Search

Objective. Heterostructured scintillators offer a promising solution to balance the sensitivity and timing in TOF-PET detectors. These scintillators utilize alternating layers of materials with complementary properties to optimize performance. However, the layering compromises time resolution due to light transport issues. This study explores double-sided readout-enabling improved light collection and Depth-of-Interaction (DOI) information retrieval-to mitigate this effect and enhance the timing capabilities of heterostructures. Approach. The time resolution and DOI performances of 3 × 3 × 20 mm 3 BGO&EJ232 heterostructures were assessed in a single and double-sided readout (SSR and DSR, respectively) configuration using high-frequency electronics. Main results. Selective analysis of photopeak events yielded a DOI resolution of 6.4 ± 0.04 mm. Notably, the Coincidence Time Resolution (CTR) improved from 262 ± 8 ps (SSR) to 174 ± 6 ps (DSR) when measured in coincidence with a fast reference detector. Additionally, symmetrical configuration of two identical heterostructures in coincidence was tested, yielding in DSR a CTR of 254 ± 8 ps for all photopeak events and 107 ± 5 ps for the fastest events. Significance. By using high-frequency double-sided readout, we could measure DOI resolution and improve the time resolution of heterostructures of up to 40%. The DOI information resulted intrinsically captured in the average between the timestamps of the two SiPMs, without requiring any further correction., (Creative Commons Attribution license.)

Recently, micro-supercapacitors (MSCs) have undergone major development as next-generation micro-electrochemical energy storage devices for self-powered, integrated, and wearable systems, thanks to their excellent performance capability. In particular, their rapid frequency response characteristics make them potential candidates to replace conventional capacitors and function as alternating current (AC) line filters to rectify pulse energy or as current ripple filters in the kHz range. However, few papers have been published about the associated fundamental device components, architectures, and correct characterization of MSCs applied in filter applications. In addition, it is a huge challenge to achieve a balance between capacitance and frequency response, not yet to be overcome. This review comprehensively summarizes recent advances in MSCs for AC line-filtering, from fundamental mechanisms to appropriate characterization and emerging applications. Special attention is given to progress in microfabrication strategies, electrode materials, and electrolytes for high-frequency MSCs. We also present perspectives and insights into the development of MSCs in different frequency ranges for AC line-filtering applications.

Chin-Kuo Chen,1,2 Shih Chieh Shen,1– 3 Li-Ang Lee,1,2 Ming-Hui Sun,2,4 Ning-Hung Chen,2,5 Li-Pang Chuang,2,5 Hsueh-Yu Li1,2 1Department of Otolaryngology-Head and Neck Surgery, Sleep Center, Chang Gung Memorial Hospital (Linkou), Taoyuan City, Taiwan; 2College of Medicine, Chang Gung University, Taoyuan City, Taiwan; 3Department of Otolaryngology-Head and Neck Surgery, New Taipei Municipal Tucheng Hospital, New Taipei City, Taiwan; 4Department of Ophthalmology, Chang Gung Memorial Hospital (Linkou), Taoyuan City, Taiwan; 5Department of Pulmonary and Critical Care Medicine, Sleep Center, Chang Gung Memorial Hospital (Linkou), Taoyuan City, TaiwanCorrespondence: Hsueh-Yu Li; Shih Chieh ShenDepartment of Otolaryngology-Head and Neck Surgery, Sleep Center, Chang Gung Memorial Hospital (Linkou), 33, No. 5, Fushing Street, Gueishan Shiang, Taoyuan City, TaiwanTel +886-3-3281200 ext.3966Fax +886-3-3979361Email hyli38@cgmh.org.tw; b9102083@cgmh.org.twPurpose: Obstructive sleep apnea (OSA) is characterized by recurring hypoxic-apneic events during sleep, and labyrinthine vascular compromise is a pathophysiologic hallmark of idiopathic sudden sensorineural hearing loss (ISSNHL). Some reports have discussed the relationship between OSA and hearing impairment; however, few have examined hearing prognosis in OSA and patients without OSA with ISSNHL. We aimed to investigate clinical manifestations of ISSNHL in patients with OSA, including severity of hearing loss and response to treatment.Patients and Methods: A case-control study was conducted by extracting data from the sleep center and cochlea center databases of the Chang Gung Memorial Hospital. A retrospective chart review was performed to include confirmed adult OSA patients diagnosed with unilateral ISSNHL. Age and sex-matched patients without OSA with ISSNHL were enrolled as controls. Pure-tone average (PTA) thresholds were measured at specific frequencies. Changes in PTA before and after standard treatment with oral prednisolone (1mg/kg/day for 5 days, then tapered) and between participants with OSA and without OSA were compared. Standard treatment was given to all ISSNHL patients.Results: Twenty-eight out of 8500 (0.33%) OSA patients experienced subsequent ISSNHL in 9 years. Patients with OSA (n=28) had poorer high-frequency perception in the unaffected ear than the patients without OSA (n=120), although the difference was not significant. Hearing in the affected ear among patients with OSA was comparable to that patients without OSA at individual frequencies and average, suggesting no difference in hearing loss in the affected ear between the two groups. In terms of high-frequencies (4000 and 8000 Hz) perception, patients with OSA had significantly poorer responses to steroid treatment than patients without OSA.Conclusion: ISSNHL may be one of the auditory complications associated with OSA. Patients with OSA had poorer prednisolone related hearing improvement in high frequencies than patients without OSA. Despite study limitations, OSA-related hypoxia and snoring noise is hazardous to hearing and standard treatments with CPAP is suggested in OSA patients for both holistic and auditory health.Keywords: obstructive sleep apnea, idiopathic sudden sensorineural hearing loss, high-frequency, hypoxemia, pure-tone average, frequencies

Introduction: Parkinson's disease (PD) is a common neurodegenerative disorder, characterised by both motor and nonmotor symptoms. There is currently no cure for PD, although there are several treatment options for relieving PD symptoms. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive brain stimulation therapy that shows promising results for the treatment of PD. Methods: Here, we present a patient with PD. We investigated whether an accelerate form of high-frequency (HF) rTMS on the contralateral side to the patient’s main difficulties is clinically effective in treating health-related quality of life (QoL) symptomatology and depressive symptoms in PD as well as the long-term effects of rTMS in PD during the maintenance phase. Results: Results showed that HF-rTMS administered over the right primary motor cortex (M1) is a safe and well-tolerated treatment that improved the patient’s health related QoL and depressive symptoms. These positive effects lasted at least five months post treatment. Conclusion: Therefore, HF-rTMS over the right M1 can be a possible treatment option for patients with PD, although further investigations are necessary to validate the findings of the present case report.

In this paper, we investigate the goodness-of-fit of the flexible four-parameter generalized Lambda Distribution (GLD) for high-frequency 5-min returns sampled from the DJI30 Index. Applying Moment Matching (MM) and Maximum Likelihood Estimation (MLE) techniques, we highlight the significance of the higher-order parameters of the GLD distribution to depict the asymmetric and fat-tailed behaviour observed in high-frequency returns data. We also show and explain why the MLE consistently outperforms the MM; especially in the presence of “outliers”. Finally, we use lambda-space scatterplots to introduce, clarify and discuss additional stylized facts of high-frequency index returns not found in the extant high-frequency literature.

This document is a corrigendum published in the journal Frontiers in Oncology. It corrects an error in the Ethics statement section of a research report article titled "The utility of high-frequency 18 MHz ultrasonography for preoperative evaluation of acral melanoma thickness in Chinese patients." The correction states that the studies involving humans were approved by the Ethics Committee of Xiangya Hospital of Central South University and were conducted in accordance with local legislation and institutional requirements. The authors apologize for the error and clarify that it does not affect the scientific conclusions of the article. [Extracted from the article]

Objectives: Congenital myasthenic syndrome (CMS) is a clinically and genetically heterogeneous group of inherited disorders characterized by neuromuscular junction defects. Mutations in GFPT1 have been shown to underlie CMS. An increasing number of patients with CMS due to mutations in GFPT1 have been reported. However, a comprehensive review of clinical and genetic analyses of GFPT-related CMS worldwide is lacking, especially, given that the common or hotspotmutations inGFPT1 have not been reported. Here, we described the clinical and genetic findings of three patients with GFPT1 mutations from southwestern China and reviewed the clinical and genetic features of patients with GFPT1-related CMS worldwide. Methods: Clinical, laboratory, electrophysiological, myopathological, and genetic analyses of three patients with GFPT1-related CMS fromsouthwestern China were conducted, and a review of previously published or reported cases about congenital myasthenic syndrome with GFPT1 mutations in the PubMed database was made. Results: The clinical, laboratory, electrophysiological, and myopathological features by muscle biopsy of three patients with GFPT1-related CMS were consistent with those of previously reported patients with GFPT1 mutations. Additionally, an abnormal decrement in high-frequency RNS was found. Two different homozygous missense mutations (c.331C>T, p.R111C; c.44C>T, p.T15M) were detected by whole-exome sequencing (WES) or targeted neuromuscular disorder gene panels. Conclusion: A distinct decremental response to high-frequency RNS was found in three patients with GFPT1-related CMS from southwestern China, which has never been reported thus far. In addition, the location and degree of tubular aggregates (TAs) seemed to be associated with the severity of clinical symptoms and serum creatine kinase levels, further expanding the phenotypic spectrum of GFPT1-related CMS. Lastly, some potential hotspot mutations in GFPT1 have been found in GFPT1-CMS worldwide. [ABSTRACT FROM AUTHOR]

Partial discharge (PD) is a phenomenon often occurring in insulation system defects (cavities), which can significantly affect life and reliability. While broad knowledge on PD phenomenology of high-frequency transformers (HFT) has been achieved under ac sinusoidal voltage, much less work has been done to infer PD behavior under emerging high frequency pulsewidth modulation (PWM) operation conditions. An impediment has been the limited appropriate test equipment. A recently developed novel ±5 kV GaN-based high-frequency PWM supply with controllable dV/dt, voltage level and frequency has been developed. This article explores the application of these measurements to the testing of materials in this electrical environment. Two commonly used windings for HFT were tested under different applied voltage magnitudes, frequencies, and slew rates. According to the test results, at high frequency (up to 50 kHz) the electric field generated by space charge deposited by PD occurring during previous PWM pulses plays an important role in PD behavior. The frequency dependent permittivity of the insulation material can also affect PD measurement results. [ABSTRACT FROM AUTHOR]

Vibration measurement and analysis play an important role in diagnosing mechanical faults, but existing vibration sensors are limited by issues such as dependence on external power sources and high costs. To overcome these challenges, the use of triboelectric nanogenerator (TENG)−based vibration sensors has recently attracted attention. These vibration sensors measure a small range of vibration frequencies and are not suitable for measuring high-frequency vibrations. Herein, a self-powered vibration sensor based on an elastic steel triboelectric nanogenerator (ES−TENG) is proposed. By optimizing the elastic steel sheet structure and combining time-frequency transformation and filtering processing methods, the measurement of medium- and high-frequency vibrations is achieved. These results demonstrate that the ES−TENG can perform vibration measurements in the range of 2–10,000 Hz, with a small average error (~0.42%) between the measured frequency and external vibration frequency values. Therefore, the ES−TENG can be used as a self-powered, highly-accurate vibration sensor for intelligent machinery monitoring. [ABSTRACT FROM AUTHOR]

Reservoir monitoring is necessary to achieve safe hydrocarbon extraction. It requires monitoring small acoustic emission (AE) events, assisting in determining the exact location, extension and direction of potential damage as early as possible. However, microcracks cannot be detected by the microseismic monitoring networks due to the limitations of frequency range and sensitivity. In contrast, the in situ AE monitoring system extends the detection range to higher frequencies and can detect very small deformation processes with high resolution and sensitivity. It provides detailed insights into ongoing deformation processes. However, the receivers of an in situ AE monitoring system need to be very close to hydraulic fracturing experiments due to the fast decay of high-frequency signals. In this work, by constructing four in situ AE monitoring models, the imaging effects of the interferometric imaging method for three different kHz-level frequency sources at different distances and orientations relative to the monitoring well are investigated. The numerical results show that: the higher the source frequency, the higher the imaging resolution; when the vertical orientation coverage of the source by the monitoring system is incomplete, the closer the source to the borehole axis, the worse the imaging resolution and location accuracy; when the vertical orientation coverage of the source by the monitoring system is complete, the imaging resolution and location accuracy are both improved, especially when the vertical azimuthal coverage angle is large. The integrity of the orientation coverage of the source by the monitoring system plays a critical role in improving source location accuracy. [ABSTRACT FROM AUTHOR]

This paper deals with the detection of small magnetization using a thin film magneto-impedance sensor with subjecting to strong normal field. The sensor was made by soft magnetic amorphous thin-film with uniaxial magnetic anisotropy in the width direction of the element. It was reported that the sensor has very high sensitivity, such as pico-tesla order, when it is driven by hundreds of MHz. In this paper, a sensitive measurement method aiming for detection of a small particle or a cluster of nano-particles, having low-remanence, is proposed. The point is the application of strong normal field in the measurement area including sensor element and particle. The normal strong field is applied in the normal direction of the sensor plane in the value almost hundreds of mT. Instead of such strong normal field, the sensor keeps high sensitivity, because of the demagnetizing force in the thickness direction. A theoretical estimation for clarifying an efficiency of the method, experimental results of sensor property and sensitivity with subjecting to the normal field, and also a confirmation of detection of a small particle using the proposed method is reported. As a special mention, detection fundamentals when a applied surface normal field has a distribution and also a particle would run through in the vicinity of sensor is discussed. [ABSTRACT FROM AUTHOR]

Air-cored planar inductors play an important part in enabling high power-density, low weight, and low-profile design of high-frequency switched-mode power applications. However, the absence of ferromagnetic core in these inductors makes the magnetic field distribution in them different from that in the cored inductors and the transformers. Due to this difference, the conventional winding loss calculation models like the 1-D Dowell's model are not suitable for these inductors. Therefore, in this article, an improved two-dimensional analytical winding loss model for multilayered air-cored inductors with a single-turn per layer is proposed based on the fundamental electromagnetic field solution incorporating the 2-D boundary values and the edge effect in its formulation. The finite element method (FEM) simulation and experimental results validate the proposed model's high-accuracy and engineering precision over a wide frequency range (up to 10 MHz). Furthermore, the results ensure the proposed analytical model to be an efficient, easier, and better substitute for the FEM based calculation approach. [ABSTRACT FROM AUTHOR]

This article proposes a novel modular multilevel dc-dc converter with high power-density potential based on a cascaded string of voltage source submodules (VSMs) merged with a current source submodule (CSM) that is configured to rapidly invert the polarity of the current in the VSM string. The proposed hybrid converter combines the modularity advantages of the modular multilevel converter (MMC) and the high effective frequency advantages of the flying capacitor converter. Unlike other hybrid nonisolated MMC structures the proposed converter features a novel CSM stage enabling a near 50% reduction in string current, and the input source and output load to be commonly grounded. In addition, the proposed operational approach enables self-balancing of the VSMs and a simple overall control structure. This article introduces the main operating principles of this novel topology termed the current shaping modular multilevel forward converter along with a proposed control design. A peak efficiency of 97.1% is measured from a laboratory-scale prototype at 950-137V and 1.45 kW. [ABSTRACT FROM AUTHOR]

The optimization of coding stimulus is a crucial factor in the study of steady-state visual evoked potential (SSVEP)-based brain-computer interface(BCI).This study proposed an encoding approach named Multi-Symbol Time Division Coding (MSTDC). This approach is based on a protocol of maximizing the distance between neural responses, which aims to encode stimulation systems implementing any number of targets with finite stimulations of different frequencies and phases. Firstly, this study designed an SSVEP-based BCI system containing forty targets with this approach. The stimulation encoding of this system was achieved with four temporal-divided stimuli that adopt the same frequency of 30 Hz and different phases. During the online experiments of twelve subjects, this system achieved an average accuracy of $96.77 \pm 2.47$ % and an average information transfer rate (ITR) of 119.05 ± 6.11 bits/min. This study also devised an SSVEP-based BCI system containing 72 targets and proposed a Template Splicing task-related component analysis (TRCA) algorithm that utilized the dataset of the previous system containing forty targets as the training dataset. The subjects acquired an average accuracy of 86.23 ± 7.75% and an average ITR of 95.68 ± 14.19 bits/min. It can be inferred that MSTDC can encode multiple targets with limited frequencies and phases of stimuli. Meanwhile, this protocol can be effortlessly expanded into other systems and sufficiently reduce the cost of collecting training data. This study provides a feasible technique for obtaining a comfortable SSVEP-based BCI with multiple targets while maintaining high information transfer rate. [ABSTRACT FROM AUTHOR]

This article explores the Bitcoin return predictability of variables constructed from one-minute high-frequency Bitcoin trading data. During the training period of 2012–2018, LASSO is used to pick out the most powerful predictors. We then use predictors selected by LASSO to predict the Bitcoin returns in the 2018–2019 test sample. An investment strategy based on the return predictions outperforms a simple buy-and-hold strategy and other strategies based on the prediction of Ordinary Least Squares and Neural Networks. [ABSTRACT FROM AUTHOR]

Background: High-frequency rTMS over the dorsolateral prefrontal cortex (DLPFC) has demonstrated mixed effects on chronic and provoked pain. Objectives/Methods: In this study, a meta-analysis was conducted to characterise the potential analgesic effects of high-frequency rTMS over the DLPFC on both chronic and provoked pain. Results: A total of 626 studies were identified in a systematic search. Twenty-six eligible studies were included for the quantitative review, among which 17 modulated chronic pain and the remaining investigated the influence on provoked pain. The left side DLPFC was uniformly targeted in the chronic pain studies. While our data identified no overall effect of TMS across chronic pain conditions, there was a significant short-term analgesia in neuropathic pain conditions only (SMD = −0.87). In terms of long-lasting analgesia, there was an overall pain reduction in the midterm (SMD = −0.53, 24.6 days average) and long term (SMD = −0.63, 3 months average) post DLPFC stimulation, although these effects were not observed within specific chronic pain conditions. Surprisingly, the number of sessions was demonstrated to have no impact on rTMS analgesia. In the analysis of provoked pain, our data also indicated a significant analgesic effect following HF-rTMS over the DLPFC (SMD = −0.73). Importantly, we identified a publication bias in the studies of provoked pain but not for chronic pain conditions. Conclusions: Overall, our findings support that HF-DLPFC stimulation is able to induce an analgesic effect in chronic pain and in response to provoked pain. These results highlight the potential of DLPFC-rTMS in the management of certain chronic pain conditions and future directions are discussed to enhance the potential long-term analgesic effects.

According to model projections, increases in the frequency and intensity of heatwaves are expected all over the world. This study analyzed, for the first time, the effect of heatwaves events on long-term surface latent (LE) and sensible heat fluxes (H) from two shallow lakes: La Salada lake (LS - 39°27′ S, 62°42′ W) and Sauce Grande lake (SG - 38°57′ S, 61°24′ W). The main drivers of LE and H are wind speed and direction, relative humidity, and the difference between air and water temperature. We found that the daily values of both fluxes were highly fluctuating. Mean daily H values ranged between -309.4 to 200.5 W m-2 and -78.6 to 104.8 W m-2 in LS and SG, respectively. LE oscillated between -152 and 463.9 W m-2 and between -59.2 and 360.1 W m-2 in LS and SG, respectively. Both fluxes decreased with the passage of heatwaves events, presenting a high variation in its amplitude. Changes up to 96% in mean daily LE and 671% in mean daily H for LS and up to 25% in LE and 987% in H for SG were accounted in days with heatwaves respect to regular ones. We analyzed the air temperature increase for both lakes under future global warming scenarios (RCP 4.5 y RCP 8.5), expecting higher amplitudes in heat fluxes. These results contribute to the development of lake models, as well as to water resources management in the future.

• A dual inner shifting-phase method can ensure the correctness of fringe step order solutions for high frequency fringe. • A U-Net model is utilized to predict the sinusoidal feature fringes to obtain wrapped phase and unwrapped phase simultaneously with one-shot projection. • 3D shape reconstruction can be realized across various fringe frequencies using only one trained model even with fringe frequencies not included in the training dataset. • A high phase unwrapping success rate of over 99% for high-frequency fringe up to 100 periods is achieved. It is still a challenge to correctly retrieve the absolute phase from a high-frequency fringe pattern in a single-shot. To address this issue, a dual inner shifting-phase method is proposed by decomposing the fringe step order number into the product of two smaller step order numbers to overcome the fault-prone problem of step order solution by the existing single inner shifting-phase method. A U-Net model is utilized to train on mixed-frequency dual inner shifting-phase fringe datasets to extract six sinusoidal feature fringes rather than absolute phases to enhance the generalization ability of the DL-CFPP. The proposed method achieves a high phase unwrapping success rate of over 99% for high frequency fringe up to 100 periods, and accurate 3D shape reconstruction across various fringe frequencies using only one trained model even with fringe frequencies not included in the training dataset. Experiments in measuring dynamic objects verified the proposed technique's advantages of robust 3D shape reconstruction with high-frequency fringe. [ABSTRACT FROM AUTHOR]

Al–Li alloy has been widely used in the aerospace field owing to its high strength and low density. In this study, alternating current cold metal transfer (AC CMT) along with a high-frequency pulse current technique was used to weld a 2060 Al–Li alloy using an ER5356 wire. The effect of pulse frequency on the arc shape, microstructure, and mechanical properties of the welded joints was examined, and mechanical performance testing was conducted. The results revealed that the arc diameter, arc length, and arc volume showed a trend of increasing first and then decreasing with an increase in the pulse frequency and reached their peak values when the pulse frequency was 50 kHz. Coupling the welding process with a high-frequency pulse resulted in grain refinement, which was attributed to the stirring action of the arc force. Both the porosity levels and grain size decreased with increasing frequency. When the pulse frequency was 70 kHz, the porosity level was the lowest, and the grain size was refined to 24.1 μm. The tensile strength of the welded joints also increased with the pulse frequency, and a maximum tensile strength of 249 MPa was observed at 70 kHz.

Adders are critical to the efficiency of arithmetic circuits in battery-powered electronic devices. This study demonstrates an 8-bit CLA (carry look-ahead adder) using single-phase ANT logic to increase the computation speed and reduce the power dissipation simultaneously. The single-phase ANT has no internal loop that optimizes the efficiency of the prior ANT. Utilizing a TSMC 40-nm technology, the proposed 8-bit CLA is fabricated. It attains the highest operating frequency of 3.2 GHz and the lowest normalized PDP (power delay product) by on-silicon measurement for 20 pF load. [Display omitted] • The CLA uses single-phase ANT logic. • Operating frequency is 3.2 GHz. • For a 20 pF load, Normalized PDP is as low as 0.125 nJ. • For a 20 pF load, Normalized Power is as low as 0.292 mW. • Implemented using TSMC 40-nm CMOS Process on a single chip, with an area of 0.641 mm 2 . [ABSTRACT FROM AUTHOR]

• A low-temperature curable soft magnetic composites (SMCs) core was proposed for high-frequency applications. • The effect of TMPTA content, compaction pressure and curing temperature on the magnetic properties of synthesized cores were investigated. • The core with 5 % TMPTA content, compacted at 400 MPa and cured at 200 °C has the best frequency stability, the lowest imaginary part of the permeability and acceptable real permeability over 30. This paper proposed low-temperature curable soft magnetic composites (SMCs) cores that consisted of permalloy powders and acrylic polymer (Trimethylpropane triacrylate, or TMPTA) for high-frequency applications. The effect of TMPTA content, compaction pressure and curing temperature on the magnetic properties of synthesized cores were investigated. The coated TMPTA insulating layer can effectively increase the electrical resistivity of the core and thereby improve the frequency characteristics. The magnetic performance of cores depends on the distribution and actual content of the TMPTA after pressing although the polymer content in the mixture is increased from 2 wt% to 6 wt%. As the compaction pressure increases from 100 MPa to 400 MPa, the relative permeability of the core increases but its imaginary part of the permeability has almost no change until 10 MHz. The increased curing temperature can increase the initial permeability of the cores but deteriorates the frequency stability and greatly increase the imaginary part of the permeability. It was noted that the core with 5 % TMPTA content, compacted at 400 MPa and cured at 200 °C has the best frequency stability, the lowest imaginary part of the permeability and acceptable real permeability over 30. It is beneficial for high frequency operation of power electronics. [ABSTRACT FROM AUTHOR]

Time-series data, which exhibit a low signal-to-noise ratio, non-stationarity, and non-linearity, are commonly seen in high-frequency stock trading, where the objective is to increase the likelihood of profit by taking advantage of tiny discrepancies in prices and trading on them quickly and in huge quantities. For this purpose, it is essential to apply a trading method that is capable of fast and accurate prediction from such time-series data. In this paper, we developed an online time series forecasting method for high-frequency trading (HFT) by integrating three neural network deep learning models, i.e., long short-term memory (LSTM), gated recurrent unit (GRU), and transformer; and we abbreviate the new method to online LGT or O-LGT. The key innovation underlying our method is its efficient storage management, which enables super-fast computing. Specifically, when computing the forecast for the immediate future, we only use the output calculated from the previous trading data (rather than the previous trading data themselves) together with the current trading data. Thus, the computing only involves updating the current data into the process. We evaluated the performance of O-LGT by analyzing high-frequency limit order book (LOB) data from the Chinese market. It shows that, in most cases, our model achieves a similar speed with a much higher accuracy than the conventional fast supervised learning models for HFT. However, with a slight sacrifice in accuracy, O-LGT is approximately 12 to 64 times faster than the existing high-accuracy neural network models for LOB data from the Chinese market.

Backing materials with tailored acoustic properties are beneficial for miniaturized ultrasonic transducer design. Whereas piezoelectric P(VDF-TrFE) films are common elements in high-frequency (>20 MHz) transducer design, their low coupling coefficient limits their sensitivity. Defining a suitable sensitivity–bandwidth trade-off for miniaturized high-frequency applications requires backings with impedances of >25 MRayl and strongly attenuating to account for miniaturized requirements. The motivation of this work is related to several medical applications such as small animal, skin or eye imaging. Simulations showed that increasing the acoustic impedance of the backing from 4.5 to 25 MRayl increases transducer sensitivity by 5 dB but decreases the bandwidth, which nevertheless remains high enough for the targeted applications. In this paper, porous sintered bronze material with spherically shaped grains, size-adapted for 25–30 MHz frequency, was impregnated with tin or epoxy resin to create multiphasic metallic backings. Microstructural characterizations of these new multiphasic composites showed that impregnation was incomplete and that a third air phase was present. The selected composites, sintered bronze–tin–air and sintered bronze–epoxy–air, at 5–35 MHz characterization, produced attenuation coefficients of 1.2 and >4 dB/mm/MHz and impedances of 32.4 and 26.4 MRayl, respectively. High-impedance composites were adopted as backing (thickness = 2 mm) to fabricate focused single-element P(VDF-TrFE)-based transducers (focal distance = 14 mm). The center frequency was 27 MHz, while the bandwidth at −6 dB was 65% for the sintered-bronze–tin–air-based transducer. We evaluated imaging performance using a pulse-echo system on a tungsten wire (diameter = 25 μm) phantom. Images confirmed the viability of integrating these backings in miniaturized transducers for imaging applications.

• HF-μDoppler can conduct microvascular imaging in newborn rat with high resolution. • HF-μDoppler can assess and monitor brain development of newborn rat. • HF-μDoppler can detect and evaluate brain injury of newborn rat. • HF-μDoppler is a reliable imaging tool for preclinical studies in neonatal diseases and development. Ultrasound imaging stands as the predominant modality for neonatal health assessment, with recent advancements in ultrafast Doppler (μDoppler) technology offering significant promise in fields such as neonatal brain imaging. Combining μDoppler with high-frequency ultrasound (HF-μDoppler) presents a potential efficient avenue to enhance in vivo microvascular imaging in small animals, notably newborn rats, a crucial preclinical animal model for neonatal disease and development research. It is necessary to verify the imaging performance of HF-μDoppler in preclinical trials. This study investigates the microvascular imaging capabilities of HF-μDoppler using a 30 MHz high-frequency linear array probe in newborn rats. Results demonstrate the clarity of cerebral microvascular imaging in rats aged 1 to 7 postnatal days, extending to whole-body microvascular imaging, encompassing the central nervous system, including the brain and spinal cord. In conclusion, HF-μDoppler technology emerges as a reliable imaging tool, offering a new perspective for preclinical investigations into neonatal diseases and development. [ABSTRACT FROM AUTHOR]

• Emulsification characteristics differences between different oils are analyzed. • Reasons for difficult demulsification of shale oil emulsions are summarized. • Optimal operating parameters for shale oil demulsification are determined. • Electrical dehydration technology is more effective for shale oil emulsions. In the face of depleting conventional oil and natural gas reserves, the exploitation of shale oil resources increasingly important. However, the high stability of shale oil emulsions presents a significant challenge to its extraction. In this paper, the differences between shale oil and conventional crude oil and the reasons for the stability of shale oil emulsions were explored. In addition, different dehydration technologies for shale oil emulsions were compared and optimum operating parameters were determined through laboratory-scale experiments. The results show that shale oil emulsions contain much smaller droplets (< 2.25 μm) compared with conventional crude oil emulsions. Further, the high wax content of shale oil allows it to form a high-strength interfacial film at the oil-water interface under the combined action of fracturing fluids and natural emulsifiers, making the emulsion highly stable. Demulsification experiments showed that the use of high-frequency alternating current (AC) pulsed electric fields is an effective method for breaking shale oil emulsions. The optimal demulsification parameters were found to be an electric field frequency of 4 kHz, a field strength of 150 kV·m-1, a residence time of 50 min, an operating temperature of 55 °C, and a demulsifier concentration of 100 ppm. Under these conditions, the dehydrated shale oil was able to meet the standards for commercial crude oil. [Display omitted] [ABSTRACT FROM AUTHOR]

• We study the effect of skin and proximity effects on the ac impedance of windings. • The effect of temperature and frequency in transformer windings is studied. • We propose an analytical method to separate skin and proximity contributions. • Experimental results and FEA simulations are used to validate the proposed method. • Presented results are based on a single-phase transformer. Eddy current effects, which include skin and proximity effects, are usually associated only with frequency, but they are also affected by temperature. This paper analyzes the effect of both, temperature and frequency on skin and proximity effects in transformer windings. When analyzing transformer windings, despite the existence of powerful finite element analysis (FEA) modules, they return the total contribution of eddy current effects and do not separate the contributions of skin and proximity effects. This paper proposes an analytical method to determine the contribution of both effects to the AC winding resistance and leakage inductance based on the orthogonality of the skin and proximity effects. This method is based on the exact solution of the skin effect for an isolated round conductor combined with Dowell's solution of the proximity effect. Presented experimental results and FEA simulations based on a single-phase transformer have determined the accuracy of the proposed method, which allows accurate prediction of the temperature and frequency behavior of the winding resistance and leakage inductance. [ABSTRACT FROM AUTHOR]

Focused ultrasonic waves are widely used in medical imaging, fibroids ablation and acoustic tweezers due to its high sensitivity and large energy at the focal spot. Although, acoustic metamaterials have emerged for acoustic focusing, they have limited to low frequency, narrowband and less acoustic transmission. Herein, an active gradient metamaterial (AGM) based on composite structure on traditional piezoelectric materials is proposed to achieve the acoustic impedance matching and underwater acoustic focusing. Based on the principle that the acoustic wave emitted from the piezoelectric plate reaches the focal spot at the same time, an aperiodic axisymmetric composite with gradient depth is established. A $200 ~\mu \text{m}$ kerf is selected, and the depth ranges from $44 ~\mu \text{m}$ to $146 ~\mu \text{m}$. The acoustic field pressure intensity is simulated with finite element software, and measured by a needle hydrophone with fabricated transducer. Based on the good agreement between the simulation and experimental results with the excitation frequency range of 4 MHz-20 MHz, the active self-focusing and broadband focusing behaviors of the AGM are demonstrated. It is expected to apply the proposed acoustic metamaterial in biomedical and industrial applications. [ABSTRACT FROM AUTHOR]

Background: Repetitive transcranial magnetic stimulation (rTMS) has proven to be an efficient treatment option for patients with treatment-resistant depression (TRD). However, the success rate of this method is still low, and the treatment outcome is unpredictable. The objective of this study was to explore clinical and structural neuroimaging factors as potential biomarkers of the efficacy of high-frequency (HF) rTMS (20 Hz) over the left dorso-lateral pre-frontal cortex (DLPFC). Methods: We analyzed the records of 131 patients with mood disorders who were treated with rTMS and were assessed at baseline at the end of the stimulation and at 1 month after the end of the treatment. The response is defined as a 50% decrease in the MADRS score between the first and the last assessment. Each of these patients underwent a T1 MRI scan of the brain, which was subsequently segmented with FreeSurfer. Whole-brain analyses [Query, Design, Estimate, Contrast (QDEC)] were conducted and corrected for multiple comparisons. Additionally, the responder status was also analyzed using binomial multivariate regression models. The explored variables were clinical and anatomical features of the rTMS target obtained from T1 MRI: target-scalp distance, DLPFC gray matter thickness, and various cortical measures of interest previously studied. Results: The results of a binomial multivariate regression model indicated that depression type (p = 0.025), gender (p = 0.010), and the severity of depression (p = 0.027) were found to be associated with response to rTMS. Additionally, the resistance stage showed a significant trend (p = 0.055). Whole-brain analyses on volume revealed that the average volume of the left part of the superior frontal and the caudal middle frontal regions is associated with the response status. Other MRI-based measures are not significantly associated with response to rTMS in our population. Conclusion: In this study, we investigated the clinical and neuroimaging biomarkers associated with responsiveness to high-frequency rTMS over the left DLPFC in a large sample of patients with TRD. Women, patients with bipolar depressive disorder (BDD), and patients who are less resistant to HF rTMS respond better. Responders present a lower volume of the left part of the superior frontal gyrus and the caudal middle frontal gyrus. These findings support further investigation into the use of clinical variables and structural MRI as possible biomarkers of rTMS treatment response. [ABSTRACT FROM AUTHOR]

High-frequency electromagnetic induction (HFEMI) sensors, operating in the frequency range from 300 kHz to 30 MHz, have been proposed for the measurement of soil electrical conductivity and dielectric permittivity that are related to the physical and chemical properties of soil. Because of the high-frequency operation, the capacitive coupling between the sensor transmitter and receiver coils is comparable to inductive coupling, creating the need for electrostatic shielding. The remnant capacitive coupling after the implementation of shielding can lead to significant difficulties in the sensor signal interpretation, because both coupling mechanisms are highly dependent on the geometry of the HFEMI sensor and applied shield. In this paper, we introduce the discussion on the relationship between the sensor geometry, shielding and the coupling mechanisms for HFEMI soil sensing. We theoretically and experimentally evaluate a typical HFEMI sensor and its shielding in the frequency range of up to 20 MHz and propose a method for evaluating the effectiveness of a shield configuration. In the case study, we experimentally analyze the HFEMI sensor above a saline solution for two shield configurations. The results agree well with the results of a finite element method analysis. [ABSTRACT FROM AUTHOR]

Former studies investigated the application of high-frequency alternating currents (HFAC) in humans for blocking the peripheral nervous system. The present trial aims to assess the effect of HFAC on the motor response, somatosensory thresholds, and peripheral nerve conduction when applied percutaneously using frequencies of 10 kHz and 20 kHz in healthy volunteers. A parallel, placebo-controlled, double-blind, randomized clinical trial was conducted. Ultrasound-guided HFAC at 10 kHz and 20 kHz and sham stimulation were delivered to the median nerve of 60 healthy volunteers for 20 min. The main assessed variables were the maximum isometric flexion strength (MFFS) of the index finger, myotonometry, pressure pain threshold (PPT), mechanical detection threshold (MDT), and sensory nerve action potential (SNAP). A decrease in the MFFS is observed immediately postintervention compared to baseline, both in the 10 kHz group (−8.5%; 95% CI −14.9 to −2.1) and the 20 kHz group (−12.0%; 95% CI −18.3 to −5.6). The between-group comparison of changes in MFFS show a greater reduction of −10.8% (95% CI −19.8 to −1.8) immediately postintervention in the 20 kHz compared to the sham stimulation group. The percutaneous stimulation applying 20 kHz HFAC to the median nerve produces a reversible postintervention reduction in strength with no adverse effects. [ABSTRACT FROM AUTHOR]

Ultrahigh-frequency surface acoustic wave (SAW) devices with high quality ($Q$) factors are essential components for the next-generation wireless communication system. In this work, we reported high-performance and ultrahigh-frequency SAW devices with single-crystalline LiTaO3/SiO2/Si [LT-on-insulator (LTOI)] multilayered heterostructure. The fabricated SAW resonators exhibited multi-resonant modes (Rayleigh, Sezawa, and LLSAW mode) with the frequency ranging from 1.81 to 8.33 GHz. Especially, the SAW resonator with the Rayleigh wave frequency over 5.0 GHz and high $Q$ value around 2300 with a wavelength of 600 nm was realized. The variation of the phase velocity, the $Q$ factor for each resonant mode, and the effective coupling coefficients ($k^{2}_{\mathrm {eff}}$) versus the normalized LiTaO3 film thickness were systematically investigated. The proposed high-frequency SAW based on LTOI multilayered heterostructure possesses the low temperature coefficient of frequency (TCF, −20 ppm/K). Furthermore, a high-performance SAW bandpass filter with the center frequency of ~3.5 GHz was achieved. The work shows the great potential of the LiTaO3 single-crystalline thin-films-based SAW for ultrahigh frequency electronics applications. [ABSTRACT FROM AUTHOR]

As the third generation of neural networks, spiking neural network (SNN) motivated by neurophysiology enjoys considerable advances due to integrating different information, such as time and space. The frequency-domain provides a powerful capability of modeling and training convolutional neural networks (CNNs). However, SNN with binary input and output will lose much information and slightly inferior to deep neural networks (DNN). We consider how to make the most of information to protect input. Binary input and output are different from DNN, the essence of difference at frequency distribution. In this work, from the insight of frequency distribution, we rethink the SNN training process and give a novel method to transfer SNN to high-frequency spiking neural network (HF-SNN). This approach preserves considerably more information than other optimizing strategies and enables flexibility in the training process. Besides, we evaluate the HF-SNN with extensive experiments on three large datasets: CIFAR-10, CIFAR-100, and ImageNet. Finally, our model supports training a deeper SNN model from scratch and achieves better performance on these datasets than the existing SNN model.

Ground-Based synthetic aperture radar (GBSAR) is a novel technique for monitoring surface deformation and structural vibrations due to its unique advantages: GBSAR can continually and simultaneously observe a large range of landscapes with a high spatiotemporal resolution. Using GBSAR under the fixed azimuth scanning mode to monitor vibrations is a promising way to monitor a bridge's structural health. Several GBSAR-based bridge vibration experiments have been conducted and verified; however, observation precision tests using high-rate global positioning system (GPS) data are rare, especially for the GAMMA portable radar interferometer II (GPRI-II). In addition, it is complicated to split high-frequency signals into valuable information and undesired noise. Considering these limitations, an on-site experiment using the GPRI-II and high-rate GPS receivers was conducted to evaluate the utility of the GPRI-II. Moreover, a denoising method based on the least-squares adjustment and a triangular chain is proposed under the assumption that the atmospheric phase delay can be eliminated between minuscule time intervals. In addition, an external comparative experiment between the GPRI-II and GPS receivers and an internal comparative experiment was performed to evaluate the effectiveness and reliability, respectively, of the proposed method. The results show that the GPRI-II observation accuracy for permanent scatterers reaches 5–6 millimeters. For the effectiveness of the proposed method, the precision improvement for distributed scatterers is more significant than that for permanent scatterers, and both the internal precision and the external precision have more conspicuous relationships with the deviation of the amplitude than with the coherence.

The traditional fiber Bragg grating (FBG) acceleration has a low operating frequency, which limits its application in transmission line galloping monitoring. We develop a slotting optimization technique to realize the accurate tracking of transmission line galloping in this work. Furthermore, this technique is applied to the development of a high-frequency FBG acceleration sensor. The width, position, and length of the slot are optimized to minimize the slot’s effect on the FBG acceleration sensor. The vibration experiment in our work studies the frequency response and the sensing property of this FBG acceleration sensor. The experimental results indicate that our high-frequency FBG acceleration sensor has not only high sensitivity but also accurate monitoring results.

Some patients with basal cell carcinoma develop a large number of basal cell carcinomas during their lives. The most common underlying genetic disease that causes multiple basal cell carcinomas is basal cell naevus syndrome. Basal cell naevus syndrome is caused by a germline mutation in patched-1 (PTCH1), a tumour suppressor gene of the hedgehog signalling pathway. However, in a significant portion of patients with multiple basal cell carcinomas, no underlying genetic cause is found. Nevertheless, these patients can experience a treatment burden comparable to that of patients with basal cell naevus syndrome. They are referred to as high-frequency basal cell carcinoma patients. Hedgehog pathway inhibitors were the first group of targeted therapy for basal cell carcinomas. This study reviews the literature on hedgehog pathway inhibitor therapy for patients with basal cell naevus syndrome or high-frequency basal cell carcinoma, to provide an overview on efficacy, safety, dosing regimens, tumour resistance and reoccurrence, and health-related quality of life.

BackgroundRepetitive transcranial magnetic stimulation (rTMS) has proven to be an efficient treatment option for patients with treatment-resistant depression (TRD). However, the success rate of this method is still low, and the treatment outcome is unpredictable. The objective of this study was to explore clinical and structural neuroimaging factors as potential biomarkers of the efficacy of high-frequency (HF) rTMS (20 Hz) over the left dorso-lateral pre-frontal cortex (DLPFC).MethodsWe analyzed the records of 131 patients with mood disorders who were treated with rTMS and were assessed at baseline at the end of the stimulation and at 1 month after the end of the treatment. The response is defined as a 50% decrease in the MADRS score between the first and the last assessment. Each of these patients underwent a T1 MRI scan of the brain, which was subsequently segmented with FreeSurfer. Whole-brain analyses [Query, Design, Estimate, Contrast (QDEC)] were conducted and corrected for multiple comparisons. Additionally, the responder status was also analyzed using binomial multivariate regression models. The explored variables were clinical and anatomical features of the rTMS target obtained from T1 MRI: target-scalp distance, DLPFC gray matter thickness, and various cortical measures of interest previously studied.ResultsThe results of a binomial multivariate regression model indicated that depression type (p = 0.025), gender (p = 0.010), and the severity of depression (p = 0.027) were found to be associated with response to rTMS. Additionally, the resistance stage showed a significant trend (p = 0.055). Whole-brain analyses on volume revealed that the average volume of the left part of the superior frontal and the caudal middle frontal regions is associated with the response status. Other MRI-based measures are not significantly associated with response to rTMS in our population.ConclusionIn this study, we investigated the clinical and neuroimaging biomarkers associated with responsiveness to high-frequency rTMS over the left DLPFC in a large sample of patients with TRD. Women, patients with bipolar depressive disorder (BDD), and patients who are less resistant to HF rTMS respond better. Responders present a lower volume of the left part of the superior frontal gyrus and the caudal middle frontal gyrus. These findings support further investigation into the use of clinical variables and structural MRI as possible biomarkers of rTMS treatment response.

Purpose: Direct subcortical motor mapping is the golden criterion to detect and monitor the motor pathway during glioma surgery. Minimal subcortical monopolar threshold (MSCMT) means the minimal distance away from the motor pathway and is critical to decide to continue or interrupt glioma resection. However, the optimal cutoff value of MSCMT for glioma resection in non-awake patients has not been reported discreetly. In this study, we try to establish the safe cutoff value of MSCMT for glioma resection and analyzed its relationship with postoperative motor deficit and long-term survivals. Methods: We designed this prospective study with high-frequency electronic stimulus method. The cutoff MSCMT of postoperative motor deficits was statistically calculated by receiver operating characteristic (ROC) curve, and its relationship with motor deficit and survivals was analyzed by logistic and Cox regression, respectively. Results: The cutoff MSCMT to predict motor deficit after surgery was 3.9 mA on day 1, 3.7 mA on day 7, 5.2 mA at 3 months, and 5.2 mA at 6 months. MSCMT ≤3.9 mA and MSCMT ≤5.2 mA independently predicted postoperative motor deficits at four times after surgery (P < 0.05) but had no effect on the removal degree of tumor (P > 0.05). In high-grade gliomas, MSCMT ≤3.9 mA independently predicted shorter progression-free survival [odds ratio (OR) = 3.381 (1.416–8.076), P = 0.006] and overall survival [OR = 3.651 (1.336–9.977), P = 0.012]. Power model has the best fitness for paired monopolar and bipolar high-frequency thresholds. Conclusions: This study showed strong cause–effect relation between MSCMT and postoperative motor deficit and prognoses. The cutoff MSCMT was dug out to avoid postoperative motor deficit. Further studies are needed to establish the results above. [ABSTRACT FROM AUTHOR]

This paper presents the investigation of high-frequency thermoacoustic oscillations and associated flame dynamics in an experimental gas turbine reheat combustor at atmospheric pressure. Examination of dynamic pressure measurements reveals bursts of high-frequency periodic oscillations which appear randomly amidst stochastic fluctuations in the reheat combustor. Analysis of the flame dynamics during these bursts of periodic behaviour reveals that increased heat release in the reactive shear layers of the reheat flame is associated with greater thermoacoustic driving potential. This redistribution of heat release is likely due to the stochastic nature of auto-ignition kernel formation. To determine the underlying flame-acoustic coupling mechanism behind the driving potential, phase-resolved flame dynamics over the acoustic cycle are investigated which reveal the presence of an oscillatory heat release pattern associated with the first transverse eigenmode. An in-phase interaction between the acoustic field and these heat release oscillations in the shear layer regions indicates that this phenomenon likely constitutes a thermoacoustic driving mechanism. This is an important step towards the development of models for high-frequency thermoacoustic driving mechanisms relevant to reheat combustion systems, which will allow accurate prediction and mitigation of thermoacoustic instabilities in future designs. [ABSTRACT FROM AUTHOR]

In this article, balance technique is applied into two-channel interleaved three-phase ac–dc converters with critical conduction mode based soft switching modulation. By adding additional inductors and coupling them with the original ones, the realization of the balance becomes possible with proper design; thus reducing the common-mode (CM) EMI noise. The balance condition is derived, and the impact of balance technique on the circuit operation especially on the switching frequency variation is quantified in order to provide the design guideline. Based on the application of balance technique, instead of the commonly used litz-wire-based inductors, PCB winding coupled inductors are adopted and designed to effectively achieve the reduction of CM EMI noise. The design methodology and process are presented, and the design tradeoff is made between the inductor loss and the inductor footprint. Finally, the effect of CM EMI noise reduction and the system efficiency with balance techniques and PCB winding magnetics are tested on a 25-kW silicon-carbide-based soft-switching three-phase ac–dc converter prototype. [ABSTRACT FROM AUTHOR]

High-frequency electromagnetic fields (eMF) can have a negative effect on both the human body and electronic devices. Monitoring and measurement of the electromagnetic field generated by devices is important from the point of view of environmental protection, the human body and electromagnetic compatibility. In this study, we tested the value of the electromagnetic field strength determined by the NHt3DL by Microrad with measurement probes during flights in the robinson r44 helicopter. the reference point for the results obtained were the normative limits of the electromagnetic field permitted to affect the crew and passengers during flight. the maximum rMS values recorded during the measurements were E = 4.399 V/m in the 100 kHz-6.5 GHz frequency band and for the magnetic component H = 2.829 A/m in the 300 kHz-30 MHz frequency band. these results were passed to the Statistica 13.3 software for a detailed stochastic analysis of the values tested. [ABSTRACT FROM AUTHOR]

Retrograde Intra-Renal Surgery (RIRS) plays a primary role in renal stone treatment context. Energy, frequency and width of laser impulse can be modulated by surgeons to achieve better outcomes. In our study, patients with single renal stone sized 10–20 mm were retrospectively divided into two groups. Patients of Group 1 underwent RIRS with Low-Energy (LE) High-Frequency (HF) settings using Lumenis® 120-W high-power Ho:YAG laser. Patients of Group 2 (control) underwent RIRS using "standard" settings by means of Sphinx® Jr 30 W Ho:YAG system. Follow-up was conducted with a CT scan at 3 months after RIRS in both groups. Procedure success was defined as stone-free or presence of ≤ 4 mm fragments (Clinical Insignificant Residual Fragments—CIRF). A total number of 199 patients were included: 86 LE/HF RIRS (Group 1) vs 113 "conventional" RIRS (Group 2). Mean operative time was 56.6 (± 19.4) min in Group 1 vs 65.2 (± 25.2) min in Group 2 (p = 0.01). Mean hospitalization time was 2.5 ± 1.7 days for Group 1 vs 2.9 ± 3.2 days for Group 2 (p = 0.2). Peri-operative complications were counted: eight in Group 1 and 11 in Group 2 (p > 0.05). At 3-month control, stone-free rate was 69% (59/86 patients) in Group 1 vs 65% (73/113 patients) in Group 2 (p = 0.6). Success rate was 93% (80/86) in Group 1 in comparison to 82% (93/113) in Group 2 (p = 0.03). In conclusion, LE/HF RIRS seems to be a feasible and effective technique with a reduction of operative time and optimal results in terms of "stone-free" and "success" rates. Further studies are needed to ensure the validity of our results and to give evidence-based statements. [ABSTRACT FROM AUTHOR]

Medium voltage cables are poor transmitters of signals with high frequency spectrum such as partial discharges. The propagating signals are strongly attenuated and distorted depending on the transmitted distance. In order to understand this process, this article provides a model to simulate the transmission of such signals on medium voltage cables. Compared to earlier approaches, this model does not neglect the wave character of the high frequency signals. Therefore, to describe the signal transmission, a comprehensible solution of the telegrapher's equations is provided. To work with this solution, the propagation constant of the medium voltage cable used must also be known. This propagation constant is calculated on the basis of the individual cable layers, considering all ohmic and dielectric losses. In contrast to previous methods, all primary line constants are modeled frequency dependent. The final transmission model is able to predict the spectrum of a transmitted signal at any distance from its origin. Validation measurements show that prediction and measurement agree with good accuracy. A possible application of the developed model is the investigation of the transmission of partial discharges on medium voltage cables. This model is probably also suitable for high voltage cables. [ABSTRACT FROM AUTHOR]

Some patients with basal cell carcinoma develop a large number of basal cell carcinomas during their lives. The most common underlying genetic disease that causes multiple basal cell carcinomas is basal cell naevus syndrome. Basal cell naevus syndrome is caused by a germline mutation in patched-1 (PTCH1), a tumour suppressor gene of the hedgehog signalling pathway. However, in a significant portion of patients with multiple basal cell carcinomas, no underlying genetic cause is found. Nevertheless, these patients can experience a treatment burden comparable to that of patients with basal cell naevus syndrome. They are referred to as high-frequency basal cell carcinoma patients. Hedgehog pathway inhibitors were the first group of targeted therapy for basal cell carcinomas. This study reviews the literature on hedgehog pathway inhibitor therapy for patients with basal cell naevus syndrome or high-frequency basal cell carcinoma, to provide an overview on efficacy, safety, dosing regimens, tumour resistance and reoccurrence, and health-related quality of life. [ABSTRACT FROM AUTHOR]