Initial Subsurface Incorporation of Oxygen into Ru(0001): A Density Functional Theory Study.

The adsorption and diffusion of oxygen on Ru(0001) surfaces as a function of coverage are systematically investigated by using density functional theory. A high incorporation barrier of low-coverage adsorbed oxygen into the subsurface is discovered. Calculations show that the adsorption of additional on-surface oxygen can lower the penetration barrier dramatically. The minimum penetration barrier obtained is 1.81 eV for a path starting with oxygen in mixed on-surface hcp and fcc sites at an oxygen coverage of 0.75 ML, which should be regarded as close to 1 ML. Energy diagrams show that oxygen-diffusion barriers on the surface and in the subsurface are much lower than the penetration barrier. Oxygen diffusion on the surface is an indispensable step for its initial incorporation into the subsurface.

Association of Lumican gene polymorphism with high myopia: a meta-analysis.

PURPOSE: Numerous studies have evaluated the association between the single-nucleotide polymorphism (SNP) (rs3759223, C→T) in Lumican gene and high myopia risk in the Chinese population. However, the results have been inconsistent. We therefore here examined whether the rs3759223 polymorphism confers high myopia risk by conducting a meta-analysis. METHODS: PubMed, EMBASE, Science Citation Index, and Chinese National Knowledge Infrastructure (up to November 30, 2012) were searched by two investigators independently. Pooled relative ratios (RRs) and 95% confidence interval (CI) were used to assess the strength of the associations between SNP rs3759223 and myopia. Statistical analysis was undertaken using the program STATA 11.0 software (Stata Corporation, College Station, TX). RESULTS: Five case-control studies involving 923 patients with high myopia and 622 controls were included in this meta-analysis. A significant relationship between SNP rs3759223 and high myopia in the Chinese population was found under the homozygote (RR = 1.47, 95% CI 1.01-2.12, p = 0.04) and recessive (RR = 1.69, 95% CI 1.09-2.62, p = 0.02) genetic models. However, no significant association was found under the heterozygote (RR = 1.01, 95% CI 0.76-1.35, p = 0.93) and dominant (RR = 1.06, 95%CI 0.90-1.26, p = 0.48) genetic models. CONCLUSIONS: This meta-analysis showed the evidence that SNP rs3759223 may affect individual susceptibility to high myopia in the Chinese population. Given the limited sample size, further investigations are needed to validate the association.

Phacoemulsification versus manual small-incision cataract surgery for age-related cataract: meta-analysis of randomized controlled trials.

BACKGROUND: To compare outcomes of phacoemulsification (PE) with manual small-incision cataract surgery (MSICS) for age-related cataract. DESIGN: Meta-analysis. PARTICIPANTS: Patients from previously reported randomized controlled trials (RCTs) of PE and MSICS with clinical outcomes. METHODS: A comprehensive literature search of Cochrane Library, PubMed and EMBASE to identify relevant RCTs comparing PE and MSICS. A meta-analysis was performed on the results and a RevMan 5.0 software (version 5.0; Cochrane Collaboration, Oxford, UK) was used for data analysis. MAIN OUTCOME MEASURES: Primary outcome measures included best corrected vision acuity (BCVA), uncorrected visual acuity (UCVA). Secondary outcome measures included surgically induced astigmatism (SIA), percentage of endothelial cell count (ECC) loss and complications. RESULTS: Six RCTs describing a total of 1315 eyes were identified. There were no significant differences between the techniques regarding the BCVA 6/9 or better (P = 0.69) and less than 6/18 (P = 0.68), percent of ECC loss (P = 0.45), intraoperative or postoperative complications (P = 0.44 and P = 0.87, respectively). However, a greater proportion of patients in the PE group had final UCVA ≥ 6/9 (P = 0.03), whereas a greater proportion of patients in the MSICS group had final UCVA < 6/18 (P = 0.03). Moreover, PE group induced less SIA (P < 0.00001). CONCLUSIONS: PE is superior to MSICS in UCVA and causes less SIA, but there were no significant differences in visual rehabilitation, ECC loss and complication rates between the two techniques.

A meta-analysis of primary dacryocystorhinostomy with and without silicone intubation.

OBJECTIVE: To examine possible differences in success rates of primary dacryocystorhinostomy (DCR) with and without silicone intubation, and to find out whether the use of silicone tubes is beneficial. DESIGN: A literature search was conducted in the PubMed, EMBASE, and Cochrane Controlled Trials Register to identify potentially relevant controlled trials. METHODS: Language was restricted to English. The surgical techniques were categorized into external DCR (EX-DCR), endonasal laser-assisted DCR (LA-DCR), and nonlaser endoscopic endonasal DCR techniques (EN-DCR). The main outcome measure was success rates after DCR-with and DCR-without silicone intubation. The statistical analysis was carried out using a RevMan 5.0 software. RESULTS: Of 188 retrieved trials from the electronic database, 9 trials (5 randomized controlled trials and 4 cohort studies) involving 514 cases met our inclusion criteria. There was no statistically significant heterogeneity between the studies. The pooled risk ratio was 0.99, with a 95% confidence interval (0.91-1.08). There was no significant difference in the success rates between the DCR with and without silicone intubation (p = 0.81). Sensitivity analysis and subgroups analyses suggested that the result was comparatively reliable. CONCLUSIONS: Based on this meta-analysis that included 5 randomized controlled trials and 4 cohort studies, no benefit was found for silicone tube intubation in primary DCR. Further well-organized, prospective, randomized studies involving larger patient numbers are required.

[Medpor plus titanic mesh implant in the repair of orbital blowout fractures].

OBJECTIVE: To study the efficacy of porous polyethylene (Medpor) plus titanic mesh sheets in the repair of orbital blowout fractures. METHODS: A total of 20 patients underwent open surgical reduction with the combined usage of Medpor and titanic mesh. And they were followed up for average period of 14.5 months (range: 9 - 18). RESULTS: There is no infection or extrusion of medpor and titanic mesh in follow-up periods. There was no instance of decreased visual acuity at post-operation. And all cases of enophthalmos were corrected. The post-operative protrusion degree of both eyes was almost identical at less than 2 mm. The movement of eye balls was satisfactory in all directions. Diplopia disappeared in 18 cases with a cure rate of 90%, 1 case improved and 1 case persisted. CONCLUSION: Medpor plus titanic mesh implant is a safe and effective treatment in the repair of orbital blow out fractures.

[Orbscan II-assisted intraocular lens power calculation after LASIK].

OBJECTIVE: To evaluate the accuracy of keratometric value derived from one zone of Orbscan II mean power map after Laser in situ keratomileusis (LASIK) in combination with Holladay IOL Consultant software to calculate the intraocular lens (IOL) power. METHODS: A two-part study was conducted at a referral practice. Part 1 was a prospective study of 118 eyes undergoing LASIK. The changes in Orbscan II mean power maps at four central zones (1.5, 2.0, 2.5 and 3.0 mm) were compared with the cornea power calculated from pre-LASIK data to determine the optimum Orbscan II correlation zone. In Part 2, the power of optimum measured by Orbscan II after LASIK was applied to IOL calculations for 62 eyes undergoing LASIK. And the results were compared with the IOL power calculated by the pre-LASIK data. RESULTS: (1) An analysis at the Orbscan II 1.5 mm measurement zone demonstrated an underestimation of net cornea power after LASIK while the 3.0 mm zones demonstrated an overestimation. The 2.0 mm and 2.5 mm zones best approximated the net cornea power calculated from pre-LASIK data; (2) The cornea power at 2.5 mm from Orbscan II was selected for IOL calculations in combination with Holladay IOL Consultant software Holladay II and HofferQ formula. The refractive error calculated by Holladay II and HofferQ formula were (0.47 ± 0.75) D and (0.52 ± 0.83) D versus the IOL power calculated by clinical history method. The refractive errors of two formula within ± 0.50 D were 48.4% and 43.5% and within ± 1.0 D 80.6% and 74.2%. CONCLUSIONS: The cornea power from 2.5 mm Orbscan II zone after LASIK in combination with Holladay II or HofferQ formula can accurately predict the IOL power for cataract surgery.

[Estimation of preoperative corneal power in patients with myopic LASIK based on postoperative corneal data measured from Orbscan II].

OBJECTIVE: Compare the change of pre- and post-operative posterior corneal curvature measurements in peripheral fitting zones using the Orbscan II topographer in patients undergoing myopic laser in situ keratomileusis (LASIK). To establish a new ratio of the anterior and posterior corneal curvature for the calculation of preoperative total corneal power using postoperative corneal data alone in patients after LASIK. METHODS: Retrospectively analyzed the changes of posterior corneal curvature in peripheral 7 to 10 mm fitting zones in 151 right eyes (151 individuals) 3 month after LASIK as measured by Orbscan II. The new ratio between the anterior and posterior corneal curvature was measured. The new ratio was used to estimate pre-operative total corneal refractive power in 30 eyes. The estimated total corneal refractive power was compared with the value measured from Orbscan II preoperatively. The accuracy of intraocular lens power estimated in 2 cases underwent cataract surgery after corneal refractive surgery was studied. RESULTS: The mean difference in estimated pre- and post-operative power of the posterior cornea was (-0.005 ± 0.154) mm (t = 0.417, P = 0.677). The ratio between the preoperative anterior central (0 - 7 mm) corneal curvature and the posterior peripheral (7 to 10 mm) corneal curvature was 1.167 ± 0.030. Estimated mean pre-operative total corneal power was (43.49 ± 1.79) D, whereas the value measuring from Orbscan II preoperatively was (43.77 ± 1.53) D. The mean difference between these two measurements was (-0.28 ± 1.00) D (t = -1.523, P = 0.139). The spherical equivalent refraction after cataract extraction of the two cases undertaken cataract surgery after corneal refractive surgery was 0.54 D and 0.69 D, respectively. CONCLUSIONS: The difference in posterior corneal curvature measurement following myopic LASIK using the peripheral fitting zone with the Orbscan II, as compared to the preoperative values, is clinically insignificant. The pre-LASIK corneal power can be estimated using post-LASIK data together with the new calculated ratio. This will be useful in post-LASIK patients requiring cataract surgery but without the availability of pre-LASIK corneal data for the estimation of the intraocular lens power.