Nanocrystal Engineering of Thin-Film Yttria-Stabilized Zirconia Electrolytes for Low-Temperature Solid-Oxide Fuel Cells.

To overcome significantly sluggish oxygen-ion conduction in the electrolytes of low-temperature solid-oxide fuel cells (SOFCs), numerous researchers have devoted considerable effort to fabricating the electrolytes as thin as possible. However, thickness is not the only factor that affects the electrolyte performance; roughness, grain size, and internal film stress also play a role. In this study, yttria-stabilized zirconia (YSZ) was deposited via a reactive sputtering process to fabricate high-performance thin-film electrolytes. Various sputtering chamber pressures (5, 10, and 15 mTorr) were investigated to improve the electrolytes. As a result, high surface area, large grain size, and residual tensile stress were successfully obtained by increasing the sputtering pressure. To clarify the correlation between the microstructure and electrolyte performance, a YSZ thin-film electrolyte was applied to anodized aluminum oxide-supported SOFCs composed of conventional electrode materials which are Ni and Pt as the anode and the cathode, respectively. The thin-film SOFC with YSZ deposited at 15 mTorr exhibited the lowest ohmic resistance and, consequently, the highest maximum power density (493 mW/cm2) at 500 °C whose performance is more than five times higher than that of the cell with YSZ deposited at 5 mTorr (94.1 mW/cm2). Despite the basic electrode materials, exceptionally high performance at low operating temperature was achieved via controlling the single fabrication condition for the electrolyte.

Novel Findings of Polypoidal Choroidal Vasculopathy via Optical Coherence Tomography Angiography.

PURPOSE: To introduce novel findings of polypoidal choroidal vasculopathy (PCV) via optical coherence tomography angiography (OCTA). METHODS: This study is a retrospective chart review of 16 patients (16 eyes) with PCV. OCTA (Avanti RTVue XR) findings were evaluated and selected for analysis after agreement by two retina specialists . RESULTS: Twenty one polyps in 16 eyes (16 patients) with PCV were included in this study. The mean patient age was 67 years (13 men and three women). The shape of polypoidal lesions on OCTA at initial were halo (five polyps), rosette (seven polyps), and vascular network (nine polyps). Eight months after anti-vascular endothelial growth factor treatment, in a total of four eyes, seven polyps could be followed up completely, the two halo type polypoidal lesions changed to rosette and vascular network type. The lesions of three rosette and two vascular network type lesions did not change in shape. In addition, the size of the polypoidal lesions (one among two halo types, two among three rosette types, and two among two vascular network types) decreased, but one halo type did not change and one rosette type increased in size on OCTA. CONCLUSIONS: En-face OCTA enabled us to categorize novel types of PCV with polypoidal lesions.

Short-duration multiple-session subthreshold micropulse yellow laser (577 nm) for chronic central serous chorioretinopathy: results at 3 years.

OBJECTIVES: To review the 3-year follow-up results of subthreshold micropulse yellow laser (SMYL) delivered by a short-duration multiple-session method for treatment of chronic central serous chorioretinopathy (CSC). METHODS: A total of 27 eyes from 27 patients with chronic CSC available for 3 years of follow-up were enrolled in this retrospective and interventional study. Patients were treated with 577-nm SMYL photocoagulation at a 15% duty cycle over multiple sessions, with low power ranging from 200 to 400 mW that was increased in 100 mW increments according to resolution of subretinal fluid at monthly follow-up. Laser titration was not performed. A treatment duration of 20 ms rather than the conventional duration (100-300 ms) was applied over the area of retinal pigment epithelium leakage and all areas of serous retinal detachment, including the fovea. RESULTS: The mean follow-up period was 3.7 ± 0.8 years (range, 3-6 years). A total of 22 out of 27 eyes (81.5%) including six cases of recurrence during the follow-up period exhibited complete resolution of subretinal detachment at final follow-up, whereas only five eyes (15.5%) had either a partial or null response to SMYL treatment. The baseline best-corrected visual acuity was 0.26 ± 0.24 logarithm of the minimum angle of resolution (logMAR), which was improved to 0.08 ± 0.15 logMAR at 1-year (p = 0.005) and 3-year (p = 0.01) follow-up. The central macular thickness at baseline was 389.6 ± 103.4 µm, which was changed to 197.2 ± 40.0 µm (p < 0.001) at 1-year follow-up, 196.4 ± 40.2 µm (p < 0.001) at 3-year follow-up. CONCLUSION: Short-duration multiple-session SMYL therapy may be effective for long-term treatment of chronic CSC.

Acoustic analysis of snoring sounds recorded with a smartphone according to obstruction site in OSAS patients.

Snoring is a sign of increased upper airway resistance and is the most common symptom suggestive of obstructive sleep apnea. Acoustic analysis of snoring sounds is a non-invasive diagnostic technique and may provide a screening test that can determine the location of obstruction sites. We recorded snoring sounds according to obstruction level, measured by DISE, using a smartphone and focused on the analysis of formant frequencies. The study group comprised 32 male patients (mean age 42.9 years). The spectrogram pattern, intensity (dB), fundamental frequencies (F 0), and formant frequencies (F 1, F 2, and F 3) of the snoring sounds were analyzed for each subject. On spectrographic analysis, retropalatal level obstruction tended to produce sharp and regular peaks, while retrolingual level obstruction tended to show peaks with a gradual onset and decay. On formant frequency analysis, F 1 (retropalatal level vs. retrolingual level: 488.1 ± 125.8 vs. 634.7 ± 196.6 Hz) and F 2 (retropalatal level vs. retrolingual level: 1267.3 ± 306.6 vs. 1723.7 ± 550.0 Hz) of retrolingual level obstructions showed significantly higher values than retropalatal level obstruction (p < 0.05). This suggests that the upper airway is more severely obstructed with retrolingual level obstruction and that there is a greater change in tongue position. Acoustic analysis of snoring is a non-invasive diagnostic technique that can be easily applied at a relatively low cost. The analysis of formant frequencies will be a useful screening test for the prediction of occlusion sites. Moreover, smartphone can be effective for recording snoring sounds.

Change in Anterior and Posterior Curvature After Cataract Surgery.

PURPOSE: To analyze the change in anterior and posterior corneal curvature after cataract surgery using a Placido-dual rotating Scheimpflug device. METHODS: In a prospective cross-sectional study, corneal curvature was measured using the Galilei G4 device (Ziemer Ophthalmic Systems, Port, Switzerland) preoperatively and 1 week and 1, 3, and 6 months after cataract surgery with a temporal limbal self-sealing 2.2-mm incision. The surgically induced astigmatism (SIA) was determined on the anterior and posterior surfaces. RESULTS: Fifty-nine patients (68 eyes) were assessed. Based on the anterior corneal surface, 16 (23.5%) eyes had a vertically steep meridian (with-the-rule [WTR] astigmatism), 32 (47.1%) had a horizontally steep meridian (against-the-rule [ATR] astigmatism), and 20 (29.4%) had oblique astigmatism. Based on the posterior corneal surface, 2 (2.9%) eyes had a horizontally steep meridian (ATR astigmatism), 62 (91.2%) had a vertically steep meridian (WTR astigmatism), and 4 (5.9%) had oblique astigmatism. SIA of the anterior and posterior corneal surfaces was 0.61 ± 0.33 and 0.20 ± 0.17 diopters (D), respectively. However, there was no significant difference between the preoperative and the 6-month postoperative data in the Jackson coefficient orthogonal coordinate system for the anterior and posterior corneal surfaces. SIA of WTR astigmatism of the posterior cornea was 0.19 ± 0.16 D at 6 months. Sixty-one of 62 eyes with WTR astigmatism in the posterior corneal surface still showed WTR astigmatism after cataract surgery. CONCLUSIONS: The tendency of SIA of the posterior cornea may not be uniform, but type of posterior corneal astigmatism did not change in most cases after the 2.2-mm temporal limbal incision cataract surgery. [J Refract Surg. 2016;32(11):754-759.].

The Role of Systemic Arterial Stiffness in Open-Angle Glaucoma with Diabetes Mellitus.

PURPOSE: To investigate the role of systemic arterial stiffness in glaucoma patients with diabetes mellitus (DM). DESIGN: Retrospective, cross-sectional study. PARTICIPANTS: DM subjects who underwent brachial-ankle pulse wave velocity (baPWV) were recruited. METHODS: Glaucoma patients (n = 75) and age-matched control subjects (n = 92) were enrolled. Systemic examination including BaPWV and detailed eye examination were performed. The glaucoma group was divided into subgroups of normal tension glaucoma (NTG, n = 55) and primary open-angle glaucoma (POAG) based on an IOP of 21 mmHg. BaPWV was used to stratify the population into 4 groups based on the rate. Stepwise multiple logistic regression analysis by baPWV quartiles was used to compare the glaucoma group with the control group. MAIN OUTCOME MEASURES: BaPWV in glaucoma with DM patients. RESULTS: Faster baPWV was positively associated with glaucoma (odds ratio: 3.74; 95% CI: 1.03-13.56, stepwise multiple logistic regression analysis) in patients with DM. Increasing baPWV was also positively associated with glaucoma (p for trend = 0.036). The NTG subgroup showed similar results to those of the glaucoma group. CONCLUSIONS: In this study, increased arterial stiffness was shown to be associated with glaucoma and may contribute to the pathogenesis of glaucoma in DM patients.

Association of IOP with Systemic Factors in a Korean Cohort.

PURPOSE: To assess the relationship of intraocular pressure (IOP) to age, sex, and other demographic and health characteristics in a Korean cohort. METHODS: This retrospective cross-sectional study included subjects (n = 155,198) without glaucoma. All participants underwent health screening at the Kangbuk Samsung Hospital from August 2012 to July 2013. Anthropometric measurements, systemic health characteristics, and ocular examination including noncontact tonometry were performed on all participants. Additionally, sociodemographic and behavioral questionnaires were obtained. The systemic variables were analyzed by multiple regression analysis to identify their relationship with IOP. RESULTS: The mean IOP tended to be highest in subjects in their 50s and lowest in subjects in their 20s and 60s for both Korean men and women. This pattern remained the same after adjusting for several demographic and health characteristics. The mean IOP for men was significantly higher than that for women (p < 0.001), but the difference between sexes decreased with increasing age. In the univariate analysis, almost all systemic factors showed a positive association with IOP except for high-density lipoprotein cholesterol. By multiple regression analysis, IOP was positively associated with sex (male), current smoking status, systolic blood pressure, fasting plasma glucose, body mass index, total cholesterol, and high-density lipoprotein (p ≤ 0.001). CONCLUSIONS: In a Korean cohort, the mean IOP was highest in subjects in their 50s. The mean IOP for men was significantly higher than that for women. Several systemic factors were significantly correlated with IOP.

Associations between Optic Cup-to-disc Ratio and Systemic Factors in the Healthy Korean Population.

PURPOSE: To assess the relationships between optic cup-to-disc ratio (CDR) and age, sex, and other demographic and health characteristics in the healthy Korean population. METHODS: The study design was retrospective and population-based. A total of 28,377 subjects who participated in the Korea National Health and Nutrition Examination Survey between 2008 and 2011 were enrolled in this study. Participants underwent structured interviews as well as systemic and ophthalmic examinations. Patients with glaucoma who were diagnosed using the International Society of Geographical and Epidemiological Ophthalmology classification were excluded. Changes in vertical CDR were examined by age in relation to systemic variables on multiple regression analysis. RESULTS: The mean vertical CDR was 0.34 ± 0.12. The vertical CDR increased with age from subjects in their 20s to those in their 80s (p < 0.001). The mean CDR in males was significantly higher than that of females (p < 0.001). On multiple regression analysis, the vertical CDR was positively associated with age (p < 0.001), male sex (p < 0.001), diastolic blood pressure (p = 0.009), and intraocular pressure (p < 0.001) but was negatively associated with body mass index (p < 0.001). CONCLUSIONS: Greater vertical CDR was related to age, male sex, higher diastolic blood pressure, higher intraocular pressure, and lower body mass index in healthy Koreans.

The role of the maxillary sinus on the voice.

The objective of the study was to determine the effect of the maxillary sinus on the voice. The prospective study was conducted at an academic secondary referral center. A prospective chart review of 43 patients (17 males, 26 females) who conducted a voice recording and survey before and 3 months after middle meatal antrostomy whose lesion was confined to the maxillary sinus. Subjective voice changes were surveyed using a questionnaire. After phonation [∧m ma: the Korean pronunciation of 'mother'], [Nu Na: the Korean pronunciation of 'sister'], we analyzed the nasal consonant [m] of [∧m ma] and nasalized vowel [a] of [∧m ma] and [a] of [Nu Na]. In the poll conducted, the change rates for males and females were 41.1 % (7/17) and 15.4 % (4/26), respectively; of the male patients, 85.7 % (6/7) felt that the sound quality was better and 14.3 % (1/6) that it was worse. However, all the female patients felt it was better. Among of the patients with an improved voice, reduced nasal sound was the most frequent observation. In an objective analysis, a tendency to lowered frequencies was observed for nasalized vowels after surgery. Significant differences were observed at second formant frequencies of [a] of [∧m ma] and first formant frequencies of [a] of [Nu Na] in female subjects (P < 0.005). Our findings indicated that the maxillary sinus plays a role in the modification of voice quality. Preoperative counseling is important for patients concerning expected changes in the voice after maxillary sinus surgery.

Efficacy and safety of transdermal fentanyl in the control of postoperative pain after photorefractive keratectomy.

PURPOSE: To evaluate the efficacy and safety of transdermal fentanyl (TDF) in the control of postoperative pain following photorefractive keratectomy (PRK). METHODS: One hundred ninety-nine consecutive PRK cases (398 eyes) were retrospectively reviewed. For postoperative pain control, 96 patients (63 females) were treated with tramadol 37.5 mg/acetaminophen 325 mg combination tablets (2 tablets bid), 103 patients (73 females) were treated with TDF (12 µg/h). Postoperative pain intensity using the visual analog scale (VAS) during postoperative 3 days including the evening of the day of the operation and peak pain intensity, rated using the verbal descriptor scale (VDS) at postoperative 4 days, were compared between 2 groups. Overall adverse events in the 2 treatment groups were also compared. RESULTS: The differences in mean pain intensity scores were significant between the control group and the fentanyl group (P=0.001, Repeated-measures analysis of variance). The proportion of severe pain (VAS>54 mm) was significantly lower in the fentanyl group than the control group by morning of postoperative 2 days (P<0.007). The proportion of patients who rated their peak pain intensity as "intolerable pain" was significantly higher (P=0.001) in the control group (30/96, 31.3%) than the fentanyl group (13/103, 12.6%). Total number of patients who reported adverse events was significantly higher in the fentanyl group (P=0.013) than the control group. However, there were no irreversible or severe adverse events in both treatment groups and nausea was the most common (14/103, 13.6%) complaint reported in the fentanyl group. CONCLUSION: TDF was more effective in the control of postoperative pain after PRK than tramadol/acetaminophen and no irreversible or severe adverse effect was reported with 12 µg/h concentration. TDF could be considered as alternative regimen of analgesic method after PRK.

A case of congenital aplasia of the epiglottis in an adult.

Aplasia or hypoplasia of the epiglottis in an adult is rarely reported congenital anomaly of the larynx. Most patients with epiglottic aplasia have presented fatal symptom of respiratory distress and severe aspiration in infancy or childhood. We present a case of congenital absence of the epiglottis found in a 33-year-old woman complaining of recurrent lingual tonsillitis. Laryngoscopic finding and CT scan revealed an isolated epiglottic aplasia and normal appearance of other laryngeal structure. This is the first description of physiologic evaluation in an epiglottic anomaly to find the compensatory mechanism of aspiration prevention. We discussed this case with a review of literature.

Analysis of obstruction site in obstructive sleep apnea syndrome patients by drug induced sleep endoscopy.

PURPOSE: We analyzed site, pattern and degree of obstruction in Korean male obstructive sleep apnea syndrome (OSAS) patients by drug-induced sleep endoscopy (DISE). We also investigated possible links between BMI, AHI and DISE findings. MATERIALS AND METHODS: Sixty-nine male patients underwent DISE. DISE findings were reported using our classification system in which modified 'VOTE classification' - obstruction type, site of obstruction, degree of obstruction and anatomical site contributing obstruction - was reported. Associations were analyzed among the results of the polysomnography, patients' characteristics and DISE finding. RESULTS: Multilevel airway obstruction was found in 84.06% of patients and 15.94% had a unilevel obstruction. Among those with unilevel obstruction, 90.90% had retropalatal level obstruction and 9.10% had retrolingual level obstruction. Palate with lateral pharyngeal wall obstruction (49.28%) is the most common obstruction type of the retropalatal level and tongue with lateral pharyngeal wall (37.68%) is the most common obstruction type of the retrolingual level. Examining the relation between obstruction site according to body mass index (BMI) and severity of OSAS (apnea hypopnea index, AHI), the lateral pharyngeal wall had an increasing tendency associated with higher BMI and higher AHI. But the lateral pharyngeal wall of both levels was statistically significant associated with higher AHI. CONCLUSION: The majority of the Korean male OSAS patients have multilevel obstruction and according to BMI and AHI, the DISE findings indicate that the lateral pharyngeal wall is the most important anatomical site contributing to obstruction regardless of the level at which the obstruction lies.

Complicated mumps viral infection: an unusual presentation affecting only submandibular gland.

This case is a single submandibular gland mumps viral infection patient without parotid gland involvement who developed complications of meningitis and orchitis. Since spontaneous remission is common in mumps viral infection, missing opportunities for exact diagnosis is frequent. As in this case, single submandibular glands infection without parotid gland involvement not only delays diagnosis but also increases risk of developing complications. This case instructs us that despite the atypical manifestation, the clinician should suspect mumps and conduct serologic tests for diagnosis while observing for complications such as meningoencephalitis and orchitis.