Middle-Ear Imaging and Estimation of The Linear Elastic Properties of The Human Tympanic Membrane

Finite-element (FE) modeling of the human middle ear could improve diagnostic techniques, such as tympanometry. Accurate representation of the mechanical properties and geometry of the middle ear, especially of the soft tissues, are crucial for FE modeling of the middle ear. The objective of this work is to quantitatively evaluate the efficacy of iodine potassium iodide (IKI) solution as a contrast agent for imaging the middle-ear soft tissues and to estimate the linear elastic properties of the human tympanic membrane (TM). In the imaging study, six human temporal bones were used, which were obtained in right-left pairs, from three cadaveric heads. All bones were fixed using formaldehyde. Only one bone from each pair was stained using IKI solution. Samples were scanned using a micro-computed tomography system. Contrast-to-noise ratios of eight middle-ear soft tissues were calculated for each temporal bone. Results from Welch\u27s t-test indicate significant difference between the two soft tissues group, i.e., stained and unstained, at a 95% confidence interval. Results from a paired t-tests for each of the individual soft tissues also indicated significant improvement of contrast in all tissues after staining. The increase in contrast with IKI solution confirms its potential application in sample-specific FE modeling. In the linear elasticity study, experiments were performed on three specimens with a custom-built pressurization unit at a quasi-static pressure of 500 Pa. The shape of each TM before and after pressurization was recorded using a Fourier transform profilometer. The samples were also imaged using micro-CT to create sample-specific FE models. For each sample, the Young’s modulus was then estimated by numerically optimizing its value in the FE model so simulated pressurized shapes matched experimental data. Also, the effects of incorporating two forms of spatial non-uniformity in the distribution of Young’s modulus were studied, including partitioning the TM into 4 quadrants and 4 concentric rings. The estimated Young’s modulus values were 2.2 MPa, 2.4 MPa and 2.0 MPa, which are similar to recent literature values using an alternative method. An improved fit between simulated and experimental data were obtained when spatial non-uniformity was incorporated

PWD-3DNet: A Deep Learning-Based Fully-Automated Segmentation of Multiple Structures on Temporal Bone CT Scans

The temporal bone is a part of the lateral skull surface that contains organs responsible for hearing and balance. Mastering surgery of the temporal bone is challenging because of this complex and microscopic three-dimensional anatomy. Segmentation of intra-temporal anatomy based on computed tomography (CT) images is necessary for applications such as surgical training and rehearsal, amongst others. However, temporal bone segmentation is challenging due to the similar intensities and complicated anatomical relationships among critical structures, undetectable small structures on standard clinical CT, and the amount of time required for manual segmentation. This paper describes a single multi-class deep learning-based pipeline as the first fully automated algorithm for segmenting multiple temporal bone structures from CT volumes, including the sigmoid sinus, facial nerve, inner ear, malleus, incus, stapes, internal carotid artery and internal auditory canal. The proposed fully convolutional network, PWD-3DNet, is a patch-wise densely connected (PWD) three-dimensional (3D) network. The accuracy and speed of the proposed algorithm was shown to surpass current manual and semi-automated segmentation techniques. The experimental results yielded significantly high Dice similarity scores and low Hausdorff distances for all temporal bone structures with an average of 86% and 0.755 millimeter (mm), respectively. We illustrated that overlapping in the inference sub-volumes improves the segmentation performance. Moreover, we proposed augmentation layers by using samples with various transformations and image artefacts to increase the robustness of PWD-3DNet against image acquisition protocols, such as smoothing caused by soft tissue scanner settings and larger voxel sizes used for radiation reduction. The proposed algorithm was tested on low-resolution CTs acquired by another center with different scanner parameters than the ones used to create the algorithm and shows potential for application beyond the particular training data used in the study

Designing a model for knowledge documentation in the Iranian medical university libraries by using structural equation modeling

Background: Organizational knowledge management requires a structure or framework to identify, extract and document knowledge. The review of knowledge management sources shows that since the late 1980s, several cycles have been introduced in the field of knowledge management, and the Mayer and Zack cycle has been one of the most important cycles. The purpose of this study was to design a model for documenting organizational experiences based on the view of point of Iranian libraries managers in medical sciences universities by using Mayer and Zack model. Methods: The research method was survey and correlation schemes are used. The population of the study consisted of 209 managers and heads of central and hospital libraries. Sampling was a stratified random sampling method. data gathering was done in 2022 by questionnaire. path- analyses and structural equation modeling was used to data analyses. RMS-Theta measure was used to test the model. Results: The results of the partial least squares test showed that the gathering knowledge and Knowledge refinement has a significant effect on knowledge documentation. Knowledge refinement had the highest and knowledge application had the lowest impact on knowledge documentation. Conclusion: The results confirmed the effects of knowledge collection and refinement on knowledge documentation. Therefore, it is possible to rely on the designed model and effective factors of knowledge documentation and generalize the obtained results for knowledge documentation in libraries and information centers

No Evidence of Systematic Change of Physical Activity Patterns Before and During the Covid-19 Pandemic and Related Mood States Among Iranian Adults Attending Team Sports Activities

Objective:; To cope with the Coronavirus Disease 2019 (COVID-19) pandemic health authorities released social restrictions. Such social restrictions impacted on the people's possibilities to move deliberately in a public space and to gather with other people. In the present study, we investigated the impact of COVID-19-related restrictions ("confinement") on physical activity (PA) patterns before and during the confinement among team sports participants. Such PA patterns were further related to current mood states, and possible sex differences were also explored.; Methods:; A total of 476 adults exercising team sport (football, futsal, volleyball, handball, and basketball; mean age: 24.66 years; 48.1% females) completed a series of self-rating questionnaires covering sociodemographic information, former and current PA patterns, and current mood states.; Results:; Compared with the period before the confinement, PA intensity decreased, but PA frequency increased during the confinement. Past, current, and changes in physical activity patterns were unrelated to participants' mood states. Sex differences in mood were spurious. Sex differences in physical activity patterns were modest, with male participants reporting a higher physical activity intensity during the confinement.; Conclusions:; The present pattern of results suggests that the COVID-19-related confinement did not impact in a uniform fashion on PA patterns of adults attending team sports. Furthermore, mood states were unrelated to current physical activity patterns. Given the complex psychosocial situation of COVID-19-related confinement, it appeared very unlikely that sole physical activity patterns could counterbalance possible impaired states of mood and behavior

The BONEBRIDGE active transcutaneous bone conduction implant: effects of location, lifts and screws on sound transmission

Abstract Background The BONEBRIDGE (MED-EL, Innsbruck, Austria) is a bone-conduction implant used in the treatment of conductive and mixed hearing loss. The BONEBRIDGE consists of an external audio processor and a bone-conduction floating mass transducer that is surgically implanted into the skull in either the transmastoid, retrosigmoid or middle fossa regions. The manufacturer includes self-tapping screws to secure the transducer; however, self-drilling screws have also been used with success. In cases where the skull is not thick enough to house the transducer, lifts are available in a variety of sizes to elevate the transducer away from the skull. The objective of the present study was to investigate the effects of screw type, lift thickness, and implant location on the sound transmission of the BONEBRIDGE. Method Six cadaveric temporal bones were embalmed and dried for use in this study. In each sample, a hole was drilled in each of the three implant locations to house the implant transducer. At the middle fossa, six pairs of screw holes were pre-drilled; four pairs to be used with self-tapping screws and lifts (1, 2, 3, and 4 mm thick lifts, respectively), one pair with self-tapping screws and no lifts, and one pair with self-drilling screws and no lifts. At the transmastoid and retrosigmoid locations, one pair of screw holes were pre-drilled in each for the use of the self-tapping screws. The vibration of transmitted sound to the cochlea was measured using a laser Doppler vibrometry technique. The measurements were performed on the cochlear promontory at eight discrete frequencies (0.5, 0.75, 1, 1.5, 2, 3, 4 and 6 kHz). Vibration velocity of the cochlear wall was measured in all samples. Measurements were analyzed using a single-factor ANOVA to investigate the effect of each modification. Results No significant differences were found related to either screw type, lift thickness, or implant location. Conclusions This is the first known study to evaluate the effect of screw type, lift thickness, and implant location on the sound transmission produced by the BONEBRIDGE bone-conduction implant. Further studies may benefit from analysis using fresh cadaveric samples or in-vivo measurements

Evaluating the effect of main factors in manufacturing production line based on simulation experiment

Productivity plays a significant role for most companies in order to measure the efficiency. In reality there is an essential need to evaluate the different factors which increasing productivity and achieving the high level of quality, high production rate , machine utilization. On the other hand, manufacturing companies are striving to sustain their competitiveness by improving productivity and quality of manufacturing industry. So it can be acquired by finding ways to deal with various industrial problems which have affected the productivity of manufacturing systems. This paper aims at applying statistical analysis and computer simulation to recognize and to weight the significance of different factors in the production line. Based on the final result the two factors which are B (Number of labor) and C (Failure time of lifter) have the most significant effect on the manufacturing system productivity. In order to achieve the maximum productivity the factors should be placed on the levels which are: A= -1, B=1, C=1 and D=1. This means that the service rate of mixer = UNIF (20, 40), number of labor=20, failure time of lifter =60 min and number of permil=5 respectively

Evaluating the effect of main factors in determining speed bump location based on Taguchi design of experiments

Use of speed bumps as a traffic-calming technique is a key issue to a safe and smooth traffic flow. Lack of consideration on finding the best location for speed bump installation before stop points, such as traffic junctions, has provided the motivation to conduct this study. This paper investigates the influence of some main factors on determining bump location and to optimize the distance from bump to stop point in order to obtain the minimum speed at this point. A robust design was used whereby the effect of environmental noises on the parameters was investigated using the Taguchi design of experiments. A 2-level L8 inner array and an L4 outer array design is used to evaluate and analyze the results. The results suggested that the linear models effectively explain the performance indicators within the ranges of the factors. It can be concluded that the optimum setting suggested is at the most influential levels of the design parameters which yields a robust and insensitive design for speed bump installation after considering the effect of environmental noises. The car speed before bump has the greatest influence and also the most robust factor in terms of signal-to-noise ratio and mean analysis

A Synchrotron and Micro-CT Study of the Human Endolymphatic Duct System : Is Meniere's Disease Caused by an Acute Endolymph Backflow?

Background: The etiology of Meniere's disease (MD) and endolymphatic hydrops believed to underlie its symptoms remain unknown. One reason may be the exceptional complexity of the human inner ear, its vulnerability, and surrounding hard bone. The vestibular organ contains an endolymphatic duct system (EDS) bridging the different fluid reservoirs. It may be essential for monitoring hydraulic equilibrium, and a dysregulation may result in distension of the fluid spaces or endolymphatic hydrops. Material and Methods: We studied the EDS using high-resolution synchrotron phase contrast non-invasive imaging (SR-PCI), and micro-computed tomography (micro-CT). Ten fresh human temporal bones underwent SR-PCI. One bone underwent micro-CT after fixation and staining with Lugol's iodine solution (I2KI) to increase tissue resolution. Data were processed using volume-rendering software to create 3D reconstructions allowing orthogonal sectioning, cropping, and tissue segmentation. Results: Combined imaging techniques with segmentation and tissue modeling demonstrated the 3D anatomy of the human saccule, utricle, endolymphatic duct, and sac together with connecting pathways. The utricular duct (UD) and utriculo-endolymphatic valve (UEV or Bast's valve) were demonstrated three-dimensionally for the first time. The reunion duct was displayed with micro-CT. It may serve as a safety valve to maintain cochlear endolymph homeostasis under certain conditions. Discussion: The thin reunion duct seems to play a minor role in the exchange of endolymph between the cochlea and vestibule under normal conditions. The saccule wall appears highly flexible, which may explain occult hydrops occasionally preceding symptoms in MD on magnetic resonance imaging (MRI). The design of the UEV and connecting ducts suggests that there is a reciprocal exchange of fluid among the utricle, semicircular canals, and the EDS. Based on the anatomic framework and previous experimental data, we speculate that precipitous vestibular symptoms in MD arise from a sudden increase in endolymph pressure caused by an uncontrolled endolymphatic sac secretion. A rapid rise in UD pressure, mediated along the fairly wide UEV, may underlie the acute vertigo attack, refuting the rupture/K+-intoxication theory

Three-dimensional tonotopic mapping of the human cochlea based on synchrotron radiation phase-contrast imaging

The human cochlea transforms sound waves into electrical signals in the acoustic nerve fibers with high acuity. This transformation occurs via vibrating anisotropic membranes (basilar and tectorial membranes) and frequency-specific hair cell receptors. Frequency-positions can be mapped within the cochlea to create a tonotopic chart which fits an almost-exponential function with lowest frequencies positioned apically and highest frequencies positioned at the cochlear base (Bekesy 1960, Greenwood 1961). To date, models of frequency positions have been based on a two-dimensional analysis with inaccurate representations of the cochlear hook region. In the present study, the first three-dimensional frequency analysis of the cochlea using dendritic mapping to obtain accurate tonotopic maps of the human basilar membrane/organ of Corti and the spiral ganglion was performed. A novel imaging technique, synchrotron radiation phase-contrast imaging, was used and a spiral ganglion frequency function was estimated by nonlinear least squares fitting a Greenwood-like function (F=A (10(ax) - K)) to the data. The three-dimensional tonotopic data presented herein has large implications for validating electrode position and creating customized frequency maps for cochlear implant recipients