b The Kuwabara flow model in a system of multiple spheres is used to predict the collection of aerosol particles from flow through a packed bed. Diffusional and interceptional collection efficiencies are predicted by a theoretical procedure which was derived using a boundary layer approach accounting for the flow interference effects of neighboring collecting spheres in packed beds. The results were compared with available experimental data and satisfactory agreement was obtained.Packed beds have been used widely for many industrial operations such as absorption, adsorption, and distillation due to their large contact area between gas phase and solid media or between liquid and solid. Recently there has been increasing interest in employing the packed bed concept for removing aerosol particles. A major advantage of aerosol filtration by packed beds is that by selecting the proper bed media, both particulate and gaseous pollutants can be simultaneously collected, the particulates removed by filtration, and the gases removed by adsorption. The possibilities for using packed beds a t high temperatures and pressures also make their development more attractive.It is well known that in packed beds consisting of fine media and operating a t a low flow rate, small particles are collected primarily by Brownian diffusion. As particle size increases, direct interception and gravitational settling become important. Eventually, inertial impaction will dominate if particle size and flow rate are further increased.In filtration study, it is first necessary to understand flow field inside the filter media. For packed beds, the individual collectors or granules either have or can be assumed to have a spherical or nearly spherical shape. These individual granules or spheres are closely packed together and the mutual interference effects of neighboring spheres on the flow field have to be taken into consideration. However, most previous theoretical studies such as those by Fuchs ( I ) and by Friedlander ( 2 ) are based on the model of an isolated sphere collector. It is therefore necessary to employ an additional empirical correction factor when these results are to be applied to packed beds. Consequently, many theoretical studies of aerosol filtration that are based on an improved model have been reported recently (3-7).A single sphere efficiency may be defined as the ratio of the cross-sectional circular area surrounded by limiting streamlines of the flow approaching the collecting sphere to the projected area of the sphere. The limiting streamlines are such that all the particles passing within them will be collected by the sphere while all the particles outside the streamlines will escape it. With this representation, the concentration ratio of the particles collected inside the packed bed to those approaching it, or the overall efficiency of particle collection by the bed, can be shown to relate to the single sphere efficiency as follows:(1)where E = overall collection efficiency of packed bed, 7 = single sphere efficiency, L ...

PurposeTo assess influence of the location of visual field (VF) loss on vision‐related quality of life (VRQOL) in patients with glaucoma.MethodsWe included 826 patients with primary open‐angle glaucoma (POAG) enrolled in the prospectively designed Life Quality of Glaucoma Patients Who Underwent Treatment (LIGHT) study organized by the Korean Glaucoma Society. We divided the integrated binocular visual field (IVF) into four regions and evaluated the associations between Rasch‐analysed 25‐item National Eye Institute Visual Function Questionnaire (NEI VFQ‐25) and location of the IVF using univariate and hierarchical multivariable linear regression.ResultsMean deviation (MD) of the IVF at superior centre showed the lowest value among the four regions. Multivariable linear regression analysis revealed significant correlation of the composite score and all subscales of the NEI VFQ‐25 except ocular pain and near activities at each of four IVF regions. Mean deviation at superior centre showed significant correlation with composite score (R2 = 0.181), near activities (R2 = 0.175), and social functioning (R2 = 0.166); MD at superior periphery showed highest correlation with role difficulties (R2 = 0.137); MD at inferior centre showed highest correlation with driving (R2 = 0.145); and MD at inferior periphery showed significant correlation with distance activities (R2 = 0.214) and dependency (R2 = 0.119).ConclusionFour different regions of the IVF had a similarly important impact on subscales of the NEI VFQ‐25 in glaucoma patients. Preservation of the superior field should be considered as much as that of the inferior field for maintaining a good VRQOL in patients with glaucoma.

PurposeChronic use of topical hypotensive agents induces several side effects caused by preservatives. The purpose of this study was to evaluate the effects of prostaglandin analogs with varying concentrations of benzalkonium chloride (BAC), preservative-free (PF), and alternative preservatives on mouse corneal tissue.MethodsThirty-five, 8- to 10-week-old female C57BL/6 mice (five mice for each group) were used for this study. To the control group, we applied normal saline, and to each drug-treated group we applied 0.02% BAC, bimatoprost 0.01% (with BAC 0.02%), latanoprost 0.005% (with BAC 0.02%), travoprost 0.004% (with 0.001% polyquad) or tafluprost 0.0015% with/without 0.001% BAC, once a day (9 p.m.) for 4 weeks. Corneal fluorescein staining was evaluated in all groups. After harvest, the corneal tissues were embedded in paraffin and then Hematoxylin-Eosin stain was performed for histopathological examination. Immunofluorescence staining was done against TNF-α, IL-6, HLA DR, pJNK, and pAkt.ResultsIn corneal fluorescein staining, severe punctate epithelial keratitis was seen in the groups of 0.02% BAC, 0.02% BAC containing bimatoprost 0.01% and latanoprost 0.005%. The surface desquamation, irregular surface, loss of cell borders, anisocytosis and stromal shrinkage were observed in the groups of BAC-containing eye drops. Moreover, the groups treated with BAC-containing eye drops have high inflammatory markers, significantly decreased cell viability-related signal, pAkt, and higher apoptosis-inducing signal, pJNK, than the control group. On the other hand, travoprost 0.004% and PF tafluprost 0.0015% have less cellular morphologic changes, lower inflammation, and higher cellular viability than BAC-containing formulations.ConclusionsCorneal damage, increased inflammation and apoptosis and low cell viability were observed in BAC-containing groups. PF or alternatively preserved glaucoma medications seem to be a reasonable and viable alternative to those preserved with BAC.

PurposeTo evaluate the efficacy and safety of fibrin bioadhesive in conjunctivolimbal autograft surgery for primary pterygium.MethodsThirty-six eyes in 34 patients were reviewed with nasal primary pterygium who were treated with pterygium excision with superior conjunctivolimbal transplantation with fibrin bioadhesive. Surgical durations were recorded and the patients were followed up on the first day after surgery and then at 1, 2, 4, 8 and 12 weeks postoperatively. The graft-recipient site attachments were examined and subjective symptoms of patients were recorded at every follow-up examinations.ResultsThe mean patient age was 57.9±10.1 (ranging from 33 to 83) years. The mean follow-up period was 22.05±5.78 weeks. The mean surgery time was 18.04±5.65 minutes. The subjective symptoms (pain, foreign body sensation, tearing and discomfort) disappeared in 23 of 36 eyes (64%) in one week after surgery, and all discomforts subsided within two weeks after surgery in all patients. The conjunctivolimbal autograft was correctly positioned and fixed in 34 of 36 eyes (94.4%) throughout the follow-up period. Graft dehiscence was seen in two eyes (5.6%), one eye was treated with remedial sutures, and the other eye showed a spontaneous healing without remedial sutures. Transient graft edema occurred in four eyes (11.2%) but subsided spontaneously within a month. There were no cases of pterygium regrowth or complications due to the fibrin bioadhesive.ConclusionsThe use of fibrin bioadhesive in conjunctivolimbal autograft surgery in primary pterygium simplifies surgical techniques, shorten surgical duration, and produce less postoperative subjective symptoms. Therefore, the fibrin bioadhesive is a safe and effective tool to attach conjunctivolimbal autograft in primary pterygium surgery.

In normal subjects without significant anisometropia, there was significant asymmetry of the RNFLT for each eye as well as between the right and left eye.