Experimental and theoretical investigation of the influence of post-curing on mixed mode fracture properties of 3d-printed polymer samples.

This study explores the mechanical properties and fracture characteristics of additively manufactured acrylonitrile butadiene styrene specimens, focusing on the impact of raster angle and post-process heat treatment. To this end, a large number of tensile and semi-circular bending samples with three distinct raster angles of 0/90°, 22/ - 68°, and 45/ - 45° were prepared and exposed to four types of heat treatments with different temperature and pressure conditions. Simultaneously, theoretical models of maximum tangential stress (MTS) and generalized MTS (GMTS) were developed to estimate the onset of specimen fracture under mixed-mode in-plane loading conditions. Recognizing the non-linear behavior within the stress-strain curve of tensile test samples, particularly in the annealed samples, an effort was undertaken to transform the original ductile material into a virtual brittle material through the application of the equivalent material concept (EMC). This approach serves the dual purpose of bypassing intricate and tedious elastoplastic analysis, while concurrently enhancing the precision of the GMTS criterion. The experimental findings have revealed that while the annealing process has a minimal effect on the yield strength, it considerably enhances energy absorption capacity, increases fracture toughness, and reduces the anisotropy. Additionally, the combined EMC-GMTS criterion has demonstrated its capability to predict the failure of the additively manufactured parts with an acceptable level of accuracy.

VO-Notches Subjected to Tension-Torsion Loading: Experimental and Theoretical Fracture Study on Polymeric Samples.

In this research, the fracture behavior of brittle specimens weakened by V-shaped notches with end holes (VO-notches) is studied. First, an experimental investigation is conducted to evaluate the effect of VO-notches on fracture behavior. To this end, VO-notched samples of PMMA are made and exposed to pure opening mode loading, pure tearing mode loading, and some combinations of these two loading types. As part of this study, samples with end-hole radii of 1, 2, and 4 mm are prepared to determine the effect of the notch end-hole size on the fracture resistance. Second, two well-known stress-based criteria, namely the maximum tangential stress (MTS) criterion and the mean stress (MS) criterion, are developed for VO-shaped notches subjected to mixed-mode I/III loading, also determining the associated fracture limit curves. A comparison between the theoretical and the experimental critical conditions indicates that the resulting VO-MTS and VO-MS criteria predict the fracture resistance of VO-notched samples with about 92% and 90% accuracy, respectively, confirming their capacity to estimate fracture conditions.

Better Compression With Deep Pre-Editing.

Could we compress images via standard codecs while avoiding visible artifacts? The answer is obvious - this is doable as long as the bit budget is generous enough. What if the allocated bit-rate for compression is insufficient? Then unfortunately, artifacts are a fact of life. Many attempts were made over the years to fight this phenomenon, with various degrees of success. In this work we aim to break the unholy connection between bit-rate and image quality, and propose a way to circumvent compression artifacts by pre-editing the incoming image and modifying its content to fit the given bits. We design this editing operation as a learned convolutional neural network, and formulate an optimization problem for its training. Our loss takes into account a proximity between the original image and the edited one, a bit-budget penalty over the proposed image, and a no-reference image quality measure for forcing the outcome to be visually pleasing. The proposed approach is demonstrated on the popular JPEG compression, showing savings in bits and/or improvements in visual quality, obtained with intricate editing effects.

The Additional Effect of Vestibular Rehabilitation Therapy on Residual Dizziness After Successful Modified Epley Procedure for Posterior Canal Benign Paroxysmal Positional Vertigo.

Purpose The aim of the study was to evaluate the additional effect of vestibular rehabilitation therapy (VRT) compared with the modified Epley procedure alone on residual dizziness after a successful modified Epley procedure in patients with posterior canal benign paroxysmal positional vertigo (BPPV). Method In this cross-sectional analytical comparative study, 47 patients (35 women and 12 men) aged 18-80 years with posterior canal BPPV were randomly assigned to one of two following groups: the control group, who received the modified Epley procedure only, and the VRT group, who received the modified Epley procedure plus vestibular rehabilitation for 4 weeks. Outcome measures, including the Dizziness Handicap Inventory (DHI), the Vertigo Symptom Scale-Long Version (VSS-L), and the Vertigo Symptom Scale-Short Form (VSS-SF), were conducted on the same session before initial therapy (T1), at 48 hr later (T2), and at 4 weeks later (T3). Presence or absence of residual dizziness was evaluated at T2. Results Residual dizziness was found in 20 (42.6%) patients after a successful modified Epley procedure. There was no statistically significant difference between the mean DHI, VSS-L, and VSS-SF scores at T1, T2, and T3 in patients who manifested with residual dizziness and those without residual dizziness in both groups. The average DHI, VSS-L, and VSS-SF score reduced during the time in both groups. These results were demonstrated that the VRT group and the control group have similar reductions in symptoms after treatment with the VRT plus modified Epley procedure and the modified Epley procedure only, respectively. Conclusions Residual dizziness is a common condition after a successful modified Epley procedure for BPPV. The VRT plus modified Epley procedure is as effective as modified Epley procedure alone in the management of residual dizziness. Further studies with supervised and customized VRT and longer follow-up periods are needed. Supplemental Material https://doi.org/10.23641/asha.14825508.

Symmetrical electrophysiological brain responses to unilateral and bilateral auditory stimuli suggest disrupted spatial processing in schizophrenia.

Research has found auditory spatial processing deficits in patients with schizophrenia (SCZ), but no study has examined SCZ patients' auditory spatial processing at both pre-attentional and attentional stages. To address this gap, we investigated schizophrenics' brain responses to sounds originating from different locations (right, left, and bilateral sources). The event-related potentials (ERPs) of 25 chronic schizophrenic patients and 25 healthy subjects were compared. Mismatch negativity (MMN) in response to frequency and duration deviants was assessed. Two P3 components (P3a and P3b) were elicited via a frequency discrimination task, and MMN and P3 were recorded through separate monaural and dichotic stimulation paradigms. Our results corroborated the previously published finding that MMN, P3a, and P3b amplitudes are reduced in SCZ patients, but they showed no significant effect of stimulus location on either MMN or P3. These results indicated similarity between the SCZ patients and healthy individuals as regards patterns of ERP responses to stimuli that come from different directions. No evidence of auditory hemispatial bias in the SCZ patients was found, supporting the existence of non-lateralized spatial processing deficits in such patients and suggesting compensatory changes in the hemispheric laterality of patients' brains.

Evaluation of Saccule Function in Patients with Vitamin D Deficiency.

BACKGROUND AND OBJECTIVES: Considering important role of vitamin D in many physiological processes including vestibular system in the ear, aim of present study is to evaluate saccule function via cervical vestibular evoked myogenic potential (cVEMP), in patients with vitamin D deficiency. Subjects and. METHODS: After routine audiological tests, cVEMP were recorded in 15 patients with vitamin D deficiency and 16 normal subjects. The short tone burst (95 dB nHL, 500 Hz) was presented to ears. cVEMP was recorded with surface electromyography over the contracted ipsilateral sternocleidomastoid muscle. RESULTS: Mean of p13, n13, interpeak latencies and amplitude ratios were measured in both groups. Statistical analysis did not show differences between two groups. CONCLUSIONS: Maybe serum 25-hydroxyvitamin D concentration was not low enough to have effect on saccule in the patients in present study or saccule have had low susceptibility to effects of vitamin D deficiency. For better judgment about effect of vitamin D deficiency on saccular function planning studies with high sample size is recommended.

NIMA: Neural Image Assessment.

Automatically learned quality assessment for images has recently become a hot topic due to its usefulness in a wide variety of applications such as evaluating image capture pipelines, storage techniques and sharing media. Despite the subjective nature of this problem, most existing methods only predict the mean opinion score provided by datasets such as AVA [1] and TID2013 [2]. Our approach differs from others in that we predict the distribution of human opinion scores using a convolutional neural network. Our architecture also has the advantage of being significantly simpler than other methods with comparable performance. Our proposed approach relies on the success (and retraining) of proven, state-of-the-art deep object recognition networks. Our resulting network can be used to not only score images reliably and with high correlation to human perception, but also to assist with adaptation and optimization of photo editing/enhancement algorithms in a photographic pipeline. All this is done without need for a "golden" reference image, consequently allowing for single-image, semantic- and perceptually-aware, no-reference quality assessment.

Static Balance in Patients with Vestibular Impairments: A Preliminary Study.

Aims. Vestibular system is indicated as one of the most important sensors responsible for static and dynamic postural control. In this study, we evaluated static balance in patients with unilateral vestibular impairments. Materials and Methods. We compared static balance control using Kistler force plate platform between 10 patients with unilateral vestibular impairments and 20 normal counterparts in the same sex ratio and age limits (50 ± 7). We evaluated excursion and velocity of center of pressure (COP) and path length in anteroposterior (AP) and mediolateral (ML) planes with eyes open and with eyes closed. Results. There was no significant difference between COP excursions in ML and AP planes between both groups with eyes open and eyes closed (p value > 0.05). In contrast, the difference between velocity and path length of COP in the mentioned planes was significant between both groups with eyes open and eyes closed (p value < 0.05). Conclusions. The present study showed the static instability and balance of patients with vestibular impairments indicated by the abnormal characteristics of body balance.

Auditory Neuropathy/Dyssynchrony in Biotinidase Deficiency.

Biotinidase deficiency is a disorder inherited autosomal recessively showing evidence of hearing loss and optic atrophy in addition to seizures, hypotonia, and ataxia. In the present study, a 2-year-old boy with Biotinidase deficiency is presented in which clinical symptoms have been reported with auditory neuropathy/auditory dyssynchrony (AN/AD). In this case, transient-evoked otoacoustic emissions showed bilaterally normal responses representing normal function of outer hair cells. In contrast, acoustic reflex test showed absent reflexes bilaterally, and visual reinforcement audiometry and auditory brainstem responses indicated severe to profound hearing loss in both ears. These results suggest AN/AD in patients with Biotinidase deficiency.

Multifocal Electroretinogram in Diabetic Macular Edema; Correlation with Visual Acuity and Optical Coherence Tomography.

PURPOSE: To evaluate multifocal electroretinogram (mfERG) changes in eyes with diabetic macular edema (DME) and investigate any possible correlation with optical coherence tomography (OCT) features and visual acuity (VA). METHODS: Twenty-nine right eyes of 29 subjects with DME due to non-proliferative diabetic retinopathy and 30 eyes of 30 normal subjects were evaluated. All patients underwent a complete ophthalmic examination. Sixty-one scaled hexagon mfERG responses were recorded. Components of the first order kernel of N1, N2, and P1 in five concentric rings centered on the fovea, were measured in both groups. Correlation and regression analyses were performed among VA, central macular thickness (CMT) based on OCT, mfERG amplitude, and latency of the N1, N2 and P1 waves. RESULTS: Significant differences were observed in all mfERG parameters in five-ring regions of the retina between eyes with DME versus controls (P < 0.05). There were significant correlations among VA with N2 (P = 0,001, b = 0.73) and P1 amplitudes (P = 0.001, b = -0.84) in the central macular area, and there was a borderline association between VA and CMT (P = 0.042, b = 0.392). CONCLUSION: Amplitudes of mfERG components (N1, P1, and N2) are significantly reduced and their latencies are delayed in eyes with DME indicating functional impairment in the outer retina. The mfERG total amplitude was significantly correlated with VA even more than CMT, therefore the combined use of OCT and mfERG for macular evaluation may better evaluate visual status in DME patients.

Effect of geometrical parameters on the performance of longitudinal functionally graded femoral prostheses.

This study aimed to assess the performance of different longitudinal functionally graded femoral prostheses. This study was also designed to develop an appropriate prosthetic geometric design for longitudinal functionally graded materials. Three-dimensional models of the femur and prostheses were developed and analyzed. The elastic modulus of these prostheses in the sagittal plane was adjusted along a gradient direction from the distal end to the proximal end. Furthermore, these prostheses were composed of titanium alloy and hydroxyapatite. Results revealed that strain energy, interface stress, and developed stress in the femoral prosthesis and the bone were influenced by prosthetic geometry and gradient index. In all of the prostheses with different geometries, strain energy increased as gradient index increased. Interface stress and developed stress decreased. The minimum principal stress and the maximum principal stress of the bone slightly increased as gradient index increased. Hence, the combination of the femoral prosthetic geometry and functionally graded materials can be employed to decrease stress shielding. Such a combination can also be utilized to achieve equilibrium in terms of the stress applied on the implanted femur constituents; thus, the lifespan of total hip replacement can be prolonged.

Effects of vowel auditory training on concurrent speech segregation in hearing impaired children.

OBJECTIVE: This clinical trial investigated the ability of concurrent speech segregation in hearing impaired children. The auditory behavioral responses and auditory late responses (ALRs) were compared between test and control groups prior to vowel auditory training and after 3 and 6 months of vowel auditory training to find the effects of bottom-up training on concurrent speech segregation in hearing impaired children. METHODS: Auditory behavioral responses for 5 vowels and ALRs for double synthetic vowels, with special physical properties, were recorded in a timetable in 30 hearing impaired children (test group = 15 and control group = 15). RESULTS: Identification score and reaction time data showed that the test group was approximately proficient for some vowels (P < .05 for vowels /æ/, /e/, and /u:/) and took less time to process after 6 months of training. N1-P2 amplitude indexing of the vowel change detection and reflecting central auditory speech representation without active client participation has been increased in the test group (P < .05). CONCLUSION: The present study showed training-related improvements in concurrent speech segregation. This information provided evidence for bottom-up training based on F0, its differences in auditory scene analysis, and neural underpinnings.

Comparison of various functionally graded femoral prostheses by finite element analysis.

This study is focused on finite element analysis of a model comprising femur into which a femoral component of a total hip replacement was implanted. The considered prosthesis is fabricated from a functionally graded material (FGM) comprising a layer of a titanium alloy bonded to a layer of hydroxyapatite. The elastic modulus of the FGM was adjusted in the radial, longitudinal, and longitudinal-radial directions by altering the volume fraction gradient exponent. Four cases were studied, involving two different methods of anchoring the prosthesis to the spongy bone and two cases of applied loading. The results revealed that the FG prostheses provoked more SED to the bone. The FG prostheses carried less stress, while more stress was induced to the bone and cement. Meanwhile, less shear interface stress was stimulated to the prosthesis-bone interface in the noncemented FG prostheses. The cement-bone interface carried more stress compared to the prosthesis-cement interface. Stair climbing induced more harmful effects to the implanted femur components compared to the normal walking by causing more stress. Therefore, stress shielding, developed stresses, and interface stresses in the THR components could be adjusted through the controlling stiffness of the FG prosthesis by managing volume fraction gradient exponent.

Nonlocal image editing.

In this paper, we introduce a new image editing tool based on the spectrum of a global filter computed from image affinities. Recently, it has been shown that the global filter derived from a fully connected graph representing the image can be approximated using the Nyström extension. This filter is computed by approximating the leading eigenvectors of the filter. These orthonormal eigenfunctions are highly expressive of the coarse and fine details in the underlying image, where each eigenvector can be interpreted as one scale of a data-dependent multiscale image decomposition. In this filtering scheme, each eigenvalue can boost or suppress the corresponding signal component in each scale. Our analysis shows that the mapping of the eigenvalues by an appropriate polynomial function endows the filter with a number of important capabilities, such as edge-aware sharpening, denoising, tone manipulation, and abstraction, to name a few. Furthermore, the edits can be easily propagated across the image.

Global Image Denoising.

Most existing state-of-the-art image denoising algorithms are based on exploiting similarity between a relatively modest number of patches. These patch-based methods are strictly dependent on patch matching, and their performance is hamstrung by the ability to reliably find sufficiently similar patches. As the number of patches grows, a point of diminishing returns is reached where the performance improvement due to more patches is offset by the lower likelihood of finding sufficiently close matches. The net effect is that while patch-based methods, such as BM3D, are excellent overall, they are ultimately limited in how well they can do on (larger) images with increasing complexity. In this paper, we address these shortcomings by developing a paradigm for truly global filtering where each pixel is estimated from all pixels in the image. Our objectives in this paper are two-fold. First, we give a statistical analysis of our proposed global filter, based on a spectral decomposition of its corresponding operator, and we study the effect of truncation of this spectral decomposition. Second, we derive an approximation to the spectral (principal) components using the Nyström extension. Using these, we demonstrate that this global filter can be implemented efficiently by sampling a fairly small percentage of the pixels in the image. Experiments illustrate that our strategy can effectively globalize any existing denoising filters to estimate each pixel using all pixels in the image, hence improving upon the best patch-based methods.

Concurrent auditory perception difficulties in older adults with right hemisphere cerebrovascular accident.

BACKGROUND: Older adults with cerebrovascular accident (CVA) show evidence of auditory and speech perception problems. In present study, it was examined whether these problems are due to impairments of concurrent auditory segregation procedure which is the basic level of auditory scene analysis and auditory organization in auditory scenes with competing sounds. METHODS: Concurrent auditory segregation using competing sentence test (CST) and dichotic digits test (DDT) was assessed and compared in 30 male older adults (15 normal and 15 cases with right hemisphere CVA) in the same age groups (60-75 years old). For the CST, participants were presented with target message in one ear and competing message in the other one. The task was to listen to target sentence and repeat back without attention to competing sentence. For the DDT, auditory stimuli were monosyllabic digits presented dichotically and the task was to repeat those. RESULTS: Comparing mean score of CST and DDT between CVA patients with right hemisphere impairment and normal participants showed statistically significant difference (p=0.001 for CST and p<0.0001 for DDT). CONCLUSION: The present study revealed that abnormal CST and DDT scores of participants with right hemisphere CVA could be related to concurrent segregation difficulties. These findings suggest that low level segregation mechanisms and/or high level attention mechanisms might contribute to the problems.

How to SAIF-ly boost denoising performance.

Spatial domain image filters (e.g., bilateral filter, non-local means, locally adaptive regression kernel) have achieved great success in denoising. Their overall performance, however, has not generally surpassed the leading transform domain-based filters (such as BM3-D). One important reason is that spatial domain filters lack efficiency to adaptively fine tune their denoising strength; something that is relatively easy to do in transform domain method with shrinkage operators. In the pixel domain, the smoothing strength is usually controlled globally by, for example, tuning a regularization parameter. In this paper, we propose spatially adaptive iterative filtering (SAIF) is the Middle Eastern/Arabic name for sword. This acronym somehow seems appropriate for what the algorithm does by precisely tuning the value of the iteration number. a new strategy to control the denoising strength locally for any spatial domain method. This approach is capable of filtering local image content iteratively using the given base filter, and the type of iteration and the iteration number are automatically optimized with respect to estimated risk (i.e., mean-squared error). In exploiting the estimated local signal-to-noise-ratio, we also present a new risk estimator that is different from the often-employed SURE method, and exceeds its performance in many cases. Experiments illustrate that our strategy can significantly relax the base algorithm's sensitivity to its tuning (smoothing) parameters, and effectively boost the performance of several existing denoising filters to generate state-of-the-art results under both simulated and practical conditions.

The role of auditory brainstem response in diagnosing auditory impairments of Dejerine-Sottas.

Dejerine-Sottas disease is classified as hereditary motor sensory neuropathy (HMSN) type III and shows evidence of Friedreich's ataxia, significant reduction in nerve conduction velocity (NCV), hypomyelination and demyelination of the nerve fibers. In this study, a 10-years-old girl with Dejerine-Sottas disease is presented in which routine clinical signs (ataxia and reduced NCV) seem with significant impairments of auditory brainstem pathway. It is indicated that pure tone audiometry, standard tympanometry (tympanometry and acoustic reflex), and otoacoustic emissions (OAEs) showed normal results in both ears (normal peripheral auditory system). In contrast, auditory brainstem responses (ABRs) indicated abnormal findings in absolute latencies of I, III, and V and inter-peak latencies of I-III and I-V. These findings suggested auditory brainstem involvement especially in low and mid regions.