Compact Measurement of the Optical Power in High-Power LED Using a Light-Absorbent Thermal Sensor.

LED (Light-Emitting Diode) presents advantages such as luminescence, reliability, durability compared with conventional lighting. It has been widely applied for life, healthcare, smart farm, industry, and lighting from indoor to the automotive headlamp. However, the LED is vulnerable to thermal damage originated from the high junction temperature, especially in high power applications. Hence, it requires precise qualification on the optical power and the junction temperature from the pilot line to secure reliability. In this study, the photo-thermal sensor is proposed by employing a sheet-type thermocouple composed of photo-absorbent metal film and thermocouple. This sensor aims low-cost qualification in pilot line for high-power luminous devices and optical monitoring of costly luminaire such as automobile LED headlamp. The sensor is designed to detect the increased temperature response of LED hot spots from the transferred thermal power and absorbed optical power. The temperature response of each sheet-type thermocouple is utilized as a signal output of the absorbed optical power and hot spot temperature based on the introduced sensor equation. The proposed thermal sensor is evaluated by comparing the experiment with the measured reference value from the integrating sphere and the attached thermocouple at a junction. The experiment result reveals 3% of the maximum error for the optical power of 645 mW.

Review of Pharmacotherapy for Tinnitus.

Various medications are currently used in the treatment of tinnitus, including anesthetics, antiarrhythmics, anticonvulsants, antidepressants, antihistamines, antipsychotics, anxiolytics, calcium channel blockers, cholinergic antagonists, NMDA antagonists, muscle relaxants, vasodilators, and vitamins. To date, however, no medications have been specifically approved to treat tinnitus by the US Food and Drug Administration (FDA). In addition, medicines used to treat other diseases, as well as foods and other ingested materials, can result in unwanted tinnitus. These include alcohol, antineoplastic chemotherapeutic agents and heavy metals, antimetabolites, antitumor agents, antibiotics, caffeine, cocaine, marijuana, nonnarcotic analgesics and antipyretics, ototoxic antibiotics and diuretics, oral contraceptives, quinine and chloroquine, and salicylates. This review, therefore, describes the medications currently used to treat tinnitus, including their mechanisms of action, therapeutic effects, dosages, and side-effects. In addition, this review describes the medications, foods, and other ingested agents that can induce unwanted tinnitus, as well as their mechanisms of action.

Assembly of metallic nanoparticle arrays on glass via nanoimprinting and thin-film dewetting.

We propose a nanofabrication process to generate large-area arrays of noble metal nanoparticles on glass substrates via nanoimprinting and dewetting of metallic thin films. Glass templates were made via pattern transfer from a topographic Si mold to an inorganically cross-linked sol-gel (IGSG) resist on glass using a two-layer polydimethylsiloxane (PDMS) stamp followed by annealing, which turned the imprinted resist into pure silica. The transparent, topographic glass successfully templated the assembly of Au and Ag nanoparticle arrays via thin-film deposition and dewetting at elevated temperatures. The microstructural and mechanical characteristics that developed during the processes were discussed. The results are promising for low-cost mass fabrication of devices for several photonic applications.

Characterization of fiber-optic light delivery and light-induced temperature changes in a rodent brain for precise optogenetic neuromodulation.

Understanding light intensity and temperature increase is of considerable importance in designing or performing in vivo optogenetic experiments. Our study describes the optimal light power at target depth in the rodent brain that would maximize activation of light-gated ion channels while minimizing temperature increase. Monte Carlo (MC) simulations of light delivery were used to provide a guideline for suitable light power at a target depth. In addition, MC simulations with the Pennes bio-heat model using data obtained from measurements with a temperature-measuring cannula having 12.3 mV/°C of thermoelectric sensitivity enabled us to predict tissue heating of 0.116 °C/mW on average at target depth of 563 µm and specifically, a maximum mean plateau temperature increase of 0.25 °C/mW at 100 µm depth for 473 nm light. Our study will help to improve the design and performance of optogenetic experiments while avoiding potential over- and under-illumination.

Micro-optical pattern-based selective transmission mechanism.

This paper presents a micro-optical pattern-based selective transmission mechanism with a simple modulation principle. The mechanism is composed of a patterned plate and liquid medium, and it does not contain a transparent conductor. The pattern uses 50 µm rectangular pyramid shapes that satisfy a retro-reflection condition. An ultraprecision diamond-cutting machine is used to precisely fabricate the metallic patterned mold, and a hot embossing process creates the micro-optical pattern. The measurement results show that the proposed mechanism displays a much higher optical performance and more durability than the existing switchable glasses in the specific condition. It has specular transmittances of 84.1% in the transparent state and 0.2% in the translucent state, and its total reflectance is 50.4%. An optical simulation verifies the measurement results with a specific analysis.

Modeling of reflection-type laser-driven white lighting considering phosphor particles and surface topography.

This paper presents a model of blue laser diode (LD)-based white lighting coupled with a yellow YAG phosphor, for use in the proper design and fabrication of phosphor in automotive headlamps. First, the sample consisted of an LD, collecting lens, and phosphor was prepared that matches the model. The light distribution of the LD and the phosphor were modeled to investigate an effect of the surface topography and phosphor particle properties on the laser-driven white lighting systems by using the commercially available optical design software. Based on the proposed model, the integral spectrum distribution and the color coordinates were discussed.

Neurotological parameters and prognosis of Bell's palsy patients.

BACKGROUND: To investigate the relationship with prognosis, various neurotological examinations evaluating all four nerves within the internal auditory canal were performed in patients with Bell's palsy. METHODS: A total of 69 consecutive patients with Bell's palsy were included. They were treated uniformly with steroid and an antiviral agent and underwent neurotological examinations consisting of electronystagmography, pure-tone audiometry (PTA), electroneurography (ENoG), caloric test, rotatory chair test and cervical vestibular evoked myogenic potentials (cVEMP). According to the final recovery state, patients were divided into two groups: a complete recovery group and an incomplete recovery group. The incidence of abnormal findings in each test was compared between the two groups. RESULTS: Fifty-six patients recovered completely and 13 patients recovered incompletely. No association was observed between the rate of ipsilesional PTA threshold and the rate of abnormal caloric test, function tests and recovery state. However, the initial state of facial palsy, ENoG and the rate of abnormal cVEMP were significantly correlated with the rate of recovery. CONCLUSION: The results indicate that Bell's palsy may be more comparable to mononeuritis multiplex and that cVEMP could be a useful tool for predicting the prognosis of Bell's palsy.

Ultraprecision XY stage using a hybrid bolt-clamped Langevin-type ultrasonic linear motor for continuous motion.

This paper presents a design and control system for an XY stage driven by an ultrasonic linear motor. In this study, a hybrid bolt-clamped Langevin-type ultrasonic linear motor was manufactured and then operated at the resonance frequency of the third longitudinal and the sixth lateral modes. These two modes were matched through the preload adjustment and precisely tuned by the frequency matching method based on the impedance matching method with consideration of the different moving weights. The XY stage was evaluated in terms of position and circular motion. To achieve both fine and stable motion, the controller consisted of a nominal characteristics trajectory following (NCTF) control for continuous motion, dead zone compensation, and a switching controller based on the different NCTFs for the macro- and micro-dynamics regimes. The experimental results showed that the developed stage enables positioning and continuous motion with nanometer-level accuracy.

Novel design and sensitivity analysis of displacement measurement system utilizing knife edge diffraction for nanopositioning stages.

This paper presents a novel design and sensitivity analysis of a knife edge-based optical displacement sensor that can be embedded with nanopositioning stages. The measurement system consists of a laser, two knife edge locations, two photodetectors, and axillary optics components in a simple configuration. The knife edge is installed on the stage parallel to its moving direction and two separated laser beams are incident on knife edges. While the stage is in motion, the direct transverse and diffracted light at each knife edge is superposed producing interference at the detector. The interference is measured with two photodetectors in a differential amplification configuration. The performance of the proposed sensor was mathematically modeled, and the effect of the optical and mechanical parameters, wavelength, beam diameter, distances from laser to knife edge to photodetector, and knife edge topography, on sensor outputs was investigated to obtain a novel analytical method to predict linearity and sensitivity. From the model, all parameters except for the beam diameter have a significant influence on measurement range and sensitivity of the proposed sensing system. To validate the model, two types of knife edges with different edge topography were used for the experiment. By utilizing a shorter wavelength, smaller sensor distance and higher edge quality increased measurement sensitivity can be obtained. The model was experimentally validated and the results showed a good agreement with the theoretically estimated results. This sensor is expected to be easily implemented into nanopositioning stage applications at a low cost and mathematical model introduced here can be used for design and performance estimation of the knife edge-based sensor as a tool.

Decreased pattern-recognition receptor-mediated cytokine mRNA expression in obese children with otitis media with effusion.

OBJECTIVES: To assess innate and humoral immune responses in middle ear effusion of obese pediatric patients with otitis media with effusion (OME). METHODS: We evaluated 219 children with OME, of whom 21 were obese and 198 were non-obese. We compared the expression in middle ear effusion of mRNAs encoding toll-like receptors (TLR) 2, 4, 5, and 9; nucleotide-binding oligomerization domains (NOD) 1 and 2; retinoic acid-inducible gene (RIG)-I; interleukins (IL)-6, -10, and -12; interferon (IFN)-γ; and tumor necrosis factor (TNF)-α mRNAs. We also compared the expression of immunoglobulins IgG, IgA, and IgM and the bacterial detection rate in the two groups. RESULTS: TLR2-mediated expression of IL-6 mRNA, TLR4-mediated expression of IL-6 and IL-10 mRNA, TLR5-mediated expression of IL-6, IL-10, and TNF-α mRNA, TLR9-mediated expression of IL-6 mRNA, and NOD2-mediated expression of IL-6, IL-12, and TNF-α mRNA were significantly lower in obese than in non-obese children (P<0.05). However, concentrations of IgG, IgA, and IgM in middle ear effusion were lower in obese than in non-obese children, but none of these differences was significant (P>0.05). CONCLUSION: Mean body mass index was higher and pattern-recognition receptor-mediated cytokine mRNA expression was lower in obese than in non-obese children with OME.

Vestibular evoked myogenic potential according to middle ear condition in chronic otitis media with tympanic membrane perforation.

CONCLUSION: Vestibular evoked myogenic potential (VEMP) function results can vary between individuals with different middle ear conditions. Therefore, by analyzing VEMP results after paper patching, we can predict the condition of the middle ear in chronic otitis media (COM) patients. OBJECTIVES: VEMP responses decrease with impairment of sound transmission, such as in conductive hearing loss (CHL). COM with tympanic membrane (TM) perforation is a common disorder that causes various degrees of CHL. The aim of this study was to evaluate and clarify the VEMP responses in patients with COM with different middle ear pathology. METHODS: This study included 50 patients with unilateral COM with TM perforation. Initial pure-tone audiometry (PTA) and VEMP responses were recorded. After paper patching, PTA and VEMP were re-performed. Each VEMP response was compared with those of the healthy controls. Moreover, VEMP responses between pre- and post-paper patching were compared. RESULTS: There was a positive correlation between normalizing of VEMP parameters, such as p13 and VEMP asymmetry ratio (VAR), and reduction of air-bone gap in patients with COM after paper patching. The VEMP response in patients with COM with intact ossicle and clean mucosa was more normalized compared with those in patients with COM with different middle ear conditions.

Effectiveness of transcutaneous electrical stimulation for chronic tinnitus.

CONCLUSION: Based on the Tinnitus Handicap Inventory (THI) and visual analog scale (VAS) scores, transcutaneous electrical stimulation (TENS) can provide relief from tinnitus. Response to electrical stimulation was best seen in patients with low-frequency tinnitus and with mild hearing loss. OBJECTIVE: TENS is known to alleviate symptoms of tinnitus. However, study of the effectiveness of TENS for tinnitus has produced variable results, and it is still unclear what kind of patients with tinnitus would respond best to TENS. Here, we assessed the effects of TENS on the perception of tinnitus using the THI and VAS questionnaires. METHODS: A total of 65 patients with tinnitus were divided into two groups: 45 patients received TENS and 20 patients received placebo (sham stimulation) twice a week over 4 weeks. THI and VAS scores were assessed before and after electrical stimulation. We also evaluated the effects of TENS on the degree of initial hearing loss and tinnitus frequency. RESULTS: Twenty-eight of 45 patients (62.2%) revealed subjective improvement in tinnitus with TENS. TENS was more effective in patients with low-frequency tinnitus or with mild hearing loss. Symptomatic improvement in the electrical stimulation group was achieved for 1 month in most patients.

Toll-like receptors, cytokines & nitric oxide synthase in patients with otitis media with effusion.

BACKGROUND & OBJECTIVES: Microbial infections in the normally sterile environment of the middle ear cavity in patients with otitis media trigger expression of Toll-like receptors (TLRs), cytokines, and nitric oxide. We evaluated the expression levels of TLR-1, -2, -4, -5, -6, and -9, interleukin (IL)-6, -8, -10, and -12, interferon-γ (IFN-γ), tumour necrosis factor-α (TNF-α), and nitric oxide (NO), in paediatric patients with otitis media with effusion (OME). METHODS: The levels of TLR, cytokine, and nitric oxide synthase (NOS) mRNAs in middle ear effusion were assessed by real-time polymerase chain reaction in 96 children with OME, 24 prone and 72 not prone to otitis. The level of expression of each mRNA was compared in the otitis-prone and non-otitis-prone groups, in patients with and without bacteria, and by frequency of ventilation tube insertion. RESULTS: The expression of TLR-1, -2, -4, -5, -6, and -9; IL-6, -8, -10, and -12; IFN-γ; TNF-α; and NOS mRNAs in the effusion fluid of both the otitis-prone and non-otitis-prone groups were measured. The expression levels of TLR-2, -4, -6, and -9 mRNA were significantly lower in the otitis-prone than in the non-otitis-prone group (P<0.05). Although higher levels of TLR, cytokine, and NOS mRNAs were generally observed in culture positive than in culture negative patients, none of these differences was statistically significant. No differences were observed in the expressions relative to the frequencies of ventilation tube insertion. INTERPRETATION & CONCLUSIONS: TLRs, cytokines, and NOS, which act cooperatively in the innate immune response, were closely associated with OME. Decreased expression of TLRs may be associated with increased susceptibility to OME.

A case of spontaneous temporomandibular joint herniation into the external auditory canal with clicking sound.

A bony defect of the external auditory canal (EAC) and herniation of the temporomandibular joint (TMJ) can be caused by tumorous conditions, inflammation, trauma, and otologic procedures. Spontaneous TMJ herniation into the EAC can be caused by a congenital bony defect known as patent Huschke's foramen, which is a very rare condition. In our case, an objective clicking sound was produced when the patient opened his mouth. A protruding mass was found in the anterior wall of the EAC during mouth closing, and herniation of the TMJ was confirmed with computed tomography. Therefore, we thought the clicking sound of our case could have resulted from spontaneous TMJ herniation through the patent foramen of Huschke.

Clinical manifestations of aural fullness.

PURPOSE: Even though aural fullness is ubiquitous among patients presenting to otolaryngology clinics, the association between aural fullness and disease development has not yet been clearly determined. MATERIALS AND METHODS: Our study was performed on outpatients from June 2006 to February 2010 whose major complaint was "ear fullness", "aural fullness", or "ear pressure". We assessed their demographic and clinical characteristics, including sex, associated diseases, symptoms, otoscopic findings, audiology test results, and final diagnoses. RESULTS: Among 432 patients, 165 (38.2%) were males and 267 (61.8%) were females, with mean ages of 42±19 years and 47±17 years, respectively. Tinnitus, hearing disturbance, autophony (p<0.01) as well as nasal obstruction and sore throat (p<0.05) showed a statistically significant correlation with aural fullness. Among patients who complained of hearing fullness, tests and measures such as impedance audiometry, speech reception threshold, and pure tone audiometry generated statistically significant results (p<0.05). Ear fullness was most frequently diagnosed as Eustachian tube dysfunction (28.9%), followed by otitis media with effusion (13.4%) and chronic otitis media (7.2%). However, 13.4% of patients could not be definitively diagnosed. CONCLUSION: Among patients complaining of ear fullness, Eustachian tube dysfunction, otitis media with effusion, chronic otitis media were most commonly observed. Performance of otoscopy, nasal endoscopy, the Valsalva maneuver, and additional audiological tests is necessary to exclude other diseases.

Rate of isolation and trends of antimicrobial resistance of multidrug resistant pseudomonas aeruginosa from otorrhea in chronic suppurative otitis media.

OBJECTIVES: To assess the rate of isolation of Pseudomonas aeruginosa (PA) and multidrug-resistant PA (MDR-PA) from patients with chronic suppurative otitis media (CSOM) otorrhea and the annual trend of antibiotic-resistance. METHODS: Otorrhea samples were collected aseptically from 1,598 CSOM patients. The rate of bacterial isolation and the results of antibiotic susceptibility testing were evaluated retrospectively. RESULTS: The PA isolation rate from CSOM otorrhea was 24.4%. Of the 398 isolated strains tested for their susceptibilities to 10 antibiotics, 395 strains showed definitive results. Of these, 183 (46.3%) were susceptible to whole antibiotics and 212 (53.7%) was resistant to more than 1 antibiotics, with the frequency of antibiotics-resistance increasing significantly over time. Although strains susceptible to all antibiotics decreased over time, the rate of isolation of MDR-PA did not change significantly. Resistance to aminoglycosides and quinolones was higher than to other antibiotics and significantly increased over time, whereas resistance to other antibiotics showed no trend. CONCLUSION: MDR-PA, assessed using five individual antibiotics and six antibiotic-classes, showed no tendency to increase or decrease over time. This may have been due to increased concern about antibiotic-resistant bacterial strains, leading to improved infection control within hospitals and healthcare centers.

Clinical analysis of auricular benign masses.

BACKGROUND AND OBJECTIVES: Auricular masses are growths on the outer ear that have not been well characterized clinically. We assessed the clinical nature and treatment of auricular benign masses in patients at our institution. SUBJECTS AND METHODS: We retrospectively identified 63 patients with auricular benign masses who underwent excision and biopsy from May 1970 to April 2011. We determined the site, cause, size, pathology and postoperative results of these auricular masses. RESULTS: Auricular benign masses occurred most commonly on the lobule (44.4%), followed by the tragus (20.6%), crus of helix (11.1%), triangular fossa (6.3%), crus of antihelix-antitragus (3.1%) and scapha (1.5%). Pathologically, the most common type of auricular mass was epidermal cysts (25.3%), followed by hypertrophic scar (12.6%), fibrous tissue-accessory ear (9.5%), chronic inflammation-nevus (7.9%), keloid (6.3%), hemangioma (4.7%), and skin tag-seborrheic keratosis (3.1%). CONCLUSIONS: The most common site of auricular benign masses is the lobule and most common pathology is an epidermal cyst.

Comparison of the clinical relevance of traditional and new classification systems of temporal bone fractures.

Temporal bone fractures are traditionally classified as transverse, longitudinal or mixed. Since these categories have shown little association with clinical symptoms, new classifications have been introduced, including those related to the involvement of the petrous bone and otic capsule. We have formulated a new classification based on the involvement of four parts of the temporal bone (squama, tympanic, mastoid, and petrous) and assessed which of these classification systems is the most rational using a retrospective chart review in hospital settings (KyungHee Medical Center, Seoul, Korea and Samsung Changwon Hospital, Changwon, Korea). The association between each classification and clinical symptoms was examined by analyzing temporal bone computed tomography scans of 129 patients diagnosed as temporal bone fractures over the past 7 years. Using the traditional classification, there was a significant correlation between transverse fractures and the incidence of sensorineural hearing loss. Patients with petrous bone fractures had significantly higher incidence rates of sensorineural hearing loss, vertigo, and eardrum perforation than patients without petrous bone involvement. Involvement of the otic capsule was significantly associated with sensorineural hearing loss and the severity of hearing loss. The associations of the traditional classification and the classification according to the involvement of the otic capsule, four parts of temporal bone with clinical symptoms were not high. Petrous bone fractures were significantly associated with sensorineural hearing loss, vertigo, and eardrum perforation, suggesting that this classification may be optimally associated with clinical symptoms including hearing and the results of otological examination.

Feasibility of three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging as a prognostic factor in patients with sudden hearing loss.

The aim of this study was to confirm the feasibility of high signal on three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging (3D FLAIR MRI) as one of the prognostic factors in recovery of sudden idiopathic hearing loss. A retrospective study was conducted using patients who were diagnosed with unilateral sudden idiopathic hearing loss from January 2008 to December 2010. A total of 120 patients were enrolled in for this study. High-intensity signal in the inner ear on precontrast 3D FLAIR MRI was observed in 31 patients (25.8%; FHS) and labyrinthine enhancement was not observed in another 89 patients (FNS; 74.2%). There was no significant difference in patients' characteristics between two groups except final hearing. Final puretone average of the FHS group was 49.4 dB, significantly worse than FNS group's 36.7 dB (p = 0.037 < 0.05). Final hearing was related to initial hearing, accompanying dizziness, and abnormal auditory brainstem response result by multiple regression analysis. However, presence of high-intensity signal on precontrast 3D FLAIR MRI did not affect final hearing significantly. Significant difference due to the presence of dizziness in final hearing was observed in whole patients and in the FHS group, whereas no significant difference in final hearing was observed in FNS group. (p = 0.063 > 0.05). From these findings, the presence of high-intensity signal on 3D FLAIR MRI is a subfactor related to dizziness rather than a single poor prognostic factor and the absence of high-intensity signal on 3D FLAIR MRI can possibly imply relative good prognosis.

Phase-locked loop based on machine surface topography measurement using lensed fibers.

We present the phase-locked loop (PLL)-based metrology concept using lensed fibers for on-machine surface topography measurement. The shape of a single-mode fiber at the endface was designed using an ABCD matrix method, and two designed lensed fibers-the ball type and the tapered type-were fabricated, and the performance was evaluated, respectively. As a result, the interferometric fringe was not found in the case of the ball lensed fiber, but the machined surface could be measured by utilization of autofocusing and intensity methods. On the other hand, a very clear Fizeau interferometric fringe was observed in the case of the tapered lensed fiber. Its performance was compared with the results of the capacitance sensor and a commercially available white-light interferometer. We confirmed that PLL-based surface profile measurement using the tapered and ball lensed fibers can be applied for on-machine surface topography measurement applications.