Jong-Hyuck Lee

Microstructural and optical characteristics of solution-grown Ga-doped ZnO nanorod arrays.

Highly oriented Ga-doped zinc oxide (ZnO) nanorod arrays have been prepared on a ZnO-buffered silicon substrate in an aqueous solution, which is a mixture of methenamine (C(6)H(12)N(4)), zinc nitrate hexahydrate (Zn(NO(3))(2)·6H(2)O), and gallium nitrate hydrate (Ga(NO(3))(3)·xH(2)O). The microstructure characteristics and optical properties of the nanorod arrays were analyzed using different characterization techniques including field-emission scanning electron microscopy (FESEM), x-ray photoelectron spectroscopy (XPS), and photoluminescence (PL). The experimental results show that the morphology, density, and surface compositions of ZnO nanorod arrays are sensitive to the concentration of gallium nitrate hydrate. The PL spectra of all ZnO nanorod arrays show three different emissions, including UV (ultraviolet), yellow, and NIR (near infrared) emissions. With the increase in the Ga doping level, the luminescence quality of ZnO nanorods has been improved. The peak of UV emission has a small redshift, which can be ascribed to the combined effect of size and Ga doping. Furthermore, Ga doping has caused defects that respond to NIR emission.

A randomised comparison of the i-gel™ and the Laryngeal Mask Airway Classic™ in infants.

We performed a randomised comparison of the i‐gel™ and the Laryngeal Mask Airway (LMA) Classic™ in children aged less than a year who were undergoing general anaesthesia for elective surgery. Fifty‐four infants were randomly allocated to either the i‐gel or the LMA Classic. We measured performance characteristics, fibreoptic views through the device and complications. Success rate at first insertion attempt was 100% (27/27) in the i‐gel group compared with 88% (23/26) in the LMA Classic group. Insertion of the device was considered easy in 26/27 (96%) patients in the i‐gel group compared with 18/26 (69%) patients in the LMA Classic group (p = 0.009). There were no differences between the groups in insertion times, fibreoptic views through the device, airway leak pressures or complications. We conclude that the i‐gel was considered easier to insert than the LMA Classic in infants.

Valsalva Retinopathy Associated With an Oratorical Contest

A 17-year-old man presented to us with a chief complaint of decreased visual acuity accompanied by central scotoma. There was nothing unusual in his medical history other than a recent oratorical contest. At the time of initial diagnosis, the corrected visual acuity was 20/20 in the right eye and 20/100 in the left eye. No significant findings were apparent on ophthalmic evaluation. On fundoscopy, there was a dumbbell-shaped macular bleed with a well-defined margin in the left eye. The clinical course was closely monitored along with drug therapy. Four weeks post presentation, the pre-retinal hemorrhage had nearly resolved. On fluorescein angiography, no significant findings were observed. In the left eye, the corrected visual acuity had improved to 20/25. Valsalva retinopathy is a pathology that occurs when a sudden increase in intra-thoracic pressure or abdominal pressure occurs in an otherwise healthy person. Here we report a case of Valsalva retinopathy occurring following an oratorical contest along with a review of the relevant literature.

Macular Infarction Associated with Reactive Arthritis

A 53-year-old woman visited the Department of Rheumatology with a chief complaint of a 3-day history of fever and chills and also presented with pain occuring in both knees at the time of outpatient visit. Based on rheumatologic and hematological lab studies, ultrasonography, and a needle aspiration biopsy of the articular cavity, the patient was diagnosed with reactive arthritis. On hospitalization day 3, consultation with the Department of Ophthalmology was requested regarding decreased visual acuity lasting for 3 days. Upon ophthalmologic examination, the corrected visual acuity was 0.1 in the right eye and 0.05 in the left eye. Upon slit lamp microscopy, there were no abnormal findings in the anterior segment. Upon fundus examination, however, there were yellow-white lesions in the macular area of both eyes. Fluorescein angiographywas performed to assess the macular lesions, and the findings were suggestive of macular infarction in both eyes. Due to a lack of other underlying disease, a past surgical history, and a past history of drug administration, the patient was diagnosed with macular infarction in both eyes associated with reactive arthritis. To date, there have been no other such cases reported. In a patient with reactive arthritis, we experienced a case of macular infarction in both eyes, which occurred without association with a past history of specific drug use or underlying disease. Herein, we report our case, with a review of the literature.

Effect of HAc and IPA Addition in Ozonated Water Cleaning System for ArF Photoresist Removal

For the improvement of ArF photoresist removal performance, the effect of acetic acid (HAc) and isopropyl alcohol (IPA) in an ozonated water cleaning system was investigated by combining experimental and simulation results. The ArF photoresist removal rate increased by 6.8 times with an increase in HAc concentration in ozonated water vapor. With a higher ozone concentration, a lower hydroxyl radical (OH°) concentration, and no reaction between photoresist by HAc observed, it is concluded that the improvement of the ArF photoresist removal rate with the addition of HAc results from a higher aqueous ozone concentration due to extended lifetime and a higher solubility of ozone due to the OH° scavenging effect. The increase in IPA concentration in ozonated water vapor also improved the ArF photoresist removal rate by 12 times. Simulation results show that OH° concentration was much lower than pure ozonated water, presumably due to a slower OH° formation rate. ArF photoresist was removed at a relatively high speed in the vapor of IPA and water mixture even in the absence of aqueous ozone. Therefore, it is concluded that the improved photoresist removal rate with an IPA addition in ozonated water mainly results from the direct oxidation of photoresist by IPA itself.

Development of parafoveal exudates and serous retinal detachment in a pregnant woman with tuberous sclerosis.

The authors describe an unusual case of a serous detachment of the fovea and decreased vision with parafoveal exudates with subsequent spontaneous resolution and return of central vision in a pregnant patient with tuberous sclerosis. To our knowledge, this is the first report of an ocular change during gestation in a patient with tuberous sclerosis.