PNEUMATIC RETINOPEXY: Analysis of Risk Factors and Complications in 850 Cases.

BACKGROUND: To study out types and incidence of the complications and reveal the risk factors that affect anatomical and visual success of pneumatic retinopexy with a high number of rhegmatogenous retinal detachment cases. METHODS: Eight hundred and fifty eyes of the 837 patients who admitted at a tertiary center, between January 2015 and January 2022 for the diagnosis of rhegmatogenous retinal detachment, then underwent pneumatic retinopexy and had at least sixth month follow-up, were included in the study. The multivariate logistic regression model was created to investigate the factors affecting anatomical and visual success. RESULTS: The anatomical success rate was 53.4% with the first pneumatic retinopexy and 99.8% after subsequent procedures. Visual acuity of >0.4 logMAR (<20/50 Snellen), proliferative vitreoretinopathy, and macular involvement was determined as significant preoperative risk factors for single operation and visual success in all univariate and multivariate analyses. In addition, pseudophakic/aphakic lens status was associated with single operation failure in all analyses. Besides, in all analyzes for single operation and visual success, new or missed tears, proliferative vitreoretinopathy, delayed subretinal fluid, macular hole, and subretinal gas were identified as significant postoperative risk factors. Among these, new or missed tears was determined as the most common complication with a rate of 24%. CONCLUSION: There are many risk factors influencing the success of pneumatic retinopexy. These factors and complications should always be considered, before applying this rapid, effective, inexpensive, and minimally invasive method.

Intrinsic relation between catalytic activity of CO oxidation on Ru nanoparticles and Ru oxides uncovered with ambient pressure XPS.

Recent progress in colloidal synthesis of nanoparticles with well-controlled size, shape, and composition, together with development of in situ surface science characterization tools, such as ambient pressure X-ray photoelectron spectroscopy (APXPS), has generated new opportunities to unravel the surface structure of working catalysts. We report an APXPS study of Ru nanoparticles to investigate catalytically active species on Ru nanoparticles under oxidizing, reducing, and CO oxidation reaction conditions. The 2.8 and 6 nm Ru nanoparticle model catalysts were synthesized in the presence of poly(vinyl pyrrolidone) polymer capping agent and deposited onto a flat Si support as two-dimensional arrays using the Langmuir-Blodgett deposition technique. Mild oxidative and reductive characteristics indicate the formation of surface oxide on the Ru nanoparticles, the thickness of which is found to be dependent on nanoparticle size. The larger 6 nm Ru nanoparticles were oxidized to a smaller extent than the smaller Ru 2.8 nm nanoparticles within the temperature range of 50-200 °C under reaction conditions, which appears to be correlated with the higher catalytic activity of the bigger nanoparticles. We found that the smaller Ru nanoparticles form bulk RuO(2) on their surfaces, causing the lower catalytic activity. As the size of the nanoparticle increases, the core-shell type RuO(2) becomes stable. Such in situ observations of Ru nanoparticles are useful in identifying the active state of the catalysts during use and, hence, may allow for rational catalyst designs for practical applications.

Assessment of Choroidal Vascularity in Inactive Thyroid Associated Orbitopathy.

Objectives: The objectives of the study were to evaluate the vascular and stromal structure of the choroid in patients with inactive thyroid associated orbitopathy (TAO) by measuring choroidal vascularity index (CVI) and choroidal thickness (CT) using enhanced depth imaging (EDI) optical coherence tomography (OCT). Methods: The choroidal image was taken with EDI mode spectral domain (SD)-OCT. All scans were taken between 9.30 am and 11.30 am to avoid the diurnal variation of CT and CVI. To calculate CVI, macular SD-OCT scans were binarized using the publicly available software ImageJ and luminal area and total choroidal area (TCA) were measured. CVI was calculated as the proportion of LA to TCA. Furthermore, the relation between CVI and axial length, gender, and age was evaluated. Results: This study included 78 individuals with a mean age of 51.4±7.3 years. Group 1 consisted of 44 patients with inactive stage TAO, and Group 2 consisted of 34 healthy controls. Subfoveal CT was 338.92±73.93 µm in Group 1 and 303.97±40.35 µm in Group 2 (p=0.174). The CVI significantly differed between the two groups, which was higher in group 1 (p=0.000). Conclusion: Although CT was not different between groups, CVI which is the indicator of the vascular status of the choroid, was higher in patients with TAO in the inactive stage compared with healthy control subjects.

A step toward the wet surface chemistry of glycine and alanine on Cu{110}: destabilization and decomposition in the presence of near-ambient water vapor.

The coadsorption of water with organic molecules under near-ambient pressure and temperature conditions opens up new reaction pathways on model catalyst surfaces that are not accessible in conventional ultrahigh-vacuum surface-science experiments. The surface chemistry of glycine and alanine at the water-exposed Cu{110} interface was studied in situ using ambient-pressure photoemission and X-ray absorption spectroscopy techniques. At water pressures above 10(-5) Torr a significant pressure-dependent decrease in the temperature for dissociative desorption was observed for both amino acids, accompanied by the appearance of a new CN intermediate, which is not observed for lower pressures. The most likely reaction mechanisms involve dehydrogenation induced by O and/or OH surface species resulting from the dissociative adsorption of water. The linear relationship between the inverse decomposition temperature and the logarithm of water pressure enables determination of the activation energy for the surface reaction, between 213 and 232 kJ/mol, and a prediction of the decomposition temperature at the solid-liquid interface by extrapolating toward the equilibrium vapor pressure. Such experiments near the equilibrium vapor pressure provide important information about elementary surface processes at the solid-liquid interface, which can be retrieved neither under ultrahigh vacuum conditions nor from interfaces immersed in a solution.

In situ oxidation study of Pt(110) and its interaction with CO.

Many interesting structures have been observed for O(2)-exposed Pt(110). These structures, along with their stability and reactivity toward CO, provide insights into catalytic processes on open Pt surfaces, which have similarities to Pt nanoparticle catalysts. In this study, we present results from ambient-pressure X-ray photoelectron spectroscopy, high-pressure scanning tunneling microscopy, and density functional theory calculations. At low oxygen pressure, only chemisorbed oxygen is observed on the Pt(110) surface. At higher pressure (0.5 Torr of O(2)), nanometer-sized islands of multilayered α-PtO(2)-like surface oxide form along with chemisorbed oxygen. Both chemisorbed oxygen and the surface oxide are removed in the presence of CO, and the rate of disappearance of the surface oxide is close to that of the chemisorbed oxygen at 270 K. The spectroscopic features of the surface oxide are similar to the oxide observed on Pt nanoparticles of a similar size, which provides us an extra incentive to revisit some single-crystal model catalyst surfaces under elevated pressure using in situ tools.

In situ observation of water dissociation with lattice incorporation at FeO particle edges using scanning tunneling microscopy and X-ray photoelectron spectroscopy.

The dissociation of H2O and formation of adsorbed hydroxyl groups on FeO particles grown on Au(111) were identified with in situ X-ray photoelectron spectroscopy (XPS) at water pressures ranging from 3 × 10(-8) to 0.1 Torr. The facile dissociation of H2O takes place at FeO particle edges, and it was successfully observed in situ with atomically resolved scanning tunneling microscopy (STM). The in situ STM studies show that adsorbed hydroxyl groups were formed exclusively along the edges of the FeO particles with the O atom becoming directly incorporated into the oxide crystalline lattice. The STM results are consistent with coordinatively unsaturated ferrous (CUF) sites along the FeO particle edge causing the observed reactivity with H2O. Our results also directly illustrate how structural defects and under-coordinated sites participate in chemical reactions.

Assessment of neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and mean platelet volume in patients with idiopathic epiretinal membrane.

PURPOSE: To assess the role of inflammation in the pathogenesis of idiopathic epiretinal membrane (iERM) using the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and mean platelet volume (MPV) as indicators of inflammation and to compare these parameter levels between iERM and control subjects. METHODS: We retrospectively analyzed the medical records of 36 patients who underwent vitrectomy-ERM peeling and 39 patients who had cataract surgery. We obtained blood samples from all individuals who participated in the study to investigate these parameters. RESULTS: Seventy-five subjects were included in this study: 36 in the iERM group and 39 in the control group. The mean neutrophil and MPV levels were significantly higher in iERM subjects than in control subjects. The mean lymphocyte level was lower in the iERM group. The mean NLR, PLR, and MPV levels were higher in iERM subjects than in control subjects. CONCLUSION: The higher NLR, PLR, and MPV levels found in patients with iERM may indicate that subclinical systemic inflammation may associate with iERM.

Evolution of structure and chemistry of bimetallic nanoparticle catalysts under reaction conditions.

Three series of bimetallic nanoparticle catalysts (Rh(x)Pd(1-x), Rh(x)Pt(1-x), and Pd(x)Pt(1-x), x = 0.2, 0.5, 0.8) were synthesized using one-step colloidal chemistry. X-ray photoelectron spectroscopy (XPS) depth profiles using different X-ray energies and scanning transmission electron microscopy showed that the as-synthesized Rh(x)Pd(1-x) and Pd(x)Pt(1-x) nanoparticles have a core-shell structure whereas the Rh(x)Pt(1-x) alloys are more homogeneous in structure. The evolution of their structures and chemistry under oxidizing and reducing conditions was studied with ambient-pressure XPS (AP-XPS) in the Torr pressure range. The Rh(x)Pd(1-x) and Rh(x)Pt(1-x) nanoparticles undergo reversible changes of surface composition and chemical state when the reactant gases change from oxidizing (NO or O(2) at 300 degrees C) to reducing (H(2) or CO at 300 degrees C) or catalytic (mixture of NO and CO at 300 degrees C). In contrast, no significant change in the distribution of the Pd and Pt atoms in the Pd(x)Pt(1-x) nanoparticles was observed. The difference in restructuring behavior under these reaction conditions in the three series of bimetallic nanoparticle catalysts is correlated with the surface free energy of the metals and the heat of formation of the metallic oxides. The observation of structural evolution of bimetallic nanoparticles under different reaction conditions suggests the importance of in situ studies of surface structures of nanoparticle catalysts.

Effect of O2, CO, and NO on surface segregation in a Rh0.5Pd0.5 bulk crystal and comparison to Rh0.5Pd0.5 nanoparticles.

We present an in situ study of the interaction of a bimetallic Rh(0.5)Pd(0.5) bulk crystal with O(2), CO, and NO using ambient pressure X-ray photoelectron spectroscopy (APXPS) and compare it to results for 15 nm nanoparticles with the same overall composition. The bulk crystal surface has less Rh present under both oxidizing and reducing conditions than the surface of nanoparticles under identical conditions. Segregation and oxidation/reduction proceeds faster and at lower temperature for nanoparticles than for the bulk crystal. The near surface of the Rh(0.5)Pd(0.5) bulk crystal after high temperature vacuum annealing is ca. 9% Rh measured by APXPS. Heating in 0.1 Torr O(2) to 350 °C increases the Rh surface composition to ca. 40%. The surface can then be reduced by heating in H(2) at 150 °C, leading to a chemically reduced surface with 30% Rh. Titration of CO by gas-phase O(2) from this Rh-rich surface proceeds at a much lower pressure than that on the Rh-deficient starting surface.

Multimodal imaging of a choroidal granuloma as a first sign of tuberculosis.

Choroidal granuloma is rarely seen as the first sign of tuberculosis(TB). Here we report a case of a 34-year old male with a choroidal mass which was associated with serous retinal detachment on EDI-OCT and the "contact sign" between the neurosensory retina and the retinal pigment epithelium. We analysed the macular microvascular features of tuberculoma with Optical Coherence Tomography Angiography(OCTA). After 3 months of antituberculosis treatment, we observed the shrinkage of granuloma with permanent changes of macular microvasculature in deep capillary plexus and choriocapillaris. In conclusion, OCT-A may provide useful information about the retinal microvascular involvement in patients with choroidal tuberculoma.

Correction: Choroidal vascularity index as an indicator of vascular status of choroid, in eyes with nanophthalmos.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Choroidal vascularity index as an indicator of vascular status of choroid, in eyes with nanophthalmos.

PURPOSE: To investigate choroidal vascular index (CVI) in eyes with nanophthalmos (NO) with the use of optical coherence tomography (OCT). METHODS: Macular enhanced depth imaging OCT scans of 25 eyes of 25 patients with NO and age-gender-matched 25 eyes of 25 control subjects were analysed. Images were binarized using the ImageJ software, and total choroid area (TCA), luminal area (LA) and stromal area (SA) were acquired. The main outcome measure was CVI, defined as the ratio of LA to TCA. RESULTS: Twenty-five eyes of 25 patients with NO and age-gender-matched control subjects were enrolled. The mean TCA, SA and LA were found to be significantly higher in patients with NO (2.51 ± 0.44 vs. 1.91 ± 0.35 mm2, P < 0.001; 0.86 ± 0.17 vs. 0.63 ± 0.13 mm2, P < 0.001; and 1.65 ± 0.29 vs. 1.27 ± 0.23 mm2, P < 0.000, respectively). On the contrary, CVI did not significantly differ between the two groups (65.72, 67.68, P = 0.099). CONCLUSION: As a novel OCT-based marker, CVI could be used to assess vascular status of the choroid in eyes with NO and can provide better understanding of the pathogenesis of this disease.

Retinal microvasculature in the remission period of Behcet's uveitis.

PURPOSE: To evaluate retinal microvasculature and blood flow during Behcet's uveitis (BU) remission via optical coherence tomography angiography (OCT-A), and compare the results with those from healthy eyes. METHODS: A total of 35 eyes of 35 BU patients presenting during the remission period of BU involving the posterior segment were enrolled, as were 30 normal eyes of 30 age and sex-matched healthy participants. Optical coherence tomography angiograms were analyzed. Foveal avascular zone (FAZ), vessel densities, and flow areas were calculated and compared. RESULTS: Thirty-five eyes of 35 BU patients and 30 normal eyes of 30 age and sex-matched subjects were included in the study. The superficial FAZ was slightly higher in the BU group than in the control group (p = 0.01), but deep FAZ was substantially higher (p < 0.001). Deep foveal and parafoveal vessel densities were significantly lower in BU eyes (p < 0.05). Flow areas in superficial and deep plexuses were lower in BU eyes (p < 0.05), however choroidal flow was similar (p > 0.05). CONCLUSION: BU can cause permanent damage especially in the deep capillary plexus and OCT-A provides a detailed view of the retinal microvasculature which helps us to visualize vascular damage in these patients. Further studies with longer follow-up periods are needed to define the role of OCT-A in the decision of treatment efficacy with different agents.

Degradation of polyvinyl alcohol under mechanothermal stretching.

Mechanical and thermal properties of polyvinyl alcohol (PVA) are characterized and analyzed using in situ X-ray photoelectron spectroscopy (XPS) and quantum chemistry calculations. It is found that the carbon peaks-commonly used as the reference for spectroscopic analysis-shift under mechanical and thermal stretching. Results also indicate that, at different temperatures and among the various functional groups present in PVA, the carbon in the C-O group is the most stable. Computational calculations showed that Hartree-Fock/10-31G (d) reproduces the binding energy of core carbon electrons with an accuracy of 95%, which is enough to characterize bonds, allowing the results of the spectroscopic analysis to be corroborated.

New ambient pressure photoemission endstation at Advanced Light Source beamline 9.3.2.

During the past decade, the application of ambient pressure photoemission spectroscopy (APPES) has been recognized as an important in situ tool to study environmental and materials science, energy related science, and many other fields. Several APPES endstations are currently under planning or development at the USA and international light sources, which will lead to a rapid expansion of this technique. The present work describes the design and performance of a new APPES instrument at the Advanced Light Source beamline 9.3.2 at Lawrence Berkeley National Laboratory. This new instrument, Scienta R4000 HiPP, is a result of collaboration between Advanced Light Source and its industrial partner VG-Scienta. The R4000 HiPP provides superior electron transmission as well as spectromicroscopy modes with 16 microm spatial resolution in one dimension and angle-resolved modes with simulated 0.5 degrees angular resolution at 24 degrees acceptance. Under maximum transmission mode, the electron detection efficiency is more than an order of magnitude better than the previous endstation at beamline 9.3.2. Herein we describe the design and performance of the system, which has been utilized to record spectra above 2 mbar.