus, motor-evoked potential, right hemisphere
Online: 11 January 2019 (16:08:14 CET)
Objective: To evaluate the effects of left intraparietal sulcus (IPS) inhibition by repetitive transcranial magnetic stimulation (rTMS) on grip force modulation (GFM) for both hands during a unimanual task. Methods: GFM induced by manual action-verb listening was evaluated for each hand in a unimanual task, and the motor-evoked potentials (MEP) were recorded for both left and right hemispheres prior to and following the left IPS inhibition. Left IPS inhibition was obtained by rTMS (5 min of 1.0 Hz, 60% of maximal stimulator output) of the international 10–20 system P3 point. Seven healthy right-handed subjects were evaluated. Results: One-way repeated measures ANOVA found that MEP amplitude and duration increased following IPS inhibition in the left hemisphere and did not change in the right hemisphere. Language-induced modulation did not change in the left hemisphere, while it was significantly attenuated in the right hemisphere. Since IPS inhibition increased the left primary motor cortex (M1) excitability, the maintenance of language-induced modulation intensity suggests it was also attenuated. Conclusion: Left IPS inhibition increased left M1 excitability without changing right M1 excitability, while attenuating the language-induced GFM for both the left and right hands.
ARTICLE | doi:10.20944/preprints201801.0042.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: matrix converter; transient electromagnetic method; simulation; space vector modulation; power factor control
Online: 7 January 2018 (14:07:44 CET)
Three-phase to single-phase matrix converter (TSMC) is used as the transmitter for transient electromagnetic method (TEM) instrument, instead of an AC-DC converter and an H-bridge inverter. The transmitter produces excitation current for primary field. The output current has a waveform with a bipolar square of half duty cycle, which is required by TEM. The space vector PWM based on input currents is discussed in detail. The control method of input power factor is proposed for TSMC. The simulation model of TSMC is established and the simulations of different conditions are completed. The simulation results show the controllability of the input power factor is illustrated.
ARTICLE | doi:10.20944/preprints202309.1521.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: random number generation; integrated photonics; photonics integrated circuit; laser; noise; modulation; quantum effects
Online: 22 September 2023 (07:39:28 CEST)
We present results of the detected voltage distribution of a quantum random number generator based on the photonic integration of semiconductor laser, delay interferometer and photodetector. We find that the integrated system behaves as expected for random number generation from gain-switched laser sources. The biggest advantage is that only electrical connections are needed to operate the system without the need for tricky and expensive optical alignment to external circuitry. We supply results showing that random bit stream created from the random numbers passes the NISTS statistical test suite tests; thus demonstrating the feasibility to generate random number via quantum means at gigabit/s rates from a single photonic integrated circuit. The results are backed by numerical simulations.
Subject: Physical Sciences, Acoustics Keywords: pyroelectricity; temperature modulation; molecular ferroelectrics; non-contact measurement; thermal diffusion model; lithium niobate
Online: 30 July 2021 (09:22:29 CEST)
A temperature-modulated pyroelectricity measurement system for a small single crystal is developed and applied to standard sample measurements performed on a thin single crystal of lithium niobate. The modulation measurement is based on the AC technique, in which the temperature of the sample is periodically oscillated, and the synchronized pyroelectric signal is extracted using a lock-in amplifier. Temperature modulation is applied by irradiating periodic light on the sample placed in the heat exchange gas. To apply this technique to the transparent reference sample, a commercially available black resin is coated on the sample’s surface to absorb the light energy and transmits it to the specimen. The experimental results are analyzed using a two-layer heat transfer model to verify the effect of the light-absorbing layer as well as the non-contact temperature modulation system.
REVIEW | doi:10.20944/preprints201911.0272.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: adaptive modulation; TVWS; CRSN; RRA; smart grid; Distributed Heterogeneous Clustered (DHC); dynamic radio
Online: 24 November 2019 (05:20:58 CET)
A cognitive radio sensor network (CRSN) based Smart Grid (SG) is a new paradigm for a modern SG. It is totally different from the traditional power grid and also different from the conventional SG that uses a static resource allocation technique to allocate resources to sensor nodes and communication devices in the SG network. Due to the challenges associated with competitive sensor nodes and communication devices in accessing and utilizing radio resources, the need for dynamic radio resource allocation (RRA) has been proposed as a solution for allocating radio resources to sensor nodes in a CRSN based smart grid ecosystem (network). These challenges include energy/power constraints, poor quality of service (QoS), interference, delay, spectrum efficiency issues, and excessive spectrum hand-offs. Hence, the optimization of resource allocation criteria, such as energy efficiency, throughput maximization, QoS guarantee, fairness, priority, interference mitigation/avoidance, etc., will go a long way in addressing the problems of RRA in a CRSN based SG. Consequently, this work explores RRA in CRSNs for SGs. Various resource allocation schemes, as well as its architecture in a CRSN for SG environment, are presented. The work reported in this paper introduces a model called the “guaranteed network connectivity channel allocation” for throughput maximization (GNC-TM) and optimal spectrum band determination in RRA for improved throughput criteria in CRSNs for SGs. The results show that the model outperforms the existing protocol in terms of throughput and error probability. Finally, the contribution to knowledge and future research direction, such as energy efficiency and hybrid energy harvesting schemes are highlighted.
ARTICLE | doi:10.20944/preprints201907.0139.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: grip force modulation; embodied language; left hand; right hemisphere; left hemisphere; unimanual task
Online: 10 July 2019 (07:37:58 CEST)
Background and objectives: The language-induced grip force modulation (GFM) can be used to better understand the link between the language and motor functions as an expression of the embodied language. However, the contribution of each brain hemisphere to the language-induced GFM is still unclear. Using six different action verbs as stimuli, this study evaluated the GFM of the left hand in unimanual task to characterize the left- and right-hemisphere contributions. Materials and Methods: The left-hand GFM of 20 healthy consistent right-handers subjects was evaluated using the verbs “to write”, “to hold”, “to pull”(left-lateralized central processing actions), “to draw”, “to tie”, and “to drive” (bi-hemispheric central processing actions) as linguistic stimuli. The time between the word onset and the first interval of statistical significance regarding the baseline (RT) was also measured. Results: The six verbs produced language-induced GFM. The modulation intensity was similar for the six verbs, but the RT was variable. The verbs “to draw”, “to tie”, and “to drive”, whose central processing of the described action is bihemispheric showed a longer Rt compared to the other verbs. Conclusions: The possibility that an action is performed by the left-hand does not interfere with the occurrence of GFM when this action verb is employed as linguistic stimulus. Therefore, the language-induced GFM seems mainly rely on the left hemisphere, and the engagement of the right hemisphere seems to slow down the increase in the GFM intensity.
ARTICLE | doi:10.20944/preprints201805.0283.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: venturini method; matrix converter; unbalanced voltage conditions; carrier-based pulse width modulation (PWM)
Online: 22 May 2018 (05:05:38 CEST)
Based on Venturini method, it is in favor of the modulation technique for controlling the matrix converter due to only use of the comparison between the duty cycles in time domain and the triangular carrier wave for generating the gating signals and the achievable voltage ratio between fundamental output magnitude and fundamental input magnitude to 0.866. However, even with simple modulation method and achieving maximum fundamental output magnitude, the possible input voltage unbalance conditions accordingly influence on the output performances (more reduction and distortion). Thus, a modified Venturini modulation method is presented in this paper, in order to solve the problems of unbalanced input voltage conditions on the matrix converter performances. The proposed strategy is to satisfy the desirable feature of the duty cycle modulating waves, as generated in the event of normal situation. Up to this approach, it can support either single-phase condition or two-phase condition. Performance of the proposed control strategy was verified by the simulated implementation in the MATLAB/Simulink software with showing good steady-state and dynamic operations.
REVIEW | doi:10.20944/preprints202104.0728.v1
Subject: Engineering, Automotive Engineering Keywords: Direct Matrix Converter (DMC; Space Vector Modulation (SVPWM); AC-AC Power Conversion; Converters; Simulation
Online: 27 April 2021 (17:26:30 CEST)
The matrix converter converts the input line voltage into a variable voltage with an unrestricted output frequency without using an intermediate circuit, dc link circuit. A pure sine in and pure sine out is the unique feature of the matrix converter. This research paper also analyzes the basic operating principle and the simulation modeling of the direct matrix converter, which is controlled by the Space Vector Pulse Width Modulation technique by using the software which is known as MATLAB/Simulink. The most desirable features in the power frequency changes can be fulfilled by using the matrix converters, and this is the reason for the tremendous interest in the topology. Since the power electronic circuits which is known as the motor drives are used to operate the AC motors at the frequencies other than that of the supply.
ARTICLE | doi:10.20944/preprints202012.0096.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: AHB LED constant-current driver; Digital Current-programmed control; discrete-time modeling; Modulation effect
Online: 4 December 2020 (10:09:24 CET)
The high-power Asymmetric half-bridge Converter (AHBC) LED constant current driver controlled by digital current mode is a fourth-order system. Static operating point, parasitic resistance, load characteristics, sampling effect, modulation mode and loop delay will have great influence on its dynamic performance. In this paper, the small-signal pulse transfer function of the driver is established by the discrete-time modeling method for the two operating points corresponding to the three modulation modes of the trailing edge, leading edge and double edge. And, the effects of parasitic parameters, delay effect, sampling effect and load effect are fully considered in modeling. For a large number of complex exponential matrix operations, the first order Taylor formula is used for approximate calculation after the coefficient matrix is obtained by substituting the data. Then, Matlab software is used to compare and analyze the discrete-time model and the discrete-average model. The results show that the proposed discrete-time model can more accurately characterize the resonant peak and high-frequency dynamic characteristics, and is very suitable for the design of high frequency digital controller.
ARTICLE | doi:10.20944/preprints201810.0108.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: LIDAR; time-of-flight; IM/DD OCDMA; free-space optical communication; modulation; spreading code
Online: 5 October 2018 (16:17:44 CEST)
In the coded pulse scanning light detection and ranging (LIDAR) system, the number of laser pulses used at a given measurement point changes depending on the modulation and the method of spreading used in optical code-division multiple access (OCDMA). The number of laser pulses determines the pulse width, output power, and duration of the pulse transmission of a measurement point. These parameters determine the maximum measurement distance of the laser and the number of measurement points that can be employed per second. In this paper, we evaluate the performance and characteristics of combinations of modulation and spreading technology that can be used for OCDMA, and study optimal combinations according to varying operating environments.
ARTICLE | doi:10.20944/preprints201801.0097.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: deep learning; automatic modulation classification; classifier fusion; convolutional neural network; long short-term memory
Online: 11 January 2018 (04:47:00 CET)
Deep learning has recently attracted much attention due to its excellent performance in processing audio, image, and video data. However, few studies are devoted to the field of automatic modulation classification (AMC). It is one of the most well-known research topics in communication signal recognition, which remains challenging for traditional methods due to the complex disturbance from other sources. This paper proposes a heterogeneous deep model fusion (HDMF) method to solve the problem in a unified framework. The contributions include: 1) The convolutional neural network (CNN) and long short-term memory (LSTM) are combined by two different ways without prior knowledge involved; 2) A large database, including eleven types of single-carrier modulation signals with various noises as well as a fading channel, is collected with various signal-to-noise ratios (SNRs) based on a real geographical environment; and 3) Experimental results demonstrate that HDMF is super capable of copping with the AMC problem, and achieves much better performance when compared with the independent network. The source code and the database will be publically available.
ARTICLE | doi:10.20944/preprints202307.0992.v1
Subject: Physical Sciences, Optics And Photonics Keywords: vectorial optical field generator; spatial light modulator; 4f system; amplitude modulation; eight-direction Sobel operator
Online: 14 July 2023 (08:38:58 CEST)
Vectorial optical fields have sparked considerable interest with potential applications such as optical nano-fabrication, optical micromachining, quantum information processing, optical imaging, and so on. Traditional compact vectorial optical generators with amplitude modulation perform poorly in terms of diffraction effect reduction. In order to address this issue, the refractive 4f system in amplitude modulation is longitudinally aligned using an optimization approach presented in this research. The phase images used for longitudinal alignment are loaded into the liquid crystal spatial light modulator (SLM), and the distance between the lens and the mirror in the reflective 4f system is adjusted for longitudinal alignment by compensating for the neglected phase in the integrated module of the compact vectorial optical field generator. The spot images collected by the CCD are processed using the improved eight-direction Sobel operator, and the longitudinal alignment in the reflective 4f system is determined by the sharpness of the image. The sharpness of the lines' edges and the overall image are both enhanced after optimization compared to before optimization. The results show that the proposed method can significantly reduce the longitudinal alignment error of the reflective 4f system in the amplitude modulation of the compact vectorial optical field generator, lessen the diffraction effect, and improve the performance of the system.
ARTICLE | doi:10.20944/preprints202003.0334.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: industrial wireless sensor networks; IEEE~802.15.4g; smart utility networks; link reliability; adaptive techniques; modulation diversity
Online: 23 March 2020 (04:34:16 CET)
Adaptive mechanisms, such as channel hopping and packet replication, are used in low-power wireless networks to deal with the spatial and temporal variations in the link quality, and meet the reliability requirements of industrial applications (i.e., PDR>99%). However, the benefits of such mechanisms are limited and may have a large impact on end-to-end latency and energy consumption. Hence, in this paper we propose using adaptive modulation diversity, which allows to dynamically select different modulations, to improve link reliability. We present three adaptive modulation diversity selection strategies and validate them using the data derived from a real-world deployment using the IEEE 802.15.4g SUN modulations (i.e., SUN-FSK, SUN-OQPSK and SUN-ODFM) in an industrial environment. The results show that by using adaptive modulation diversity it is possible to improve link reliability regardless of node conditions.
ARTICLE | doi:10.20944/preprints202310.1032.v1
Subject: Physical Sciences, Other Keywords: distributed feedback (DFB) semiconductor lasers; modulation bandwidth enhancement; detuned-loading effect; reconstruction-equivalent-chirp (REC) technique
Online: 17 October 2023 (08:04:07 CEST)
A novel high-speed directly modulated two-section distributed feedback (TS-DFB) semiconductor laser based on the detuned-loading effect is proposed and simulated. Grating structure is designed by reconstruction-equivalent-chirp (REC) technique. A π phase-shift is introduced into the reflection grating, which can provide a narrow-band reflection region with a sharp falling slope on both sides of the reflection spectrum, thus enhancing the detuned-loading effect. Owing to its unique dual-falling-edges structure the bandwidth can be improved even when the lasing wavelength shifts beyond the left falling edge due to thermal effect in actual test, in which condition the detuned-loading effect can be used twice, which greatly improves the yield. The modulation bandwidth is increased from 17.5 GHz for a single DFB laser to around 24 GHz when the lasing wavelength is located on the left falling edge of the TS-DFB laser based on detuned-loading effect, and can be increased to 22 GHz for the right side. An eight-channel laser array with precise wavelength spacing is investigated, with side mode suppression ratio (SMSR) > 36dB. Besides, TS-DFB lasers with uniform reflection grating are studied and simulated result shows that modulation characteristic is far inferior to the laser with a phase-shifted grating reflector.
ARTICLE | doi:10.20944/preprints202212.0382.v2
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Saccharomyces cerevisiae; beta-glucans; selenium; zinc; gut barrier; modulation; COVID-19; nutritional supplementation; allergy; inflammatory process
Online: 25 January 2023 (04:43:01 CET)
This study evaluated the anti-inflammatory effects, protection of gut barrier integrity, and stimulation of phagocytosis in peripheral cells of a nutritional supplement based on a synergistic combination of yeast-based ingredients with a unique 1,3/1,6-glucan complex and a consortium of postbiotic Saccharomyces cerevisiae rich in selenium and zinc. The anti-inflammatory effect in Caco-2 cells in the presence and absence of a pro-inflammatory challenge (tumour necrosis factor alpha [TNF-α]/interferon gamma [IFN-ɣ]) showed statistically significant reductions of IFN-ɣ induced protein-10 (IP-10), and monocyte chemoattractant protein-1 (MCP-1) levels vs. controls (p < 0.001). Disruption of the gut integrity in the presence or absence of Escherichia coli (ETEC H10407) showed transepithelial electrical resistance (TEER) values higher in the ABB C1® group after 6 hours of testing. Spontaneous build-up of the gut epithelium monolayer over 22 days was also greater in the ABB C1® condition vs. a negative control. ABB C1® showed a significantly higher capacity to stimulate phagocytosis as compared with controls of algae β-1,3-glucan and yeast β-1,3/1,6 glucan (p < 0.001). This study supports the mechanism of action by which ABB C1® may improve the immune response and be useful to prevent infection and allergy in clinical practice.
Subject: Chemistry And Materials Science, Surfaces, Coatings And Films Keywords: ITO; electrical properties; doping limits; modulation doping; thickness dependence; low-temperature processing; in-operando Hall effect
Online: 23 April 2019 (12:13:38 CEST)
Low-temperature processed ITO thin films offer the potential of overcoming the doping limit by suppressing the equilibrium of compensating oxygen interstitial defects. To elucidate this potential, electrical properties of Sn-doped In2O3 (ITO) thin films are studied in dependence on film thickness. In-operando conductivity and Hall effect measurements during annealing of room temperature deposited films with different film thickness in different environments allow to discriminate between the effects of crystallization, grain growth, donor activation and oxygen diffusion on carrier concentrations and mobilities. At 200 °C, a control of carrier concentration by oxygen incorporation or extraction is only possible for very thin films. The electrical properties of thicker films deposited at room temperature are mostly affected by grain size. The remaining diffusivity of compensating oxygen defects at 200 °C is sufficient to screen the high Fermi level induced by deposition of Al2O3 using atomic layer deposition (ALD), which disables the use of defect modulation doping at this temperature. The results indicate that achieving higher carrier concentrations requires a control of the oxygen pressure during deposition in combination with seed layers to enhance crystallinity or the use of near room temperature ALD.
ARTICLE | doi:10.20944/preprints202310.1234.v1
Subject: Engineering, Aerospace Engineering Keywords: brushless direct current motors; current control; pulse width modulation; speed control of BLDC motors; more electric aircraft
Online: 19 October 2023 (09:49:33 CEST)
Rising fuel costs, significant air pollution, and the need to mitigate the negative consequences of oil consumption have diminished the relevance of traditional vehicles. This shift encourages the adoption of safer, more efficient, and eco-friendly transportation alternatives, such as fuel cell, electric, and hybrid vehicles. Brushless direct current motors are gaining popularity due to their high efficiency, power factor, torque, and controllability. By 2030, Brushless Direct Current motors are expected to replace conventional motors as the standard for power transfer, especially in dynamic applications like automobiles, more electric aircraft. This study explores a control technique to improve real-time control of brushless direct current motors in electric vehicles It presents speed control of these system for electric vehicle applications and an overview of electric vehicle technologies. A model for the 120-degree mode was developed using electrical and mechanical equations in MATLAB/Simulink. Three scenarios were examined to assess the potential of controlling brushless direct current motors using constant and dynamic speed and torque. The actual value reached the reference value in the first two scenarios.
COMMUNICATION | doi:10.20944/preprints202309.0519.v1
Subject: Physical Sciences, Optics And Photonics Keywords: diamond; femtosecond laser; transmission spectra; self-phase modulation broadening; Bragg gratings; electron-hole plasma; nanoplasmonics; electron-phonon thermalization
Online: 7 September 2023 (11:01:35 CEST)
Self-phase modulation (SPM) broadening of laser spectra was studied in a transmission mode in natural and synthetic diamonds at variable laser wavelengths (515 and 1030 nm), pulse energies and widths (0.3 - 12 ps, positively chirped pulses), providing their filamentary propagation. Besides the monotonous SPM broadening of the laser spectra versus pulse energy, more pronounced for the (sub)picosecond pulsewiths and more doped natural diamond, periodical low-frequency modulation was observed in the spectra at the shorter laser pulsewidths, indicating dynamic Bragg filtering of the supercontinuum due to ultrafast plasma and nanoplasmonic effects. Damping of broadening and ultramodulation for the longer picosecond pulsewidths was related to thermalized electron-hole plasma regime established for the laser pulsewidths longer, than 2 ps. Unexpectedly, at higher pulse energies and corresponding longer microfilaments, the number of spectral modulation features increases, indicating dynamic variation of the periods in the longitudinal plasma Bragg gratings along the filaments due to prompt secondary laser-plasmon interactions.
ARTICLE | doi:10.20944/preprints202104.0528.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Interactomics; host-parasite-microbiome relationships; extra-intestinal effects; D-amino ac-id/SCFA-induced modulation; Yeast ubiquinone salvation.
Online: 20 April 2021 (11:12:14 CEST)
Cryptosporidiosis is a major human health concern globally. Despite well-established methods, misdiagnosis remains common. Our understanding of the cryptosporidiosis biochemical mechanism remains limited, compounding the difficulty of clinical diagnosis. Here, we used a systems biology approach to investigate the underlying biochemical interactions in C57BL/6J mice infected with Cryptosporidium parvum. Faecal samples were collected daily following infection. Blood, liver tissues and luminal contents were collected 10 days post infection (dpi). High-resolution liquid chromatography and low-resolution gas chromatography coupled with mass spectrometry were used to analyse the proteomes and metabolomes of these samples. Faeces and luminal contents were additionally subjected to 16S rRNA gene sequencing. Univariate and multivariate statistical analysis of the acquired data illustrated altered host and microbial energy pathways during infection. Glycolysis/citrate cycle metabolites were depleted, while short-chain fatty acids and D-amino acids accumulated. An increased abundance of bacteria associated with a stressed gut environment was seen. Host proteins involved in energy pathways and Lactobacillus glyceraldehyde-3-phosphate dehydrogenase were upregulated during cryptosporidiosis. Liver oxalate also increased during infection. Microbiome-parasite relationships were observed to be more influential than the host-parasite association in mediating major biochemical changes in the mouse gut during cryptosporidiosis. Defining this parasite-microbiome interaction is the first step towards building a comprehensive cryptosporidiosis model towards biomarker discovery, and rapid and accurate diagnostics.
ARTICLE | doi:10.20944/preprints202103.0750.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: Underwater Communication; Wireless Communication; Acoustic Communication; Ultrasound Acoustics; Digital Signal Processing; Chirp Modulation; Chirp Slope Keying; Chirp Spread Spectrum
Online: 30 March 2021 (14:25:50 CEST)
We propose an asynchronous acoustic chirp slope keying to map bit sequences on single or multiple bands without preamble or error correction coding on the physical layer. Details of the implementation are disclosed and discussed, the performance verified on laboratory scale in a pool measurement, as well as simulated for a channel containing Rayleigh fading and Additive White Gaussian Noise. For time-bandwidth products of 50 in single band mode, a raw data rate of 100~bit/s is simulated to achieve bit error rates below 0.001 for signal-to-noise ratios above -6~dB. In dual-band mode and a data rate of 200~bit/s, this bit error level was achieved for signal-to-noise ratios above 0~dB for time-bandwidth product of 25. The packet error rates follow this behavior with an offset of 1~dB.
REVIEW | doi:10.20944/preprints202011.0721.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Non-invasive direct current stimulation; Cortical, Suboccipital and Spinal stimulation; Quantitative sensory testing, Pain outcome measures, Endogenous pain modulation.
Online: 30 November 2020 (11:44:44 CET)
Background: Objectives. The objective of this study was to compare the efficacy of direct current stimulation (DCS) applied at the transcranial, suboccipital and spinal level on experimental sensory modalities and pain outcome measures in healthy subjects. The hypothesis of this study was that systematic analysis of the efficacy of DCS on modulating evoked thermal and mechanical pain modalities and mechanisms such as endogenous pain modulation in healthy individuals would reveal sensitive outcome measures help develop this technique for the control of chronic pain. Materials and Methods. Database searches were conducted up to December 2019 for randomized controlled trials that performed sham-controlled DCS of experimental sensory modalities and pain outcomes following transcranial, suboccipital and spinal locations in healthy participants. Standardized mean differences with 95% confidence intervals were calculated for sensory modalities, including random-effect metanalysis. Results: Thirty-one studies were included for analysis (647 participants). A significant decrease in pain intensity for active vs sham transcranial stimulation was identified for pain intensity (n=158; SMD=0.79; 95% CI=0.56 to 1.02), a significant increase in heat pain threshold (n=222; SMD=1.16; 95% CI=0.95 to 1.37), and a significant increase in cold pain threshold (n = 155; SMD = 0.77, 95% CI 0.53 to 1.01). No significant modulation of pressure pain threshold was identified with DCS and only a limited number of studies focused on experimental pain modulation following neuromodulation at the suboccipital or spinal level. Conclusions: These results show significant transcranial DCS neuromodulation of pain intensity and on thermal pain modalities. Future studies should focus on endogenous pain and sensory modality modulation with sham-controlled DCS applied at transcranial, suboccipital and spinal locations.
ARTICLE | doi:10.20944/preprints202103.0521.v1
Subject: Physical Sciences, Acoustics Keywords: Two-layer fluid; shear flow; air-water interface; surface tension; vortex sheet; Kelvin-Helmholtz instability; negative-energy wave; modulation instability
Online: 22 March 2021 (11:26:38 CET)
The modulation instability of surface capillary-gravity water waves is analysed in a shear flow model with a tangential discontinuity of velocity. It is assumed that air blows along the surface of the water with a uniform profile in the vertical direction. Such a model, despite its simplicity, plays an important role in hydrodynamics as the reference model for investigating basic physical phenomena of wave-current interactions and acquiring insights into a series of complex phenomena. In certain cases where the wavelength of interfacial perturbations is much bigger than the width of the shear fow profile, the model with the tangential discontinuity in the velocity is adequate for describing physical phenomena at least within limited spatial and temporal frameworks. A detailed analysis of the air-flow conditions under which modulation instability sets in is presented. It is also shown that the interfacial waves are subject to dissipative or radiative instability when negativeenergy waves appear at the interface.
ARTICLE | doi:10.20944/preprints202309.0443.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: metasurface; metamaterials; reconfigurable intelligent surfaces (RIS); intelligent reflecting surfaces (IRS); wireless sensors; localization; radar; radar cross section (RCS); beam-steering; modulation
Online: 7 September 2023 (04:03:44 CEST)
In this paper, we propose a reconfigurable intelligent surface (RIS) that can dynamically switch the transmission and reflection phase of incident electromagnetic waves in real time to realize the dual-beam or quad-beam and convert polarization of the transmitted beam. Such surfaces can redirect a wireless signal at will to establish robust connectivity when the designated line-of-sight channel is disturbed, thereby enhancing the performance of wireless communication systems by creating an intelligent radio environment. When integrated with a sensing element, they are integral to performing joint detection and communication functions in future wireless sensor networks. In this work, we first analyze the scattering performance of a reconfigurable unit element and then design a RIS. The dynamic field scattering manipulation capability of the RIS is validated by full-wave electromagnetic simulations to realize six different functions. The scattering characteristics of the proposed unit element, which incorporates two p-i-n diodes, have been substantiated through practical implementation. This involved the construction of a simple prototype and the subsequent examination of its scattering properties via the free-space measurement method. The obtained transmission and reflection coefficients from the measurements are in agreement with the anticipated outcomes from simulations.
ARTICLE | doi:10.20944/preprints202208.0030.v1
Subject: Medicine And Pharmacology, Cardiac And Cardiovascular Systems Keywords: ascending aorta aneurysm; bicuspid aorta valve; tricuspid aorta valve; ERG transcriptional factor pathway; TGF-β-SMAD, Notch, and NO pathways modulation.
Online: 2 August 2022 (03:43:22 CEST)
Abstract: The pathobiology of ascending aorta aneurysms (AAA) onset and progression is not well understood and only partially characterized. AAA are also complicated in case of bicuspid aorta valve (BAV) anatomy. There is emerging evidence about the crucial role of endothelium-related pathways, which show in AAA an altered expression and function. Here, we examined the involvement of ERG-related pathways in the differential progression of disease in aortic tissues from patients having a BAV or tricuspid aorta valve (TAV) with or without AAA. Our findings identified ERG as a novel endothelial-specific regulator of TGF-β-SMAD, Notch, and NO pathways, by modulating a differential fibrotic or calcified AAA progression in BAV and TAV aortas. We provided evidence that calcification is correlated to different ERG expression (as gene and protein), which appears to be under control of Notch signaling. The latter, when increased, associated with an early calcification in aortas with BAV valve and aneurysmatic, was demonstrated to favor the progression versus severe complications, i.e., dissection or rupture. In TAV aneurysmatic aortas, ERG appeared to modulate fibrosis. Therefore, we proposed that ERG may represent a sensitive tissue biomarker to monitor AAA progression and a target to develop therapeutic strategies and influence surgical procedures.
REVIEW | doi:10.20944/preprints201808.0489.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: chemotherapy; breast cancer metastasis; stress response; ATF3; seed and soil theory; cancer-host interaction; tumor microenvironment; immune modulation; tumor immune environment
Online: 29 August 2018 (09:05:46 CEST)
An emerging picture in cancer biology is that, paradoxically, chemotherapy can actively induce changes that favor cancer progression. These pro-cancer changes can be either inside (intrinsic) or outside (extrinsic) the cancer cells. In this review, we will discuss the extrinsic pro-cancer effect of chemotherapy; that is, the effect of chemotherapy on the non-cancer host cells to promote cancer progression. We will focus on metastasis, and will first discuss recent data from mouse models of breast cancer. Intriguingly, despite reducing the size of primary tumors, chemotherapy changes the tumor microenvironment, resulting in an increased escape of cancer cells into the blood stream. Furthermore, chemotherapry changes the tissue microenvironment at the distant sites, making it more hospitable to cancer cells upon their arrival. We will then discuss the idea and evidence that these devastating pro-metastatic effects of chemotherapy can be explained in the context of stress response. At the end, we will discuss the potential relevance of these mouse data to human breast cancer and their implication on chemotherapy in the clinic.
REVIEW | doi:10.20944/preprints201811.0179.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: calorie restriction mimetics; anti-aging; lifespan extension; glucose metabolism modulation; chitosan; acarbose; SGLT2 inhibitor; 2-deoxy-D-glucose; D-allulose; D-glucosamine
Online: 7 November 2018 (15:26:42 CET)
Calorie restriction (CR) has been shown to prolong the lifespan of humans, but enforcing long-term CR is difficult. Therefore, a compound that reproduces the effect of CR without CR is needed. In this review, we summarize the current knowledge on compounds with CR mimetic (CRM) effects. More than 10 compounds have been listed as CRMs, some of which are conventionally categorized as upstream-type CRMs showing glycolytic inhibition while the others are categorized as downstream-type CRMs that regulate or genetically modulate intracellular signaling proteins. Among these, we focus on upstream-type CRMs and propose their classification as compounds with energy metabolism inhibition effects, particularly glucose metabolism modulation effects. The upstream-type CRMs reviewed include chitosan, acarbose, sodium-glucose cotransporter 2 inhibitors, and hexose analogs such as 2-deoxy-D-glucose, D-glucosamine, and D-allulose, which show anti-aging and longevity effects. Finally, we discuss the molecular definition of upstream-type CRMs.
ARTICLE | doi:10.20944/preprints202305.0051.v3
Subject: Physical Sciences, Quantum Science And Technology Keywords: Quantum K-Means; Quantum Machine Learning; Quantum Computing; K-Means Clustering; 6G Communication; Quadrature Amplitude Modulation; Quantum-Classical Hybrid Algorithms; Quantum-Inspired Algorithms
Online: 19 September 2023 (04:33:13 CEST)
Nearest-neighbour clustering is a simple yet powerful machine learning algorithm that finds natural application in the decoding of signals in classical optical-fibre communication systems. Quantum k-means clustering promises a speed-up over the classical k-means algorithm; however, it has been shown to currently not provide this speed-up for decoding optical-fibre signals due to the embedding of classical data, which introduces inaccuracies and slowdowns. Although still not achieving an exponential speed-up for NISQ implementations, this work proposes the generalised inverse stereographic projection as an improved embedding into the Bloch sphere for quantum distance estimation in k-nearest-neighbour clustering, which allows us to get closer to the classical performance. We also use the generalised inverse stereographic projection to develop an analogous classical clustering algorithm and benchmark its accuracy, runtime and convergence for decoding real-world experimental optical-fibre communication data. This proposed `quantum-inspired' algorithm provides an improvement in both the accuracy and convergence rate with respect to the k-means algorithm. Hence, this work presents two main contributions. Firstly, we propose the general inverse stereographic projection into the Bloch sphere as a better embedding for quantum machine learning algorithms; here, we use the problem of clustering quadrature amplitude modulated optical-fibre signals as an example. Secondly, as a purely classical contribution inspired by the first contribution, we propose and benchmark the use of the general inverse stereographic projection and spherical centroid for clustering optical-fibre signals, showing that optimizing the radius yields a consistent improvement in accuracy and convergence rate.
ARTICLE | doi:10.20944/preprints202201.0463.v1
Subject: Physical Sciences, Optics And Photonics Keywords: nonlinear refractive index; noncolinear degenerate phase modulation; femtosecond pulses; quantum dots; inline digital holograms; pump-probe digital holography; diffraction patterns; digital holography; phase shift
Online: 31 January 2022 (13:23:58 CET)
We report on the application of time-resolved inline digital holography to study the nonlinear optical properties of quantum dots deposited onto the sample glass. Fresnel diffraction patterns of the probe pulse due to noncollinear degenerate phase modulation induced by the femtosecond pump pulse were extracted from the set of inline digital holograms and analyzed. Absolute values of the nonlinear refractive index of both sample glass substrate and the deposited layer of quantum dots were evaluated using the proposed technique. To characterize the inhomogeneous distribution of samples’ nonlinear optical properties we proposed to plot an optical nonlinearity map calculated as a local standard deviation of diffraction patterns intensity induced by noncollinear degenerate phase modulation.
ARTICLE | doi:10.20944/preprints202304.0509.v1
Subject: Physical Sciences, Optics And Photonics Keywords: synthetic diamond; ultrashort laser pulses; self-phase modulation; spontaneous Raman scattering; delayed phonon-based Kerr non-linearity; electron-phonon thermalization; phonon-phonon anharmonicity and decay
Online: 18 April 2023 (09:36:36 CEST)
In synthetic diamond plate, the intrapulse correlated dynamics of self-phase modulation and spontaneous Raman scattering by optical phonons were for the first time directly investigated for tightly focused (focusing numerical aperture NA = 0.25) positively-chirped visible-range ultrashort laser pulses with variable durations (0.3-9.5 ps) and energies, transmitted through the sample. The observed modulation of the transmitted light spectra and Stokes Raman scattering spectra for the different pulse durations were related to nonthermal excitation of nonlinear phonon polarization and its eventual picosecond-scale suppression due to thermal decay of optical phonons on the timescale of electron-phonon thermalization in the material.
ARTICLE | doi:10.20944/preprints201907.0295.v1
Subject: Engineering, Control And Systems Engineering Keywords: decoupled controller; ferrite material; proportional integral (PI); solid state transformer (SST); space vector pulse width modulation (SVPWM); voltage source converter (VSC); voltage source inverter (VSI)
Online: 26 July 2019 (01:02:25 CEST)
This paper presents a symmetrical topology for the design of solid-state transformer, made up of power switching converters, to replace conventional bulky transformers. The proposed circuitry not only reduces the overall size but also provides power flow control with the ability to be interfaced with renewable energy resources (RESs) to fulfill the future grid requirements at consumer end. Solid state transformer provides bidirectional power flow with variable voltage and frequency operation and has the ability to maintain unity power factor, and current total harmonic distortion (THD) for any type of load within defined limits of IEEE standard. Solid State Transformer offers much smaller size as compared to that of the conventional iron core transformer. MATLAB/Simulink platform is adopted to test the validity of the proposed circuit for different scenarios by providing the simulation results evaluated at 25 kHz switching frequency.
ARTICLE | doi:10.20944/preprints202106.0409.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: DC-link current; harmonic mitigation; voltage source inverters; multi-converter systems; carrier wave interleaving scheme; DC-grid; phase-shifting; capacitor current ripple; unipolar sinusoidal pulse width modulation
Online: 15 June 2021 (14:26:57 CEST)
DC-connected parallel inverter systems are gaining popularity in industrial applications. However, such parallel systems generate excess current ripple (harmonics) at the DC-link due to harmonic interactions between the inverters in addition to the harmonics from the PWM switching. These DC-link harmonics cause the failure of fragile components such as DC-link capacitors. This paper proposes an interleaving scheme to minimize the current harmonics induced in the DC-link of such a system. The results show that when the carrier waves of the two inverters are phase-shifted by 90° angle, the maximum high-frequency harmonic ripple cancellation occurs, which reduces the overall RMS value of the DC-capacitor current.The outcome of this proposed solution is a cost-effective DC-harmonics mitigating strategy for the industrial designers to practically configuring multi-inverter systems, even when most of the drives are not operating at rated power levels. Experimental and simulation results presented in this paper verify the effectiveness of the proposed carrier-based phase-shifting scheme for two different configurations of common DC connected multi-converter systems.
ARTICLE | doi:10.20944/preprints201612.0068.v2
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: modulation of nuclear gene expression; mitochondrial 18 kDa translocator protein (TSPO); TSPO ligand; PK 11195; 2-Cl-MGV-1; retrograde mitochondrial-nuclear signaling pathway; microscopy; mitochondria; cell nucleus
Online: 17 March 2017 (17:28:28 CET)
It is known that knockdown of the mitochondrial 18 kDa translocator protein (TSPO) as well as TSPO ligands modulate various functions, including functions related to cancer. To study the ability of TSPO to regulate gene expression regarding such functions, we applied microarray analysis of gene expression to U118MG glioblastoma cells. Within 15 minutes, the classical TSPO ligand PK 11195 induced changes in expression of immediate early genes and transcription factors. These changes also included gene products that are part of the canonical pathway serving to modulate general gene expression. These changes are in accord with reverse transcriptase (RT) real-time -PCR. At the time points of 15, 30, 45, and 60 minutes, as well as 3 and 24 hours of PK 11195 exposure, the functions associated with the changes in gene expression in these glioblastoma cells covered well known TSPO functions. These functions included cell viability, proliferation, differentiation, adhesion, migration, tumorigenesis, and angiogenesis. This was corroborated microscopically for cell migration, cell accumulation, adhesion, and neuronal differentiation. Changes in gene expression at 24 hours of PK 11195 exposure were related to downregulation of tumorigenesis and upregulation of programmed cell death. In the vehicle treated as well as PK 11195 exposed cell cultures, our triple labeling showed intense TSPO labeling in the mitochondria but no TSPO signal in the cell nuclei. Thus, mitochondrial TSPO appears to be part of the mitochondria-to-nucleus signaling pathway for modulation of nuclear gene expression. The novel TSPO ligand 2-Cl-MGV-1 appeared to be very specific regarding modulation of gene expression of immediate early genes and transcription factors.