Mean Resonance Frequency Research Articles

Mandibulada posterior bölgeye uygulanan implantlarda preoperatif kemik kalitesi ve primer stabilite arasındaki korelasyon

Aim: This study aimed to investigate preoperative bone quality obtained from the Hounsfield unit and fractal analysis scores in cone beam computed tomography (CBCT) sections and compare this value with primer stability derived from resonance frequency analysis scores soon after placement of implants in the mandibular posterior region. 
 Material and Method: A total of 36 implant regions were examined retrospectively. Primary outcome variables include the Hounsfield unit, fractal analysis, and resonance frequency analysis scores soon after implant placement. Hounsfield unit and fractal analysis scores were calculated on the preoperative CBCT. 
 Results: The mean Hounsfield unit, fractal analysis and resonance frequency analysis scores of all implants were 76.44, 0.65 and 67.44, respectively. No statistically significant correlation was found between the Hounsfield unit, fractal analysis and resonance frequency analysis scores (p>0.05). Resonance frequency analysis scores (p=0.002) and Hounsfield unit scores (p=0.050) were significantly superior in males. Age was found to be related to resonance frequency analysis scores (r=0.445, p=0.007). 
 Conclusion: The preoperative bone quality of alveolar bone measured from cone beam computed tomography by Hounsfield unit or fractal analysis may be insufficient to determine initial implant stability. Further studies are needed to investigate parameters related to the prediction of implant stability.

AutoHVSR: A machine-learning-supported algorithm for the fully-automated processing of horizontal-to-vertical spectral ratio measurements

The horizontal-to-vertical spectral ratio (HVSR) has seen widespread use as a tool for measuring a site’s resonant behavior. However, the processing of HVSR with traditional methods can be tedious and time-consuming when the HVSR is complex and exhibits multiple resonances. This work proposes the AutoHVSR algorithm that allows for fully-automated processing of HVSR measurements, including those with zero, one, or multiple clear resonances. The AutoHVSR algorithm accepts microtremor or earthquake recordings and user-defined HVSR processing parameters as input and returns the computed HVSR from each time window or earthquake record, the mean/median HVSR curve, and statistics on each automatically identified HVSR resonance in terms of frequency and amplitude. The AutoHVSR algorithm integrates robust signal processing and computational methods with state-of-the-art machine-learning models trained using a diverse dataset of 1108 HVSR measurements. The AutoHVSR algorithm demonstrates excellent performance by correctly determining the number of HVSR resonances for 1098 of the 1108 HVSR measurements (>99%) and predicting the mean resonant frequency of the correctly identified resonances with a root mean square error (RMSE) of 0.05 Hz. Furthermore, the AutoHVSR algorithm was able to produce these predictions in 13 min (including HVSR processing time) compared to the 30 h required for traditional processing (a speed up of 138). The AutoHVSR algorithm is further demonstrated on a challenging dataset from Canterbury, New Zealand that included many HVSR curves with multiple and/or ambiguous resonances. Despite the challenging nature of the Canterbury dataset, the AutoHVSR algorithm was capable of correctly determining the number of HVSR resonances for 113 of the 129 HVSR measurements (>87%) and predicting the mean resonant frequency of the correctly identified resonances with a RMSE of 0.10 Hz. The AutoHVSR algorithm produced these predictions under 2 min (including HVSR processing time) compared to the 4 h required for traditional processing (a speed up of 120). Finally, while the AutoHVSR algorithm was developed using microtremor measurements where the horizontal components were combined using the geometric mean, it is shown to extend without modification to microtremor HVSR measurements where the two horizontal components are rotated azimuthally and to HVSR measurements from earthquake recordings. The AutoHVSR algorithm has been made publicly available in v0.3.0 of HVSRweb, it can be accessed at https://hvsrweb.designsafe-ci.org/.

Gender and ear differences in multi-frequency tympanometry

Objective: The aim of the study was to find the effects of gender and ear difference of multi-frequency tympanometry in Indian young adult population.Method: A total of 30 individuals include 15 males and females with normal hearing were taken for the study. Resonant frequency and F45 were determined in both ears of all individuals and compared.Result: The test results showed that the mean resonant frequency and mean F45 have no significant difference in left and right ears. Females have slightly better RF and F45 than males.

Wideband acoustic immittance in superior semicircular canal dehiscence

ObjectiveThe apparent effect of superior semicircular canal dehiscence (SSCD) on middle ear- and cochlear impedance has led researchers to investigate the use of wideband acoustic immittance as a screening tool when SSCD is suspected. The purpose of the study was to describe the absorbance characteristics and tympanometric values of ears with confirmed SSCD measured at tympanometric peak pressure (TPP) and at ambient pressure. MethodsWideband Acoustic Immittance was performed at ambient pressure and at TPP on ten participants (12 ears) with confirmed SSCD, as well as on an age- and gender matched control group (12 ears). Inferential statistics were used to determine whether statistical differences existed for the absorbance values at each of the averaged frequencies, the resonance frequency (RF) and tympanometric data between the SSCD and control groups. ResultsThe mean absorbance of the SSCD group reached a maximum at 890.9 Hz and a minimum at 6349.6 Hz. When testing absorbance at TPP, a statistically significant increase/peak in the absorbance values of the SSCD group (compared to those of the control group) was found from 630 to 890.9 Hz and a decrease from 4489.8 to 6349.6 Hz. Similar patterns were observed for absorbance at ambient pressure. A lower mean RF for ears with SSCD as well as an increased mean admittance magnitude (AM) value at RF was found compared to those of the control group. ConclusionThe use of SSCD as a screening tool when SSCD is suspected was strengthened by results similar to those of previous studies. As a result of the significant difference in RF of SSCD ears compared to the RF of the control group, the potential value of measuring the RF of the middle ear to differentiate between mass-and stiffness dominated pathologies, was also illustrated.

The Effect of Postmenopausal Osteoporosis on Middle Ear Resonance Frequency.

Background: The effect of postmenopausal osteoporosis on the middle ear mechano-acoustic system is unknown. The aim of this study is to investigate whether or not middle ear resonance frequency is affected in females with postmenopausal osteoporosis.Methods:The study included postmenopausal women aged 45-60 years, separated into 2 groups as females with postmenopausal osteoporosis and healthy postmenopausal females (control group). A detailed anamnesis was taken from all subjects and then the ear, nose, and throat examinations were done followed by pure tone audiometry, tympanometry, and multifrequency tympanometry tests. The groups were compared in respect of pure tone average, bone conduction threshold, RF, static admittance, and tympanometric peak pressure values.Results: The mean age of the patients was 59.2 ± 4.53 years (range, 48-65 years) in the postmenopausal osteoporosis group and 57.11 ± 4.27 years (range, 48-65 years) in the control group (P > .05). The mean resonance frequency values for the postmenopausal osteoporosis and control group were 954.41 ± 127.47 and 935.29 ± 126.39 Hz (P > .05 ). The mean static admittance values for the postmenopausal osteoporosis and control group were 0.82 ± 0.33 and 0.85 ± 0.3 mmho, and mean tympanometric peak pressure values were −7.35 ± 18.52 and −6.94 ± 19.52 daPa (P > .05 for both static admittance and tympanometric peak pressure). The mean pure tone averagevalues for the postmenopausal osteoporosis and control group were 20.96 ± 6.82 and 15.60 ± 7.81 dB, and mean bone conduction threshold values were 17.57 ± 6.03 and 12.10 ± 6.52 dB (P < .05 for both pure tone average and bone conduction threshold).Conclusions: The results showed that the middle ear resonance frequency values were not affected in postmenopausal osteoporosis patients, but there was seen to be greater sensorineural hearing loss in females with postmenopausal osteoporosis compared to healthy postmenopausal females.

Fabrication of 32 × 32 2D Capacitive Micromachined Ultrasonic Transducer (CMUT) Arrays on a Borosilicate Glass Substrate With Silicon-Through-Wafer Interconnects Using Sacrificial Release Process

Close integration of transducer arrays with supporting electronic circuits is essential in achieving efficient and compact ultrasound systems. An integral part of hybrid integration of 2D CMUT array to CMOS electronics is the introduction of through-glass-via (TGV) interconnects in glass substrates as an integral part of the 2D CMUT array fabrication. Micro-cracks around via locations, via discontinuity, and poor coplanarity between the vias and glass substrate are some of the challenges with laser-drilled, paste-filled copper-through-glass-via (Cu-TGV) interconnects. This study provides a detailed fabrication process for making <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$32\times 32$ </tex-math></inline-formula> -element 2D CMUT arrays on a composite glass substrate incorporating silicon-through-glass vias (Si-TGV) as interconnects using sacrificial release approach. On one column of a fabricated 2D CMUT array, we measured a mean resonant frequency of 5.6 MHz in air and an average device capacitance of 1.5 pF. With the introduction of a buried top electrode in the device structure, we achieved a collapse voltage of 93 V, which is considerably lower than the collapse voltage measured in our previously demonstrated 2D CMUT arrays with top electrode on top of the nitride plate. The fabricated array is flip-chip bonded on a custom-designed driving integrated circuit to demonstrate the complete system operation. We measured a peak-to-peak pressure of 1.82 MPa at 3.4 MHz, and 5 mm from the array surface in a 0.33 mm focal spot size. [2021-0101]

A Discovery of Resonance Frequencies on Twelve Meridians of Human Body by Bioimpedance Spectroscopy Method

Objective: The resonance frequency (Fr) of twelve meridians was observed by means of sweep frequency of weak constant current, and a method of evaluating Fr was explored. Method: Four-electrode bioimpedance spectroscopy was used in the study. Constant current of 1~100Hz was applied from a phase-locked amplifier through the excitation electrode to the twelve meridians of 30 healthy subjects. Data were collected by the test electrode and the Fr of the twelve meridians was obtained by data fitting in Matlab. Result: Among the twelve meridians, the Fr of the small intestine meridian is the lowest, and the gallbladder meridian is the highest, which are 23.18±0.99Hz and 28.27±1.39 Hz, respectively. The mean resonance frequencies of meridians of the same name on hand and foot are 24.80±1.34Hz and 26.22±1.17Hz, respectively. The Fr of the Shao Yin meridian of the hands and feet is basically equal, the other five pairs of foot meridians are all higher than the hand meridian, and the difference of the Yang meridian of the same name is greater than the Yin meridian of the same name, the Fr of hand Shao Yang meridian, hand Tai Yang meridian and hand Yang Ming meridian were lower than those of foot meridians. The mean value of 6 pairs of yin and yang meridians are 25.59 ± 1.97Hz and 25.42 ± 0.70Hz, respectively. Conclusion: The resonance frequencies of the twelve meridians ranged from 23 to 28Hz approximately.

Investigation of Cylindrical Piezoelectric and Specific Multi-Channel Circular MEMS-Transducer Array Resonator of Ultrasonic Ablation.

Background: A cylindrical piezoelectric element and a specific multi-channel circular microelectromechanical systems (MEMS)-transducer array of ultrasonic system were used for ultrasonic energy generation and ablation. A relatively long time is required for the heat to be conducted to the target position. Ultrasound thermal therapy has great potential for treating deep hyperplastic tissues and tumors, such as breast cancer and liver tumors. Methods: Ultrasound ablation technology produces thermal energy by heating the surface of a target, and the heat gradually penetrates to the target’s interior. Beamforming was performed to observe energy distribution. A resonance method was used to generate ablation energy for verification. Energy was generated according to the coordinates of geometric graph positions to reach the ablation temperature. Results: The mean resonance frequency of Channels 1–8 was 2.5 MHz, and the cylindrical piezoelectric ultrasonic element of Channel A was 4.2546 Ω at 5.7946 MHz. High-intensity ultrasound has gradually been applied in clinical treatment. Widely adopted, ultrasonic hyperthermia involves the use of high-intensity ultrasound to heat tissues at 42–45 °C for 30–60 min. Conclusion: In the ultrasonic energy method, when the target position reaches a temperature that significantly reduces the cell viability (46.9 °C), protein surface modification occurs on the surface of the target.

Rising Resonance Frequency Is the Sole Sign of Early Middle Ear Disease in Children With Adenoid Hypertrophy.

The present study seeks to estimate the potential of multifrequency tympanometry in the diagnosis of primal otologic disorder in children with adenoid hypertrophy (AH). Prospective observational study. Tertiary pediatric institution. One hundred thirty-one children presenting consecutively at the otolaryngology clinic were divided on the basis of AH into 98 patients and 33 controls. Middle ear status was assessed using pneumatic otoscopy, standard, and wide band tympanometry. Tympanogram type/intratympanic pressure, and resonance frequency (RF) were correlated with each other as well as with a set of clinical parameters. Receiver operating characteristic analysis was employed to reveal the diagnostic value of RF. Mean RF declined in chronic otitis media with effusion by 43.25% (p < 0.001). In our entire cohort, children with AH under the age of 7 years presented with a relative risk = 2.43 of producing "B" tympanogram (p = 0.016) than their older peers. In patients' ears with normal, type "A," tympanogram, RF was the sole tympanometric marker of AH, being elevated by 28.26% in mean value (p = 0.010). On receiver operating characteristic analysis of RF's discriminating capability, the area under the curve was equal to 0.647 (p = 0.010). The optimal cut-off value of RF was set at 899 Hz. AH may induce middle ear stiffening, as RF's increase indicates. Wide band tympanometry output could be a warning sign of ongoing compliance reduction to the sound transmission apparatus, at a time point when physical examination and 226 Hz tympanometry are still unremarkable.

Fabrication of 2D Capacitive Micromachined Ultrasonic Transducer (CMUT) Arrays on Insulating Substrates With Through-Wafer Interconnects Using Sacrificial Release Process

A critical component in a three-dimensional (3D) ultrasound imaging system is a two-dimensional (2D) transducer array. A 2D transducer array is also essential for the implementation of a compact form factor focused ultrasound system for therapeutic applications. Considering the difficulty associated with developing 2D transducer arrays using piezoelectric technology, capacitive micromachined ultrasonic transducer (CMUT) technology with the inherent advantages has emerged as a candidate to develop these devices. Previously, we demonstrated that 2D CMUT arrays can be fabricated with through-glass-via interconnects on borosilicate substrates using anodic bonding. In this paper, we present a fabrication process for implementing $16\times 16$ -element 2D CMUT arrays on an alkali-free glass substrate using the sacrificial release method. The vacuum-sealed $16\times 16$ -element 2D CMUT array is built on an SGW3 glass substrate with copper through-glass interconnects. The fabrication process developed for the 2D CMUT array is described in detail. Across the 256 elements of the 2D CMUT array, the mean resonant frequency is measured as 4.76 MHz with a standard deviation of 46.6 kHz. Also, the mean device capacitance across the array is measured as 1.17 pF with a standard deviation of 0.12 pF, and these results agree with the finite-element analysis. This study shows an alternative method to fabricate 2D CMUT arrays on glass substrates with metal interconnects, especially when the substrate is not suitable for anodic bonding. In addition to improved reliability and reduction in parasitic interconnect capacitance and resistance, this fabrication method benefits from the flexibility of developing 2D CMUT arrays on any type of insulating substrate, and still attain optimum uniformity in both yield and functionality of the fabricated devices. [2019-0246]

Comparative Study between an Immediate Loading Protocol Using the Digital Workflow and a Conventional Protocol for Dental Implant Treatment: A Randomized Clinical Trial

Background: The purposes of this randomized clinical trial study was to compare the immediate loading of dental implants while employing digital workflow and conventional implants in terms of the success rate, marginal bone level, and patient satisfaction. Methods: Fifty patients who had edentulous area on the mandibular premolar or molar area were included in the study. Twenty-five patients were assigned to immediate loading implant treatment using the digital technique and 25 patients were assigned to conventional loading implant treatment. In the first group, the patients were received digital impression (Cerec Omnicam, Dentsply Sirona®, York, PA, USA), designed, producing zirconia crown, and inserted on the same surgery day. The second group, after a healing period of three months, was received analog impression following conventional impression for the zirconia crown. Clinical outcome and radiographic bone level were evaluated after three, six, and 12 months. Patient satisfaction was measured at 12 months after inserting the implant. Results: There was no implants and protheses failure in both groups. The mean resonance frequency analysis values at the day of surgery were 78.26 ± 4.09 in immediate loading using the digital group (ILD) and 73.74 ± 5.14 in the conventional loading group (CL), respectively. Insertion torque values at the day of surgery were 36.60 ± 12.64 in ILD and 38.8 ± 12.19 CL, respectively. The marginal bone level in CL at three, six, and 12 months were 0.14 ± 0.28 mm, 0.18 ± 0.30 mm, and 0.17 ± 0.29 mm, respectively, while in ILD at three, six, and 12 months were 0.18 ± 0.33 mm and 0.16 ± 0.27 mm and 0.15 ± 0.31, respectively. There was no statistically significant difference between the two groups. Only one question in patient satisfaction’s questionnaire was “Now, can your dental implant and crown be used well?” had been significantly different in favor to the conventional group. Conclusion: Within the limitation of this study, it may be concluded that, after one-year follow up, there were no statistically significant differences between the immediate loading of dental implants employed from the digital workflow and conventional implant treatment technique in the success rate and marginal bone level. In patient satisfaction, there was only statistic significant difference in question related to implant prosthetic function in favor of the CL group, whereas the question concerning speaking, cleansing, price, and expectation displayed no difference.

Comparison between the influence of implant diameter and implant length on the primary stability

INTRODUCTION The primary stability is a factor for successful osseointegration of dental implants. It is believed that factors that can increase the contact area between the implant and the bone, such as the implant shape, length, and diameter, can also increase the primary stability. AIM The aim of this study was to determine whether the increase of implant length or the increase of implant diameter would contribute more to the enhancement of primary stability. MATERIALS AND METHODS The implant primary stability of 60 implants distributed in 6 groups, according their diameter, length and surface topography was evaluated using three methods: assessment of mean insertion torque, periotest values, and resonance frequency analysis. RESULTS AND DISCUSSION The results demonstrated that the primary stability achieved by increasing the diameter of the implants by 0.7 mm was comparable to that obtained by increasing their length by 2 mm at a smaller diameter (4.1 mm). When the difference in the diameter increased more (from 0.7 mm to 1.5 mm, when comparing the 3.3 mm/10 mm and 4.8 mm/8 mm implants), the increase of the length of the smaller diameter implants did not result in primary stability values comparable to those obtained during the insertion of wider and shorter implants. CONCLUSION Considering our results as well as the literature data, we can conclude that the increase of the implant diameter affects more the improving of the primary stability than the increase of the implant length. However, it should be taken into account that this refers to a specific diameter change of 1.5 mm and length change of 2 mm. More studies, including implants with a greater difference in the length and a different diameter to length ratio, are needed to confirm or reject this relation.

Normalisation values for the resonant frequency of the middle ear in rats

p { margin-bottom: 0.08in; direction: ltr; color: rgb(0, 0, 0); }p.western { font-family: Cambria, serif; font-size: 12pt; }p.cjk { font-family: MS Mincho, ＭＳ 明朝, monospace; font-size: 12pt; }p.ctl { font-family: Cambria, serif; font-size: 12pt; } Objective : In earlier studies, the resonant frequency (RF) of the middle ear has been investigated in a number of different animals. However, no study has so far specifically addressed the measurement of RF in rats. With this in mind, in our study, multifrequency tympanometry (MFT) was performed on rats and RF value measurements were taken. The aim was to ascertain the normal values for rats used in our university experiments and to provide guidance for further research to be undertaken in this area. Materials and Methods: For the study, 16 male and 16 female adult Sprague Downey rats (32 animals, 64 ears) aged 10 months old and in healthy condition were used. MFT at 226Hz frequency and above was performed on all the rats after they had been anaesthetised. In the first instance tympanograms were recorded using the 226Hz probe tone, following which MFT measurements were performed. RF values for the middle ear were determined in the range 200-2000Hz. Results: For male rats, the mean RF value was 426.56 (± 193.01 Hz), whilst for female rats the mean was 496.88 (± 132.55) Hz. When the values obtained for the male and female rats were compared, no statistically significant difference was observed between the two groups (p=0.061). Accordingly, the mean RF value for the rats as a whole (obtained for 64 ears) was calculated to be 461.7 (± 168.02) Hz. Conclusion: In this research, RF values for the middle ear of rats has been demonstrated to be measurable. However, further research is needed into the relationship between RF and the characteristics of the middle ear in rats.

Can Wideband Tympanometry Be Used as a Screening Test for Superior Semicircular Canal Dehiscence?

Objectives We explored whether wideband tympanometry (WBT) could be used as a screening test for superior semicircular canal dehiscence (SSCD), and obtained new WBT data (given that the test is not yet in common clinical use) on patients with SSCD.Methods We compared the WBT data of patients clinically and radiologically diagnosed with SSCD in our hospital between 2013 and 2018 to those of healthy volunteers. We compared the resonance frequency (RF), maximum absorbance frequency (MAF), and maximum absorbance ratio (MAR). The t-test was used for statistical analysis with the significance level set to P<0.05. In addition, we used receiver operating characteristic analysis to derive cutoff values for SSCD diagnosis in terms of sensitivity and specificity.Results Seventeen patients (four with bilateral and 13 with unilateral disease; 17 ears) diagnosed with SSCD and 27 healthy volunteers (47 ears) were included. The mean RFs of the SSCD patients and healthy subjects were 548.7 Hz (range, 243 to 853 Hz) and 935.1 Hz (range, 239 to 1,875 Hz), respectively (P<0.001). The mean MARs of the SSCD patients and healthy subjects were 89.4% (range, 62% to 100%) and 82.4% (range, 63% to 99%), respectively (P=0.005). The mean MAFs of the SSCD patients and healthy subjects were 1,706.3 Hz (range, 613 to 3,816 Hz) and 2,668 Hz (range, 876 to 4,387 Hz), respectively (P<0.001). In terms of SSCD diagnosis, a MAR above 86% afforded 81% sensitivity and 77% specificity; an RF below 728 Hz, 86% sensitivity and 81% specificity; and an MAF below 1,835 Hz, 79% sensitivity and 67% specificity.Conclusion WBT may be a useful clinical screening test for SSCD. The RF and MAF were lower, and the MAR higher, in SSCD patients than in normal controls.

Effects of low-intensity laser therapy on the stability of orthodontic mini-implants: a randomised controlled clinical trial.

To investigate the effect of low-intensity laser therapy on mini-implant stability using resonance frequency analysis during canine retraction with fixed appliances. A split-mouth randomised clinical trial. Subjects were recruited and treated in the outpatient clinic, Department of Orthodontics, Faculty of Dentistry, Cairo University. Fifteen subjects with mean age 20.9 (±3.4) years who required extraction of maxillary first premolar teeth and mini-implant-supported canine retraction. Thirty orthodontic mini-implants were inserted bilaterally in the maxillary arches of recruited subjects following alignment and levelling. Mini-implants were immediately loaded with a force of 150 g using nickel titanium coil springs with split-mouth randomisation to a low-intensity laser-treated side and control side. The experimental sides were exposed to low-intensity laser therapy from a diode laser with a wavelength of 940 nm at (0, 7, 14, 21 days) after mini-implant placement. Mini-implant stability was measured using resonance frequency analysis at (0, 1, 2, 3, 4, 6, 8, 10 weeks) after implant placement. A total sample of 28 mini-implants were investigated with 14 in each group. Clinically, both mini-implant groups had the same overall success rate of 78.5%. There were no significant differences in resonance frequency scores between low-intensity laser and control sides from baseline to week 2. However, from week 3 to 10, the low-intensity laser sides showed significantly increased mean resonance frequency values compared to control (P > 0.05). Despite evidence of some significant differences in resonance frequency between mini-implants exposed to low-intensity laser light over a 10 weeks period there were no differences in mini-implant stability. Low-intensity laser light cannot be recommended as a clinically useful adjunct to promoting mini-implant stability during canine retraction.

Effect of frequency on pressure cost of ventilation and gas exchange in newborns receiving high-frequency oscillatory ventilation.

BackgroundWe hypothesized that ventilating at the resonant frequency of the respiratory system optimizes gas exchange while limiting the mechanical stress to the lung in newborns receiving high-frequency oscillatory ventilation (HFOV). We characterized the frequency dependence of oscillatory mechanics, gas exchange, and pressure transmission during HFOV.MethodsWe studied 13 newborn infants with a median (interquartile range) gestational age of 29.3 (26.4-30.4) weeks and body weight of 1.00 (0.84-1.43) kg. Different frequencies (5, 8, 10, 12, and 15 Hz) were tested, keeping carbon dioxide diffusion coefficient (DCO2) constant. Oscillatory mechanics and transcutaneous blood gas were measured at each frequency. The attenuation of pressure swings (ΔP) from the airways opening to the distal end of the tracheal tube (TT) and to the alveolar compartment was mathematically estimated.ResultsBlood gases were unaffected by frequency. The mean (SD) resonant frequency was 16.6 (3.5) Hz. Damping of ΔP increased with frequency and with lung compliance. ΔP at the distal end of the TT was insensitive to frequency, whereas ΔP at the peripheral level decreased with frequency.ConclusionThere is no optimal frequency for gas exchange when DCO2 is held constant. Greater attenuation of oscillatory pressure at higher frequencies offers more protection from barotrauma, especially in patients with poor compliance.

Quantifying seismic vulnerability, dynamical shear strain and liquefaction of the Quaternary deposits in the Doon valley near the Main Boundary Thrust in the Northwest Himalaya, India

Erosion and deposition are two conjugate surface dynamical processes that affect differently to the soft soil site characteristics of Quaternary deposits in the Doon valley and at its northern topographic transition zone near the Main Boundary Thrust (MBT). During an impending large magnitude earthquake, what would be the seismic vulnerability and liquefaction susceptibility of the soft soil at both the regions? We quantified Seismic Vulnerability Index, effective dynamical shear strain and the expected ground deformation in the valley soft soil through H/V site characteristics using seismic ambient noise data. At the in-accessible topographic transition zone near the MBT, site effects were studied using Moderate and Light magnitude earthquakes recorded by three Broad Band Seismographs (BBS). Results show unique dual peak mean resonant frequencies (1.11 and 1.38 Hz) and amplification factors (1.69 and 1.51) at the topographic transition zone, which highlights a bimodal distribution of site effects, where the top soil formation is influenced by erosion and deposition due to topographic slope instability apart from fluvial re-working. Here, relatively compact Oldest Doon gravel is present in the foothill terraces with the re-worked fluvial deposition of the Youngest Doon gravel. However, in the valley and its terraces the soft soil formed under fluvial environ is relatively thick (10 to < 535 m) and show a distinct single peak mean amplification factor >2 and mean resonant frequency of 1.1 Hz.The spot resonant frequencies increases from 1 Hz to more than 6 Hz from the HFT region to the MBT, while the amplification factor decreases from 14 to 1. In general, the valley soft soil is susceptible for liquefaction because the estimated dynamical shear strain is 15–25 millistrains under medium (2.2 m/s2, 225 years) and long (4.6 m/s2, 2500 years) term strong motion conditions, which is much higher than the soil plasticity limit of ten millistrains that lead to liquefaction. Dynamical shear strain distribution with depth at eight boreholes in the valley indicate ∼20 m is the liquefaction potential depth, where the pore pressure induced peak shear strain exceeds the threshold shear strain of 0.01% during the passage of seismic waves. Isolated locations in the valley like that at Dharmawala (H1), where all site parameters are very high, and would be hazardously vulnerable to liquefaction. However near the MBT the liquefaction possibility of soft soil is less, but would experience ground deformation of more than 50 cm.

Integration Frequency Response of Human Dynamic Balance Under Passive Motion Stimulus by Using Center of Gravity

This study investigated the frequency response of body oscillations in the medio-lateral (M-L) direction during upright stance and proposes an M-L balance assessment method. Previous investigations have commonly used a visual tracking task and measured the displacement of the center of pressure, but these methods are affected by the body’s subjective factors and do not reliably represent human dynamic balance. In this study, 10 subjects were settled on a 6-DOF motion platform in a specific posture, and the passive motion stimulus was tracked using a sinusoidal waveform with a frequency range of 0.05-1.5 Hz. The Bode diagram, which consisted of the magnitude and phase-shift between the motion of platform and the body’s center of gravity (COG), was obtained by measuring the COG displacement. The results show that, at 0.5-1.0 Hz, the subjects had a higher probability of losing their balance. The mean cut-off frequency (COF) was 0.62 Hz, so the bandwidth of the body oscillation was 0.1-0.6 Hz. Furthermore, the COF could be used to quantify balance ability, i.e. a higher COF corresponded to better balance ability. Additionally, the mean resonance frequency was 0.44 Hz, which reflected spontaneous body sway. In conclusion, this study determined the integration frequency response of human dynamic balance under passive motion stimulus using COG, and proposed a more objective and accurate method for evaluating balance ability.

Sweep frequency impedance measures in young infants: developmental characteristics from birth to 6 months

Objective: International Journal of Audiology To study the developmental characteristics of sweep frequency impedance (SFI) measures in healthy infants from birth to 6 months. Design: All infants were assessed using high-frequency tympanometry (HFT), distortion product otoacoustic emission (DPOAE) and SFI tests. SFI measures consisted of measurement of resonance frequency (RF) and mobility (ΔSPL) of the outer and middle ear. A mixed model analysis of variance was applied to the SFI data to examine the effect of age on RF and ΔSPL. Study sample: Study included 117 ears from 83 infants of different age groups from birth to 6 months. Results: The mean RF of the outer ear increased from 279 Hz at birth to 545 Hz at 4 months, whereas mean ΔSPL of the outer ear decreased from 7.9 dB at birth to 3.7 dB at 4 months of age. In contrast, the mean RF and ΔSPL of the middle ear did not change significantly with age up to 6 months. Conclusions: Developmental characteristics should be considered when evaluating the function of the outer and middle ear of young infants (≤6 months) using the SFI. The preliminary normative SFI data established in this study may be used to assist with the evaluation.

Can resonance frequency of the outer ear be measured in neonates using wideband tympanometry?

This study investigated the feasibility of measuring the resonance frequency (RF) in healthy neonates’ ears using wideband tympanometry (WBT). WBT measures admittance and absorbance as a function of frequency and ear canal pressure. Clinically, RF is the frequency at which the susceptance, the vertical component of admittance, equals zero. In this study, RF was successfully measured in 154 ears (114 newborns) out of 297 ears (182 newborns), which passed a battery of tests including automated auditory brainstem response, 1000-Hz tympanometry and distortion product otoacoustic emissions. The success rate of measuring RF in healthy neonates was 51.9%. The normative data revealed a mean RF of 323 Hz (SD = 67 Hz; range = 240-595 Hz; median = 313.5 Hz; 90% range = 246-440 Hz). No significant gender or ear effects were found. The results of the present study are consistent with the resonance frequency of the outer ear (i.e., elastic ear canal wall) in neonates using a sweep frequency impedance technique (Murakos...