Short pulse pumped X-ray lasers

Double laser pulses of duration similar to 75 ps and short laser pulses similar to 1 ps superimposed on longer duration background pulses have been shown to efficiently pump lasing in Ne-like and Ni-like ions. For the 75 ps pumping, X-ray laser output without travelling wave pumping is shown to be well-described by a model of ASE output. With I ps pumping, the X-ray laser output with different velocity travelling wave pumping is well-fitted with an extension to the ASE model allowing for travelling wave excitation of the gain along the plasma line. The model is used to investigate the production of short (<1 ps) x-ray laser pulses and the effects of non-ideal travelling wave velocities on the X-ray laser output. Resonance line spectra of emission perpendicular to the plasma line are measured and simulated. It is shown that an accurate opacity model for the more intense Ne-like ions is needed to correctly simulate the spectra.

Absolute photoionization cross sections for Xe4+, Xe5+, and Xe6+ near 13.5 nm: Experiment and theory

Absolute photoionization cross-section measurements for a mixture of ground and metastable states of Xe4+, Xe5+, and Xe6+ are reported in the photon energy range of 4d -> nf transitions, which occur within or adjacent to the 13.5 nm window for extreme ultraviolet lithography light source development. The reported values allow the quantification of opacity effects in xenon plasmas due to these 4d -> nf autoionizing states. The oscillator strengths for the 4d -> 4f and 4d -> 5f transitions in Xeq+ (q=1-6) ions are calculated using nonrelativistic Hartree-Fock and random phase approximations. These are compared with published experimental values for Xe+ to Xe3+ and with the values obtained from the present experimental cross-section measurements for Xe4+ to Xe6+. The calculations assisted in the determination of the metastable content in the ion beams for Xe5+ and Xe6+. The experiments were performed by merging a synchrotron photon beam generated by an undulator beamline of the Advanced Light Source with an ion beam produced by an electron cyclotron resonance ion source.

Mutations in sodium-borate cotransporter SLC4A11 cause recessive congenital hereditary endothelial dystrophy (CHED2)

Congenital hereditary endothelial dystrophy ( CHED) is a heritable, bilateral corneal dystrophy characterized by corneal opacification and nystagmus. We describe seven different mutations in the SLC4A11 gene in ten families with autosomal recessive CHED. Mutations in SLC4A11, which encodes a membrane-bound sodium-borate cotransporter, cause loss of function of the protein either by blocking its membrane targeting or nonsense-mediated decay.

Limbal stem cell deficiency and ocular phenotype in ectrodactyly-ectodermal dysplasia-clefting syndrome caused by p63 mutations

Objective: To describe the ocular phenotype in patients with ectrodactyly-ectodermal dysplasia-clefting (EEC) syndrome (MIM#604292) and to determine the pathogenic basis of visual morbidity. Design: Retrospective case series. Participants: Nineteen families (23 patients) affected by EEC syndrome from the United Kingdom, Ireland, and Italy. Methods: General medical examination to fulfill the diagnostic criteria for EEC syndrome and determine the phenotypic severity. Mutational analysis of p63 was performed by polymerase chain reaction-based bidirectional Sanger sequencing. All patients with EEC syndrome underwent a complete ophthalmic examination and ocular surface assessment. Limbal stem cell deficiency (LSCD) was diagnosed clinically on the basis of corneal conjunctivalization and anatomy of the limbal palisades of Vogt. Impression cytology using immunofluorescent antibodies was performed in 1 individual. Histologic and immunohistochemical analyses were performed on a corneal button and corneal pannus from 2 EEC patients. Main Outcome Measures: The EEC syndrome phenotypic severity (EEC score), best-corrected Snellen visual acuity (decimal fraction), slit-lamp biomicroscopy, tear function index, tear breakup time, LSCD, p63 DNA sequence variants, impression cytology, and corneal histopathology. Results: Eleven heterozygous missense mutations in the DNA binding domain of p63 were identified in all patients with EEC syndrome. All patients had ocular involvement and the commonest was an anomaly of the meibomian glands and lacrimal drainage system defects. The major cause of visual morbidity was progressive LSCD, which was detected in 61% (14/23). Limbal stem cell deficiency was related to advancing age and caused a progressive keratopathy, resulting in a dense vascularized corneal pannus, and eventually leading to visual impairment. Histologic analysis and impression cytology confirmed LSCD. Conclusions: Heterozygous p63 mutations cause the EEC syndrome and result in visual impairment owing to progressive LSCD. There was no relationship of limbal stem cell failure with the severity of EEC syndrome, as classified by the EEC score, or the underlying molecular defect in p63. Financial Disclosure(s): The authors have no proprietary or commercial interest in any of the materials discussed in this article. © 2012 American Academy of Ophthalmology.

COLORIMETRIC POLYMER FILM SENSORS FOR DISSOLVED CARBON-DIOXIDE

Plasticized and unplasticized polymer colorimetric film sensors for gaseous CO2, containing the dye m-cresol purple, are tested as sensors for dissolved CO2. The plasticized polymer m-cresol purple film sensor develops a measurable degree of opacity when exposed to aqueous solution, especially in neutral, compared with alkaline, solution. However, it is shown that a presoaked, fogged plasticized polymer m-cresol purple film does function as a quantitative sensor for dissolved CO2 over the range 0-4% CO2. An unplasticized polymer m-cresol purple film remains largely dear upon exposure to aqueous solution and also functions as a quantitative sensor for dissolved CO2 over the range 0-4% CO2. However, in both types of films the dye interacts with electrolytes present in solution; invariably the dye appears to be converted from its initial deprotonated form (blue) to its protonated form (yellow) and the rate of this process appears to increase with increasing ionic strength, anionic charge and decreasing pH. The 90% response and recovery times for an unplasticized film are determined as 19 s(CO2:0-->5%) and 21 s (CO2:5-->3.6%), respectively.

The Ties That Bind Us: Ritual, Fusion, and Identification

Most social scientists endorse some version of the claim that participating in collective rituals promotes social cohesion. The systematic testing and evaluation of this claim, however, has been prevented by a lack of precision regarding the nature of both ‘ritual’and ‘social cohesion’ as well as a lack of integration between the theories and findings of the social and evolutionary sciences. By directly addressing these challenges, we argue that a systematic investigation and evaluation of the claim that ritual promotes social cohesion is achievable.

We present a general and testable theory of the relationship between ritual, cohesion, and cooperation that more precisely connects particular elements of ‘ritual,’ such as causal opacity and emotional arousal, to two particular forms
of ‘social cohesion’: group identification and identity fusion. Further, we ground this theory in an evolutionary account of why particular modes of ritual practice would be adaptive for societies with particular resource acquisition strategies. In setting out our conceptual framework we report numerous ongoing investigations that test our hypotheses against data from controlled psychological experiments as well as from theethnographic, archaeological, and historical records.

Nebular emission-line profiles of Type Ib/c supernovae - Probing the ejecta asphericity

In order to assess qualitatively the ejecta geometry of stripped-envelope core-collapse supernovae (SNe), we investigate 98 late-time spectra of 39 objects, many of them previously unpublished. We perform a Gauss-fitting of the [O ] ??6300, 6364 feature in all spectra, with the position, full width at half maximum and intensity of the ?6300 Gaussian as free parameters, and the ?6364 Gaussian added appropriately to account for the doublet nature of the [O ] feature. On the basis of the best-fitting parameters, the objects are organized into morphological classes, and we conclude that at least half of all Type Ib/c SNe must be aspherical. Bipolar jet models do not seem to be universally applicable, as we find too few symmetric double-peaked [O ] profiles. In some objects, the [O ] line exhibits a variety of shifted secondary peaks or shoulders, interpreted as blobs of matter ejected at high velocity and possibly accompanied by neutron-star kicks to assure momentum conservation. At phases earlier than ~200 d, a systematic blueshift of the [O ] ??6300, 6364 line centroids can be discerned. Residual opacity provides the most convincing explanation of this phenomenon, photons emitted on the rear side of the SN being scattered or absorbed on their way through the ejecta. Once modified to account for the doublet nature of the oxygen feature, the profile of Mg i] ?4571 at sufficiently late phases generally resembles that of [O ] ??6300, 6364, suggesting negligible contamination from other lines and confirming that O and Mg are similarly distributed within the ejecta. © 2009 RAS.

Mycobacterium chelonae keratitis:Resolution after debridement and presoaked collagen shields

We report a case of Mycobacterium chelonae keratitis following corneal injury by a foreign body. Diagnosis was made by Ziehl-Neelsen staining and Lowenstein-Jensen culture of corneal scrapings. On the basis of the in vitro susceptibility testing, the patient was treated with topical fortified amikacin. Given the lack of response to this therapy, we decided to carry out a debridement of the infiltrative areas to eliminate infected tissue, and to use an amikacin-soaked collagen shield supplemented every 4 h with topical fortified amikacin to promote healing of the debrided area and to potentiate the effects of the antibiotic therapy. After this treatment, clinical resolution was observed and a further acid-fast stain and culture for mycobacterium were negative. Debridement of the infiltrative areas could be used in cases of mycobacterium keratitis when early diagnosis is made and before the corneal infection has become widespread.

A new model of posterior capsule opacification in rodents

PURPOSE. To describe a new model of posterior capsule opacification (PCO) in rodents METHODS. An extracapsular lens extraction (ECLE), by continuous curvilinear capsulorrhexis and hydrodissection, was performed in 42 consecutive Brown Norway rats. Animals were killed at 0, 6, and 24 hours and 3, 7, and 14 days after surgery. Eyes were enucleated and processed for light microscopy and immunohistochemistry. RESULTS. In 34 (81%) of the animals the operated eye appeared well healed before death, with a clear cornea and a well-formed anterior chamber. In eight (19%) there was no view of anterior segment structures because of hyphema, fibrin, or corneal opacification. PCO was clinically evident 3 days after ECLE and was present in all animals at 2 weeks. Immediately after ECLE, lens epithelial cells (LECs) were present in the inner surface of the anterior capsule and lens bow. Twenty-four hours after surgery, LECs started to migrate toward the center of the posterior capsule. At 3 days, multilayered LECs, some spindle shaped, were present throughout the lens capsule. Capsular wrinkling was apparent. Lens fibers and Soemmering's ring were observed in all animals 14 days after surgery, indicating some degree of cellular differentiation. Activated macrophages were present in greater numbers at 3 and 14 days after surgery (P <0.05), when proliferation and migration of LECs appeared to be greatest, and lens fiber differentiation was evident, respectively. CONCLUSIONS. In rodents PCO occurs after ECLE and is associated with low-grade inflammation, mostly of mononuclear macrophages. Although no intraocular lens implantation was performed, this model appears to be valuable for studying the sequence of events that leads to PCO after cataract surgery and the extracellular matrix cues that promote lens fiber differentiation.

Long-term graft survival in patients with flexible open-loop anterior- chamber intraocular lenses

Purpose. To evaluate the long-term graft survival and complications of flexible, open-loop anterior-chamber intraocular lenses in patients with penetrating keratoplasty for pseudophakic or aphakic bullous keratopathy. Methods. We reviewed charts of all consecutive patients who underwent penetrating keratoplasty for pseudophakic or aphakic bullous keratopathy combined with implantation of a flexible, open-loop, anterior-chamber intraocular lens at our institution between 1983 and 1988. One-hundred one eyes of 99 patients were evaluated. Graft-survival rates were calculated by using the Kaplan-Meier actuarial method. Results. Mean follow-up was 49.8 months (range. 1-144). The probability of graft survival at 1, 2, 4, 6, and 8 years was 93, 87, 78, 65, and 65%, respectively. A total of 25 (24.8%) grafts failed. Progressive corneal edema without signs of rejection was the most common finding in patients with failed grafts (10 eyes, 40%). The most frequent complication observed was newly diagnosed or worsening of preexisting glaucoma (46 eyes, 45.5%). Conclusions. Our long-term results support flexible, open-loop anterior-chamber intraocular lenses as a reasonable option, at the time of penetrating keratoplasty, in patients with pseudophakic and aphakic bullous keratopathy.

Primary cysts of the iris pigment epithelium. Clinical features and natural course in 234 patients

Objective: To describe the clinical characteristics, natural course, and complications of a large group of patients with primary iris pigment epithelium (IPE) cysts. Design: Observational case series. Participants: Two hundred thirty-four patients with primary IPE cysts participated. Results: Primary IPE cysts were classified as central in 6 patients (3%), midzonal in 50 patients (21%), peripheral in 170 patients (73%), and dislodged in 8 patients (3%). Central (pupillary) IPE cysts were found only in males, peripheral IPE cysts were found most often in females (69%), and no gender predilection was detected for midzonal and dislodged IPE cysts. Central and peripheral IPE cysts occurred in young patients (mean age, 20 and 33 years, respectively), whereas midzonal and dislodged IPE cysts were seen in slightly older patients (mean age, 52 and 45 years, respectively). Central IPE cysts were visible when the pupil was not dilated and appeared most often as a round or collapsed brown lesion arising from the pupillary margin, most commonly superonasally. Midzonal IPE cysts were brown and fusiform, best visualized after pupillary dilation. Peripheral IPE cysts produced a characteristic bulging in the iris stroma near the iris root, but they were directly visible in only 78% of cases. After wide dilation and patient and slit-lamp positioning, they appeared as a round clear lesion behind the iris, most often in the inferotemporal quadrant. Finally, dislodged IPE cysts appeared as a brown oval lesion, free floating in the anterior chamber (12%) or in the vitreous (12%), or fixed in the anterior chamber angle (75%). One hundred twenty-four patients (53%) were followed for a mean of 35 months (range, 3 months-19 years). In these patients, complications associated with IPE cysts included lens subluxation in one case (1%), iritis in one case (1%), focal cataract in two cases (2%), glaucoma in two cases (2%), and corneal touch in five cases (4%). Conclusion: Primary IPE cysts have characteristic clinical features that serve to differentiate them from intraocular malignancies. Most cysts have a benign clinical course, and treatment is rarely necessary.

Indications for penetrating keratoplasty and associated procedures, 1989-1995

Purpose. To identify changing trends in indications for penetrating keratoplasty and associated surgical procedures. Methods. Review of charts from all patients who underwent penetrating keratoplasty at Wills Eye Hospital from January 1, 1989 through December 31, 1995. Results. A total of 2,442 corneal transplants were performed in 2,186 patients. The leading indication for penetrating keratoplasty was pseudophakic corneal edema, accounting for 634 cases (26.0%); 54.7% of them were associated with anterior chamber intraocular lenses, 36.4% with posterior chamber intraocular lenses, and 3.1% with iris-fixated intraocular lenses. Regraft (17.8%), Fuchs' dystrophy (15.7%), and keratoconus (13.2%) followed pseudophakic corneal edema in frequency. Cataract extraction, with or without intraocular lens implantation, was combined with penetrating keratoplasty in 439 cases of 1,264 phakic eyes (34.7%). Intraocular lens exchange was performed in 285 of the 634 cases of pseudophakic cornea edema (44.9%). Conclusion. Pseudophakic corneal edema was the leading indication for penetrating keratoplasty, with an increasing number of cases associated with posterior chamber intraocular lenses during the study period (p = 0.001). The number of regrafts steadily increased between 1989 and 1995 (p = 0.001), being the second most common indication for corneal transplantation since 1992.

Contact lens use after contact lens-associated infectious ulcers

Purpose: The purpose of this study was to evaluate the outcome of patients with healed moderate to severe contact lens-associated corneal infectious ulcers who were re-fit with contact lenses. Methods: We retrospectively studied patients who were fit with contact lenses on our service and who had had moderate to severe corneal infectious ulcers associated with previous contact lens use. Six patients were included in the study. Results: Gas permeable contact lenses were fit in five patients, and a soft contact lens was fit in one patient. Successful fit was achieved in all cases and visual acuities were equal to or better than 20/30 in all patients. No significant complications were observed after a mean follow-up of 23 months (range, 6-45 months). Conclusion: In this small series of patients with a history of moderate to severe contact-lens related infectious keratitis, no complications were observed after contact lenses were refit. Contact lens wear in patients with a history of infectious keratitis may be safe and useful in order to achieve visual rehabilitation.

Surveillance for ocular hypertension: An evidence synthesis and economic evaluation

OBJECTIVES: To determine effective and efficient monitoring criteria for ocular hypertension [raised intraocular pressure (IOP)] through (i) identification and validation of glaucoma risk prediction models; and (ii) development of models to determine optimal surveillance pathways.

DESIGN: A discrete event simulation economic modelling evaluation. Data from systematic reviews of risk prediction models and agreement between tonometers, secondary analyses of existing datasets (to validate identified risk models and determine optimal monitoring criteria) and public preferences were used to structure and populate the economic model.

SETTING: Primary and secondary care.

PARTICIPANTS: Adults with ocular hypertension (IOP > 21 mmHg) and the public (surveillance preferences).

INTERVENTIONS: We compared five pathways: two based on National Institute for Health and Clinical Excellence (NICE) guidelines with monitoring interval and treatment depending on initial risk stratification, 'NICE intensive' (4-monthly to annual monitoring) and 'NICE conservative' (6-monthly to biennial monitoring); two pathways, differing in location (hospital and community), with monitoring biennially and treatment initiated for a ≥ 6% 5-year glaucoma risk; and a 'treat all' pathway involving treatment with a prostaglandin analogue if IOP > 21 mmHg and IOP measured annually in the community.

MAIN OUTCOME MEASURES: Glaucoma cases detected; tonometer agreement; public preferences; costs; willingness to pay and quality-adjusted life-years (QALYs).

RESULTS: The best available glaucoma risk prediction model estimated the 5-year risk based on age and ocular predictors (IOP, central corneal thickness, optic nerve damage and index of visual field status). Taking the average of two IOP readings, by tonometry, true change was detected at two years. Sizeable measurement variability was noted between tonometers. There was a general public preference for monitoring; good communication and understanding of the process predicted service value. 'Treat all' was the least costly and 'NICE intensive' the most costly pathway. Biennial monitoring reduced the number of cases of glaucoma conversion compared with a 'treat all' pathway and provided more QALYs, but the incremental cost-effectiveness ratio (ICER) was considerably more than £30,000. The 'NICE intensive' pathway also avoided glaucoma conversion, but NICE-based pathways were either dominated (more costly and less effective) by biennial hospital monitoring or had a ICERs > £30,000. Results were not sensitive to the risk threshold for initiating surveillance but were sensitive to the risk threshold for initiating treatment, NHS costs and treatment adherence.

LIMITATIONS: Optimal monitoring intervals were based on IOP data. There were insufficient data to determine the optimal frequency of measurement of the visual field or optic nerve head for identification of glaucoma. The economic modelling took a 20-year time horizon which may be insufficient to capture long-term benefits. Sensitivity analyses may not fully capture the uncertainty surrounding parameter estimates.

CONCLUSIONS: For confirmed ocular hypertension, findings suggest that there is no clear benefit from intensive monitoring. Consideration of the patient experience is important. A cohort study is recommended to provide data to refine the glaucoma risk prediction model, determine the optimum type and frequency of serial glaucoma tests and estimate costs and patient preferences for monitoring and treatment.

FUNDING: The National Institute for Health Research Health Technology Assessment Programme.

Simultaneous use of mitomycin-C with Baerveldt implantation

BACKGROUND AND OBJECTIVE: To evaluate the outcome of Baerveldt implantation with adjunctive mitomycin-C in cases of complicated glaucoma. PATIENTS AND METHODS: The authors reviewed the charts of all patients who had undergone Baerveldt implantation with mitomycin-C between January 1993 and March 1995. Success was defined before data collection as an intraocular pressure (IOP) between 5 and 21 mm Hg, with or without medications. The success rate was calculated using the Kaplan-Meier actuarial method. RESULTS: Twenty-nine patients were identified. The mean preoperative IOP was 33.6 mm Hg, with an average of 2.0 antiglaucoma medications. The probability of success at 6 and 12 months for patients who received mitomycin-C during Baerveldt implantation was 82.4% and 73.3%, respectively. Choroidal effusion with a flat anterior chamber (10.3%), corneal edema (6.8%), and conjunctival erosion (6.8%) were the most frequent complications. CONCLUSION: In this retrospective series of complicated glaucoma, the implantation of a Baerveldt drainage device with adjunctive mitomycin-C had a satisfactory outcome. The complications encountered and the clinical efficacy were comparable to those of previously reported series in which mitomycin-C was not used.