Miracle-dz/UniFAR-FTUs huggingface dataset:
Low-Resolution Digital Pre-Compensation for High-Speed Optical Links Based on Dynamic Digital-to-Analog Conversion

Digital precompensation (DPC) is considered a promising technique for high-throughput optical communication systems. The digital signal processing (DSP) at the transmitter relies on the availability of high-speed and high-resolution digital-to-analog devices to generate complex analog waveforms. However, one major challenge in current digital-to-analog converters (DACs) technology is the limited resolution, which introduces dominant quantization distortions when extensive DSP is implemented. In this paper, a dynamic quantization approach is suggested, termed as digital-resolution-enhancer (DRE), which mitigates the quantization distortion effects. This approach is based on the underlying assumption that quantization is a non-linear deterministic operation, implying that its impact on transmission can be anticipated and minimized. The proposed method is theoretically and experimentally investigated with special focus on linear precompensation for bandwidth limited systems. Simulation results demonstrate that the DRE improves the signal-to-quantization noise-ratio by up to 8 dB. Thus, the DPC can be applied with the reduced number of DAC's bits. Conversely, the DRE can enable the use of more complex DPC schemes using the same DACs hardware, and consequently, achieve extended reaches and higher transmission rates. Numerical simulations are verified by a set of extensive lab experiments. For electrical back-to-back (BTB) transmission, with an analog bandwidth of 13 GHz, 45 Gbaud QAM-64 is demonstrated using only 4 bits DACs. For optical BTB setup with an overall optoelectronic bandwidth of less than 5 GHz, 32 Gbaud QAM-4 is demonstrated using only 2.6 bits DACs.
A Systematic Review of Integrated Functional Near-Infrared Spectroscopy (fNIRS) and Transcranial Magnetic Stimulation (TMS) Studies

Background: The capacity for TMS to elicit neural activity and manipulate cortical excitability has created significant expectation regarding its use in both cognitive and clinical neuroscience. However, the absence of an ability to quantify stimulation effects, particularly outside of the motor cortex, has led clinicians and researchers to pair noninvasive brain stimulation with noninvasive neuroimaging techniques. fNIRS, as an optical and wearable neuroimaging technique, is an ideal candidate for integrated use with TMS. Together, TMS+fNIRS may offer a hybrid alternative to “blind” stimulation to assess NIBS in therapy and research. Objective: In this systematic review, the current body of research into the transient and prolonged effects of TMS on fNIRS-based cortical hemodynamic measures while at rest and during tasks are discussed. Additionally, studies investigating the relation of fNIRS to measures of cortical excitability as produced by TMS-evoked Motor-Evoked-Potential (MEP) are evaluated. The aim of this review is to outline the integrated use of TMS+fNIRS and consolidate findings related to use of fNIRS to monitor changes attributed to TMS and the relationship of fNIRS to cortical excitability itself. Methods: Key terms were searched in PubMed and Web-of-Science to identify studies investigating the use of both fNIRS and TMS. Works from Google-Scholar and referenced works in identified papers were also assessed for relevance. All published experimental studies using both fNIRS and TMS techniques in the study methodology were included. Results: A combined literature search of neuroimaging and neurostimulation studies identified 53 papers detailing the joint use of fNIRS and TMS. 22/53 investigated the immediate effects of TMS at rest in the DLPFC and M1 as measured by fNIRS. 21/22 studies reported a significant effect in [HbO] for 40/54 stimulation conditions with 14 resulting an increase and 26 in a decrease. While 15/22 studies also reported [HbR], only 5/37 conditions were significant. Task effects of fNIRS+TMS were detailed in 16 studies, including 10 with clinical populations. Most studies only reported significant changes in [HbO] related measures. Studies comparing fNIRS to changes in MEP-measured cortical excitability suggest that fNIRS measures may be spatially more diffuse but share similar traits. Conclusion: This review summarizes the progress in the development of this emerging hybrid neuroimaging & neurostimulation methodology and its applications. Despite encouraging progress and novel applications, a lack of replicated works, along with highly disparate methodological approaches, highlight the need for further controlled studies. Interpretation of current research directions, technical challenges of TMS+fNIRS, and recommendations regarding future works are discussed.
Design Considerations of Five-Phase Machine With Double p/3p Polarity

In the context of traction drives with required torque transient capabilities and a classically wide flux weakening speed range, this paper gives design considerations of a particular double-polarity (DP) five-phase machine. Beyond its intrinsic fault tolerance due to its five phases, its specificity is the ability to develop torques of comparable values under three kinds of supply: with only first, third or both first, and third sinusoidal currents. This property, due to first $(E_{1})$ and third $(E_{3})$ harmonic electromotive forces of comparable values, gives more degrees of freedom for the control of the machine. Unlike three-phase sinusoidal machine, flux weakening is no more the unique solution when maximum voltage is reached. Thanks to the extra degrees of freedom in this kind of machines, more possibilities for the control of the torque and current supply can be applied. At first, elements for the choice of slots/poles combination of such DP machines are given. Then, in the case of an interior permanent magnet synchronous machine, possible adaptations of the rotor are proposed in order to bring the double p/3p polarity property. The last design criterion considered is the level of eddy-current losses, important at high frequencies. For the proof of the concept effectiveness, a prototype with a five-phase fractional-slot concentrated winding of 40 slots and 16/48 poles is presented with results from the experimental setup and finite element modeling. A comparison with the equivalent no-fault-tolerant three-phase 24 slots/16 poles machines is also carried out.
A Knee–Ankle–Foot Orthosis to Assist the Sound Limb of Transfemoral Amputees

As a consequence of limb loss, trans-femoral amputees exert 60% additional knee extension torque and 50% more plantar flexion torque in the healthy limb compared to non-amputees. In this paper, we developed an active knee–ankle–foot orthosis (KAFO) designed to assist the healthy leg of trans-femoral amputees in activities of daily living, such as walking, ascending/descending stairs, and transitioning from sit-to-stand with adequate range of motion, speed, and peak torque. Our KAFO was designed to exceed the performance of similar assistive devices reported in literature in terms of: 1) portability; 2) power; 3) compliance; and 4) versatility. It is based on one-degree-of-freedom active series-elastic actuators in both the knee and ankle, with an additional passive degree of freedom at the ankle level to allow natural inversion/eversion. The knee module consists of a worm-gear surrounded by two pre-compressed springs. The ankle actuator relies on a mechanically adjustable compliance system combined with a 4-bar linkage transmission. The actuators were designed to optimize the torque output at the joints while fulfilling low-power requirements. This novel KAFO is controlled with a three-layer structure. The optimized low level, based on a closed-loop torque controller, has adequate performances for the targeted application. The device is also shown to fulfill the three pre-defined functional requirements for all locomotion modes.
Icariin Protects Bone Marrow Mesenchymal Stem Cells Against Iron Overload Induced Dysfunction Through Mitochondrial Fusion and Fission, PI3K/AKT/mTOR and MAPK Pathways

Iron overload has been reported to contribute to bone marrow mesenchymal stem cells (BMSCs) damage, but the precise mechanism still remains elusive. Icariin, a major bioactive monomer belonging to flavonoid glucosides isolated from Herba Epimedii, has been shown to protect cells from oxidative stress induced apoptosis. The aim of this study was to investigate whether icariin protected against iron overload induced dysfunction of BMSCs and its underlying mechanism. In this study, we found that iron overload induced by 100 μM ferric ammonium citrate (FAC) caused apoptosis of BMSCs, promoted cleaved caspase-3 and BAX protein expressions while inhibited Bcl-2 protein expression, which effects were significantly attenuated by icariin treatment. In addition, iron overload induced significant depolarization of mitochondrial membrane potential (MMP), reactive oxygen species (ROS) generation and inhibition of mitochondrial fusion/fission, which effects were also attenuated by icariin treatment. Meanwhile, we found that iron overload induced by 100 μM FAC significantly inhibited mitochondrial fission protein FIS1 and fusion protein MFN2 expressions, inhibited DRP1 and Cytochrome C protein translocation from the cytoplasm to mitochondria. Icariin at concentration of 1 μM was able to promote mitochondrial fission protein FIS1 and fusion protein MFN2 expressions, and increase DRP1 and cytochrome C protein translocation from the cytoplasm to mitochondria. Further, osteogenic differentiation and proliferation of BMSCs was significantly inhibited by iron overload, but icariin treatment rescued both osteogenic differentiation and proliferation of BMSCs. Further studies showed that icariin attenuated iron overload induced inactivation of the PI3K/AKT/mTOR pathway and activation of the ERK1/2 and JNK pathways. In summary, our study indicated that icariin was able to protect against iron overload induced dysfunction of BMSCs. These effects were potentially related to the modulation of mitochondrial fusion and fission, activation of the PI3K/AKT/mTOR pathway and inhibition of ERK1/2 and JNK pathways.
Effects of Dietary Supplementation With Enterococcus faecium and Clostridium butyricum, Either Alone or in Combination, on Growth and Fecal Microbiota Composition of Post-weaning Pigs at a Commercial Farm

Lactic acid bacteria (LAB) and butyric acid bacteria (BAB) are commonly used as probiotics in swine production. However, their combined effect on post-weaning pigs has not been assessed. Therefore, here we investigated the individual and combined efficacy of dietary Enterococcus faecium and Clostridium butyricum on the growth and gut microbiota of post-weaning pigs at a commercial farm. Four independent trials were conducted, in each of which five pens containing 10 pigs were assigned to one of five treatments: C, basal diet; L, basal diet + live E. faecium; D, basal diet + heat-killed E. faecium; M, basal diet + C. butyricum; or L+M, basal diet + live E. faecium + C. butyricum. Each trial was conducted over a 90-day period that was divided into two phases (Phase 1, days 0–40 post-weaning; and Phase 2, days 40–90 post-weaning), with the probiotics being supplemented only during Phase 1. Ten pigs in each pen were used for body weight (BW) analysis and fecal samples were collected from five or six of these pigs. In addition, the fecal samples from one randomly selected trial were used for gut microbiota analysis. We found that pigs in the L, D, and L+M treatment groups had a significantly higher BW than those in C (p < 0.05) but pigs in the L+M treatment group had a similar BW to those in the L and M groups. Furthermore, there were no significant differences in alpha diversity among the treatments but the beta diversity (weighted UniFrac distances) showed distinct clustering patterns, with pigs in C having discrete microbiota from those in all of the probiotics treatment groups except D (C vs. L, q = 0.04; C vs. M, q = 0.06; C vs. L+M, q = 0.06). These findings indicate that dietary supplementation with live or heat-killed E. faecium enhances growth performance in pigs but there is no synergistic effect when E. faecium is used in combination with C. butyricum. Furthermore, the addition of live E. faecium and C. butyricum to the diet of pigs may change the structure of the gut microbiota.
Risk-Based Stochastic Allocation of ESS to Ensure Voltage Stability Margin for Distribution Systems

High intermittency in today's renewable-rich distribution systems, and the prohibitive cost of upgrading the system infrastructure, has rendered voltage instability a real concern for heavily loaded systems. The voltage instability of distribution systems can spread to the corresponding transmission grid, as proven by real-life incidents. Recent advances in energy storage systems (ESSs), however, have offered a viable means of enhancing the reliability and robustness of power systems. In this paper, the optimal placement, sizing, and operation of ESS devices in wind-intensive distribution power systems are studied. The objectives of this paper are to minimize the ESS size (power and energy), required to ensure a desired voltage stability margin (VSM), and to minimize the reactive power loss and reactive power import from the upstream network. Wind uncertainty has been accounted for through a risk-based stochastic optimization framework. Besides, active network management (ANM) tools, such as the tap position of on-load tap changers, modelled by using a new method, and reactive power capabilities of both ESS devices and wind farms, are used as additional means to reduce the required ESS size. The results show that the required ESS significantly increases with increase in the desired VSM. Nevertheless, the increase can be considerably curtailed by using risk-based VS constraints and ANM tools.
Realization of Extremely High and Low Impedance Transforming Ratios Using Cross-Shaped Impedance Transformer

In this brief, the design methodology of microstrip impedance transformers with extreme (i.e., extremely high and extremely low) impedance transforming ratios is proposed by deploying the cross-shaped structure (CSS) configuration. The proposed impedance transformer can significantly eliminate the line width limitation of traditional quarter-wave impedance transformer and hence an extremely wide range of impedance transformation can be easily realized. At the same time, the impedance transformer provides a good frequency selectivity, especially in the narrowband regime. To demonstrate the outstanding performance of proposed CSS impedance transformer, two examples, with the load-to-source impedances of 2000-to-50 <inline-formula> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> and 5-to-<inline-formula> <tex-math notation="LaTeX">$50~\Omega $ </tex-math></inline-formula>, respectively, are presented and prototyped. The measurement results are in good agreement with the simulated counterparts and hence, the outstanding performance of extreme impedance transforming ratios is validated.
Functional Age-Related Changes Within the Human Auditory System Studied by Audiometric Examination

Age related hearing loss (presbycusis) is one of the most common sensory deficits in the aging population. The main subjective ailment in the elderly is the deterioration of speech understanding, especially in a noisy environment, which cannot solely be explained by increased hearing thresholds. The examination methods used in presbycusis are primarily focused on the peripheral pathologies (e.g., hearing sensitivity measured by hearing thresholds), with only a limited capacity to detect the central lesion. In our study, auditory tests focused on central auditory abilities were used in addition to classical examination tests, with the aim to compare auditory abilities between an elderly group (elderly, mean age 70.4 years) and young controls (young, mean age 24.4 years) with clinically normal auditory thresholds, and to clarify the interactions between peripheral and central auditory impairments. Despite the fact that the elderly were selected to show natural age-related deterioration of hearing (auditory thresholds did not exceed 20 dB HL for main speech frequencies) and with clinically normal speech reception thresholds (SRTs), the detailed examination of their auditory functions revealed deteriorated processing of temporal parameters [gap detection threshold (GDT), interaural time difference (ITD) detection] which was partially responsible for the altered perception of distorted speech (speech in babble noise, gated speech). An analysis of interactions between peripheral and central auditory abilities, showed a stronger influence of peripheral function than temporal processing ability on speech perception in silence in the elderly with normal cognitive function. However, in a more natural environment mimicked by the addition of background noise, the role of temporal processing increased rapidly.
Enhanced Second Harmonic Imaging Using a Pulse Compression Technique Combined with Ultrasound Pulse Inversion

Pulse Inversion (PI) is a transmission technique used for harmonic imaging. By transmitting two phase inverted signals, which allow cancelling out the fundamental component, PI is able to achieve better image quality thanks to the reduced clutter/reverberation and to the improved bandwidth of the second harmonic. Here, a technique based on Resolution Enhancement Compression (REC) that improves the performance of PI is proposed. It consists in boosting the energy of the excitation signal at the frequencies where the probe is less efficient, which further improves the bandwidth of the second harmonic signal. The proposed approach (REC-PI) is combined with coherent plane wave compounding and implemented on the UlaOp-256 ultrasound scanner. Promising results are obtained from in-vitro experiments using an excitation signal designed to provide a 35% increase in axial resolution over the one obtained with a broadband pulse excitation. The experimental measured axial resolution from the echoes was improved by 25.4% for the wire phantom, when using the REC-PI technique compared to classical PI. Further, the axial speckle size evaluated on the in-vitro phantom B-mode image was enhanced by 20%. The CNR was also improved by 18.2 dB. These results demonstrate the feasibility of our approach and its implementation on the research scanner UlaOp-256.
Bacillus subtilis Spore Resistance to Simulated Mars Surface Conditions

In a Mars exploration scenario, knowing if and how highly resistant Bacillus subtilis spores would survive on the Martian surface is crucial to design planetary protection measures and avoid false positives in life-detection experiments. Therefore, in this study a systematic screening was performed to determine whether B. subtilis spores could survive an average day on Mars. For that, spores from two comprehensive sets of isogenic B. subtilis mutant strains, defective in DNA protection or repair genes, were exposed to 24 h of simulated Martian atmospheric environment with or without 8 h of Martian UV radiation [M(+)UV and M(-)UV, respectively]. When exposed to M(+)UV, spore survival was dependent on: (1) core dehydration maintenance, (2) protection of DNA by α/β-type small acid soluble proteins (SASP), and (3) removal and repair of the major UV photoproduct (SP) in spore DNA. In turn, when exposed to M(-)UV, spore survival was mainly dependent on protection by the multilayered spore coat, and DNA double-strand breaks represent the main lesion accumulated. Bacillus subtilis spores were able to survive for at least a limited time in a simulated Martian environment, both with or without solar UV radiation. Moreover, M(-)UV-treated spores exhibited survival rates significantly higher than the M(+)UV-treated spores. This suggests that on a real Martian surface, radiation shielding of spores (e.g., by dust, rocks, or spacecraft surface irregularities) might significantly extend survival rates. Mutagenesis were strongly dependent on the functionality of all structural components with small acid-soluble spore proteins, coat layers and dipicolinic acid as key protectants and efficiency DNA damage removal by AP endonucleases (ExoA and Nfo), non-homologous end joining (NHEJ), mismatch repair (MMR) and error-prone translesion synthesis (TLS). Thus, future efforts should focus on: (1) determining the DNA damage in wild-type spores exposed to M(+/-)UV and (2) assessing spore survival and viability with shielding of spores via Mars regolith and other relevant materials.
Very Short-Term Wind Power Prediction Interval Framework via Bi-Level Optimization and Novel Convex Cost Function

Substantial challenges in power systems operation and control as a result of the intermittent and stochastic nature of wind power generation can be significantly alleviated by proficient very short-term wind power prediction interval (WPPI) models. In WPPI models, minimization of cost functions is conducted to train prediction engines and consequently tune their parameters. The prevalent cost functions of prediction engines in WPPI models are mainly non-differentiable and non-convex, and therefore the training process becomes problematic. To transcend such a crucial barrier, this paper addresses a new very short-term WPPI framework based on a bi-level formulation and benefiting from a differentiable and convex cost function. The prediction engine is trained by classical global optimization of the cost function in the lower-level problem, while hyperparameters that control the quality of the WPPIs are injected thereto from the upper-level problem. The hyperparameters can be tuned such that the most useful WPPIs are constructed from the lower-level problem depending on the power system operator's preferences. Lessening the need to heuristically tune a large number of prediction engine parameters is the foremost contribution of this work to the WPPI literature. The superior performance of the proposed WPPI is verified in the multistep ahead prediction of real wind power generation data in comparison to well-tailored benchmark models.
Advanced Adaptive Photonic RF Filters with 80 Taps Based on an Integrated Optical Micro-Comb Source

We demonstrate a photonic radio frequency (RF) transversal filter based on an integrated optical micro-comb source featuring a record low free spectral range of 49 GHz, yielding 80 micro-comb lines across the C-band. This record high number of taps, or wavelengths for the transversal filter results in significantly increased performance including a QRF factor more than four times higher than previous results. Furthermore, by employing both positive and negative taps, an improved out-of-band rejection of up to 48.9 dB is demonstrated using a Gaussian apodization, together with a tunable center frequency covering the RF spectra range, with a widely tunable 3-dB bandwidth and versatile dynamically adjustable filter shapes. Our experimental results match well with theory, showing that our transversal filter is a competitive solution to implement advanced adaptive RF filters with broad operational bandwidth, high frequency selectivity, high reconfigurability, and potentially reduced cost and footprint. This approach is promising for applications in modern radar and communications systems.