Distal Research Articles

Impact of Contralateral Hemiplegia on Lower Limb Joint Kinematics and Dynamics: A Musculoskeletal Modeling Approach

This study investigates the biomechanical differences between typically developed (TD) individuals and those with contralateral hemiplegia (CH) using musculoskeletal modeling in OpenSim. Ten TD participants and ten CH patients were analyzed for joint angles and external joint moments around the three anatomical axes: frontal, sagittal, and transverse. The analysis focused on hip, pelvis, lumbar, knee, ankle, and subtalar joint movements, leveraging MRI-derived bone length data and gait analysis. Significant differences (p < 0.05) were observed in hip flexion, pelvis tilt, lumbar extension, and ankle joint angles, highlighting the impact of hemiplegia on these specific joints. However, parameters like hip adduction and rotation, knee moment, and subtalar joint dynamics did not show significant differences, with p > 0.05. The comparison of joint angle and joint moment correlations between TD and CH participants highlights diverse coordination patterns in CH. Joint angles show significant shifts, such as HF and LR (−0.35 to −0.97) and PR and LR (0.22 to −0.78), reflecting disrupted interactions, while others like HR and LR (0.42 to 0.75) exhibit stronger coupling in CH individuals. Joint moments remain mostly stable, with HF and HA (0.54 to 0.53) and PR and LR (−0.51 to −0.50) showing negligible changes. However, some moments, like KA and HF (0.11 to −0.13) and PT and KA (0.75 to 0.67), reveal weakened or altered relationships. These findings underscore biomechanical adaptations and compensatory strategies in CH patients, affecting joint coordination. Overall, CH individuals exhibit stronger negative correlations, reflecting impaired coordination. These findings provide insight into the musculoskeletal alterations in hemiplegic patients, potentially guiding the development of targeted rehabilitation strategies.

Comparison of Water-Equivalent and Effective Diameter-Based Size-Specific Dose Estimates in Computed Tomography Pulmonary Angiography: Implications for Radiation Dose Optimization

This retrospective study investigates dose estimation in computed tomography pulmonary angiography (CTPA) by analyzing 200 examinations from 96 male and 104 female patients. Two size-specific dose estimation (SSDE) methods were evaluated: one based on effective diameter (SSDEDeff) and the other on water-equivalent diameter (SSDEDw). The effective diameter (Deff) was manually measured using the lateral (LAT) and anteroposterior (AP) dimensions, while the water-equivalent diameter (Dw) was calculated from the region of interest (ROI) using mean Hounsfield Unit (HU) values and cross-sectional area. SSDE calculations were compared to the conventional CT dose metric, CTDIvol, to assess its underestimation relative to SSDEDw. The findings revealed a dose underestimation of up to 18% for CTDIvol compared to SSDEDw, particularly for patients with larger body habitus. SSDEDeff consistently overestimated the dose by 7.73% compared to SSDEDw, as Deff relied only on external dimensions while Dw considered tissue attenuation for a more individualized dose assessment. High correlations were observed between lateral diameter (dLAT) and both Deff (R2 = 0.9175) and Dw (R2 = 0.7578). However, the systematic overestimation by SSDEDeff emphasizes the importance of clearly specifying the metric used for SSDE, as differences can influence reported doses by 5-10%, affecting clinical dose monitoring and adherence to diagnostic reference levels. This study highlights the limitations of CTDIvol and SSDEDeff compared to SSDEDw, especially in regions with heterogeneous tissue. The results support the use of individualized radiation dose assessments to improve radiation safety, particularly in CTPA, which has seen increased application during the COVID-19 pandemic.

Factors associated with postoperative coronal imbalance in adult patients with severe and rigid scoliosis: a retrospective study

BackgroundExtensive studies examined coronal imbalance (CIB) in adolescent and adult degenerative scoliosis; however, few studies addresses on CIB in adult with severe rigid scoliosis (SRS). Therefore, we analyzed postoperative SRS patients to identify factors associated with postoperative CIB.MethodsIn this retrospective study, we investigated SRS patients undergoing one-stage posterior column osteotomy (PCO) and fusion at our hospital between August 2012 and January 2019. The preoperative, postoperative and follow-up whole-spine anteroposterior (AP) radiographs were evaluated. Potential risk factors for postoperative CIB were analyzed using the LASSO regression, and independent risk factors were identified using binary logistic regression. A nomogram prediction model was constructed and validated.ResultsNinety eligible SRS patients were included. Postoperative radiographs showed a main curve correction rate of 54.17 ± 14.02%; however, follow-up CIB persisted in 26.67% of patients. Three independent variables affecting follow-up CIB were identified by LASSO regression, including preoperative CIB+ [OR = 12.414 (95% CI: 2.228, 69.162), P = 0.004], major curve flexibility index < 10% [OR = 14.300 (95% CI: 2.200, 92.957), P = 0.005], and immediate postoperative CIB [OR = 5.169 (95% CI: 1.387, 19.263), P = 0.014]. ROC and DCA analysis demonstrated that the nomogram had good predictive performance.ConclusionsPreoperative CIB+, major curve flexibility index < 10%, and immediate postoperative CIB were significantly associated with postoperative CIB. These findings offer valuable guidance to improve surgical outcomes and reduce complications.

Andalusian and Classical Ottoman Mosque Architecture Features

Cultures have met and influenced each other throughout history, and new and original products have emerged. Andalusian works, which were formed under the influence of Islamic and Christian architectural culture in history, and Ottoman architectural works, which were put forward by considering aesthetics and symmetry, are worth examining and are the subject of many scientific studies. In this study, the characteristics of Andalusian and Ottoman mosque architectures, which represent two peaks in Islamic civilization, were examined and compared. There is a perfect harmony between the multi-column and horseshoe-shaped arches in Andalusian mosques, but this situation creates a dim image. In terms of external appearance, it is reported that the mosques face north, and there is one square-based minaret here. The minarets, which have survived to the present day, have the appearance of a high building and terraces on the upper parts used for observation purposes. In the Ottoman Empire, minarets were built more than once in mosques built by dynasty members and in sultanate mosques, giving the city an aesthetic appearance and being symmetrical with the mosque. In this study, architectural features of mosques in terms of columns, plan, facade arrangement, light order and amount, mortar figures, plant and flower figures, tile decoration, Kufic script, use of bricks, number of minarets, the shape of minarets, arch, color type, and construction process. These features were compared and discussed in the light of social and cultural effects. Keywords: Andalusia; Ottoman; Architecture; Mosque; Culture.

Relationship Between the Subchondral Trabecular Bone Microstructure in the Hip Joint and Pain in Patients with Hip Osteoarthritis.

This study aimed to investigate the relationship between clinical findings and the trabecular microstructure of the subchondral bone in patients with hip osteoarthritis (OA) due to developmental dysplasia of the hip (DDH) using multidetector row computed tomography (MDCT). A total of 63 patients (69 hips) with OA due to DDH were retrospectively reviewed, with 12 healthy controls being included for comparison. Clinical evaluation was performed using the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ). The trabecular bone microstructure was analyzed using MDCT. Regions of interest in the subchondral trabecular bones of the acetabulum and femoral head were defined in the coronal view, and various trabecular microstructural parameters were evaluated. Bone volume fraction (BV/TV) and trabecular thickness (Tb.Th) exhibited a significant positive correlation with the OA stage, whereas trabecular separation (Tb.Sp) showed a negative correlation. In addition, BV/TV and Tb.Th were negatively correlated with the JHEQ total and pain scores, whereas Tb.Sp was positively correlated with the pain score in all regions. This is the first study to evaluate the bone microstructure and its relationship with clinical findings in patients with hip OA due to DDH. Our findings suggest that as OA progresses, osteosclerotic changes increase in the acetabulum and femoral head; these changes are associated with worsening clinical symptoms, particularly pain. Targeting the subchondral bone may emerge as a novel treatment strategy for patients with OA due to DDH; nevertheless, further comprehensive studies are required.

Temporal dynamics of BMP/Nodal ratio drive tissue-specific gastrulation morphogenesis.

Anteroposterior (AP) elongation of the vertebrate body plan is driven by convergence and extension (C&E) gastrulation movements in both the mesoderm and neuroectoderm, but how or whether molecular regulation of C&E differs between tissues remains an open question. Using a zebrafish explant model of AP axis extension, we show that C&E of the neuroectoderm and mesoderm can be uncoupled ex vivo, and that morphogenesis of individual tissues results from distinct morphogen signaling dynamics. Using precise temporal manipulation of BMP and Nodal signaling, we identify a critical developmental window during which high or low BMP/Nodal ratios induce neuroectoderm- or mesoderm-driven C&E, respectively. Increased BMP activity similarly enhances C&E specifically in the ectoderm of intact zebrafish gastrulae, highlighting the in vivo relevance of our findings. Together, these results demonstrate that temporal dynamics of BMP and Nodal morphogen signaling activate distinct morphogenetic programs governing C&E gastrulation movements within individual tissues.

Effect of bifocal soft contact lenses in combination with instillations of the combined drug (Phenylephrine 5% and Tropicamide 0.8%) on the anatomical and functional parameters of the eyes and progression of myopia in pediatric patients

AIM: The study aimed to assess the influence of combined optical and pharmacological effects on the anatomical and functional parameters of the eyes and changes in refraction in pediatric patients with progressive myopia. MATERIAL AND METHODS: Bifocal soft contact lenses (BSCL) Prima BIO Bifocal were prescribed to 43 pediatric patients. At the start of the study, the average age of the children was 10.42±0.26 years, and the average myopia was 3.43±0.19 D. The effect of a combination of optical and medicinal products on the visual apparatus of children was evaluated, namely, bifocal SCLs that form peripheral myopic defocus and instillations of a combined drug containing 0.8% tropicamide and 5% phenylephrine. The combined eye drops, which contained 0.8% tropicamide and 5% phenylephrine, was prescribed once a day at night for 1 month to 23 pediatric patients after wearing the lenses for 1 month (group 1). In group 2 (n=20), patients did not receive any additional treatment, except for optical exposure. RESULTS: The habitual tone of accommodation (HTA) slightly increased after 1 month of using BSCL. In group 1, the HTA decreased to the initial level after 6 and 12 months, whereas it remained high in group 2. Over the year, refraction increased by 0.39 D in group 1 and 0.18 D in group 2 (p 0.05). The annual progression gradient decreased by 2.3 times in group 1 and 5.2 times in group 2. Over the year, the anteroposterior axis increased by 0.13 mm in group 1 and 0.05 mm in group 2. Choroidal thickness increased by 19.09 and 24.77 µm, relative accommodation reserve increased by 0.98 and 1.24 D, and the accommodation amplitude increased by 1.28 and 1.05 D, respectively. CONCLUSION: BSCLs contribute to the reduction of the annual gradient of progression (AGP) and increase in accommodation and choroidal thickness. Instillations of the drug while using BSCL help reduce the habitual tone of accommodation (HTA).

Cut-off value for the posterior tibial slope indicating the risk for retear of the anterior cruciate ligament.

The significance of the posterior tibial slope (PTS) has increasingly come into focus in anterior cruciate ligament (ACL) reconstruction being a risk factor for ACL graft failure. Nevertheless, inconsistent data on the critical value of the PTS exist. The purpose of this study was to define a cut-off value for the PTS in ACL surgery. In a retrospective cohort study, 350 revision ACL reconstructions (ACL-RR) with a failed ACL hamstring graft and 350 primary ACL reconstructions (ACL-R) were matched according to age, gender, concomitant injuries and graft characteristics and compared to a healthy control group. Using the proximal anatomic axis, lateral knee radiographs were evaluated for the PTS, interrater reliability was defined, ROC curves, Fischer's exact test and Baptista-Pike method were applied to define specificity and the odds ratio for a critical PTS value. Radiographic evaluation proved excellent interrater reliability (intraclass correlation coefficient 0.969). Evaluation of the PTS revealed 10.0 ± 2.2 (5-15) degrees in the ACL-RR group, 7.8 ± 1.8 (4.2-13) degrees in the ACL-R group and 6.6 ± 1.9 (3.6-12) degrees in the control group with significant differences between the groups (p < 0.001). A PTS value of 10.1 degrees proved a specificity of 98% for the prediction of an ACL graft failure and indicated an 11-fold risk for a retear of the ACL. A PTS exceeding 10.1 degrees carries an 11-fold risk for ACL graft failure and, therefore, should be considered in ACL reconstruction. These findings might serve as a cut-off value for the indication of a slope-reducing high tibial osteotomy in ACL surgery. Level III.

Mean pulmonary artery pressure prediction with explainable multi-view cardiac MR cine series deep learning model

BackgroundPulmonary hypertension (PH) is a heterogeneous condition and regardless of aetiology impacts negatively on survival. Diagnosis of PH is based on hemodynamic parameters measured invasively at right heart catheterization (RHC), however, a non-invasive alternative would be clinically valuable. Our aim was to estimate RHC parameters non-invasively from cardiac MR data using deep learning models and to identify key contributing imaging features. MethodsWe constructed an explainable convolutional neural network (CNN) taking cardiac MR cine series from 4 different views as input to predict mean pulmonary artery pressure (mPAP). The model was trained and evaluated on 1646 examinations. The model’s attention weight and predictive performance associated with each frame, view, or phase was used to judge its importance. Additionally, the importance of each cardiac chamber was inferred by perturbing part of the input pixels. ResultsThe model achieved a Pearson Correlation Coefficient (PCC) of 0.80 and R2 of 0.64 in predicting mPAP, and identified the right ventricle (RV) region on short-axis (SAX) view to be especially informative. ConclusionsHemodynamic parameters can be estimated non-invasively with a CNN, using MR cine series from 4 views, revealing key contributing features at the same time.

Postural Responses in Trauma-Experienced Individuals

Background: Balance and proprioception are essential elements in postural control and injury prevention. Proprioception, the body’s sense of position and movement, is closely tied to balance, which depends on input from the visual, vestibular, and somatosensory systems. This article explores the link between trauma experiences and proprioceptive dysfunction, emphasizing how heightened muscle tone, dissociation, and altered sensory processing contribute to balance issues and the risk of injury. Method: The study included 48 participants, aged 18–25. Participants completed the Emotional Regulation Scale, Dissociative Experiences Scale II, and Childhood Trauma Questionnaire, after which they had to stand on a BTrackS Balance Plate while being exposed to images that are designed to evoke emotions from the OASIS image set. The balance plate software calculated outcomes of the participants’ postural sway (total sway, sway area, root mean square (RMS) to the mediolateral (ML) and anteroposterior (AP) way, and excursion to ML and AP ways). Results: Dissociative experience shows significant correlation with RMS ML when viewing positive pictures (rτ = 0.207, p = 0.045) and when viewing negative pictures again; scores with RMS ML (rτ = 0.204, p = 0.049) but also with RMS AP (rτ = 0.209, p = 0.042) and with Excursion ML (rτ = 0.200, p = 0.049) were significant. Experiences of physical abuse affected certain indicators of postural sway when viewing positive images compared to participants with no such experience (sway area: U = 374.50, p = 0.027; RMS AP: U = 383.50, p = 0.016; Excursion ML: U = 397.00, p = 0.007). Similarly, physical neglect affected postural sway during viewing of negative images (sway area: U = 366.50, p = 0.003; RMS AP: U = 371.00, p = 0.004; Excursion ML: U = 347.00, p = 0.034; and Excursion AP: U = 353.00, p = 0.010). Conclusions: The study highlights that dissociation disrupts balance in trauma survivors, especially under emotional stress which highlights the potential for motor-based treatments.

Rarγ-Foxa1 signaling promotes luminal identity in prostate progenitors and is disrupted in prostate cancer.

Retinoic acid (RA) signaling is a master regulator of vertebrate development with crucial roles in body axis orientation and tissue differentiation, including in the reproductive system. However, a mechanistic understanding of how RA signaling governs cell lineage identity is often missing. Here, leveraging prostate organoid technology, we show that RA signaling orchestrates the commitment of adult mouse prostate progenitors to glandular identity, epithelial barrier integrity, and specification of prostatic lumen. RA-dependent RARγ activation promotes the expression of Foxa1, which synergizes with the androgen pathway for luminal expansion, cytoarchitecture and function. FOXA1 mutations are common in prostate and breast cancers, though their pathogenic mechanism is incompletely understood. Combining functional genetics with structural modeling of FOXA1 folding and chromatin binding analyses, we discover that FOXA1F254E255 is a loss-of-function mutation compromising its transcriptional function and luminal fate commitment of prostate progenitors. Overall, we define RA as an instructive signal for glandular identity in adult prostate progenitors. Importantly, we identify cancer-associated FOXA1 indels affecting residue F254 as loss-of-function mutations promoting dedifferentiation of adult prostate progenitors.

The temporal specificity of BOLD fMRI is systematically related to anatomical and vascular features of the human brain

Abstract The ability to detect fast responses with functional MRI depends on the speed of hemodynamic responses to neural activity, because hemodynamic responses act as a temporal low-pass filter which blurs rapid changes. However, the shape and timing of hemodynamic responses are highly variable across the brain and across stimuli. This heterogeneity of responses implies that the temporal specificity of fMRI signals, or the ability of fMRI to preserve fast information, could also vary substantially across the cortex. In this work we investigated how local differences in hemodynamic response timing affect the temporal specificity of fMRI. We used ultra-high field (7T) fMRI at high spatiotemporal resolution, studying the primary visual cortex (V1) as a model area for investigation. We used visual stimuli oscillating at slow and fast frequencies to probe the temporal specificity of individual voxels. As expected, we identified substantial variability in temporal specificity, with some voxels preserving their responses to fast neural activity more effectively than others. We investigated which voxels had the highest temporal specificity, and tested whether voxel timing was related to anatomical and vascular features. We found that low temporal specificity is only weakly explained by the presence of large veins or cerebral cortical depth. Notably, however, temporal specificity depended strongly on a voxel’s position along the anterior-posterior anatomical axis of V1, with voxels within the calcarine sulcus being capable of preserving close to 25% of their amplitude as the frequency of stimulation increased from 0.05Hz to 0.20Hz, and voxels nearest to the occipital pole preserving less than 18%. These results indicate that detection biases in high-resolution fMRI will depend on the anatomical and vascular features of the area being imaged, and that these biases will differ depending on the timing of the underlying neuronal activity. While we attribute this variance primarily to hemodynamic effects, neuronal nonlinearities may also influence response timing. Importantly, this spatial heterogeneity of temporal specificity suggests that it could be exploited to achieve higher specificity in some locations, and that tailored data analysis strategies may help improve the detection and interpretation of fast fMRI responses.

Active Remote Focus Stabilization in Oblique Plane Microscopy.

Light-sheet fluorescence microscopy (LSFM) has demonstrated great potential in the life sciences owing to its efficient volumetric imaging capabilities. For long term imaging, the light-sheet typically needs to be stabilized to the detection focal plane for the best imaging results. Current light-sheet stabilization methods rely on fluorescence emission from the sample, which may interrupt the scientific imaging and add to sample photobleaching. Here we show that for oblique plane microscopes (OPM), a subset of LSFM where a single primary objective is used for illumination and detection, light-sheet stabilization can be achieved without expending sample fluorescence. Our method achieves ~43nm axial precision and maintains the light-sheet well within the depth of focus of the detection system for hour-long acquisition runs in a lab environment that would otherwise detune the system. We demonstrate subcellular imaging of the actin skeleton in melanoma cancer cells with a stabilized OPM.

CineECG Repolarization Gradients Predict Acute Hemodynamic Response in CRT Patients.

A variable proportion of non-responders to cardiac resynchronization therapy (CRT) warrants the search for new approaches to optimize the position of the left ventricular (LV) lead and the CRT device programming. CineECG is a novel ECG modality proposed for the spatial visualization and quantification of myocardial depolarization and repolarization sequences. The present study aimed to evaluate CineECG-derived parameters in different pacing modes and to test their associations with acute hemodynamic responses in CRT patients. CineECG was used to construct the average electrical path within the cardiac anatomy from the 12-lead ECG. CineECG and LV dP/dt max were tested in 15 patients with nonischemic dilated cardiomyopathy and left bundle branch block (QRS: 170 ± 17 ms; LVEF: 26 ± 5.5%) under pacing protocols with different LV lead localizations. The CineECG-derived path directions were computed for the QRS and ST-T intervals for the anteroposterior (Xh), interventricular (Yh), and apicobasal (Zh) axes. In a multivariate linear regression analysis with adjustment for the pacing protocol type, the ST-T path direction Yh was independently associated with the increase in dP/dt max during CRT, [regression coefficient 639.4 (95% confidence interval: 187.9-1090.9), p = 0.006]. In ROC curve analysis, the ST-T path direction Yh was associated with the achievement of a 10% increase in dP/dt max (AUC: 0.779, p = 0.002) with the optimal cut-off > 0.084 (left-to-right direction) with sensitivity 0.67 and specificity 0.92. The acute hemodynamic response in CRT patients was associated with specific CineECG repolarization sequence parameters, warranting their further testing as potential predictors of clinical outcomes.

A transphyletic study of metazoan β-catenin protein complexes

Beta-catenin is essential for diverse biological processes, such as body axis determination and cell differentiation, during metazoan embryonic development. Beta-catenin is thought to exert such functions through complexes formed with various proteins. Although β-catenin complex proteins have been identified in several bilaterians, little is known about the structural and functional properties of β-catenin complexes in early metazoan evolution. In the present study, we performed a comparative analysis of β-catenin sequences in nonbilaterian lineages that diverged early in metazoan evolution. We also carried out transphyletic function experiments with β-catenin from nonbilaterian metazoans using developing Xenopus embryos, including secondary axis induction in embryos and proteomic analysis of β-catenin protein complexes. Comparative functional analysis of nonbilaterian β-catenins demonstrated sequence characteristics important for β-catenin functions, and the deep origin and evolutionary conservation of the cadherin–catenin complex. Proteins that co-immunoprecipitated with β-catenin included several proteins conserved among metazoans. These data provide new insights into the conserved repertoire of β-catenin complexes.

Imaging and clinical significance of tubular cell in lateral facial recess

Objective:To observe the position and morphology of tubular cell in lateral facial recess by CT scanning and surgical finding, and its clinical significance. Methods:Thirty patients（32 ears） with cholesteatoma and/or adhesive otitis media requiring radical mastoidectomy and tympanoplasty were included in this study. To observe the morphology of the tubular cell in the lateral facial recess cavity through temporal bone HRCT and surgery, and to analyze its relationship with the facial nerve. Results:Tubular cell were found in 59.4%（19/32） ears by temporal bone HRCT and through surgeon. The length ranged from 1.5-6.5 mm, with median length of 2.5 mm. All of them opened in the facial recess, ran on the posterior wall of the facial recess, and even reached the bottom of the inferior tympanic cavity or the level of the inferior wall of the external auditory canal（sagittal view and surgical findings）. Probing from the inside out, the tubular cell located between the second genu of the facial nerve and the chorda tympani, which was a part of the lateral wall of the facial nerve（facial crest）. When the tubular cell is occupied by granulation tissue, it is easy to be regarded as the facial nerve. Fully drilling out the tubular cell is helpful to cut down the facial nerve crest. In the study, the follow-up and/or postoperative no facial paralysis happens during the operation and in the follow up. Conclusion:Preoperative temporal bone HRCT can clearly show the tubular cell in the lateral facial recess cavity. Comprehensive and accurate identification of these structures is helpful to fully cut down the facial nerve crest and remove the hidden lesions in the posterior tympanic cavity.

A Descriptive Comparison of Oral Cavity Movements Between Brass Instrumentalists Performing Large Interval Slurs.

We have previously described patterns of oral cavity movement in advanced French horn players during the performance of large interval slurs. The current study expands upon that work by reporting comparisons between horn, trumpet, and trombone players performing similar large interval exercises. Real-time MRI (RT-MRI) films at 20 msec resolution were simultaneously obtained in the sagittal and coronal planes in 10 trumpet players, 9 horn players, and 10 trombone players as they performed 2 repetitions each of slur sequences spanning 1 octave and 1 octave + 3rd (interval of a tenth) at a mezzo forte dynamic level. Nine profile lines were overlaid on the sagittal images allowing the measurement of dorsal tongue edge movement using a customized MATLAB toolkit. Image J (FIJI) was utilized to measure the cross-sectional area formed between the dorsal edge of the tongue and the hard palate as depicted in coronal images. In horn and trumpet players, but not in trombone players, sagittal and coronal views demonstrate patterned tongue movements that narrow and widen the air channel during ascending and descending slurs, respectively. The magnitude of these movements is greater during larger intervals, though not perfectly consistent within each slur sequence. The sagittal views revealed these patterns to be most prominent in the anterior oral cavity rather than the middle and posterior oral cavity across all instruments. Conformational changes of the oral cavity (vocal-tract tuning) during large interval slurs in the upper register may assist performance in trumpet and horn players. Trombone players may also employ these strategies when the extreme upper register is involved, but future study must verify this.

Low-side and multi-tone suppression in the base of the gerbil cochlea

The cochlea’s mechanical response to sound stimulation is nonlinear, likely due to saturation of the mechano-electric transduction current that is part of an electromechanical feedback loop. The ability of a second tone or tones to reduce the response to a probe tone is one manifestation of nonlinearity, termed suppression. Using optical coherence tomography to measure motion within the organ of Corti, regional motion variations have been observed. Here, we report on the suppression that occurs within the organ of Corti when a high sound level, low frequency suppressor tone was delivered along with a sweep of discreet single-tones. Responses were measured in the base of the gerbil cochlea at two best frequency locations, with two different directions of observation relative to the sensory tissue’s anatomical axes. Suppression extended over a wide frequency range in the outer hair cell region, whereas it was typically limited to the best frequency peak in the reticular lamina region and at the basilar membrane. Aspects of the observed suppression were consistent with the effect of a saturating nonlinearity. Recent measurements have noted the three-dimensional nature of organ of Corti motion. The effects of suppression observed here could be due to a combination of reduced motion amplitude and altered vibration axis.

Cone beam computed tomography outcomes in patients diagnosed with compromised bone health undergoing dental implant therapy and bone augmentation

Studies examining mid-term treatment outcomes of implant placement with bone augmentation in patients with compromised bone health are lacking. The purpose of this prospective, nonrandomized cohort study was to evaluate the cone bean computed tomography (CBCT) outcomes of implant placement with bone augmentation in postmenopausal women. For this best practice, standard of care study, 78 participants received 1 test implant along with 1 or a combination of 3 bone augmentation procedures: particulate graft, expansion, or block graft. Participants were categorized as healthy (n=49) or bone compromised (n=29). Using CBCT scans made preoperatively, immediately postoperatively, and 2 years postoperatively, the augmented alveolar ridge widths were measured in a buccolingual (BL) dimension 2mm and 6mm apical to the coronal aspect of the implant's rough surface. Additionally, peri-implant bone height was measured on the mesial and distal implant surfaces at the mid-alveolar aspect of the ridge using a coronal panoramic view. Both study groups exhibited an increase in horizontal BL measurements at the 2-mm and 6-mm landmarks from preoperative to immediate postoperative time points and a minimal decrease from intermediate postoperative to 2 years postoperative. The mean proximal height decreased over time in healthy participants but did not show a significant change in participants with compromised bone. The linear mixed effects model results revealed that the mean difference between groups significantly decreased over time at the 2-mm landmark (P<.05); however, no significant group-time interactions were found for the BL width at the 6-mm landmark and proximal height measurements (P=.627). Mid-term CBCT measurements showed significant bone augmentation immediately after surgery and 2 years after surgery and stable proximal bone adjacent to implants in postmenopausal women diagnosed with compromised bone health.

A Broadband Coaxial‐to‐Elliptical Waveguide Transition Using Step‐Impedance Probe

ABSTRACTIn this letter, a broadband coaxial‐to‐elliptical waveguide (EWG) transition is proposed using the E‐plane stepped‐impedance probe (SIP). According to the E‐field distribution of the dominate TEc11 mode of the EWG, the SIP is arranged along the short axis of the EWG, and then the dominate TEc11 mode of the EWG can be excited well while its first two high‐order modes (TEc21 and TEs11) are suppressed. Accordingly, a wideband transition with single‐mode operation is achieved. To obtain good matching in the wideband, four‐step SIP is optimized. For verification, a back‐to‐back transition centered at 4.9 GHz is designed and measured. The measured impedance bandwidth with |S11| &lt; −15 dB is over 58.4%. Within it, the minimum insertion loss is 0.03 dB. Good agreement between the simulated and measured results can be observed.