Comparisons of Audiologic Characteristics in Patients with Continuous and Intermittent Tinnitus.

BACKGROUND: No studies to date have compared audiologic characteristics in patients with continuous and intermittent tinnitus. The present study classified tinnitus patients into continuous and intermittent groups based on tinnitus duration and compared their audiologic characteristics. METHODS: This study enrolled 604 patients with tinnitus from January 2019 to December 2022. Clinical manifestations, PTA results, the frequency and loudness of tinnitus, ABR, DPOAE, and TEOAE tests were compared in patients with continuous and intermittent tinnitus. RESULTS: Of the 604 patients, 231 (38.2%) had continuous and 373 (61.8%) had intermittent tinnitus. There were no significant between-group differences in otologic symptoms, tinnitus onomatopoeia. PTA showed that hearing thresholds, except at 125 Hz, were significantly higher in patients with continuous rather than intermittent tinnitus. The loudness of tinnitus was significantly greater in patients with continuous rather than intermittent tinnitus. ABR tests showed that the absolute latency of wave V was significantly longer in continuous than in intermittent tinnitus. Signal-to-noise ratios on TEOAE tests were significantly lower in patients with continuous rather than intermittent tinnitus at all frequencies tested (1, 1.5, 2, 3, and 4 kHz). Response rates to sound stimuli at all frequencies, except for 1 kHz, were significantly lower on DPOAE tests in patients with continuous rather than intermittent tinnitus. CONCLUSIONS: Continuous tinnitus is more common in males, more persistent over time, and is associated with a higher rate of hearing loss. In contrast, intermittent tinnitus is more common in women, appears acutely, and is associated with a relatively lower rate of hearing loss. Based on the findings of the current paper, it seems that audiologic characteristics may differ between patients with continuous and intermittent tinnitus.

Herpes Zoster Oticus with Concurrent Hearing Loss: A Study on Clinical Characteristics and Prognosis.

This study aimed to analyze the clinical characteristics and treatment prognoses of patients with Herpes Zoster Oticus (HZO) and concurrent hearing loss (HL). Various clinical characteristics of 192 patients with HZO, with or without concurrent HL, from 2016 to 2020 were retrospectively analyzed through a chart review. All patients were followed-up until recovery or up to 12 months. Demographic and clinical findings were compared between the groups, and the recovery rates of facial palsy, hearing, and other clinical features were analyzed. Facial palsy recovery was analyzed using the House-Brackmann (HB) grading system, and hearing recovery rates were analyzed using the Siegel criteria. Of the 192 patients diagnosed with HZO, 142 had no hearing loss (HZO without HL), and 50 had hearing loss (HZO with HL). While both groups had similar ages, treatment timings, and underlying diseases, the HZO w HL group had a significantly higher rate of dizziness and tinnitus, but received more intratympanic steroid injections. In terms of facial palsy, there were no significant differences in the initial HB grade or recovery rates between the groups. Within the HZO w HL group, hearing loss severity varied, with 52% experiencing mild loss and only 16% achieving complete recovery. Descending-type audiograms were the most common at 66%. In patients with HZO, there was no statistically significant difference between the degree of initial facial paralysis and the degree of recovery of the final facial paralysis according to concurrent HL. However, among patients with concurrent HL, the hearing recovery rate in the HZO group was low.

Association between Serum Varicella-Zoster Virus IgM and IgG and Prognosis of Ramsay Hunt Syndrome.

Ramsay Hunt syndrome (RHS) has a poor prognosis because of varicella-zoster virus (VZV) infection. This is most closely related to severe inflammation in the geniculate ganglion of the facial nerve due to VZV infection or reactivation. This study investigated whether there were differences in the prognosis and accompanying symptoms of facial paralysis based on the presence or absence of VZV IgM and IgG antibodies. This study was conducted as a retrospective chart analysis of 105 patients with RHS who were admitted to our hospital between 2015 and 2021. The House-Brackmann (HB) grade and electroneurography (ENoG) was used to evaluate the degree of facial paralysis. Patients' subjective symptoms were evaluated by dividing them into dizziness, tinnitus, hyperacusis, and hearing loss. No difference was observed in the initial HB grade with or without IgM; however, the final HB grade was significantly higher in IgM-positive patients than in IgM-negative patients (p < 0.05). Further, when IgM was positive, the value of the orbicularis oculi muscle in the ENoG test results was significantly higher (p < 0.05), and symptoms of tinnitus and hyperacusis occurred more frequently (p < 0.05). The initial and final HB grades were significantly higher in IgG-positive patients than in IgG-negative patients (p < 0.05). When IgG was positive, the values of nasalis and oris muscles in the ENoG test results were significantly higher (p < 0.05), and symptoms of dizziness occurred more frequently (p < 0.05). This study confirmed that the more active the immunological action of the VZV in the body, the greater the damage to the facial and vestibulocochlear nerves, which are associated with the degree of facial paralysis and the accompanying otologic symptoms.

Hybrid carbon thermal interface materials for thermoelectric generator devices.

Thermal interface materials (TIMs) are extensively used in electronic devices as efficient heat transfer materials. We fabricated all-carbon TIMs by hybridizing single-wall carbon nanotubes (SWCNTs) with graphite and demonstrated their performance by applying them to a thermoelectric generator (TEG) device. The hybrid carbon TIM exhibited maximum thermal conductivity when the SWCNT content was near 10 wt%. The TIM thermal contact resistance measured by a home-made calorimeter setup was 2.19 × 10-4 m2K/W, which did not vary with temperature but decreased with applied pressure. Post-treatment of the TIM with a silane coupling agent further reduced the TIM thermal contact resistance by 30%. When the TIM was placed between a TEG device and a copper heat reservoir, the TEG output power increased with the temperature difference across the TEG and applied pressure. Moreover, the post-treatment of the TIM enhanced the output power of the TEG device by up to 18.5%. This work provides a simple and effective pathway towards a carbon-based TIM that can be applied to a high temperature TEG.

Polymer-dispersed liquid crystal devices with graphene electrodes.

Although polymer-dispersed liquid crystal (PDLC) devices have considerable potential application in smart windows, the high material cost of the indium tin oxide (ITO) electrodes conventionally used in these devices hinders their wide usage. In this work, we explore the use of graphene electrodes as a potential substitute for ITO electrodes in PDLC devices. The fabricated PDLC devices with graphene electrodes exhibit higher contrast and faster response than PDLC devices with ITO electrodes fabricated using the same chemical formulation and polymerization process. However, they also exhibit higher operation voltage and haze, which is primarily attributed to the inherently large resistance and inhomogeneity of the large-area graphene sheets initially transferred onto the transparent substrates. PDLC devices with graphene electrodes are robust under standard operating conditions and also have the advantage of flexibility and stretchability, unlike PDLCs with ITO electrodes.

Optical Properties of Cu-Doped ZnO Films Prepared by Cu Solution Coating.

This work demonstrates the fabrication of Cu-doped ZnO films by Cu solution coating method. Cu ink was spin coated on ZnO thin films prepared by e-beam deposition. After curing and annealing at high temperatures, structural, morphological and optical properties of the films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectrofluorometer, respectively. The XRD results showed that ZnO films formed polycrystalline with a hexagonal wurtzite structure, and the grain size increased with increasing the annealing temperature from 500 to 850 °C. The changes in lattice parameters were caused by grain size, strain, and residual stress. Morphological analysis have revealed that the Cu-doped ZnO film after annealing at 500 °C has flat surface with uniformly distributed grain size, which became porous after higher temperature annealing process. Energy dispersive spectroscopy (EDS) and photoluminescence spectras have shown the presence of Zn, Cu, and O elements, and combined violet, blue, green and weak red emissions between 350 and 650 nm in the ZnO films, respectively.

Electrically tunable birefringence of a polymer composite with long-range orientational ordering of liquid crystals.

We report an optical film with electrically tunable birefringence in which the liquid crystals (LCs), mixed with the host polymer, form long-range ordering. The film was prepared through polymerization without phase separation between the LCs and polymers. Driving voltage below 30 V for full switching of birefringence is achieved in a 6 µm-thick film. Electro-optical investigations for the film suggest that the long-range ordering of the LCs mixed in the film caused by polymerization lead to rotations of the LCs as well as optical anisotropy in the film. These films with electrically tunable birefringence could have applications as flexible light modulators and phase retardation films for 2D-3D image switching.

Electroluminescent devices with function of electro-optic shutter.

The polymer-dispersed liquid crystal (PDLC) was used as a dielectric layer of electroluminescent (EL) device to provide multi-function of electroluminescence and electro-optic shutter. A 50 µm-thick PDLC layer was formed between a transparent electrode and a ZnS:Cu phosphor layer. The electro-optic properties of the EL device were not distorted by the introduction of the PDLC layer. The extraction efficiency of luminescence was improved by more than 14% by PDLC layer. The transmittance of the PDLC was also founded not to be degraded significantly by excitation frequency. Therefore, the electroluminescence of the device was ignited by excitation frequency at a given voltage for full transparency of the PDLC. This device has great potential for applications in transparent displays with the function of a privacy window.