Effect of thermal dissipation by adding graphene materials to surface coating of LED lighting module.

The effect of thermal dissipation by adding graphene nano-platelets to two different commercially available thermal dissipation coatings (ceramic coating and powder coating) was studied. Steady state temperatures of each points of LED modules was monitored in a closed system, with an integral photo detection sphere where there is no external air flow. Having eliminated the contributions of thermal conduction and air flow convection, the module with a conventional heat dissipation coatings showed 8-16% enhancement of thermal dissipation compared to that of non-coated LED module. The addition of graphene is shown to have about 3% additional enhancement. By analyzing thermal resistance of each component of the LED module, the improved thermal conductivity of the graphene added coatings contributes to the enhancement of slight improvement with heat dissipation.

Electrochemical characterization of nano-sized Pd-based catalysts as cathode materials in direct methanol fuel cells.

To improve the catalytic activity of palladium (Pd) as a cathode catalyst in direct methanol fuel cells (DMFCs), we prepared palladium-titanium oxide (Pd-TiO2) catalysts which the Pd and TiO2 nanoparticles were simultaneously impregnated on carbon. We selected Pd and TiO2 as catalytic materials because of their electrochemical stability in acid solution. The crystal structure and the loading amount of Pd and TiO2 on carbon were characterized by X-ray diffraction (XRD) and energy dispersive X-ray microanalysis (EDX). The electrochemical characterization of Pd-TiO2/C catalysts for the oxygen reduction reaction was carried out in half and single cell systems. The catalytic activities of the Pd-TiO2 catalysts were strongly influenced by the TiO2 content. In the single cell test, the Pd-TiO2 catalysts showed very comparable performance to the Pt catalyst.

Electrochemical characterization of Pt-Ru-Pd catalysts for methanol oxidation reaction in direct methanol fuel cells.

PtRuPd nanoparticles on carbon black were prepared and characterized as electrocatalysts for methanol oxidation reaction in direct methanol fuel cells. Nano-sized Pd (2-4 nm) particles were deposited on Pt/C and PtRu/C (commercial products) by a simple chemical reduction process. The structural and physical information of the PtRuPd/C were confirmed by TEM and XRD, and their electrocatalytic activities were measured by cyclic voltammetry and linear sweep voltammetry. The catalysts containing Pd showed higher electrocatalytic activity for methanol oxidation reaction than the other catalysts. This might be attributed to an increase in the electrochemical surface area of Pt, which is caused by the addition of Pd; this results in increased catalyst utilization.

Normal range of exophthalmos values on orbit computerized tomography in Koreans.

The value of parameters in Hertel's exophthalmometry was measured by using orbit computerized tomography (CT) in this study. We selected images that revealed the center of the lens, the largest eyeball contour and the optic canal on the axial view of orbit CT. Parameters of exophthalmometry on orbit CT were the distance between the lateral orbital rims of both eyes (A), the shortest distance from the corneal center to line A (B), the B/A ratio, the distance between the lateral orbital rim and the medial orbital rim (C), the length of the line passing through the lens center from the apex to line C (D) and the D/C ratio. To compare the center position of the eye, we measure the axial length (E) and the longest distance between the corneal apex and the posterior pole (F) which is parallel to line B. We also calculated B-F/2 and Hertel-F/2 in order to know if there is a difference between measurements of orbit CT and of Hertel's exophthalmometer. Subjects were classified into group 1 (aged 8-13 years old) and group 2 (aged 20 years old more). Sixteen subjects were enrolled in group 1 (32 eyes). In group 2, 100 subjects were male (200 eyes) and 35 were female (70 eyes). In group 1, the mean value was 89.94 mm for A, 13.49 mm for B, 35.13 mm for C, 10.64 mm for D, 24.40 mm for E, 24.20 mm for F, 0.15 for the B/A ratio and 0.30 for the D/C ratio. In group 2, the mean value was 100.93 mm for A, 15.03 mm for B, 38.78 mm for C, 12.03 mm for D, 24.62 mm for E, 24.33 mm for F, 0.15 for the B/A ratio and 0.31 for the D/C ratio. There was a statistically significant difference between the two groups for parameters A, B, C and D (p = 0.001), but no significant difference for the B/A (p = 0.239) and D/C ratios (p = 0.803). In the males and females of group 2, there was a statistically significant difference for the B/A ratio (p = 0.028). We suggest that the value of the D/C ratio (0.30-0.31) could be used as the index of protrusion. The normal values of exophthalmometry parameters measured by orbit CT could also be helpful to evaluate the exact protrusion in orbital diseases.

Serous retinal detachment in a patient with rhino-orbital mucormycosis.

BACKGROUND: Rhino-orbital mucormycosis is a difficult disease to treat. We report one case of rhino-orbital mucormycosis, complicated by serous retinal detachment, that responded to aggressive treatment. CASE: A 38-year-old man with diabetic ketoacidosis was referred to the emergency department of our hospital with fever, proptotic right eye, and complaint of lethargy. OBSERVATIONS: Fundus examination showed serous retinal detachment and focal lesions of retinitis with exudate at the inferior portion coincident with the position of opacification in the orbit on MRI. Fluorescein angiography showed pooling of dye in the detached retina and leakage from focal lesions of retinitis. We thoroughly removed the large necrotic materials in the orbit and sinus through the lower conjunctiva without enucleation or exenteration. Microscopic examination and culture of the necrotic materials that were removed from the orbit proved that the patient had mucormycosis. The serous retinal detachment improved 10 days after orbital debridement combined with intravenous and local (intraorbital) amphotericin B treatment. Visual acuity recovered to 20/50. CONCLUSION: We propose that inflammation of the sclera in close contact with necrotic fungi materials may cause serous retinal detachment.

Leaching behavior and characteristics of glass components and surrogate nuclides in radioactive vitrified waste forms.

Several vitrified waste forms were fabricated and characterized, which contain simulated radioactive waste incineration ash, and a long-term leaching test was conducted by an ISO method for 820 days to assess the chemical durability of vitrified waste forms. Two semi-empirical mechanism models were applied to find out the dominant leaching mechanism of glass elements. For glass elements, dissolution associated with diffusion was the dominant leaching mechanism and leaching characteristics also depend upon solubilities of components. A type of prediction model was applied to observe the long-term leaching behavior of major glass elements and surrogates. Diffusion coefficients and dissolution rate constants, the main parameters in the long-term prediction model, were obtained for glass elements and surrogate nuclides using experimental data for short and long-term periods. The model could be used to predict long-term behavior of such elements to observe and assess the stability of vitrified waste forms.

TCDD-up-regulation of IGFBP-6 and IL-5R alpha subunit genes in vivo and in vitro.

Although the potent environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has been well known for its immunosuppressive activity, the mechanisms of its action have been difficult to elucidate. This is partly due to its inability to exert its effects in vitro. To further elucidate the underlying mechanisms of TCDD effects, we screened for genes that are regulated by the in vivo TCDD treatment of mice that are challenged with allogeneic tumor cells. RNA, collected from lymphoid organs including the thymus, draining lymph nodes, and bone marrow, was reverse-transcribed to cDNA and hybridized to DNA arrays that consisted of 588 genes (ClonTech, USA). The expression of the NF-kappaB p65, c-jun, and p27(Kip1) genes was increased by the TCDD treatment, as previously reported. In addition, we found that the expression of several genes, which were not reported as regulated by TCDD, were modulated by TCDD. Some genes, including insulin-like growth factor-binding protein-6 (IGFBP-6) and IL-5R alpha, were upregulated; while other genes, including CD14, were down-regulated. The expression of the IGFBP-6 and IL-5R alpha subunit genes by TCDD in the thymus was confirmed by RT-PCR and Western blot analyses. Furthermore, TCDD effects on the expression of the IGFBP-6 gene was also observed with EL4 mouse thymoma cells. This suggests that IGFBP-6 may be involved in thymic atrophy, and EL4 cells may be used as an in vitro model for studying molecular mechanisms of thymic atrophy.

Electroretinographic studies in rhegmatogenous retinal detachment before and after reattachment surgery.

Changes in the scotopic electroretinogram (ERG) and oscillatory potentials (Ops) were examined in patients who had rhegmatogenous retinal detachment within 3 days before and also at regular intervals after a successful reattachment operation. Electroretinograms were recorded in 38 patients (age 10 to 62 years) for the recent 5 year period. The amplitudes of the scotopic a-wave and b-wave in the detached eye were significantly decreased compared to the fellow normal eye preoperatively. Statistically significant differences were found between the preoperative and the postoperative recordings of the diseased eye. However, postoperative interocular differences in the amplitude of the a-wave between the reattached and normal fellow eye were not statistically significant. The amplitudes of the a-wave and b-wave were inversely related to the extent of the retinal detachment area, the duration of the detachment, and the extent of the buckles that were applied. Significant interocular differences in the b/a wave amplitude ratio and the Ops amplitude were observed. These results strongly suggest that the retinal function, even after successful reattachment surgery, might be compromised mainly by an inner retinal malfunction rather than from a photoreceptor dysfunction.

Long-term visual recovery after scleral buckling procedure of rhegmatogenous retinal detachment involving the macula.

The long-term visual recovery after a scleral buckling procedure for rhegmatogenous retinal detachment involving the macula was investigated retrospectively. The patients had been treated with a segmental or encircling scleral buckle procedure and in this study the follow-up period was between 5 and 11 years. In order to investigate the natural course of functional recovery of the reattached retina, all cases with a history of intraocular surgery or trauma were excluded. In this investigation, 34 patients were selected in which 35 eyes were studied. The best corrected visual acuities between a 6-month and 5-year postoperative period were compared. They were found to be more improved 5 years after surgery than after 6-month by two or more lines in 19 eyes (54%). In these 19 eyes, the visual acuities continued to improve up to 10 years after surgery. Improvement in the long-term postoperative visual acuity was found to correlate with the shorter duration of macular detachment (30 days), zero or mild myopia (-6 diopters) and to a lesser extent, retinal detachment. the visual function of the reattached human retinas may continue to improve over the long term, especially when these beneficial factors are present.

Occlusions of branch retinal arterioles following amniotic fluid embolism.

Amniotic fluid embolism is a serious complication of pregnancy with a high mortality. We present a 28-year-old healthy woman who underwent dilatation and curettage for an elective abortion, followed by the sudden loss of vision in her left eye. Occlusion of one branch retinal arteriole was the initial finding of her left fundus, and two occlusions developed consecutively on the color fundus photographs. Fluorescein angiography demonstrated occlusions in three retinal arterioles among seven retinal arterioles originating from the optic disc. These findings suggest that possible mechanisms of amniotic fluid embolism are the unusual cause in retinal arteriolar occlusions. Here clinical course and ophthalmic findings are reviewed, and the relationship between amniotic fluid embolism and retinal arteriolar occlusions is discussed.

Weber-Christian disease presenting with proptosis: a case report.

Weber-Christian disease (WCD) is a rare inflammatory disease of adipose tissue, which is characterized by painful cutaneous nodules and constitutional symptoms. Although any area of the body containing fat can be affected by WCD, the involvement of retrobulbar fat is uncommon and proptosis is a rare presenting manifestation. We report a case who presented with proptosis of the right eye which is accompanied by painful subcutaneous nodules, high fever and myalgia. Biopsies of retrobulbar tissue and suprapubic nodule showed lobular panniculitis with mixed cellular infiltration, mainly composed of histiocytes and lymphocytes. He responded well to high-dose glucocorticoid.

Choroidal Langerhans' cell histiocytosis.

PURPOSE: To report a patient with choroidal Langerhans' cell histiocytosis. METHODS: A solitary tumor was found in the left eye of a 49-year-old male who had no definite history of systemic disorders, but had observed visual disturbances for a period of 1 month. Ultrasonography, fluorescein angiography, and indocyanine green angiography were performed and the eyeball was enucleated. We prepared the specimen for microscopic examinations. RESULTS: Fluorescein angiographic findings of the lesion were mottled hyperfluorescence in the arteriovenous phase and strong hyperfluorescence in the late phase. Hypofluorescence in both early and late phases showed on indocyanine green angiogram. The lesion of choroid was widely infiltrated by histiocytes, though no extraocular invasion was found. Immunohistochemical studies including S-100 and CD 68 staining revealed characteristic features of Langerhans' cell histiocytosis. Electron microscopic examination of the histiocytes showed histiocytosis X body (Birbeck granule) in the cytoplasm and indented nucleus. CONCLUSION: We consider that this is a case of choroidal Langerhans' cell histiocytosis with no evidence of systemic lesions.

Hepatocellular carcinoma metastatic to the orbit.

Orbital metastases of hepatocellular carcinoma are rare. The authors report a case of hepatocellular carcinoma metastatic to the orbit. A 56-year-old woman with hepatitis B infection as confirmed serologic test for hepatitis B surface antigen (HBsAg) demonstrated superior displacement of the left eyeball. The clinical appearance of the patient demonstrated an inferior displacement of the right eye. MRI disclosed an orbital mass that extended toward the lower eyelid and into the temporal fossa with destruction of the lateral orbital wall. Upon subsequent abdominal computed tomographic scans, the primary tumor was found in the liver. A biopsy specimen of the orbit showed trabecular structures with eosinophilic cytoplasm. Bile canaliculi and sinusoids were also seen. The tumor cells showed vesicular nuclei with mitoses. Immunohistochemical markers such as high-molecular-weight keratin and alpha-fetoprotein showed a positive response. However, immunohistochemical markers such as low-molecular-weight keratin and polyclonal carcinoembryonic antigen showed as negative. We diagnosed the tumor as a hepatocellular carcinoma metastatic to the orbit. A review of the pertinent literature disclosed relatively few occurrences of hepatocellular carcinoma metastasizing to the orbit.

Inflammatory response in experimental Staphylococcus and Pseudomonas endophthalmitis.

Staphylococcus epidermidis [2.0 x 10(4) colony-forming units (CFU)/0. 1 ml] and Pseudomonas aeruginosa (2.0 x 10(3) CFU/ml) were inoculated in the vitreous humor of rabbits. In S. epidermidis endophthalmitis, the numbers of microorganisms reached a maximum (4. 1 x 10(7) CFU/ml) at day 2 after inoculation and then declined spontaneously. However, clinical scores were observed to be worst at day 5. In P. aeruginosa endophthalmitis, the numbers of microorganisms reached a maximum (9.3 x 10(6) CFU/ml) 36 h after inoculation. However, culture results were persistently positive until day 15. Electroretinogram (ERG) b-wave amplitudes in S. epidermidis endophthalmitis continued to decrease from day 3 (>24%) until day 5, and then recovered to the preinoculative level of amplitudes at day 7. ERG b-wave amplitudes in P. aeruginosa endophthalmitis continued to decrease after 24 h (>24%). ERG b-wave amplitudes from day 7 to day 15 were flat. The inflammatory response continued under the absence of microorganisms in S. epidermidis endophthalmitis. The time in which a maximum in the number of microorganisms was reached was earlier than that in the clinical examination scores in both S. epidermidis and P. aeruginosa endophthalmitis.

Ciliary body schwannoma.

PURPOSE: Intraocular schwannomas are very rare, benign, peripheral nerve neoplasms. The authors report a case of ciliary body schwannoma. METHOD: A 39-year-old Korean woman presented with slowly decreasing visual acuity and proptosis of the right eye for 4 years. At the time of her visit, the eyeball protruded and deviated laterally. She could not sense light with her right eye. We enucleated the eyeball. The enucleated eyeball with tumor was examined histopathologically, immunohistochemically, and under electron microscope. RESULTS: Microscopic examination revealed spindle cells and characteristic Antoni type A and B areas with Verocay bodies. Immunohistochemical study showed tumor cell expressions of S-100 and vimentin, but other immunohistochemical studies were negative. Electron microscopic examination demonstrated Luse body. CONCLUSIONS: We diagnosed the tumor as a schwannoma arising from the ciliary body on the basis of the above mentioned results. Schwannomas are very rare intraocular neoplasms, but they are benign so we should differentiate from other intraocular neoplasms.

Mitomycin C-induced apoptosis in cultured human Tenon's capsule fibroblasts.

To investigate the mitomycin C-induced apoptotic cell death of fibroblasts, the primarily cultured human Tenon's capsule fibroblasts were exposed to a clinically used dosage of 0.4 mg/ml of mitomycin C for 5 minutes. TUNEL (TdT-mediated dUTP-biotin nick end labeling) assay and electron microscopic studies were performed to determine the extent of mitomycin C-induced apoptosis. A flow cytometric study was performed to quantify the apoptotic cell population over time. The TUNEL stains were positive and electron microscopy showed features of apoptotic cell death in some fibroblasts 3 and 5 days after treatment. Flow cytometric analysis using Annexin V-propidium iodide double staining detected apoptotic cells 3 days after treatment. These apoptotic cell populations increased at 4 days and were sustained for one week. This study revealed that the clinical effects of mitomycin C on fibroblasts may be mediated not only by antiproliferative but also apoptotic cell death to some degree. Therefore, the apoptotic cell death of fibroblasts induced by mitomycin C should be considered to properly understand the mechanism of wound healing after trabeculectomy with adjunctive mitomycin C.

Continued lodging of retinal emboli in a patient with internal carotid artery and ophthalmic artery occlusions.

Internal carotid artery or ophthalmic artery occlusions are devastating ophthalmological events which lead to severe impairment of vision. A case of multiple branch retinal artery occlusions in a 63-year-old male with internal carotid artery and ophthalmic artery occlusions on brain angiography is presented. Emboli lodging in branches of the retinal arteries were bright, glistening, yellow or orange in appearance. Such a distinctive ophthalmoscopic appearance led to the diagnosis of cholesterol emboli. Fluorescein and indocyanine green angiography disclosed delayed filling of the retinal vessels and choroid, and showed multiple hypofluorescence distal to the vessels in which the emboli were lodged. At the time of initial examination, the number of emboli lodged in retinal arteries was estimated at more than 20. As time passed, a few of the previous emboli disappeared and new emboli appeared in other sites on fundus examination. We think that the lodging of new emboli in other sites is due to the continued break-up of atheromatous tissue through the collateral circulation associated with the occlusion of the internal carotid and ophthalmic arteries.

Central retinal vein occlusion combined with cilioretinal artery occlusion.

A healthy 65-year-old man with sudden profound visual loss in his right eye presented with clinical signs of central retinal venous occlusion and retinal whitening, indicative of a cilioretinal arterial obstruction. He had been diagnosed with cilioretinal artery occlusion at a private ophthalmology clinic three days before being referred to our department. On fluorescein angiogram of the affected eye, the proximal portion of the retinal arteries filled with dye 27.3 seconds after injection, indicating a delay in retinal arterial filling. Moreover, the cilioretinal artery did not fill at that phase, but went on to fill 45.1 seconds after injection. Over 63.4 seconds after the filling of the retinal arteries, the laminar flow of the retinal venous vessels appeared. This was not until 90.7 seconds after injection. This patient was elderly, had no systemic diseases, and showed non-ischemic CRVO, prolonged retinal arterial filling on fluorescein angiography, and poor prognosis in visual acuity. His clinical course seemed to favor the pathogenetic hypothesis of a primary arterial affection.

The electroretinogram in chronic renal failure.

To evaluate functional changes of the retina in patients with chronic renal failure (CRF), we analyzed maximal combined response according to the recommendations of the International Society of Clinical Electrophysiology of Vision. Oscillatory potentials were extracted from maximal combined response by high pass filtering. Because most CRF patients suffer from hypertension, hypertensive patients were selected for the control group. Values recorded in CRF patients were compared with those recorded in hypertensive patients and in the normal control group. CRF patients underwent laboratory tests which included complete blood cell count and the determination of blood urea nitrogen, creatinine, natrium, and potassium levels. The parameters of electroretinograms obtained from CRF patients were compared with those obtained from the normal control group, in the former group all amplitudes were significantly lower and all implicit times except those of b-wave were significantly delayed (P < 0.05). In CRF patients, decreased b-amplitude of maximal combined response and delayed implicit time of oscillatory potentials 1, and 2 were significantly different from those in hypertensive patients (P < 0.05). CRF patients had anemia, and their blood urea nitrogen and creatinine levels appeared abnormal. There was, however, no clinical correlation between biochemical data and electroretinograms. Consequently, retinal function in CRF patients was severely damaged compared with control groups (i.e., normal and hypertensive patients). We suggest that these findings are result of anemia and uremia in addition to hypertensive retinal damage.

Timing of dexamethasone treatment in experimental Staphylococcus aureus endophthalmitis.

PURPOSE: This study sought to determine whether intravitreal dexamethasone with vancomycin preserves retinal function in eyes with experimental Staphylococcus aureus endophthalmitis better than intravitreal vancomycin alone. METHODS: Twenty-four rabbits received intravitreal injections in both eyes with S. aureus. Right eyes were treated with intravitreal dexamethasone plus vancomycin and left eyes were treated with vancomycin alone at 24, 36, 48, or 72 hours after inoculation. Evaluation was performed by slit-lamp biomicroscopy, indirect ophthalmoscopy, and electroretinogram. Vitreous humor cultures and histopathologic examinations were performed on the eyes after the rabbits were killed. RESULTS: The combination of intravitreal dexamethasone and vancomycin resulted in significantly less inflammation than vancomycin alone at 24 and 36 hours after inoculation, but electroretinograms showed significantly better preservation only at 36 hours after bacterial inoculation. Viable bacteria were cultured from eyes treated 48 and 72 hours after inoculation. CONCLUSION: Intravitreal dexamethasone was found to be beneficial by electroretinography when administered 36 hours after infection. In the authors' model, a single intravitreal injection of vancomycin with or without the addition of dexamethasone was insufficient to sterilize eyes 48 and 72 hours after bacterial inoculation.