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Abstract: A number of cylindrical fallouts were observed in a tunnel under construction and temporary grouting as well as immediate backfilling was performed in order to control cavity expansion. The exact dimension of the largest fallout, i.e., height, cannot be measured due to limited access to the site and, therefore, experimental as well as empirical approaches were employed to estimate the fallout size. Additional boreholes were drilled immediately after the installation of permanent reinforcement and the accuracy of the proposed Tunnel Electromagnetic Prospecting System (TEPS), a non-destructive experimental testing method used to estimate the fallout volume, is verified with borehole core data. It is found that the empirical approach based on a bulking factor is easy to apply if a reference value is available. It is also proven that the TEPS method, which is fairly simple and inexpensive during the test process, gives satisfactory results when compared with borehole data. Finally, an effective reinforcement design is considered and the safety of the reinforced fallout area is evaluated through numerical analysis. Future work will be concentrated on the refinement of the measured data from TEPS and the reinforcement effect of the auxiliary techniques utilized in the fallout area. [Copyright &y& Elsevier]

A number of specimens made of gypsum with three and 16 flaws have been prepared and tested in compression. Results from these experiments are compared with observations from similar specimens with two flaws. The comparisons indicate that the cracking pattern observed in specimens with multiple flaws is analogous to the pattern obtained in specimens with two flaws. Two types of cracks initiate from the tips of the flaws: wing cracks and secondary cracks. Wing cracks are tensile cracks that initiate at an angle with the flaw and propagate in a stable manner towards the direction of maximum compression. Secondary cracks are shear cracks that initially propagate along their own plane in a stable manner. Two types of secondary cracks are possible: coplanar or quasi-coplanar, and oblique. As the load is increased, wing cracks propagate in a stable manner and secondary cracks may propagate in an unstable manner and produce coalescence, which occurs when two flaws are linked together. Nine types of coalescence have been observed, and each type is characteristic of a particular flaw geometry. The stresses at which wing and secondary cracks initiate and coalescence occurs strongly depend on the geometry of the flaws and on the number of the flaws; as the flaw inclination angle increases, the spacing increases, or the number of flaws decreases, initiation and coalescence stresses increase. [Copyright &y& Elsevier]

Purpose We compared the lamina cribrosa thickness (LCT) of normal subjects and patients with unilateral branch retinal vein occlusion (BRVO), and investigated the correlation between the LCT and the BRVO subtypes. Methods A total of 46 eyes of 46 patients with naïve untreated BRVO and 31 eyes of 31 normal control subjects were included in this study. The occlusion site was divided into 2 BRVO types: arteriovenous crossing BRVO (AV- BRVO) and optic nerve BRVO (ON- BRVO). The optic nerve head (ONH) was scanned using enhanced-depth imaging ( EDI) with the Spectralis OCT system. The mean LCT was defined at the centers of the mid-superior, central, and mid-inferior horizontal B-scans. The inter-eye differences and intra-eye differences in the LCT in BRVO were analyzed using the paired t-test. Results The mean LCT of both eyes in the patients with BRVO was thinner than that of the normal subject eyes (both P < .001). Although the LCT of the BRVO-affected eyes were slightly thinner than that of the fellow eyes (237.0 µm vs. 241.4 µm), there was no statistically significant difference. Moreover, there were no significant LCT differences according to site of occlusion (AV- BRVO 237.6 µm vs. ON- BRVO 234.4 µm, P > .05). Conclusions The lamina cribrosa was thinner in both eyes of the unilateral BRVO patients than in those of the normal subjects, but there was no difference in the LCT regardless of the anatomical site of the occlusion. These findings suggest that BRVO and glaucoma may have a common structural pathogenic mechanism. [ABSTRACT FROM AUTHOR]

PurposeThe purpose of this study is to determine the efficacy of half-fluence photodynamic therapy (PDT) depending on the degree of hyperfluorescence based on indocyanine green angiography (ICGA) for treatment of chronic central serous chorioretinopathy (CSC).MethodsWe conducted a prospective study of 30 eyes of 30 patients with chronic CSC. Half-fluence PDT (25 J/cm2 for 83 s) with ICGA guidance was applied to the area of choroidal hyperpermeability. The baseline middle-phase ICGA findings were classified as intense or weak hyperfluorescence depending on the degree of hyperpermeability from choriocapillaris. Changes in mean best-corrected visual acuity, resolution of subretinal fluid, recurrence rate, and complications were compared between the two groups.ResultsThe baseline ICGA findings showed intense hyperfluorescence in 16 eyes (53.3%) and weak hyperfluorescence in 14 eyes (46.7%). Subretinal fluid showed complete resolution in both the groups 1 month after a single application of half-fluence PDT. Recurrence of subretinal fluid was observed in one of 14 eyes (7.1%) with weak hyperfluorescence and in no eyes (0%) with intense hyperfluorescence. No statistically significant difference in the rate of recurrence was observed between the two groups.ConclusionHalf-fluence PDT appears to be an effective and safe treatment option for patients with chronic CSC regardless of the degree of hyperfluorescence based on ICGA. According to these findings, choroidal hyperpermeability, rather than dysfunction of retinal pigment epithelium, might be more important as primary pathogenesis of chronic CSC. [ABSTRACT FROM AUTHOR]