Incidence, causes, and neodymium:YAG laser treatment of pupillary capture

OBJECTIVE: To report the incidence of and factors associated with pupillary capture after cataract surgery and evaluate the outcomes of treatment with the neodymium:YAG (Nd:YAG) laser. SETTING: Unit of Ophthalmology, University of Edinburgh, and Royal Infirmary of Edinburgh Trust Hospital, Edinburgh, United Kingdom. METHODS: This prospective study comprised 792 consecutive patients having cataract extraction by one surgeon from 1989 to 1993. Outcome measures were incidence of pupillary capture associated with eye disease and treatment, surgical technique, and intraocular lens (IOL) placement and style; postoperative progress; and results of Nd:YAG treatment. RESULTS: Pupillary capture developed in 30 of the 764 patients (3.9%) having implantation of a posterior chamber IOL a mean of 14 weeks postoperatively (range 2 to 44 weeks). The incidence was significantly higher in eyes with angle-closure glaucoma, combined glaucoma and cataract surgery, can-opener capsulotomy, manual extraction, sulcus IOL implantation, large-optic IOLs, and one-piece IOLs. Neodymium:YAG laser treatment was successful in 8 of 12 eyes. CONCLUSION: Pupiliary capture may be anticipated and when recognized at an early stage, treated successfully with an Nd:YAG laser in most cases.     

EFFECTS OF CARBON DEPOSITS ON THE SPECIFIC ACTIVITY OF NICKEL AND NICKEL BIMETALLIC CATALYSTS

The effects of carbon formation on methanation activity of nickel and nickel bimetallic catalysts were investigated. Carbon was deposited on these catalysts at 675-700 K, 1 atm, H₂/CO = 2 and space velocities of 80,000 to 200,000 h^-1 over a period of 6-24 hours. Specific methanation activities were measured before and after carbon depositing treatments at 500-575 K, 1 atm H₂/CO = 4 and space velocities of 100,000 h^-1. The results show that Ni/Al₂O₃ loses 20-60% of its initial activity within 10-15 hours of treatment. Platinum and cobalt promoted nickel are significantly more resistant to deactivation by carbon. However, Ni-MoO₂ is highly susceptible to deactivation, losing essentially all of its activity within a few hours. Data showing the effects of reaction conditions, metal concentration and catalyst composition on the extent of deactivation and the effects of deactivation on catalyst strength are presented and discussed     

Design, Synthesis, and Catalytic Properties of Silica-Supported, Pt-Promoted Iron Fischer–Tropsch Catalysts

Silica-supported iron catalysts (Fe/SiO₂, FePt/SiO₂, and FePtK/SiO₂) were prepared using a novel nonaqueous (acetone) evaporative deposition technique. This preparation leads to relatively well-dispersed iron phases at modest (10%) metal loadings. Moreover, catalytic activities of these catalysts for Fischer–Tropsch synthesis are high and comparable to industrially relevant precipitated iron catalysts. Catalyst activities were tested following a nonregular L18 orthogonal array that enabled the number of 150-h activity tests to be reduced from 54 to 18; this statistical design was augmented with five additional runs to provide replication. Primary independent variables affecting catalysts' activity were promoter type, pretreatment gas composition (H₂, H₂/CO, or CO), pretreatment temperature (250, 280, or 320 °C), and reaction temperature (250 or 265 °C); iron carbide level measured from Mössbauer spectroscopy was correlated with activity in a separate analysis. Activity was found to increase in the order Fe/SiO₂, FePt/SiO₂, and FePtK/SiO₂. For a given catalyst composition, activity increases to a maximum with increasing pretreatment temperature and increasing time. Catalyst activity was also positively correlated with increasing chi-carbide content for Fe/SiO₂ and FePt/SiO₂ catalysts but not for FePtK/SiO₂. While pretreatment atmosphere greatly influences initial activity–time behavior, activity is less dependent on pretreatment after about 150 h of reaction. Steady-state methane and C₂₊ hydrocarbon selectivities (CO₂-free basis) for the FePtK/SiO₂ catalyst at 250–265 °C, 10 atm, and H₂/CO = 1 are 7–9 and 91–93%, respectively, while its hydrocarbon productivity at 250 °C (normalized to 15 atm, H₂/CO = 0.7) of 0.27 g HC/g_cat/h is comparable to those reported for unsupported precipitated iron catalysts of high activity and selectivity. These results indicate that preparation of an active, selective, stable, attrition-resistant supported iron catalyst for Fischer–Tropsch synthesis is feasible. Promise for additional improvements in catalyst performance through application of advanced preparation methods and optimization of catalyst chemical and physical properties is also indicated.     

Vertical impedance measurements on concrete bridge decks for assessing susceptibility of reinforcing steel to corrosion

Corrosion is a pressing problem for aging concrete infrastructure, especially bridge decks. Because of its sensitivity to factors that affect corrosion of reinforcing steel in concrete, resistivity is an important structural health indicator for reinforced concrete structures. In this research, an instrument was developed to measure vertical impedance on concrete bridge decks. Measurements of vertical impedance on slabs prepared in the laboratory, on slabs removed from decommissioned bridge decks, and on an in-service bridge deck in the field demonstrate the utility of the new apparatus.     

Interpersonal problems, attachment styles, and outcome in brief dynamic psychotherapy

The Inventory of Interpersonal Problems (IIP) has been used to identify dysfunctional patterns in interpersonal interactions. Interpersonal problems can be organized in two dimensions, and the two-dimensional space can be divided into eight equal sectors (octants). Subscales of the IIP describe each of these octants. The instrument has been used to identify (a) interpersonal problems that are discussed most often in a brief dynamic psychotherapy and (b) problems that are treated most easily. The results show that problems in the "exploitable" octant improve most frequently, whereas problems in the "dominating," "vindictive," and "cold" octants do not improve as readily. Attachment styles in adulthood were examined (following a model proposed by Bowlby), and different attachment styles were found to correspond to different types of interpersonal problems. Finally, these variables were related to the ability to describe other people clearly. The article also discusses implications for brief dynamic psychotherapy.