Triboelectric nanogenerators (TENGs) have emerged as a next-generation sustainable power source for Internet of Things technology. Polyvinylidene fluoride (PVDF) nanofibers (NFs) have been investigated widely to enhance the TENG performance by controlling their polarity; however, controlling the surface morphology of the PVDF NFs has rarely been studied. Here, surface-roughened, churros-like PVDF NFs were fabricated by controlling the solvent evaporation kinetics. The solvent evaporation rate was modulated by varying the relative humidity (RH) during the electrospinning process. With increasing RH, the fraction of polar β-phase in the PVDF NFs increased, the specific surface area of the PVDF NFs increased gradually and the surface morphology changed from smooth to rough, finally resulting in a churros-like structure. Therefore, the output performance of the TENG devices was enhanced with increasing RH, because of the combined effects of the enlarged surface area and the increased fraction of the polar phase in the PVDF NFs. The TENG device with the churros-like PVDF NFs showed an output voltage of 234 V, current of 11 μA, and power density up to 1738 μW/cm2, giving it the capability to turn on 60 series-connected commercial light-emitting diodes without using an external charge storage circuit.

Objectives: The Chronic Otitis Media Questionnaire-12 (COMQ-12) assesses patient-reported health-related quality of life. A multinational collaborative project was performed to translate and appraise the psychometric properties of the COMQ-12 across Europe, Asia, and South America. Methods: Eight otology units from seven countries (China, Colombia, France, Italy, Japan, Korea, Turkey) created native versions of the COMQ-12 by the process of translation and back-translation. Questionnaire reliability was assessed on the basis of internal consistency by calculating Cronbach's coefficient alpha. Exploratory factor analysis was performed to identify underlying correlations between individual questionnaire items. Results: This study included 478 participants from 8 countries. Calculated values for Cronbach's coefficient alpha were between 0.71 and 0.90. Exploratory factor analysis allowed the identification of three dominant factors, the primary factor (related to hearing problems) explaining 42% of the total variance, the secondary factor (related to daily activities) explaining 30% of the variance, and the third factor (related to acute disease activity) explaining 28% of the variance. Conclusions: This is a large study of patients with chronic otitis media, from centers from within many different countries spanning Europe, Asia, and South America. This study supports the use of the COMQ-12 within the individual countries where it was tested.

Background and ObjectivesA number of etiologies of idiopathic sudden sensorineural hearing loss (ISSNHL) have been proposed, including viral infection, vascular disturbance, and immune-mediated mechanisms. Intralabyrinthine hemorrhage (ILH) as a cause of SSNHL is extremely rare, and there have been no studies defining the characteristics of hearing impairment and prognosis in patients with ISSNHL due to ILH. This study aimed to investigate the difference in impaired hearing patterns and prognosis for hearing recovery between patients with ISSNHL due to ILH confirmed by magnetic resonance imaging (MRI) and sex- and age-matched patients with ISSNHL due to causes other than ILH.Subjects and MethodsWe compared the results of audiometry and MRI in 12 patients who had ILH on MRI (hemorrhage group) and in 23 sex- and age-matched controls without abnormal findings related to their hearing loss on MRI (non-hemorrhage group). Initial hearing impairment, progression, and recovery of hearing loss were compared between the two groups.ResultsA majority of patients (92%) in the hemorrhage group complained of dizziness. Initial hearing impairment was more frequent in the hemorrhage group than in the non-hemorrhage group (94.09±35.9 vs. 66.66±30.1, p-value=0.036). The final recovery threshold in the hemorrhage group was worse (78.19±46.26 vs. 37.17±31.96, p-value=0.014) than that in the non-hemorrhage group. In the hemorrhage group, hearing recovery seemed to occur less often at high frequencies (2,000, 4,000, and 8,000 Hz) than at low frequencies (250, 500, and 1,000 Hz).ConclusionsThe presence of ILH was associated with poor hearing prognosis and the occurrence of vertigo. The abrupt onset of hearing loss associated with vertigo and the presence of hyperresonance on fat-suppressed T1-weighted MRI images of labyrinthic fluid strongly suggests acute intralabyrinthine hemorrhage, and is predictive of considerable hearing impairment and poor prognosis.

Background and Objectives The Chronic Otitis Media Questionnaire-12 (COMQ-12) was developed in the United Kingdom to assess disease specific Health-Related Quality of Life (HRQoL) of chronic otitis media (COM) patients. We assessed the validity of Korean version of COMQ-12 (K-COMQ-12) and its correlation with the disease activity of COM classified according to the type of surgery. Materials and Method We translated the original COMQ-12 into Korean and also performed a back-translation of the translated text into English. Enrolled were 106 COM patients and 106 healthy subjects. Cronbach alpha was used to evaluate internal consistency, and factor analysis was performed to prove reliability. We compared K-COMQ-12 scores between normal subjects and COM patients to assess validity. The scores were also compared by dividing groups according to disease activity of COM. Results Cronbach's alpha showed good internal consistency (0.939). There was a significant difference in K-COMQ-12 scores between healthy subjects (1.99±4.34) and COM patients (22.69±12.41). Also, scores go higher as the disease activity of COM increased. A cutoff score of 6 of K-COMQ-12 sets 0.915 of sensitivity and 0.934 of specificity. Conclusion The K-COMQ-12 is a reliable and valid tool to assess HRQoL in patients with COM. The K-COMQ-12 could be also used as an objective tool that reflects the disease activity of COM.

Stem cells possess a promising potential in the clinical field. The application and effective delivery of stem cells to the desired target organ or site of injury plays an important role. This review describes strategies on understanding the effective delivery of stem cells labeled with superparamagnetic iron oxide nanoparticles (SPION) using an external magnet to enhance stem cell migration in vivo and in vitro. Fourteen total publications among 174 articles were selected. Stem cell type, SPION characteristics, labeling time, and magnetic force in vivo are considered important factors affecting the effective delivery of stem cells to the homing site. Most papers reported that the efficiency was increased when magnet is applied compared to those without. Ten studies analyzed the homing competency of SPION-labeled MSCs in vitro by observing the migration of the cell toward the external magnet. In cell-based experiments, the mechanism of magnetic attraction, the kind of nanoparticles, and various stem cells were studied well. Meta-analysis has shown the mean size of nanoparticles and degree of recovery or regeneration of damaged target organs upon in vivo studies. This strategy may provide a guideline for designing studies involving stem cell homing and further expand stem cell.

The present study explores the scientific evidence on whether music exposure temporarily or permanently affects hearing sensitivity in young adults. Six electronic databases were searched using related keywords for the four categories of personal listening devices, listening habits, hearing outcomes, and age. The Hedges’ g and its 95% confidence intervals (CIs) were estimated. A Higgins I2 was also used to check for heterogeneity. To test for publication bias, funnel plots were drawn using Egger’s regression. Based on the inclusion criteria, 16 studies were divided into two groups to identify short-term hearing changes (n = 7) and long-term hearing changes (n = 9). In the short term, there was no significant immediate change in the thresholds or amplitudes after the music exposure, although pure-tone thresholds (PTAs) and distortion product otoacoustic emissions (DPOAEs) did show the highest effect size (−0.344, CI −0.727 to 0.038) and (0.124, CI −0.047 to 0.296) at 4 kHz. On the other hand, for long-term hearing changes, the PTA provided the highest effect size at 6 kHz (−0.525, CI −0.897 to −0.154) and 8 kHz (–0.486, CI −0.819 to −0.152), while also implying that habitual and repeated personal listening device (PLD) usage can act on some significant hearing changes in audiological tests. We conclude that the use of a PLD produces a few temporary hearing changes at 4 kHz after its use but that the changes are then reversed. However, it is important to note heavy PLD users’ experience regarding permanent changes in their hearing thresholds at high frequencies, and the public should be educated on this issue.

HighlightsThere is a problem of mismatch of the center of the bone conduction-floating mass transducer (BC-FMT) between the computer simulation and the actual drilling.Image-guided surgical navigation to aid in the placement of the BC-FMT at the simulated location is a simple procedure.This preoperative simulation method is feasible, but this study suggests that applied neuronavigation is essential for Bonebridge implantation.

This study aimed to assess the long-term recurrence rate and correlations between recurrence and potential risk factors in patients with benign paroxysmal positional vertigo (BPPV).Design: A total of 548 consecutive patients who demonstrated typical posterior or horizontal BPPV between January 2010 and December 2012 were included in this prospective study. All patients were contacted by phone every 6 months for 5 years and were asked to revisit the clinic when they experienced positional vertigo to be reexamined for recurrence. Recurrence of BPPV was defined as having positional vertigo and nystagmus confirmed following a symptom-free period of at least 7 days after complete resolution. We assessed the 5-year recurrence rate of BPPV, and the time point of recurrence in all patients as well as the risk factors of BPPV recurrence, including the clinical characteristics, therapeutic results of BPPV, and various comorbidities.Results: Among the 548 patients, 121 (22.1 %) had at least one recurrence. Of these, 78 patients (54.5%) had only one recurrence within 5 years, while 43 (45.5%) patients experienced two or more recurrences. A recurrence occurred within 1 year in 82 patients (67.8%). The Cox proportional hazard ratio analysis found that head trauma (p = 0.015), Meniere's disease (p = 0.016), the number of canalith repositioning procedures performed (p = 0.037), and the number of previous vertigo attacks (p = 0.038) were significant risk factors of BPPV recurrence as opposed to hypertension or hyperlipidemia. Conclusions:The recurrence rate of BPPV was 22.1% at 5 years after the initial treatment. About 70% of recurred patients had a recurrence within 1 year. Head trauma, ipsilateral Meniere's disease, the number of canalith repositioning procedures performed, and the number of previous vertigo attacks were significant risk factors of BPPV recurrence.