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Objective: To compare peel-induced maculopathy (PIM) using surgical forceps versus the microvacuum pick (MVP). Methods: Consecutive eyes undergoing internal limiting membrane (ILM) peeling using either the MVP or forceps were assessed. En face optical coherence tomography (OCT) images at the level of the nerve fiber layer were generated for 6-month postoperative visit. The percentage of the imaged area showing PIM was termed the PIM index. PIM severity was additionally measured using a qualitative PIM severity scale. Results: Seventy-four consecutive eyes underwent ILM peeling with either the MVP (36/74; 49%) or forceps (38/74; 51%). At month-6 postoperatively, the mean PIM index for forceps was 7.7% vs 4.7% for the MVP ( P < 0.001, R 2 = 0.15). At 6 months, 26/38 eyes (68.5%) in the forceps group had either moderate or severe PIM compared to 12/36 eyes (33.3%) in the MVP group ( P = 0.001). Conclusions: ILM peeling with the MVP resulted in lower PIM severity compared to forceps. [ Ophthalmic Surg Lasers Imaging Retina 2023;54:37–42.]

Purpose: This work analyzes a series of eyes with brolucizumab-associated intraocular inflammation (IOI) without retinal vasculitis reported to the American Society of Retina Specialists. Methods: The American Society of Retina Specialists Research and Safety in Therapeutics Committee analyzed clinical characteristics from submitted reports of IOI after brolucizumab. Eyes with retinal vasculitis or that received intraocular antibiotics were excluded. Results: Forty-nine eyes of 45 patients were collected. Mean visual acuity (VA) at baseline was 20/49 (range, 20/20-5/200). Patients presented with IOI a mean of 24 days (range, 3-63 days) after their most recent brolucizumab injection; 61% presented for an unscheduled visit while 39% presented at routine follow-up. Mean VA at IOI presentation was 20/67 (range, 20/20-3/200). The most common symptoms were floaters (78%) and blurry vision (76%). Pain (20%) and redness (16%) were less common; 3 (6%) eyes were asymptomatic. IOI was anterior only in 18%, posterior only in 31%, and both anterior and posterior in 51% of eyes. Treatment included topical steroids alone in 67% of eyes, whereas 10% of eyes received no treatment. Mean VA at last follow-up was 20/56 (range, 20/20-1/200). Three (6%) eyes lost 3 or more lines and 1 (2%) eye lost 6 or more lines. Conclusions: Brolucizumab-associated IOI without retinal vasculitis typically presented with a delayed onset of a few weeks. Often, VA decline was relatively mild. Most symptoms resolved and nearly all had a return-to-baseline VA, but a small percentage of patients had a significant decrease in VA at last follow-up.

To identify characteristics associated with progression from vitreomacular traction (VMT) to a full-thickness macular hole (FTMH) or lamellar hole (LH).Post-hoc analysis of the Phase III clinical trial comparing ocriplasmin with placebo for treatment of vitreomacular adhesion (MIVI-TRUST). Exact logistic regression analyses were used to identify baseline characteristics significantly associated with progression from vitreomacular traction to FTMH or LH over the 6-month study period.Twenty eyes (4.5%) developed an FTMH and 38 (9.7%) developed an LH during the study period. The rate of progression to FTMH or LH did not differ significantly between ocriplasmin- and saline-treated eyes (P = 0.090 for FTMH, P = 0.369 for LH). On univariate analysis, the presence of subretinal fluid (adjusted odds ratio 5.64, 95% confidence interval 2.02-17.17, P0.001) and mean subretinal fluid thickness (adjusted odds ratio 1.10, 95% confidence interval 1.04-1.16, P = 0.003) were associated with FTMH development. Both remained significantly associated with FTMH development on multivariate testing. On univariate analysis, the presence of macular schisis (adjusted odds ratio 2.26, 95% confidence interval 1.30-3.82, P = 0.004) and mean retinal thickness (adjusted odds ratio 1.06, 95% confidence interval 1.01-1.10, P = 0.010) were associated with LH development. Schisis remained a significant predictor of LH formation on multivariate testing.Vitreomacular traction is more likely to progress to FTMH when associated with subretinal fluid, but when associated with intraretinal changes (such as schisis), vitreomacular traction appears more likely to progress to a LH after a single intravitreal injection of ocriplasmin or saline.

Purpose: To analyze a case series of retinal vasculitis reported to the American Society of Retina Specialists (ASRS) following Food and Drug Administration approval of brolucizumab for treatment of neovascular age-related macular degeneration. Methods: The ASRS Research and Safety in Therapeutics Committee analyzed clinical and imaging characteristics from submitted reports of retinal vasculitis after brolucizumab. Results: Retinal vasculitis was reported in 26 eyes of 25 patients (22 [88%] female) after treatment with brolucizumab. Imaging studies were available for 24 of 26 eyes. Most cases (92%) were associated with intraocular inflammation, which presented at a mean of 25 days (range, 3-63 days) after the most recent brolucizumab injection. Mean visual acuity (VA) was 20/52 (range, 20/25-4/200) before the adverse event, 20/151 (range, 20/25-hand motion) at presentation of the adverse event, and 20/243 (range, 20/30-light perception) at last follow-up. Twelve eyes (46%) had a greater than 3-line decrease in VA at final follow-up, and 12 eyes (46%) had a final VA of 20/200 or worse. Analysis of retinal imaging identified vasculopathy that involved retinal arteries (91%), retinal veins (79%), and choroidal vessels (48%). Occlusive disease was apparent on imaging in 83% of eyes. Treatment approaches were varied. Conclusions: Retinal vasculitis has been identified in a series of eyes following brolucizumab. Although a few eyes in this series were asymptomatic or minimally symptomatic, some eyes had significant vision loss. A careful examination for signs of active inflammation prior to brolucizumab injection is recommended. Once vasculopathy is suspected, angiographic imaging may help define the spectrum of involvement. Optimal treatment strategies remain unknown.

Optical coherence tomography angiography (OCT-A) provides rapid, flow-based imaging of the retinal and choroidal vasculature in a noninvasive manner. This review contrasts this novel technique with conventional angiography and discusses its current uses and limitations in the management of age-related macular degeneration (AMD).Initial work with OCT-A has focused on its ability to identify choriocapillaris flow alterations in dry AMD and to sensitively detect choroidal neovascular membranes (CNVs) in neovascular AMD. Reduced choriocapillaris flow beyond the borders of geographic atrophy seen on OCT-A suggests a primary vascular cause in geographic atrophy. Longitudinal OCT-A analysis of CNV morphology has demonstrated the transition from an immature to mature CNV phenotype following treatment. Current clinical applications of OCT-A include identification of asymptomatic CNV and monitoring for CNV development in the setting of an acquired vitelliform lesion.OCT-A remains a promising diagnostic tool but one still very much in evolution. Larger studies will be needed to more accurately describe its sensitivity and specificity for CNV detection and to better characterize longitudinal CNV morphologic changes. Anticipated hardware and software updates including swept-source light sources, automated montaging, and manual adjustment of interscan timing should enhance the capabilities of OCT-A in the management of AMD.

BACKGROUND AND OBJECTIVE: To investigate cases of retained intraocular perfluoro-n-octane (PFO) after pars plana vitrectomy (PPV) for retinal detachment (RD). PATIENTS AND METHODS: Retrospective, noncomparative case series of six eyes with retained intraocular PFO after RD repair. Clinical data were supplemented with an experimental silicone eye model. RESULTS: A cluster of six cases of retained intraocular PFO after PPV for RD repair were noted shortly after transitioning to valved cannulas. PFO was noted in the anterior chamber (AC) and/or vitreous and removed with AC paracentesis, AC wash-out, and/or PPV. A silicone eye model demonstrated that PFO levels are maintained anterior to cannula insertion with valved cannulas only. CONCLUSION: The authors hypothesize that anterior PFO fill using valved cannulas can lead to sequestration within the AC, zonules, ciliary sulcus, ciliary teeth, and/or capsular bag. They suggest vigilance in not overfilling PFO, particularly when transitioning to use of valved cannulas, to minimize the risk of intraocular retention. [ Ophthalmic Surg Lasers Imaging Retina . 2015;46:451–456.]

The solid electrolyte interphase (SEI) forms during the initial cycles in lithium ion batteries and evolves throughout the battery life. By protecting the electrode and passing lithium ions, the SEI plays an important role in the performance and degradation of lithium ion batteries. Identifying how the SEI forms and evolves during battery cycling helps us understand and mitigate battery degradation. In this work, we address the SEI chemical and electrochemical evolution during its formation process and provide a correlation between these properties. It is found that the SEI chemistry, not just its thickness, has a distinct influence on its impedance, which may ultimately impact the battery performance.

In the nearly two decades following the publication of the Branch Retinal Vein Occlusion Study (BVOS) and Central Retinal Vein Occlusion Study (CVOS), pharmacologic therapy for retinal vein occlusion (RVO) was almost nonexistent. However, the introduction of intravitreal therapy — namely corticosteroids and anti-VEGF agents — has provided a host of new pharmacologic options to clinicians. As evidenced by several large-scale clinical trials,1-4 intravitreal monotherapy is effective for the vast majority of patients with RVO and has thus become the predominant therapeutic approach.5 Unfortunately, a small minority of patients display recalcitrant macular edema despite frequent intravitreal monotherapy dosing. In the SCORE trials, 11.6% to 12.0% of patients treated with repeated intravitreal triamcinolone lost at least 15 letters, and more than 20% had central point thicknesses greater than 500 μm at 12-month follow-up.1,2 Although the rate of refractory edema was lower in the BRAVO/CRUISE trial (0.7% to 3.8% lost at least 15 letters, and 6.7% to 15.9% had central foveal thickness greater than 400 μm at 12 months), frequent ranibizumab monotherapy was not universally successful.3,4 Such recalcitrant cases have prompted the search for therapeutic alternatives, most notably combination pharmacologic and pharmaco-laser treatments.

An industrial base oil, a blend of different paraffin fractions, is heated to 130 degrees C (1) in the ambient and (2) for use as a lubricant in a steel pin on a steel disk sliding experiment. The base oil was tested with and without test antioxidants: dimethyl disulfide (DMDS) and alkylated diphenylamine (ADPA). Primary and secondary oxidation products were monitored continuously by FTIR over a 100 h period. In addition, friction and wear of the steel pin were monitored over the same period and the chemical transformation of the pin surface was monitored by XPS. The objective of this work is to observe the catalytic action of the steel components on the oil aging process and the efficacy of the antioxidant to reduce oxidation of oil used in tribology as a lubricant. Possible mechanistic explanations of the aging process as well as its impact on friction and wear are discussed.

To determine the ocular toxicity of intravitreally injected daptomycin, a novel antibiotic for treatment of vancomycin-resistant organisms, and its efficacy in treating intraocular infection with coagulase-negative Staphylococcus epidermidis.Four doses of intravitreal daptomycin were injected (75, 188, 375, and 750 μg) into 1 eye of Dutch belted rabbits (n = 3 per dose). Clinical examination, electroretinography, and histologic analysis were performed preinjection and 2 weeks after injection and compared with the fellow eye that received only intravitreal balanced salt solution. Experimental S epidermidis endophthalmitis was induced in Dutch belted rabbits (n = 24), and the ability of 200 μg of intravitreal daptomycin to result in culture-negative vitreous samples was measured at 24 hours and 48 hours.Seventy-five micrograms and 188 μg of daptomycin demonstrated acceptable safety profiles when injected intravitreally in Dutch belted rabbits. There was a dose-dependent increase in cataract formation, electroretinogram suppression, and photoreceptor damage with higher doses. Two hundred micrograms of intravitreal daptomycin resulted in near-complete vitreous sterilization 24 hours after treatment. Vitreous sterilization was complete by 48 hours.A dose of 200 μg of intravitreal daptomycin appears to be safe and efficacious in a rabbit model of bacterial endophthalmitis. Future investigations should focus on daptomycin as a therapeutic option for treating intraocular infection caused by vancomycin-resistant organisms.

To investigate agreement in intraocular pressure (IOP) measurements among Icare rebound tonometry, Tonopen tonometry, and Goldmann applanation tonometry following vitreoretinal surgery.Reliability analysis of tonometers.Fifty-eyes of 50 adults undergoing vitreoretinal surgery were enrolled. IOP was measured on first postoperative day using Icare (Tiolat, Helsinki, Finland), followed by Tonopen (Reichert, Depew, New York, USA) and Goldmann (Haag-Streit USA, Mason, Ohio, USA) in randomized order. Intraclass correlation coefficients (ICC) and Bland-Altman plots were calculated for all subcategories.Icare successfully measured IOP in all eyes, while Goldmann was unmeasurable in 6 eyes (12%) and Tonopen in 1 eye (2%). Mean IOP by Icare, Tonopen, and Goldmann was 15.9 ± 8.9, 16.9 ± 6.2, and 16.0 ± 7.3 mm Hg, respectively (P = .76). Type of intraocular tamponade, status of lens, status of cornea, gauge of instrumentation, and history of prior vitrectomy did not result in significant differences among the 3 tonometers. ICC was excellent (0.75) in all subgroups, except at IOP10 and ≥ 23 mm Hg (based on Icare). In eyes with IOP10 mm Hg, Icare underestimated IOP (mm Hg; P = .01) compared to Goldmann (2.0 ± 2.1) and Tonopen (3.5 ± 2.4), whereas at IOP ≥ 23 mm Hg Icare was overestimated (P = .01) compared to Goldmann (3.77 ± 3.49) and Tonopen (4.97 ± 3.33). Overall, differences in IOP were ≤ 3 mm Hg in 58% of eyes for Icare-Tonopen, 72% for Tonopen-Goldmann, and 62% for Icare-Goldmann.IOP measurements using Icare rebound tonometry, Tonopen, and Goldmann tonometry are in excellent agreement following vitreoretinal surgery. However, Icare overestimates at IOP ≥ 23 and underestimates at IOP10 mm Hg.

A radiotracer method was developed to measure wear rates of piston rings and cylinder bores in spark-ignition (SI) engines. Piston rings were made radioactive by neutron activation and blocks were activated by surface layer activation. With this radiotracer system, top compression ring wear can be determined to better than ±5 μg/h and cylinder-bore wear can be determined to better than ±1 nm/h simultaneously in a 1 h measurement period. This sensitivity is superior to any other real-time wear measurement system currently available. High-sensitivity wear data is necessary to develop engine hardware and lubrication systems that will prevent excessive wear over the life of the engine. Details of the design and operation of the wear measurement system are presented as well as representative data on a production V6 SI engine.

Importance Use of laser vitreolysis for symptomatic floaters has increased in recent years, but prospective studies are not available and the complication profile is poorly understood. Objective To analyze cases of complications following laser vitreolysis as voluntarily reported to the American Society of Retina Specialists Research and Safety in Therapeutics (ASRS ReST) Committee, an independent task force formed to monitor device-related and drug-related safety events. Design, Setting, and Participants A retrospective assessment was performed of all cases of complications following laser vitreolysis that were voluntarily reported by practitioners throughout the United States to the ASRS ReST Committee from the first report on September 19, 2016, through March 16, 2017, the date of data analysis and manuscript writing. Main Outcomes and Measures Complications reported to the ASRS ReST Committee following laser vitreolysis were analyzed by type to gain an understanding of the spectrum of potential complications. Results A total of 16 complications following laser vitreolysis were reported in 15 patients by 7 US vitreoretinal specialists during the study period. Complications included elevated intraocular pressure leading to glaucoma; cataracts, including posterior capsule defects requiring cataract surgery; retinal tear; retinal detachment; retinal hemorrhages; scotomas; and an increased number of floaters. Conclusions and Relevance This report presents a spectrum of complications reported to the ASRS ReST Committee across 6 months. The rate of complications cannot be determined because the denominator of total cases is unknown. Also, these findings cannot determine whether there is a causal association between these complications and laser vitreolysis. Prospective studies are warranted to better understand the efficacy of this procedure and the frequency of attendant complications. Until then, practitioners should be aware of the profile of potential complications to properly inform patients during the consent process. The ASRS ReST Committee will continue to monitor device-related and drug-related adverse events and encourages active surveillance and reporting by all physicians.

We describe and implement a microelectrode procedure for the determination of important transport properties required for the evaluation of liquid electrolytes used in lithium-based batteries. Three solvents of interest (propylene carbonate, ethylene carbonate, and diethyl carbonate) and two lithium salts (lithium hexafluorophosphate and lithium perchlorate) are investigated. In addition, by combining microelectrode and radiometric analyses, we are able to characterize fully the transport phenomena in the nonaqueous solvent + salt systems. Thus a radiometric technique is used to monitor solvent transport, both under diffusion and current-passage conditions, and the solvent diffusion coefficient is reported as a function of salt concentration.

Radiotracer methods have been developed to quantify the amount of platinum and rhodium deposited on automotive catalytic converters as a function of production conditions. In particular, this study determined the effects of selective adsorption and evaporation processes on the aqueous impregnation of converters with platinum group metal salts. The radiotracers used in this study, 191 Pt and 105 Rh, were produced by thermal neutron activation of Pt and Ru. Chemical processing was performed to remove undesired radioactive products and to ensure that each tracer was in its appropriate chemical state. This radiotracer method has been shown to be capable of measuring the platinum and rhodium loading on an entire substrate with a precision better than ±0.5%. At this precision level, the influence of selective adsorption and evaporation were determined.

To characterize a unique cytomegalovirus (CMV)-associated retinopathy in patients with limited immune dysfunction.Retrospective observational case series. CMV was confirmed as the pathogenic agent via polymerase chain reaction analysis of aqueous or vitreous humor samples or via immunohistochemical analysis of retinal biopsy specimens.Five non-HIV patients with granular necrotizing retinitis, vitritis, and severe occlusive vasculopathy were identified. Patient histories all suggested a basis for limited immune dysfunction including advanced age (n = 4), diabetes mellitus (n = 4), and noncytotoxic immunotherapy (n = 3). Diagnosis of CMV retinitis was delayed in all cases and patients received either no antiviral therapy (n = 2) or incorrect antiviral therapy (n = 3) for presumed herpes simplex/varicella zoster-related acute retinal necrosis. Retinitis subsequently regressed in all cases with introduction of systemic ganciclovir/valganciclovir (n = 5) and/or intravitreal foscarnet (n = 2). Four of five patients developed neovascularization because of extensive retinal ischemia.The clinical expression of CMV-associated retinopathy is strongly related to immune status. In patients with limited immune dysfunction, a mixed clinical picture of intraocular inflammation with panretinal occlusive vasculopathy, more characteristic of acute retinal necrosis, and peripheral slowly progressive granular retinitis, more characteristic of classic CMV retinitis, is observed. Recognition of this atypical clinical presentation, which the authors term chronic retinal necrosis, should prompt molecular testing for CMV to determine the appropriate antiviral therapy. Consideration should also be given to prophylactic panretinal photocoagulation in such eyes, given the high risk of neovascular complications.

To evaluate the anatomical and functional outcomes of pars plana vitrectomy without adjuvant scleral buckling, prophylactic 360° endolaser photocoagulation, or perfluorocarbon liquid use for the treatment of primary uncomplicated rhegmatogenous retinal detachment.Retrospective interventional case series of consecutive patients undergoing vitrectomy for noncomplex rhegmatogenous retinal detachment over a 10-year period. Main outcome measures included primary anatomical success rate, defined as retinal reattachment at final follow-up after a single operation, proportion of eyes achieving a final best-corrected visual acuity ≤ logarithm of the minimum angle of resolution 0.3 (≥ Snellen 20/40), and postoperative complications.With a mean follow-up of 31 months, primary anatomical success was achieved in 95.7% (89 of 93) of eyes. Final anatomical success, defined as retinal attachment at final follow-up without regard to additional procedures, was achieved in 98.9% (92 of 93). Final best-corrected visual acuity of ≤ logarithm of the minimum angle of resolution 0.3 (≥ Snellen 20/40) was achieved in 77.4% of eyes in the cohort. Postoperative proliferative vitreoretinopathy developed in 3.2% of eyes. No new retinal breaks developed postoperatively in the absence of clinically evident proliferative vitreoretinopathy.Thorough pars plana vitrectomy alone, without adjuvant scleral buckling, 360° endolaser photocoagulation, or routine perfluorocarbon liquid use, yields high anatomical and functional success rates and low complication rates in the treatment of primary uncomplicated rhegmatogenous retinal detachment. In the absence of observable proliferative vitreoretinopathy, postoperative vitreous base contraction does not appear to be a clinically relevant phenomenon.

In lubricated sliding contacts, components wear out and the lubricating oil ages with time. The present work explores the interactive influence between lubricant aging and component wear. The flat face of a steel pin is slid against a rotating steel disk under near isothermal conditions while the contact is immersed in a reservoir of lubricant (hexadecane). The chemical changes in the oil with time are measured by vibrational spectroscopy and gas chromatography. The corresponding chemistry of the pin surface is recorded using X-ray photoelectron spectroscopy while the morphology of the worn pins; surface and subsurface, are observed using a combination of focused ion beam milling and scanning electron 5 microscopy. When compared to thermal auto-oxidation of the lubricant alone, steel on steel friction and wear are found to accentuate the decomposition of oil and to reduce the beneficial impact of antioxidants. The catalytic action of nascent iron, an outcome of pin wear and disk wear, is shown to contribute to this detrimental effect. Over long periods of sliding, the decomposition products of lubricant aging on their own, as well as in conjunction with their products of reaction with iron, generate a thick tribofilm that is highly protective in terms of friction and wear.

A radiotracer method has been developed to characterize new fuel-cell membrane materials having high ionic conductance. Three radiotracers were employed simultaneously in cell studies and measured by a combination of liquid-scintillation and γ-ray counting. This new method has been shown capable of measuring equilibrium concentrations and transport rates of sodium cations (representing counterions), chlorine anions (representing coions) and water molecules in ion-exchange membranes.

Closed cell electrolysis of heavy water at palladium cathodes was maintained for 100 days by the catalytic recombination of evolved gases. Closed cell operation eliminated several experimental complications including electrolytic isotope separation effects. This allowed for the detection of tritium accumulation at a level two orders of magnitude below that cited by Fleischmann, Pons, and Hawkins as evidence for cold fusion. Closed cell electrolysis of alkaline heavy water was performed in six cells with several variations in palladium cathode pretreatment, anode type, cell vessel material, electrolyte preparation, and current density. In each case, light water control cells were operated under otherwise identical conditions. Under conditions close to those under which cold fusion phenomena have been reported, radiochemical measurements have indicated no accumulation of tritium.

The equilibrium and transport properties of a poly(perfluorosulfonic acid) membrane containing a dilute sulfuric acid solution are investigated over the temperature range from 20 to 90°C, which is of interest for polymer‐electrolyte fuel cells. The membrane porosity, proton diffusion coefficient, and electrokinetic permeability are measured and tabulated as a function of temperature. A combination of electrochemical and radiotracer techniques are employed. The electrokinetic Peclet number, a dimensionless group that characterizes the importance of electro‐osmotic water transport by the membrane, is shown to have only a slight dependence on temperature. A previously developed equilibrium model, containing no adjustable parameters, is used to describe the equilibrium data. Published values for the dipole moment, dielectric constant, and index of refraction of water, along with the ionic radii of protons and bisulfate ions are the only model inputs that are not measured directly. The equilibrium model also is shown to be in qualitative agreement with published Monte Carlo simulations of counterion profiles near a charged surface, such as a membrane pore wall.

One of the primary obstacles to be overcome for the development of economical fuel cells is the high cost of the membrane electrolyte. The currently favoured polymer electrolytes consist of poly(tetrafluoroethylene) backbone structures and poly(perfluorosulphonic acid) side chains. In an effort to find lower cost membranes, some radiation-grafted copolymer membranes were investigated. All the membranes contained poly(styrenesulphonic acid) side chains. Three different backbone polymer structures were studied: low-density poly(styrene), poly(tetrafluoroethylene)/poly(perfluoropropylene), and poly(tetrafluoroethylene). The results indicate that the membrane consisting of a poly(tetrafluoroethylene)/poly(styrenesulphonic acid) copolymer is a promising candidate as a fuel-cell electrolyte.

One of the major obstacle to overcome for the realization of economical hydrogen-oxygen, polymer-electrolyte fuel cells is the high capital cost of the inert perfluorosulfonic acid (PSA) membranes, which provide a pathway for ionic transport between the cell electrodes. It has recently been shown that composite polymer membrane can be synthesized by depositing PSA polymers onto porous poly (tetrafluorethyene) (PTFE) substrates. The resulting membrane are mechanically durable and quite thin relative to traditional PSA membranes; the authors expect the composite membranes to be of low resistance and cost. In this paper, the authors examine the composite membrane properties as a function of the membrane composition. Our results allow us to form a conceptual model to explain both the equilibrium and transport characteristics of these materials. For high PSA contents, the membrane behavior is similar to that of the PSA polymer; the water permeability, however, is reduced significantly. For intermediate PSA contents, the membranes have a high porosity and match the thickness of the PTFE substrate ([approx]50 [mu]m); membrane of this composition range are potentially useful candidates for fuel cells because of their high resistance to water transport and reduced ionic resistance. Composite membrane of very low PSA content demonstrate characteristicsmore » similar to the hydrophobic PTFE substrate and are not of interest for fuel cells.« less

Closed cell electrolysis of heavy water at palladium cathodes was maintained for 100 days by the catalytic recombination of evolved gases. Closed cell operation eliminated several experimental complications including electrolytic isotope separation effects. This allowed for the detection of tritium accumulation at a level two orders of magnitude below that cited by Fleischmann, Pons, and Hawkins as evidence for cold fusion. Closed cell electrolysis of alkaline heavy water was performed in six cells with several variations in palladium cathode pretreatment, anode type, cell vessel material, electrolyte preparation, and current density. In each case, light water control cells were operated under otherwise identical conditions. Under conditions close to those under which cold fusion phenomena have been reported, radiochemical measurements have indicated no accumulation of tritium.

Les effets de la separation electrolytique des impuretes de tritium contenues dans l'eau lourde sont etudies. L'accumulation de tritium lors de l'electrolyse de l'eau sur une cathode de palladium est examinee

A radiotracer method has been developed to measure piston ring and cylinder bore wear rates in spark-ignition (SI) engines. The method has sufficient sensitivity to measure ring and bore wear rates in real time during normal operating conditions. This work reports measurements on the rates of break-in and steady-state wear of piston rings and cylinder bores during a variety of engine operating conditions. Results show that piston ring break-in is minimal and that ring wear rates are constant at steady-state engine operation. The key factor affecting ring wear is engine brake mean effective pressure (BMEP). Ring wear behavior is repeatable for a given engine type and between two different engine designs. Cylinder bore wear is dominated by initial break-in, cold-start wear, and changes in operating conditions. Wear of the cylinder bore during steady-state operating conditions is very low when compared to break-in and changes in conditions. Both piston ring and cylinder bore wear rates as measured by the radiotracer method are reasonable when compared with long-term wear observed in vehicle tests.

To evaluate the impact of different scan patterns and scan densities on small full-thickness macular hole (MH) detection.Retrospective cross-sectional analysis.Analysis was performed on 25 eyes from 24 patients with full-thickness MHs imaged with the Heidelberg Spectralis HRA+OCT. Included eyes underwent concurrent imaging with a standard (61-line) raster volume and a 24-line radial pattern. A 6-line radial scan pattern was extrapolated from the higher-density radial pattern. Comparisons of the missed hole rate as well as the proportion of individual B-scans demonstrating a full-thickness defect (termed "full-thickness detection index") were carried out for the 3 scan patterns. Additionally, qualitative and quantitative hole parameters were evaluated to identify factors associated with "missed" holes.Full-thickness defects were missed at substantially higher rates using both standard raster volume (20.0%, 90% confidence interval [CI] 8.2%-37.5%) and 6-line radial scanning (12.0%, 90% CI 3.7%-30.4%) when compared to 24-line radial scanning (0% for both comparisons). Full-thickness detection indices were significantly higher for both radial scan patterns when compared to raster scanning (P.001 for both comparisons). Missed holes were smaller and commonly associated with prehole flaps.High-density radial scanning demonstrated superior detection rates of small full-thickness MHs compared to standard raster volume scanning. This finding may be attributable to the greater foveolar scan density attained with radial scan patterns. Failure to utilize radial scanning in the setting of suspected macular holes may lead to a delay in surgical treatment, with attendant worse anatomic and visual outcomes.

We assessed recent trends in the use of diagnostic testing for neovascular age-related macular degeneration (NVAMD) and macular edema (ME).Claims data from a managed-care network were analyzed on patients with NVAMD (n = 22,954) or ME (n = 31,810) to assess the use of fluorescein angiography (FA), fundus photography (FP), and optical coherence tomography (OCT) from 2001 to 2009. Repeated-measures logistic regression was performed to compare patients' odds of undergoing these procedures in 2001, 2005, and 2009. In addition, the proportions of patients with an incident NVAMD or ME diagnosis in 2003 or 2008 who underwent FA, FP, and OCT were compared.From 2001 to 2009, among patients with NVAMD, the odds of undergoing OCT increased 23-fold, whereas the odds of receiving FA and FP decreased by 68% and 79%, respectively. Similar trends were observed for ME. From 2003 to 2008, the proportion of patients undergoing OCT within 1 year of initial diagnosis increased by 315% for NVAMD and by 143% for ME; the proportion undergoing OCT without FA within 1 year increased by 463% for NVAMD and by 216% for ME.Use of OCT increased dramatically during the past decade, whereas use of FA and FP declined considerably, suggesting that OCT may be replacing more traditional diagnostic testing in patients with NVAMD or ME. Future studies should evaluate whether this increased reliance on OCT instead of FA and FP affects patient outcomes.

With the development of pars plana vitrectomy in the 1970s and pneumatic retinopexy in the 1980s, the primacy of scleral buckling for repair of rhegmatogenous retinal detachment (RRD) came under challenge. While a degree of consensus exists for certain forms of complex RRD, there remains little agreement concerning the optimal treatment of primary noncomplex RRD. This debate is further muddied by application of adjuvant procedures to supplement the primary surgical approach. This article aims to present the current evidence regarding repair of primary noncomplex RRD. A brief summary of primary surgical approaches—pneumatic retinopexy, scleral buckling, and pars plana vitrectomy—will be presented along with a short discussion on potential adjuvant procedures. The remainder of the article focuses on reported outcomes for the different treatment modalities for primary noncomplex RRD.

With the dissemination of optical coherence tomography over the past two decades, the role of persistent vitreomacular adhesion (VMA) in the development of numerous macular pathologies - including idiopathic macular hole, vitreomacular traction syndrome, cystoid and diabetic macular edema, neovascularization in diabetic retinopathy and retinal vein occlusion, exudative age-related macular degeneration, and myopic traction maculopathy - has been established. While invasive vitreoretinal procedures have long been utilized to address complications related to these disorders, such an approach is hampered by incomplete vitreoretinal separation and vitreous removal, surgical complications, and high costs. In light of such limitations, investigators have increasingly looked to nonsurgical means for the treatment of persistent pathologic VMA. Chief among these alternative measures is the intravitreal application of pharmacologic agents for the induction of vitreous liquefaction and/or vitreoretinal separation, an approach termed pharmacologic vitreolysis. This article aims to review the available evidence regarding the use of pharmacologic agents in the treatment of VMA-related pathology. In addition, a discussion of vitreous molecular organization and principles of physiologic posterior vitreous detachment is provided to allow for a consideration of vitreolytic agent mode of action and molecular targets.

A radiometric method has been developed for the determination of camshaft wear during engine operation. After a radioactive tracer is induced at the tips of one or more cam lobes by the technique of surface layer activation, calibration procedures are performed to determine the amount of radioactive material remaining versus the depth worn. The decrease in {gamma}-ray intensity measured external to the engine is then directly related to cam lobe wear. By incorporating a high-resolution detector and an internal radioactive standard, measurement accuracy better than {plus}{equals}0.2 {mu}m at 95% confidence has been achieved. Without the requirement of engine disassembly, this method has provided unique measurements of break-in wear and wear as a function of operating conditions. Because this approach requires only low levels of radiation, it has significant potential applications in wear control.

Les effets de la separation electrolytique des impuretes de tritium contenues dans l'eau lourde sont etudies. L'accumulation de tritium lors de l'electrolyse de l'eau sur une cathode de palladium est examinee

Sintered nickel positive electrodes were prepared by electroimpregnating nickel hydroxide inside a porous nickel plaque in a nickel nitrate solution. The distribution of nickel hydroxide inside the plaque was measured using a radio-tracer method with /sup 63/Ni as the radioactivity source. Autoradiography and ..beta.. counting were used to follow qualitative and quantitative distributions, respectively, of the pore filling process. Relatively uniform distribution was observed at low current density, and the precipitation of Ni(OH)/sub 2/ extends to the center of the plaque. At high current density, most of the Ni(OH)/sub 2/ aggregated in the region just underneath the plaque surface, causing a somewhat nonuniform distribution. Nickel hydroxide also precipitates heavily on the surface of the plaque at high current density, reducing the penetration of electrolyte to the inside of the plaque.