Probe Frequency Research Articles

Frequency detection, frequency discrimination, and spectro-temporal pattern perception in older and younger typically hearing adults

Elderly adults often experience difficulties in speech understanding, possibly due to age-related deficits in frequency perception. It is unclear whether age-related deficits in frequency perception differ between the apical or basal regions of the cochlea. It is also unclear how aging might differently affect frequency discrimination or detection of a change in frequency within a stimulus. In the present study, pure-tone frequency thresholds were measured in 19 older (61–74 years) and 20 younger (22–28 years) typically hearing adults. Participants were asked to discriminate between reference and probe frequencies or to detect changes in frequency within a probe stimulus. Broadband spectro-temporal pattern perception was also measured using the spectro-temporal modulated ripple test (SMRT). Frequency thresholds were significantly poorer in the basal than in the apical region of the cochlea; the deficit in the basal region was 2 times larger for the older than for the younger group. Frequency thresholds were significantly poorer in the older group, especially in the basal region where frequency detection thresholds were 3.9 times poorer for the older than for the younger group. SMRT thresholds were 1.5 times better for the younger than for the older group. Significant age effects were observed for SMRT thresholds and for frequency thresholds only in the basal region. SMRT thresholds were significantly correlated with frequency thresholds only in the older group. The poorer frequency and spectro-temporal pattern perception may contribute to age-related deficits in speech perception, even when audiometric thresholds are nearly normal.

Dielectric constant measurement sensitivity in electrostatic force and force gradient microscopy-based modes

Understanding the nanoscale electrostatic interaction between a conductive atomic force microscopy (AFM) probe and a dielectric film is central to the operation of various nanoscale dielectric microscopies and determination of dielectric properties of the film. There is no simple analytical description of the electrostatic interaction generated in the confined probe-sample geometry for neither static nor dynamic AFM modes used in dielectric measurements. An accurate description of the involved physics is obtained only by means of a finite element analysis modeling of the system. However, the alternative to using the numerical analysis is not very popular due to being slower and requiring relatively high computation resources. In this work, we revised the contributions from different parts of the AFM probe to the probe-sample capacitance by both analytical and numerical methods. We tried to reconciliate the two approaches and observed the differences as a function of geometry and material parameters. Under various noise levels, the efficiency of an analytical model was tested against a finite element analysis that captures in detail the electrostatic interaction in AFM-based dielectric measurements. The investigation was performed in both spectroscopic force-distance curves and constant height scans with measurements for deflection and frequency of the AFM probe. The obtained measurement sensitivities are relevant in selecting the optimal scanning mode and its operational parameters for a given film thicknesses and dielectric constants but also show the critical role of the numerical analysis to the correct interpretation of the measurements.

Analytical Methods for Calculating Dimensional Uncertainty In Ultrasonic Testing

This paper depicts a project undertaken in the offices at Defence Research development Organisation (DRDO), Gas Turbine Research Establishment (GTRE)) Bangalore. Non-Destructive Testing (NDT) methods are used to determine the integrity and reliability of parts without impairing their future usability. They can be classified as methods used for the detection of Surface, Internal anomalies. Ultrasonic Testing is a versatile NDT method which can be used for both the above purposes and use high-frequency sound waves (above 20 KHz) to penetrate the object and conduct the examination. This method was selected for the purpose of estimating the associated dimensional uncertainties while sizing the defects. Specimens were manufactured with artificial holes of 0.5 mm diameter and varying depths in cylinders made out of work-house aerospace materials of Ti-64 (blades and disks of a compressor), Su-718 (Super alloy used for hot end parts) and S-80 (stainless steel used for gear parts) in conformance to international standards. These blocks were subjected to Contact and Immersion Ultrasonic Testing methods. Transducers (probes) of two different frequencies (5 MHz and 10 MHz) were chosen for both the methods to understand the effect of probe sensitivity on the uncertainty estimation. For each of the blocks conducted three different trials for the measured depth of defect Vs actual depth of defect and values were tabulated. Regression Analysis was chosen for obtaining the Type-A uncertainty owing to the availability of limited data and linear relationship among the variables, while Type-B was derived from standard statistical calculations specified in "Guide to Expression of Uncertainty in Measurement" (GUM) as per ISO 17025 and combination of random and systematic errors. Standard uncertainty was calculated for both Type-A and B methods. Combined uncertainty was derived which represents the contribution of ultrasonic system, calibration blocks along with measurement results. The expanded uncertainty represents the combined uncertainty with a confidence interval of k=2 (i.e. 95 % confidence level).The combined and expanded uncertainty were obtained by Type B method. It was analysed and concluded that Type-A is conservative in approach and under estimates standard uncertainty values, whereas Type-B results in higher estimates. The results show that the uncertainties are sensitive to variations associated with material attenuation property, defect diameter, probe frequency.

Cola acuminata Mitigates Cognitive Deficit and Oxidative Stress in Mercury Chloride-induced Neurotoxicity in Male Wistar Rats

Cola acuminata is used in traditional medicine for the management of memory impairment and other neurodegenera-tive conditions. This study investigated the effects of Cola acuminata aqueous leaves extract (ALECA) on mercury chloride-induced neurotoxicity in Wistar rats. Twenty male Wistar rats weighing between 160 and 210 g were randomly assigned to four groups (n = 5). The control group received 0.5 mL of distilled water; the mercury chloride (HgCl2) group received HgCl2 (5 mg/kg b.w.); the ALECA100 and ALECA300 groups received ALECA (100 and 300 mg/kg b.w., respectively), followed by the administration of HgCl2 (5 mg/kg b.w.) for two weeks. The rats were subjected to behavioural tests in the Morris water maze and light and dark field box. The rats were then sacrificed to obtain their brains, which were homogenized for biochemical assays of acetylcholinesterase (AChE), malondialdehyde (MDA), total protein (TP), and glutathione (GSH) using standard methods. The results revealed a significant increase in escape latency, a significant decrease in probing frequency and brain GSH, and a significant (p<0.05) increase in brain MDA and TP levels and AChE activity in the rats exposed to HgCl2. However, administration of either 100 or 300 mg/kg ALECA protected against memory impairment with a significantly reduced escape latency, increased probing frequency and brain GSH, and decreased (p<0.05) MDA, TP and AChE. This study concludes that ALECA mitigated HgCl2-induced neurotoxicity via reduction of oxidative stress and enhanced cholinergic functions

Advanced Ultrasonic Inspection of Thick-Section Composite Structures for In-Field Asset Maintenance.

An investigation into the inspection capabilities of in-field advanced ultrasound detection for use on ultra-thick (20 to 100 mm) glass fibre-reinforced polyester composites is presented. Plates were manufactured using custom moulding techniques, such that delamination flaws were created at calibrated depths. The full matrix capture technique with an on-board total focussing method was used to detect flaws scanned by a 0.5 MHz linear array probe. Flaw through-thickness dimensions were altered to assess the threshold for crack face separation at which delaminations could be identified. Furthermore, part thickness and in-plane flaw dimensions were varied to identify the inspection capability limitations of advanced ultrasonics for thick composites. The results presented in this study demonstrate an inverse relationship between the ability to find delaminations and plate thicknesses, with inspections successful at depths up to 74 mm. When the delamination thickness exhibited surface-to-surface contact, the inspection capability was reduced to 35 mm. There was an exponential decay relationship between the accuracy of the flaw depth measurement and plate thickness, likely due to the necessity of low probe frequencies. The effective inspection depth was determined to be in the range of 1 to 20 times the wavelength. It is speculated that the accuracy of measurements could be improved using probes with novel coupling solutions, and detectors with optimised signal processing/filtration algorithms.

Voltage fluctuations and probe frequency jitter in electric force microscopy of a conductor.

Electric force microscopy probes the statistics of electric field fluctuations from a sample surface, both through measurement of the noncontact friction exerted on the oscillating charged probe and by determination of the power spectrum of stochastic probe frequency fluctuations, referred to as "jitter." Here we calculate the frequency jitter power spectrum determined over a conducting sample of finite thickness, whose response is characterized by a dielectric function that is wavevector-dependent. These calculations complement previous predictions of the coefficient of noncontact friction in an electric force microscopy measurement for the same model, and also previous predictions of the jitter power spectrum for a dielectric continuum. The inclusion both of a finite sample thickness and a wavevector-dependent dielectric response can significantly enhance the magnitude of the predicted jitter spectrum for a conductor, relative to a simpler model of an infinitely thick dielectric continuum. These calculations provide a baseline prediction of the jitter power spectrum generated by the dynamics of conduction electrons in a metal sample.

Nail Ultrasound in Psoriasis and Psoriatic Arthritis-A Narrative Review.

Ultrasonography has advantages for assessing psoriatic arthritis (PsA) due to its ability to evaluate several targets, including joints, entheses, and tendons, but also skin and nails. Although ultrasound is widely used in PsA, nail ultrasound, despite its potential as a non-invasive method for the early detection of inflammation in the nail apparatus, has low applicability in medical practice, as probes with a higher frequency are needed compared with the frequency of probes usually used. In the present article, we have narratively evaluated the studies published in the last 5 years (19 February 2018-18 February 2023) on nail ultrasound value in the diagnosis and monitoring of PsA. The studies published during this period share common measurement parameters, such as the OMERACT definition of enthesis published in 2018. We included original articles published in PubMed and Web of Science using the following search terms in all possible combinations: psoriatic arthritis, psoriasis, ultrasound, and nail. Articles were declared relevant if they presented data on nail morphology, power Doppler evaluation and nearby structure evaluation, while focusing on digitorum extensor enthesitis. In most of the studies, common morphological parameters were generally increased in patients with psoriasis or PsA and were demonstrated to change with medication. The thickness of the extensor tendon was greater in patients with PsA and psoriasis versus controls and it was correlated with nail clinical changes, especially the presence of onycholysis. The presence of PD showed large variability in healthy individuals. The link between enthesitis and nail involvement is still a subject of controversy, taking into account the latest histological findings. The use of ultrasound in the evaluation of nail and DIP enthesitis remains a challenge and an area of research in the coming years.

Factors influencing the Shear Wave Elastography evaluation of the patellar tendon.

There is no clear standardization for tendon Shear Wave Elastography (SWE), and data regarding the factors that influence the correctness of evaluation are scarce. We aimed to determine the intra- and interobserver agreement in patellar tendon SWE, and to establish the influence of various factors on elasticity values. We recruited 37 healthy volunteers; SWE of the patellar tendon was performed by two examiners. The following factors were analyzed: probe frequency, degree of joint flexion, size of region of interest (ROI), distance of the color box from the probe footprint, utilization of coupling gel as standoff, and the effect of physical exercise on elastic modulus values. Highest overall interobserver [k=0.767, 95%CI (0.717-0.799), p<0.001] and intraobserver agreement [k=0.920 (0.909-0.929) for examiner 1, k=0.891 (0.875-0.905) for examiner 2] was obtained with the knee in the neutral position, using the L18-5 probe. With the knee flexed at 30º and 45º, the elasticity values were higher compared to the neutral position (p<0.001). With the probe immersed in 0.25 and 0.50 cm coupling gel, the median values were lower compared to the probe placed on the skin (p=0.001, p=0.018). The ROI dimensions and the placement of the SWE box at the level of the skin or at 0.5 cm below skin did not significantly influence the elastic modulus. After physical exercise, the elasticity values decreased in the proximal and middle portion of the tendon (p=0.002, p<0.001). The best results obtained in patellar tendon SWE were with the knee in neutral position, in the proximal or middle tendon, after 10 minutes of relaxation and with the probe placed directly on the skin with minimal pressure. The size and position of ROI do not significantly influence the examination.

Revealing the frequency-dependent oscillations in the nonlinear terahertz response induced by the Josephson current.

Nonlinear responses of superconductors to intense terahertz radiation has been an active research frontier. Using terahertz pump-terahertz probe spectroscopy, we investigate the c-axis nonlinear optical response of a high-temperature superconducting cuprate. After excitation by a single-cycle terahertz pump pulse, the reflectivity of the probe pulse oscillates as the pump-probe delay is varied. Interestingly, the oscillatory central frequency scales linearly with the probe frequency, a fact widely overlooked in pump-probe experiments. By theoretically solving the nonlinear optical reflection problem on the interface, we show that our observation is well explained by the Josephson-type third-order nonlinear electrodynamics, together with the emission coefficient from inside the material into free space. The latter results in a strong enhancement of the emitted signal whose physical frequency is around the Josephson plasma edge. Our result offers a benchmark for and new insights into strong-field terahertz spectroscopy of related quantum materials.

Aphids on Aphid-Susceptible Cultivars Have Easy Access to Turnip Mosaic Virus, and Effective Inoculation on Aphid-Resistant Cultivars of Oilseed Rape (Brassica napus).

Plant viruses improve transmission efficiency by directly and indirectly influencing vector behavior, but the impact of plant cultivars on these modifications is rarely studied. Using electropenetrography (EPG) technology, a comparative study of the effects of turnip mosaic virus (TuMV) infection on quantitative probing behaviors of the cabbage aphid (Brevicoryne brassicae) was conducted on two oilseed rape cultivars ('Deleyou6' and 'Zhongshuang11'). Compared to mock-inoculated plants, cabbage aphids on infected plants increased the frequency of brief probing, cell penetration, and salivation. Additionally, aphids on infected 'Deleyou6' prolonged cell penetration time and decreased ingestion, but not on infected 'Zhongshuang11', suggesting that aphids were more likely to acquire and vector TuMV on the aphid-susceptible cultivar 'Deleyou6' than on resistant cultivars. TuMV also affected aphid probing behavior directly. Viruliferous aphids reduced the pathway duration, secreted more saliva, and ingested less sap than non-viruliferous aphids. In comparison with non-viruliferous aphids, viruliferous aphids started the first probe earlier and increased brief probing and cell penetration frequencies on the aphid-resistant cultivar 'Zhongshuang11'. Based on these observations, viruliferous aphids can be inoculated with TuMV more efficiently on 'Zhongshuang11' than on 'Deleyou6'. Although aphid resistance and TuMV infection may influence aphid probing behavior, oilseed rape resistance to aphids does not impede TuMV transmission effectively.

Ultra-high frequency lung ultrasound in preterm neonates: a test validation study on interpretation agreement and reliability

ObjectiveTo verify if increasing frequency, through the use of ultra-high frequency transducers, has an impact on lung ultrasound pattern recognition.DesignTest validation study.SettingTertiary academic referral neonatal intensive care unit.PatientsNeonates admitted with...

Optimizing Choice and Timing of Behavioral Outcome Tests After Repetitive Mild Traumatic Brain Injury: A Machine Learning-Based Approach on Multiple Pre-Clinical Experiments.

Repetitive mild traumatic brain injury (rmTBI) is a potentially debilitating condition with long-term sequelae. Animal models are used to study rmTBI in a controlled environment, but there is currently no established standard battery of behavioral tests used. Primarily, we aimed to identify the best combination and timing of behavioral tests to distinguish injured from uninjured animals in rmTBI studies, and secondarily, to determine whether combinations of independent experiments have better behavioral outcome prediction accuracy than individual experiments. Data from 1203 mice from 58 rmTBI experiments, some of which have already been published, were used. In total, 11 types of behavioral tests were measured by 37 parameters at 13 time points during the first 6 months after injury. Univariate regression analyses were used to identify optimal combinations of behavioral tests and whether the inclusion of multiple heterogenous experiments improved accuracy. k-means clustering was used to determine whether a combination of multiple tests could distinguish mice with rmTBI from uninjured mice. We found that a combination of behavioral tests outperformed individual tests alone when distinguishing animals with rmTBI from uninjured animals. The best timing for most individual behavioral tests was 3-4 months after first injury. Overall, Morris water maze (MWM; hidden and probe frequency) was the behavioral test with the best capability of detecting injury effects (area under the curve [AUC] = 0.98). Combinations of open field tests and elevated plus mazes also performed well (AUC = 0.92), as did the forced swim test alone (AUC = 0.90). In summary, multiple heterogeneous experiments tended to predict outcome better than individual experiments, and MWM 3-4 months after injury was the optimal test, also several combinations also performed well. In order to design future pre-clinical rmTBI trials, we have included an interactive application available online utilizing the data from the study via the Supplementary URL.

Investigation of gyrotron-based collective Thomson scattering for fast ion diagnostics in a compact high-field tokamak

As a promising method for fast ion diagnostics, collective Thomson scattering (CTS) can measure the one-dimensional velocity distribution of fast ions with high spatial and temporal resolution. The feasibility of diagnosing fast ions in a compact high-field tokamak by CTS was studied in this work, and the results showed that a wide range of probing frequencies could be applied. A high-frequency case and a low-frequency case were mainly considered for fast ion diagnostics in a compact high-field tokamak. The use of a high probing frequency could effectively avoid the refraction effect of the beams, while the application of a low probing frequency allows greater flexibility in the selection of scattering angle which may help to improve the spatial resolution. Based on typical plasma conditions (B 0 = 12.2 T, n e0 = 4.3 × 1020 m−3, T e0 = 22.2 keV, T i0 = 19.8 keV) for a compact high-field tokamak, a 220 GHz CTS diagnostic that utilizes a small scattering angle of θ = 30° and a 160 GHz CTS diagnostic that utilizes an orthogonal geometry were proposed. Further study showed that the high-frequency case could operate in a wider range of plasma conditions and provide more information on fast ions while the low-frequency case could achieve higher spatial resolution of the poloidal direction.

A Map-Matching Algorithm With Extraction of Multi-Group Information for Low-Frequency Data

The growing use of probe vehicles generates a huge number of global navigation satellite systems (GNSS) data. Limited by satellite positioning technology, further improving the accuracy of map matching (MM) is challenging work, especially for low-frequency trajectories. When matching a trajectory, the ego vehicle’s spatial-temporal information of the present trip is most useful with the least amount of data. In addition, there is a large number of other data, e.g., other vehicles’ state and past prediction results, but it is hard to extract useful information for matching maps and inferring paths. Most of the MM studies have used only the ego vehicle’s data and ignored other vehicles’ data. Based on those, this article designs a new MM method to make full use of “big data.” We first sort all the data into four groups according to their spatial and temporal distance from the present matching probe, which allows us to sort for their usefulness. Then we design three different methods to extract valuable information (scores) from them: a score for speed and bearing, one for historical usage, and another for traffic state using a spectral graph Markov neural network. Finally, we use a modified top-K shortest-path method to search the candidate paths within an ellipse region and then use the fused score to infer the path (projected location). We test the proposed method against baseline algorithms using a real-world dataset in China. The results show that all scoring methods can enhance MM accuracy. Furthermore, our method outperforms the others, especially when the GNSS probing frequency is ≤ 0.01 Hz.

Long-latency component of stimulus frequency otoacoustic emissions: Relationship to behavioral measures

Uncertainties regarding the generation mechanism and source of human stimulus frequency otoacoustic emissions (SFOAEs), as well as the possible generation of artifacts, have previously restricted the use of SFOAEs in clinical settings for assessing cochlear function. Over the years, advanced time-frequency analysis of SFOAEs, using models of SFOAE delays as a function of frequency, have been implemented in an effort to isolate the long-latency (LL) component of SFOAEs—improving the signal-to-noise ratio and the artifact rejection as noteworthy byproducts. In order to test the hypothesis that behavioral measures and SFOAE LL component both reflect the activity of limited cochlear regions, the relationship between SFOAE LL component and behavioral measures was investigated. SFOAEs, behavioral thresholds and psychophysical tuning curves (PTCs) were measured for probe frequencies centered around 0.75, 1, 2, 4, 8, 10, 12.5 and 14 kHz. Stimulus levels for PTCs (10 dB SL) and SFOAEs (10, 20 and 30 dB SL) were referenced to behavioral thresholds at each frequency. Using the same in situ calibration technique using Thevenin-equivalent source parameters, behavioral thresholds and SFOAE-estimated thresholds from input-output functions of the SFOAE LL component were strongly correlated. Furthermore, there was a strong correlation between SFOAE-based and psychophysical tuning estimates.

Structural analysis of the ex-port plug collective thomson scattering transmission lines for ITER

The main function of the Collective Thomson Scattering (CTS) diagnostic system for ITER is to diagnose the alpha particles resulting from Deuterium-Tritium fusion reactions. It consists of a microwave scattering diagnostic with a probing frequency of 60 GHz and emitted power of 1.2 MW from the gyrotron, with one launcher and nine receiver transmission lines.The CTS will be installed in the equatorial port EP#12, which is one of the ports that have to be operational for the ITER First Plasma. The transmission lines outside the Port Plug (Ex-PP) are routed through the Interspace, Port Cell, Gallery, Assembly Building and Diagnostic Building, reaching more than 100 m in length. The preliminary design of the ex-PP components is currently being undertaken in the framework of an Implementing Agreement between ITER Organization, the Instituto Superior Técnico (IST) and CIEMAT. Within this collaboration, CIEMAT is responsible for the structural analyses and calculations required to ensure the structural integrity and performance of the preliminary design of the Ex-PP transmission line components, which will be summarized in this paper.In this work, the required analysis and calculations will be presented together with the redesign performed for the transmission lines in order to guarantee that their components will withstand the loads defined in the Ex-PP CTS Load Specifications. The evaluation of the structural integrity of the CTS Ex-PP components will be carried out in accordance with the 2007 RCC-MR Code for mechanical components in nuclear installations.

Unveiling a Pump-Induced Magnon Mode via Its Strong Interaction with Walker Modes

We observe a power-dependent anticrossing of Walker spin-wave modes under microwave pumping when a ferrimagnet is placed in a microwave waveguide that does not support any discrete photon mode. We interpret this unexpected anticrossing as the generation of a pump-induced magnon mode that couples strongly to the Walker modes of the ferrimagnet. This anticrossing inherits an excellent tunability from the pump, which allows us to control the anticrossing via the pump power, frequency, and waveform. Further, we realize a remarkable functionality of this anticrossing, namely, a microwave frequency comb, in terms of the nonlinear interaction that mixes the pump and probe frequencies. Such a frequency comb originates from the magnetic dynamics and thereby does not suffer from the charge noise. The unveiled hybrid magnonics driven away from its equilibrium enriches the utilization of anticrossing for coherent information processing.

Determination of the radial position of zero density for profile reflectometry on experimental advanced superconducting tokamak

The Experimental Advanced Superconducting Tokamak (EAST) reflectometry is a Frequency-Modulated Continuous-Wave monostatic system with the transmission lines similar to the ITER reflectometer design. One of the most significant and common problems for reflectometry to reconstruct the density profile is the determination of initialization, i.e. zero density position (R start), which could be determined by the extraordinary mode (X-mode) reflectometry. The main source of noise still comes from the wave scattering of plasmas despite the sweeping period of around 10 microseconds. It is found that to reduce the random noise of R start, averaging on 25 periods is the optimal solution. During the L-mode discharges with only lower hybrid wave (LHW) heating, R start would move outwards and its fluctuation and the high frequency components of turbulence around R start would be obviously increased when the 2.45 GHz system is switched on, while no obvious change is observed in the 4.6 GHz case. These phenomena are consistent with that 2.45 GHz LHW has less current drive ability than 4.6 GHz LHW on EAST. During ELMy H-mode, the peak of R start is consistent with Deuterium signal and the maximum displacement is about 3 cm. The comparison of density profiles from reflectometry and Lithium beam emission spectroscopy (Li-BES) suggests that setting the density at R start to (4 ± 2)× 1017 m-3 is much better than zero, while this value is somewhat empirical and closely related to the amplitude threshold for determining the first probing frequency corresponding to R start.

COMPARISON OF GENEXPERT® PROBE MISSING IN HOTSPOT RRDR OF RPOB GENE AMONG PRIMARY AND ACQUIRED DRUG RESISTANT CASES OF PULMONARY TUBERCULOSIS

There are differences in probe pattern missing in rifampicin resistance determining region of rpoB gene among primary and acquired resistant TB cases. This study aimed to observe the Xpert® MTB RIF Assay presenting probe missing in Hotspot RRDR of rpoB Gene among primary and acquired drug-resistant cases of pulmonary tuberculosis in a tertiary care setting of Lahore. This comparative cross-sectional work was undertaken at The University of Lahore in cooperation with the Department of Pulmonology and HRI-NIH TB Research Centre KEMULahore. Confirmed TB patients being sent for Xpert® MTB RIF Assay were the target population in this study. Based on previous TB treatment history, patients were divided into primary and acquired drug-resistant TB cases. Samples were subjected to Xpert® MTB RIF Assay, and any probes missing, i.e., probes A, B, C, D or E, were observed. Data from a total of 170 cases were finalized for analysis consisting of 84(49.4%) acquired TB cases and 86(50.6%)primary TB cases. A total of 90(52.9%) male and 80(47.1%) females were enrolled. The mean age of patients was 35.45±16.11 years. The proportion of missing probe E (78.2%) remained at the topmost, followed by none of the probes missing at 8.3%, probe A at 5.3%, probe C at 3.5%, probe B at 2.9% and probe D at 1.8%. There are variations in frequencies of probe missing in RDRR regions of rpoB genes among rifampicin-resistant cases of primary andacquired TB. A high frequency of no missing probes among primary resistant was found.

Fano resonances and slow light in a nanocavity assisted by metallic nanoparticles‐quantum dot system

AbstractDouble Fano resonances in a nanocavity assisted by metallic nanoparticles (MNPs)‐quantum dot (QD) system are demonstrated theoretically. The nanocavity is assumed to couple with the QD and QD is assumed to locate in the plasmon field produced by two excited MNPs nearby. The nanocavity is driven by a control field and a probing field. Double Fano resonances can be manipulated by the system parameters such as frequency detuning and coupling strength among the nanocavity, the mechanical oscillator, MNPs and QD. Especially, we find the second Fano resonance appears due to the interaction between the nanocavity with the QD‐MNPs. We also discuss the transmission and group delay in the double Fano resonance transparency windows which show tunable fast and slow light for different probe frequency. Our results may provide possible applications in designing optical buffer, switching, and so forth.