bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal variation of CCN concentrations and aerosol activation properties in boreal forest
Authors: Sihto S.-L. , Mikkilä J. , Vanhanen J. , Ehn M. , Liao L. , Lehtipalo K. , Aalto P. P. , Duplissy J. , Petäjä T. , Kerminen V.-M. , Boy M. , Kulmala M.
Published: November 2010

Abstract. As a part of EUCAARI activities, the annual cycle of cloud condensation nuclei (CCN) concentrations and critical diameter for cloud droplet activation as a function of supersaturation were measured using a CCN counter and a HTDMA (hygroscopic tandem DMA) at SMEAR II station, Hyytiälä, Finland. The critical diameters for cloud droplet activation were estimated from (i) the CCN concentration and particle size distribution data, and (ii) the hygroscopic growth factors by applying κ-Köhler theory. The critical diameters derived by these two methods were in good agreement with each other. The effect of new particle formation on the diurnal variation of CCN concentration and critical diameters was studied. New particle formation was observed to increase the CCN concentrations by 70–110%, depending on the supersaturation level. The average value for the κ-parameter determined from hygroscopicity measurements was κ = 0.18 and it predicted well the CCN activation in Hyytiälä boreal forest conditions. The derived critical diameters and κ-parameter indicate that aerosol particles at CCN sizes in Hyytiälä are mostly organic, but contain also more soluble, probably inorganic salts like ammonium sulphate, making the particles more CCN active than pure secondary organic aerosol.
Three-year ground based measurements of Aerosol Optical Depth over the Eastern Mediterranean: the urban environment of Athens
Authors: Gerasopoulos E. , Amiridis V. , Kazadzis S. , Kokkalis P. , Eleftheratos K. , Andreae M. O. , Andreae T. W. , El-Askary H. , Zerefos C. S.
Published: November 2010

Abstract. Three years (2006–2008) of ground-based observations of the Aerosol Optical Depth (AOD) in the urban environment of Athens, in the Eastern Mediterranean, are analysed in this work. Measurements were acquired with a Multi-Filter Rotating Shadowband Radiometer at five wavelengths. The daily average AOD at 500 nm is 0.23, and the mean Ångström coefficient calculated between 415 and 867 nm is 1.41. The annual variability of AOD has a spring maximum dominated by coarse dust particles from the Sahara (AOD 0.34–0.42), while the diurnal pattern is typical for urban sites, with AOD steadily increasing throughout the day. Secondary contributors of high aerosol loadings over Athens are identified, namely the Istanbul metropolitan area, the extended areas of biomass burning around the north coast of the Black Sea, power plants spread throughout the Balkans and the industrial area in the Po valley, with average daily AOD in the range of 0.25–0.35. The geographical distribution of the above sources in conjunction with the prevailing synoptic situation and contribution of local sources, lead to mixed types of aerosols over Athens with highly variable contribution of fine and coarse particles to AOD in the range 10%–90%. This is the first long-term, ground based data set available for Athens, and has also been used for the validation of satellite derived AOD by MODIS, showing good agreement on an annual basis, but with an overestimation of satellite AODs in the warm period.
Assessment of the CALIPSO Lidar 532 nm attenuated backscatter calibration using the NASA LaRC Airborne High Spectral Resolution Lidar
Authors: Rogers R. R. , Hostetler C. A. , Hair J. W. , Ferrare R. A. , Liu Z. , Obland M. D. , Harper D. B. , Cook A. L. , Powell K. A. , Vaughan M. A. , Winker D. M.
Published: November 2010

Abstract. The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) spacecraft has provided global, high-resolution vertical profiles of aerosols and clouds since it became operational on 13 June 2006. On 14 June 2006, the NASA Langley Research Center (LaRC) High Spectral Resolution Lidar (HSRL) was deployed aboard the NASA Langley B-200 aircraft for the first of a series of 86 underflights of the CALIPSO satellite to provide validation measurements for the CALIOP data products. To better assess the range of conditions under which CALIOP data products are produced, these validation flights were conducted under both daytime and nighttime lighting conditions, in multiple seasons, and over a large range of latitudes and aerosol and cloud conditions. This paper presents a quantitative assessment of the CALIOP 532 nm calibration (through the 532 nm total attenuated backscatter) using an internally calibrated airborne HSRL underflight data and is the most extensive study of CALIOP 532 nm calibration. Results show that average HSRL and CALIOP 532 nm total attenuated backscatter agree on average within 2.7±2.1% (CALIOP lower) at night and within 2.9±3.9% (CALIOP lower) during the day, demonstrating the accuracy of the CALIOP 532 nm calibration algorithms. Additionally, comparisons with HSRL show consistency of the CALIOP calibration before and after the laser switch in 2009 as well as improvements in the daytime version 3.01 calibration scheme compared with the version 2 calibration scheme. Potential systematic uncertainties in the methodology relevant to validating satellite lidar measurements with an airborne lidar system are discussed and found to be less than 3.7% for this validation effort with HSRL. Results from this study are also compared to prior assessments of the CALIOP 532 nm attenuated backscatter calibration.
On the structural changes in the Brewer-Dobson circulation after 2000
Authors: Bönisch H. , Engel A. , Birner Th. , Hoor P. , Tarasick D. W. , Ray E. A.
Published: November 2010

Abstract. In this paper we present evidence that the observed increase in tropical upwelling after the year 2000 may be attributed to a change in the Brewer-Dobson circulation pattern. For this purpose, we use the concept of transit times derived from residual circulation trajectories and different in-situ measurements of ozone and nitrous dioxide. Observations from the Canadian midlatitude ozone profile record, probability density functions of in-situ N2O observations and a shift of the N2O-O3 correlation slopes, taken together, indicate that the increased upwelling in the tropics after the year 2000 appears to have triggered an intensification of tracer transport from the tropics into the extratropics in the lower stratosphere below about 500 K. This finding is corroborated by the fact that transit times along the shallow branch of the residual circulation into the LMS have decreased for the same time period (1993–2003). On a longer time scale (1979–2009), the transit time of the shallow residual circulation branch show a steady decrease of about −1 month/decade over the last 30 years, while the transit times of the deep branch remain unchanged. This highlights the fact that a change in the upwelling across the tropical tropopause is not a direct indicator for changes of the whole Brewer-Dobson circulation.
BrO vertical distributions from SCIAMACHY limb measurements: comparison of algorithms and retrieval results
Authors: Rozanov A. , Kühl S. , Doicu A. , McLinden C. , Puķīte J. , Bovensmann H. , Burrows J.P. , Deutschmann T. , Dorf M. , Goutail F. , Grunow K. , Hendrick F. , von Hobe M. , Hrechanyy S. , Lichtenberg G. , Pfeilsticker K. , Pommereau J. P. , Van Roozendael M. , Stroh F. , Wagner T.
Published: November 2010

Abstract. This study presents two scientific and one operational retrieval algorithms used to obtain vertical distributions of bromine monoxide (BrO) from observations of the scattered solar light performed by the SCIAMACHY instrument in limb viewing geometry. The study begins with a discussion of the theoretical basis of all algorithms followed by an investigation of the retrieval sensitivity. Simulations with three different radiative transfer models allow us to analyze influence of the forward model implementation upon the retrieval results. By means of synthetic retrievals we analyze major sources of uncertainties in the resulting BrO profiles such as different BrO cross sections, their temperature dependence, and stratospheric aerosols. Finally, the reliability of SCIAMACHY BrO profile retrievals is demonstrated comparing results from different algorithms to balloon-borne observations.
Meteorological profiling of the lower troposphere using the research UAV "M2AV Carolo"
Authors: Martin S. , Bange J. , Beyrich F.
Published: November 2010

Abstract. Vertical profiles of temperature, humidity and wind up to a height of 1500 m a.g.l. (above ground level) were measured with the automatically operating small unmanned research aircraft M2AV (Meteorological Mini Aerial Vehicle) during the LITFASS-2009 (LIndenberg-To-Falkenberg: Aircraft, Scintillometer and large-eddy Simulation) experiment. The campaign took place in July 2009 over the heterogeneous landscape around the Meteorologcial Observatory Lindenberg – Richard-Aßmann-Observatory in the eastern part of Germany. Due to a high vertical resolution of about 10 cm the M2AV data show details of the turbulent structure of the atmospheric boundary layer (ABL). One profile takes about 10–15 min allowing for a continuous monitoring of certain phases of ABL development by successive ascents and descents during one flight (50–60 min duration). Two case studies of measurements performed during the morning and evening ABL transition periods are discussed in detail. Comparison of the aircraft-based temperature, humidity and wind profiles with tower, sodar/RASS, wind profiler/RASS, radiosoundings and microwave radiometer profiler measurements show good agreement taking into account the different sampling strategies of these measurement systems.
CIAO: the CNR-IMAA advanced observatory for atmospheric research
Authors: Madonna F. , Amodeo A. , Boselli A. , Cornacchia C. , D'Amico G. , Giunta A. , Mona L. , Pappalardo G. , Cuomo V.
Published: November 2010

Abstract. The long-term observations of aerosol and clouds are of crucial importance to understand the weather climate system. At the Istituto di Metodologie per l'Analisi Ambientale of the Italian National Research Council (CNR-IMAA) an advanced atmospheric observatory, named CIAO, is operative. CIAO (CNR-IMAA Atmospheric Observatory) main scientific objective is the long-term measurement for the climatology of aerosol and cloud properties. Its equipment addresses the state-of-the-art for the ground-based remote sensing of aerosol, water vapour and clouds including active and passive sensors, like lidars, ceilometers, radiometers, a radar. This paper describes the CIAO infrastructure, its scientific activities as well as the observation strategy. The observation strategy is mainly organized in order to provide quality assured measurements for satellite validation and model evaluation and to fully exploit the synergy and integration of the active and passive sensors for the improvement of the atmospheric profiling. Data quality is ensured both by the application of protocols and dedicated quality assurance programmes mainly related to the projects and networks in which the infrastructure is involved. The paper also introduces examples of observations performed at CIAO and of the synergies and integration algorithms (using Raman lidar and microwave profiler data) developed and implemented at the observatory for the optimization and improvement of water vapour profiling. The CIAO database represents an optimal basis to study the synergy between different sensors and to investigate aerosol-clouds interactions, and can give a significant contribution to the validation programmes of the incoming new generation satellite missions.
Modelling and quantifying the effect of heterogeneity in soil physical conditions on fungal growth
Authors: Pajor R. , Falconer R. , Hapca S. , Otten W.
Published: November 2010

Abstract. Despite the importance of fungi in soil ecosystem services, a theoretical framework that links soil management strategies with fungal ecology is still lacking. One of the key challenges is to understand how the complex geometrical shape of pores in soil affects fungal spread and species interaction. Progress in this area has long been hampered by a lack of experimental techniques for quantification. In this paper we use X-ray computed tomography to quantify and characterize the pore geometry at microscopic scales (30 μm) that are relevant for fungal spread in soil. We analysed the pore geometry for replicated samples with bulk-densities ranging from 1.2–1.6 g/cm3. The bulk-density of soils significantly affected the total volume, mean pore diameter and connectivity of the pore volume. A previously described fungal growth model comprising a minimal set of physiological processes required to produce a range of phenotypic responses was used to analyse the effect of these geometric descriptors on fungal invasion, and we showed that the degree and rate of fungal invasion was affected mainly by pore volume and pore connectivity. The presented experimental and theoretical framework is a significant first step towards understanding how environmental change and soil management impact on fungal diversity in soils.
Global fungal spore emissions, review and synthesis of literature data
Authors: Dallafior T. N. , Sesartic A.
Published: November 2010

Abstract. The present paper summarizes fungal spore emission fluxes in different biomes. A literature study of more than 150 papers has been conducted and emission fluxes have been calculated based on 35 fungal spore concentration datasets. Biome area data has been derived from the World Resource Institute. Several assumptions and simplifications needed to be adopted while aggregating the data: results from different measurement methods have been treated equally, while diurnal and seasonal cycles have been neglected. Moreover flux data were aggregated to very coarse biome areas due to scarcity of data. Results show number fluxes per square meter and second of 3.13 for forest, 24.7 for shrub, 31.77 for crop, 0.03 for tundra, and 1.45 for grassland. No data were found for land ice. The annual mean global fluxes amount to 4×10−13 kg m−2 s−1 as the best estimates, and 2.2×10−13 kg m−2 s−1 and 8.9×10−13 kg m−2 s−1 as the low and high estimate, respectively.
Questions of importance to the conservation of biological diversity: answers from the past
Authors: Willis K. J. , Bhagwat S. A.
Published: November 2010

Abstract. Paleoecological records are replete with examples of biotic responses to past climate change and human impact, but how can we use these records in the conservation of current and future biodiversity? A recently published list of (One Hundred Questions of Importance to the Conservation of Global Biological Diversity) (Sutherland et al., 2009) highlights a number of key research questions that need a temporal perspective. Many of these questions are related to the determination of ecological processes in order to assess ecosystem function and services, climate change-integrated conservation strategies, and ecosystem management and restoration. However, it is noticeable that not a single contributor to this list was from the paleo-research community and that extremely few paleo-records are ever used in the development of terrestrial conservation management plans. This lack of dialogue between conservationists and the paleo-community is partially driven by a perception that the data provided by paleoecological records are purely descriptive and not of relevance to the day-to-day management and conservation of biological diversity. This paper illustrates, through a series of case-studies, how long-term ecological records (>50 years) can provide a test of predictions and assumptions of ecological processes that are directly relevant to management strategies necessary to retain biological diversity in a changing climate. This discussion paper includes information on diversity baselines, thresholds, resilience, and restoration of ecological processes.
Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow
Authors: Morgenstern U. , Stewart M. K. , Stenger R.
Published: November 2010

Abstract. Tritium measurements of streamwater draining the Toenepi catchment, a small dairy farming area in Waikato, New Zealand, have shown that the mean transit time of the water varies with the flow rate of the stream. Mean transit times through the catchment are 2–5 years during high baseflow conditions in winter, increasing to 30–40 years as baseflow decreases in summer, and then dramatically older water during drought conditions with mean transit time of more than 100 years. Older water is gained in the lower reaches of the stream, compared to younger water in the headwater catchment. The groundwater store supplying baseflow was estimated from the mean transit time and average baseflow to be 15.4 × 106 m3 of water, about 1 m water equivalent over the catchment and 2.3 times total annual streamflow. Nitrate is relatively high at higher flow rates in winter, but is low at times of low flow with old water. This reflects both lower nitrate loading in the catchment several decades ago as compared to current intensive dairy farming, and denitrification processes occurring in the older groundwater. Silica, leached from the aquifer material and accumulating in the water in proportion to contact time, is high at times of low streamflow with old water. There was a good correlation between silica concentration and streamwater age, which potentially allows silica concentrations to be used as a proxy for age when calibrated by tritium measurements. This study shows that tritium dating of stream water is possible with single tritium measurements now that bomb-test tritium has effectively disappeared from hydrological systems in New Zealand, without the need for time-series data.
Performance and reliability of multimodel hydrological ensemble simulations based on seventeen lumped models and a thousand catchments
Authors: Velázquez J. A. , Anctil F. , Perrin C.
Published: November 2010

Abstract. This work investigates the added value of ensembles constructed from seventeen lumped hydrological models against their simple average counterparts. It is thus hypothesized that there is more information provided by all the outputs of these models than by their single aggregated predictors. For all available 1061 catchments, results showed that the mean continuous ranked probability score of the ensemble simulations were better than the mean average error of the aggregated simulations, confirming the added value of retaining all the components of the model outputs. Reliability of the simulation ensembles is also achieved for about 30% of the catchments, as assessed by rank histograms and reliability plots. Nonetheless this imperfection, the ensemble simulations were shown to have better skills than the deterministic simulations at discriminating between events and non-events, as confirmed by relative operating characteristic scores especially for larger streamflows. From 7 to 10 models are deemed sufficient to construct ensembles with improved performance, based on a genetic algorithm search optimizing the continuous ranked probability score. In fact, many model subsets were found improving the performance of the reference ensemble. This is thus not essential to implement as much as seventeen lumped hydrological models. The gain in performance of the optimized subsets is accompanied by some improvement of the ensemble reliability in most cases. Nonetheless, a calibration of the predictive distribution is still needed for many catchments.
Self-potential investigations of a gravel bar in a restored river corridor
Authors: Linde N. , Doetsch J. , Jougnot D. , Genoni O. , Dürst Y. , Minsley B. J. , Vogt T. , Pasquale N. , Luster J.
Published: November 2010

Abstract. Self-potentials (SP) are sensitive to water fluxes and concentration gradients in both saturated and unsaturated geological media, but quantitative interpretations of SP field data are often hindered by the superposition of different source contributions and time-varying electrode potentials. Self-potential mapping and close to two months of SP monitoring on a gravel bar were performed to investigate the origins of SP signals at a restored river section of the Thur River in northeastern Switzerland. The SP mapping and subsequent inversion of the data indicate that the SP sources are mainly located in the upper few meters in regions of soil cover rather than bare gravel. Wavelet analyses of the time-series indicate a strong, but non-linear influence of water table and water content variations, as well as rainfall intensity on the recorded SP signals. Modeling of the SP response with respect to an increase in the water table elevation and precipitation indicate that the distribution of soil properties in the vadose zone has a very strong influence. We conclude that the observed SP responses on the gravel bar are more complicated than previously proposed relationships between SP signals and hydraulic head or the thickness of the vadose zone. We suggest that future SP monitoring in restored river corridors should either focus on quantifying vadose zone processes by installing vertical profiles of closely spaced SP electrodes or by installing the electrodes within the river to avoid signals arising from vadose zone processes and time-varying electrochemical conditions in the vicinity of the electrodes.
Alexander von Humboldt's charts of the Earth's magnetic field: an assessment based on modern models
Authors: Mandea M. , Korte M. , Soloviev A. , Gvishiani A.
Published: November 2010

Abstract. The 19th century witnessed a resurgence of interest in Earth's magnetic field. Both observational and theoretical aspects were involved, and one of the emblematic figures of this period was Alexander von Humboldt. Throughout a long life he maintained a strong interest in a broad area of subjects, however, here we are interested in his role in geomagnetism, and particularly in his pioneering contributions to charting the geomagnetic field. Alexander von Humboldt efforts in measuring and charting the Earth's magnetic field are recounted and the maps of declination, inclination and total intensity he had prepared are compared, favorably, with maps for the same epoch based on a modern model of the geomagnetic field, gufm1. This modern assessment of the accuracy of von Humboldt's geomagnetic charts illustrates the importance of his work, being also our homage to the 150th anniversary of the death of Alexander von Humboldt.
Thermophysical property anomalies of Baltic seawater
Authors: Feistel R. , Marion G. M. , Pawlowicz R. , Wright D. G.
Published: November 2010

Abstract. While the thermodynamic properties of Standard Seawater are very well known, the quantitative effect of sea salt composition anomalies on various properties is difficult to estimate since comprehensive lab experiments with the various natural waters are scarce. Coastal and estuarine waters exhibit significant anomalies which also influence to an unknown amount the routine salinity calculation from conductivity measurements. Recent numerical models of multi-component aqueous electrolytes permit the simulation of physical chemical properties of seawater with variable solute composition. In this paper, the FREZCHEM model is used to derive a Gibbs function for Baltic seawater, and the LSEA_DELS model to provide estimates for the conductivity anomaly relative to Standard Seawater. From additional information such as direct density measurements or empirical salinity anomaly parameterisation, the quantitative deviations of properties between Baltic and Standard Seawater are calculated as functions of salinity and temperature. While several quantities show anomalies that are comparable with their measurement uncertainties and do not demand special improvement, others exhibit more significant deviations from Standard Seawater properties. In particular density and sound speed turn out to be significantly sensitive to the presence of anomalous solute. Suitable general correction methods are suggested to be applied to Baltic Sea samples with known Practical Salinity and, optionally, directly determined density.
Quality of Vision Index: A New Method to Appraise Visual Function Changes in Age-Related Macular Degeneration
Authors: Piermarocchi Stefano , Varano Monica , Parravano Mahachstina , Oddone Francesco , Sartore Mauro , Ferrara Roberto , Sera Francesco , Virgili Gianni
Published: November 2010

Purpose

TO explore the correlation between psychophysical measures of visual function and vision-related quality of life (QOL) in exudative age-related macular degeneration (AMD) and to obtain a new quality of vision index expressed as corrected visual acuity (cVA) that is scaled like visual acuity (VA), but that incorporates the weighted contribution of VA, contrast sensitivity (CS), and reading ability.

Methods

Visual acuity, CS, and reading ability were measured in 293 patients with AMD in this multicenter prospective study. Vision-related QOL was quantified by the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25). The validity of the questionnaire was assessed using Rasch analysis. The relationship between psychophysical tests and NEI-VFQ-25 scores was investigated. A cVA index was developed integrating Rasch-scaled NEI-VFQ-25 score with VA, CS, and reading ability as a tool to be used for evaluating vision-related QOL on the same scale as VA.

Results

A total of 27.5% of the variability of VFQ score was found to be explained by VA alone in patients with AMD. The proportion of Rasch-scaled QOL estimate variance explained by cVA was 33.2% as compared to 27.5% explained by VA and 24.5% by CS, which was a statistically significant improvement in both cases (p=0.015 and p<0.001, respectively). The correlation of reading ability with vision-related QOL was largely mediated by VA and CS and therefore it was not retained in the vision index.

Conclusions

Visual acuity is poorly correlated with vision-related QOL in patients with AMD. Even though the new cVA index is a new method which better correlates with vision-related QOL, the major components of the individual perception of vision remain unexplained by common psycho-metric tests.
Long-Term Follow-Up of Spontaneous Retinal Pigment Epithelium Tears in Age-Related Macular Degeneration Treated with Anti-VEGF Therapy
Authors: Lesniak Sebastian P. , Fine Howard F. , Prenner Jonathan L. , Roth Daniel B.
Published: November 2010

Purpose

TO describe the clinical response following anti-vascular endothelial growth factor (VEGF) therapy in patients with spontaneous retinal pigment epithelium (RPE) tears secondary to age-related macular degeneration (AMD).

Methods

Retrospective chart review of patients with AMD who developed a spontaneous RPE tear and were subsequently treated with anti-VEGF therapy at a single institution.

Results

In 5 patients included in the study, the median number (range) of injections received was 14.2 (5–18). The median baseline acuity was 20/200, which remained stable at 12 months and improved to 20/60 at 24 months. These changes were not statistically different.

Conclusions

Anti-VEGF therapy appears safe in eyes with spontaneous RPE tear secondary to AMD and may help to stabilize or even improve acuity in some cases.
Retreatment of Residual Refractive Errors with Flap Lift Laser in Situ Keratomileusis
Authors: McAlinden Colm , Moore Jonathan E.
Published: November 2010

Purpose

TO investigate the outcomes of flap lift laser-assisted in situ keratomileusis (LASIK) for residual refractive errors.

Methods

In this prospective study, 60 eyes of 48 patients (mean age 36 years; age range 23–53 years) underwent flap lift retreatment surgery following initial LASIK for the correction of residual refractive errors. All treatments were wavefront guided using the VISX S4 Star excimer laser. The main outcome measures were predictability, safety, efficacy, and stability.

Results

Following retreatment, epithelial ingrowth occurred in 23.3% (n=14) of eyes, which required a flap lift and scrape procedure in 4 eyes and a second flap lift and scrape procedure in 2 eyes. De novo dry eye occurred in 8.3% (n=5) of eyes. At 6 months, the mean (±SD) post-retreatment Snellen decimal uncorrected visual acuity (UCVA), sphere, cylinder, spherical equivalent (SE), defocus equivalent (DE), and best corrected visual acuity (BCVA) was 1.03±0.23, 0.08±0.34 diopters (D) (range −0.75 to +1.25 D), −0.53±0.37 D (range 0 to −1.75 D), −0.04±0.34 D (range −1.11 to +1.04 D), 0.29±0.41 D (range 0 to 1.94 D), and 1.13±0.15 (range 0.5 to 1.5), respectively. Seventy-three percent (n=44) of eyes had an UCVA equal to or greater than 1 (6/6), 88.3% (n=53) and 98.3% (n=59) of eyes were within ±0.50 D and ±1.00 D of SE, respectively, and 3.3% (n=2) of eyes lost 1 line of BCVA.

Conclusions

A high incidence (23.3%, n=14) of epithelial ingrowth occurred following retreatment surgery and de novo dry eye occurred in 8.3% (n=5) of eyes. Despite this, reasonable visual and refractive outcomes were achieved at 6 months post-retreatment.
Impact of AREDS in a Developing Country 5 Years after Publication of the Study
Authors: Fahed Daoud C. , Ghazi Nicola G. , Jabbour Nabil M. , Fahed Charbel D. , Fahed John C. , Salti Haytham I.
Published: November 2010

Purpose

The Age-Related Eye Disease Study (AREDS) is the only large-scale study to demonstrate a reduction in the risk of progression to end-stage age-related macular degeneration (AMD) when vitamin supplementation was given to patients with advanced forms of the disease. Our study assesses the impact of this study on vitamin supplementation in patients with advanced AMD from 5 years before publication of the AREDS results until 5 years after.

Methods

Medical records of patients with AMD presenting between September 1996 and October 2006 were reviewed. Patients were subclassified according to AREDS categories. The proportion of advanced cases on vitamin replacement before October 2001 was compared to that after October 2001. Since October 2001, the different reasons for abstinence were investigated and analyzed.

Results

Only 2403 patients of the 40,000 medical records reviewed met the AREDS AMD criteria. Of these, 137 patients verifying categories 3 and 4 were diagnosed prior to October 2001. Fourteen were on supplements then. Fifty-three patients complied with the represcribed vitamins during subsequent visits after October 2001, raising the percentage significantly to 48.9% (p<0.001). Also, from October 2001 until October 2006, an additional 76 patients verified categories 3 and 4. Fifty-three (69.7%) of them were on vitamins (p=0.001). Financial burden was the principal reason for abstinence in 67.7% of patients prescribed vitamins after October 2001.

Conclusions

The results of AREDS had an impressive impact on prescribing supplements in AREDS category 3 and 4 patients in Lebanon. The main reason for noncompliance is financial.
Pentosidine and N-Carboxymethyl-Lysine: Biomarkers for Type 2 Diabetic Retinopathy
Authors: Ghanem Asaad A. , Elewa Ahmed , Arafa Lamiaa F.
Published: November 2010

Purpose

Advanced glycation end products (AGEs) accumulation may result from chronic hyperglycemia promoting generation and onset of microangiopathy. The aim of this study was to investigate the association between diabetic retinopathy (DR) and levels of AGEs, pentosidine, and N-carboxymethyl-lysine (CML) in aqueous humor and serum of human patients and their role in predicting the progression of DR.

Methods

Ninety patients with type 2 diabetes mellitus and 30 nondiabetic patients underwent cataract surgery. The diabetic group was divided into 3 subgroups: 35 patients with mild nonproliferative diabetic retinopathy (mild NPDR), 30 patients with severe nonproliferative diabetic retinopathy (severe NPDR), and 25 patients with proliferative diabetic retinopathy (PDR). In the samples, pentosidine was measured by high-performance liquid chromatography and CML using a competitive enzyme-linked immunosorbent assay.

Results

Serum levels of pentosidine and CML were significantly increased in patients with type 2 diabetes compared to nondiabetic controls (p<0.001). In diabetic patients, serum pentosidine and CML levels were significantly higher in patients who had PDR than in those with mild NPDR or severe NPDR (both p<0.001). A significant difference was found between aqueous humor CML levels in diabetic and nondiabetic patients and increased along with progression of DR. Significant correlations existed between serum pentosidine and aqueous CML in severe NPDR and PDR (p<0.001).

Conclusions

In patients with type 2 DM, serum levels of pentosidine and CML are related to severity of retinopathy. In addition, aqueous humor level of CML increased along with progression of DR. Pentosidine and CML can be used as biochemical markers of glycoxidation and related to onset or progression of DR.
Cataract-Related Acute Vitreomacular Traction Syndrome
Authors: Panagiotidis Dimitrios , Karagiannis Dimitrios , Theodossiadis Panagiotis , Alonistiotis Dimitrios , Charonis Alexandros , Tsoumbris Ioannis , Vergados Ioannis
Published: November 2010

Purpose

To report the acute and transient (within 10 days) presentation of vitreomacular traction following routine cataract surgery.

Methods

This is a case series of 5 patients with no evidence of posterior vitreous detachment preoperatively who presented with acute vitreomacular traction following routine cataract surgery. All patients presented the first postoperative day with dramatically reduced visual acuity. The patients underwent optical coherence tomography and if necessary fundus fluorescein angiography. Images were suggestive of vitreomacular syndrome.

Results

In all 5 cases, there was spontaneous resolution of the traction within 10 days. The latter was probably related to the development of posterior vitreous detachment due to the uncomplicated cataract surgery. In 2 cases there were significant retinal pigment epithelium changes and decreased retinal thickness following the resolution of the traction leaving permanent metamorphopsia and slightly decreased visual acuity.

Conclusions

Cataract-related acute vitreomacular traction is a rare phenomenon and not well-recognized; however, it resolves spontaneously within 10 days.
Combined Ex-PRESS LR-50/IOL Implantation in Modified Deep Sclerectomy plus Phacoemulsification for Glaucoma Associated with Cataract
Authors: Gindroz Fanny , Roy Sylvain , Mermoud André , Schnyder Corinne C.
Published: November 2010

Purpose

This is a prospective study reporting on modified deep sclerectomy (DS) using the Ex-PRESS LR-50 in combined cataract and glaucoma surgery.

Methods

Twenty-four eyes of 24 patients with medically uncontrolled glaucoma underwent modified DS. After phacoemulsification and intraocular lens implantation, the Ex-PRESS LR-50 was inserted into the anterior chamber under a scleral flap. A partial posterior DS was performed to provide an intrascleral bleb. The complete success rate was intraocular pressure (IOP) without medication ≤18 mmHg; the qualified success rate was IOP ≤18 mmHg with or without medication. Postoperative bleb management (subconjunctival mitomycin C injections ± needling) was performed in case of postoperative hypertension or bleb fibrosis.

Results

Follow-up was 40.1±10.8 (mean ± SD) months. Preoperatively, IOP was 18.1±5.3 mmHg, best-corrected visual acuity (BCVA) was 0.6±0.3, and number of medications was 2.3±1.1. The IOP decreased by 25.4% at 24 months and by 27.0% at 48 months. At 24 months, 19 patients (86.3%) achieved a BCVA of 0.5 or better, and at 48 months the mean BCVA was 0.7±0.3. At the last visit, the mean number of medications was 0.6±0.8 (p<0.05). The complete and qualified success rates were 45.6% and 85.2%. Mitomycin C injections were performed in 5 eyes. No conjunctival erosions over the Ex-PRESS LR-50 were seen.

Conclusions

The Ex-PRESS LR-50 inserted into the anterior chamber after modified DS efficiently lowers IOP in combined surgery, preventing conjunctival erosion, a significant complication when using this device without scleral flap coverage.
Alteration of Rod and Cone Function in Children with Usher Syndrome
Authors: Malm Eva , Ponjavic Vesna , Möller Claes , Kimberling William J. , Stone Edwin S. , Andréasson Sten
Published: November 2010

Purpose

TO evaluate the retinal function, with emphasis on phenotype and rate of progression, in infants and children with different genotypes of Usher syndrome.

Methods

Fourteen children (2–10 years of age) with retinitis pigmentosa and hearing impairment were examined with full-field electroretinography (ERG) during general anesthesia, ophthalmologic examination, and genetic analysis. Five children were repeatedly examined (follow-up 5–10 years) with full-field ERG under local anesthesia and in 2 children multifocal ERG and optical coherence tomography (OCT) were performed. These results were compared to full-field ERG data from 58 children without retinal eye disorder.

Results

Six children were genotyped as Usher 1B, 2A, and 3A. Full-field ERG demonstrated early alterations corresponding to a rod-cone dystrophy in all children. A remaining rod function could be verified in the majority of the children up to 4 years of age. After 4 years of age, there was a further deterioration of the rod function; the progress was severe in Usher types 1 and 2 and moderate in Usher type 3. In all children, the cone function was moderately reduced, in a few cases almost normal. The results from the 58 children without retinal disorder confirm that full-field ERG during general anesthesia is reliable. Multifocal ERG confirmed a preserved central cone function and in OCT there were discrete structural alterations.

Conclusions

Full-field ERG during general anesthesia in children with Usher syndrome demonstrates variable phenotypes and different degrees in rate of progression during childhood.
Pulmonary Edema following Instillation of Topical Phenylephrine Eyedrops in a Child under General Anesthesia
Authors: Venkatakrishnan Jaichandran , Jagadeesh Viswanathan , Kannan Rajagopal
Published: November 2010

Purpose

To report a case of pulmonary edema, in a child under general anesthesia, due to iatrogenic acute hypertensive crisis following instillation of 1 drop of 5% phenylephrine eyedrops.

Methods

A 2-year-old boy was scheduled for examination of both eyes and enucleation of the left eye under general anesthesia. In the preoperative ward, 1 drop of 2.5% phenylephrine eyedrops was instilled 3 times by the nursing staff. The child was induced with the volatile agent Sevoflurane and intubated with Inj atracurium besylate 0.5 mg/kg IV. Anesthesia was maintained with N2O/oxygen (2:1)/Sevofurane 1.5% and Inj fentanyl 1 μg/kg IV. As the pupil was not dilated optimally for examination, 1 drop of 5% phenylephrine eyedrops was instilled. Approximately 10 minutes following its instillation, tachycardia and rise in blood pressure occurred. Auscultation of the chest revealed bilateral coarse crepitations and pink frothy secretions were noted in the Portex endotracheal tube.

Results

Pulmonary edema was effectively settled using positive pressure ventilation with 100% oxygen, Inj lasix 1 mg/kg IV, and Inj hydrocortisone 100 mg IV. The concentration of inhalational agent, Sevoflurane, was increased. Within about 15 minutes, both heart rate and blood pressure gradually returned to normal limits. Following surgery, the child was extubated, fully awake.

Conclusions

To produce maximum mydriasis, with minimum systemic effects, preventive strategies such as using the lowest drug concentration, punctual occlusion, eyelid closure, allowing adequate time for the pharmacologic effect to occur, and the use of microdrops in infants should be adopted.
Severe Global Inflammatory Involvement of Ocular Segments and Optic Disc Swelling in a 12-Year-Old Girl with Kawasaki Disease
Authors: Grouteau Erick , Debuisson Cécile , Brochard Karine , Paranon Soizic , Beaudon Cécile Lesage , Pajot Christine , Claudet Isabelle
Published: November 2010

Purpose

Pediatric Kawasaki ocular involvement is dominated by bulbar conjunctival injection and mild, self-limited anterior uveitis. Posterior segment involvement is rare.

Methods/Results

Case report. Despite early efficient treatment including aspirin and intravenous immunoglobulins, a 12-year-old girl developed a severe bilateral global inflammatory ocular involvement including punctuated keratitis, retrodescemetic precipitates, anterior uveitis, vitritis, and bilateral optic disc swelling with papillitis. This is the first description of severe bilateral global inflammatory involvement of the eyes in Kawasaki disease (KD). Usually subclinical and self-limited, eye involvement in KD can lead to severe visual impairment.

Conclusions

Inflammation of both anterior and posterior segments does not seem to respond to KD-specific treatment and could justify a specific ophthalmologic therapeutic approach.
TGF-β and RPE-Derived Cells in Taut Subretinal Strands from Patients with Proliferative Vitreoretinopathy
Authors: Winkler Jörg , Hoerauf Hans
Published: November 2010

Purpose

TO investigate the distribution of transforming growth factor-β (TGF-β) and cells derived from the retinal pigment epithelium (RPE) as a major source for TGF-β in subretinal strands (SRSs), originating from patients with proliferative vitreoretinopathy (PVR) and proliferative diabetic vitreoretinopathy (PDVR).

Methods

Nine SRSs (PVR: n = 6 and PDVR: n = 3) were obtained during pars plana vitrectomy. Specimens were processed for immunohistochemical analysis in paraffin wax or studied by transmission electron microscopy.

Results

Staining for TGF-β was consistent in all specimens. The content of RPE-derived cells identified by anticytokeratin staining revealed considerable differences, ranging from <10 to >90%.

Conclusions

The widespread immunoreactivity for TGF-β in SRSs suggests a significant role of this group of cytokines in the pathologic course of PVR.
Mining Functional Data in Prediction Markets
Authors: Foutz Natasha Zhang , Jank Wolfgang
Published: November 2010

Prerelease demand forecasting is one of the most crucial yet difficult tasks facing marketers in the $60 billion motion picture industry. We propose functional data analysis of prediction markets to address this long‐standing challenge. In prediction markets, prices of a movie's stock reflect the dynamic demand expectations prior to the movie's release. Using functional data analysis, we identify a small number of distinguishing shapes, e.g., the last‐moment velocity spurt, that carry information about a movie's future demand and produce early and accurate prerelease forecasts.
Implementation of sustainability drivers in the design of industrial chemical processes
Authors: Tugnoli Alessandro , Santarelli Francesco , Cozzani Valerio
Published: November 2010

A methodology based on key performance indicators was developed and applied to the design of sustainable industrial processes. The methodology provides a procedure for the definition of a dynamic set of quantitative key performance indicators suitable to capture the environmental, economic and societal impacts of process options, thus, tracing the sustainability footprint of alternatives. The preliminary design of a production plant for cyclohexanone is presented as the leading case in the discussion. The influence of design choices on environmental impact profiles, economic efficiency and inherent safety performance was pointed out. The application evidenced that the definition of appropriate indicators may have an important added value in supporting design activities, both for the correct assessment of alternative options and for the proactive identification of design improvements. © 2011 American Institute of Chemical Engineers AIChE J, 2011
Demyelination causes synaptic alterations in hippocampi from multiple sclerosis patients
Authors: Dutta Ranjan , Chang Ansi , Doud Mary K. , Kidd Grahame J. , Ribaudo Michael V. , Young Elizabeth A. , Fox Robert J. , Staugaitis Susan M. , Trapp Bruce D.
Published: November 2010

Objective:

Multiple Sclerosis (MS) is an inflammatory demyelinating disease of the human central nervous system. Although the clinical impact of gray matter pathology in MS brains is unknown, 30 to 40% of MS patients demonstrate memory impairment. The molecular basis of this memory dysfunction has not yet been investigated in MS patients.

Methods:

To investigate possible mechanisms of memory impairment in MS patients, we compared morphological and molecular changes in myelinated and demyelinated hippocampi from postmortem MS brains.

Results:

Demyelinated hippocampi had minimal neuronal loss but significant decreases in synaptic density. Neuronal proteins essential for axonal transport, synaptic plasticity, glutamate neurotransmission, glutamate homeostasis, and memory/learning were significantly decreased in demyelinated hippocampi, but not in demyelinated motor cortices from MS brains.

Interpretation:

Collectively, these data support hippocampal demyelination as a cause of synaptic alterations in MS patients and establish that the neuronal genes regulated by myelination reflect specific functions of neuronal subpopulations. Ann Neurol 2011;69:445–454
Anatomy of disturbed sleep in pallido‐ponto‐nigral degeneration
Authors: Spector Andrew R. , Dugger Brittany N. , Wszolek Zbigniew K. , Uitti Ryan J. , Fredrickson Paul , Kaplan Joseph , Boeve Bradley F. , Dickson Dennis W. , Strongosky Audrey , Lin Siong‐chi
Published: November 2010

Objective:

Pallido‐ponto‐nigral degeneration (PPND), caused by an N279K mutation of the MAPT gene, is 1 of a family of disorders collectively referred to as frontotemporal dementia and parkinsonism linked to chromosome 17. This study aims to characterize the nature of the sleep disturbance in PPND and compare these findings to those in other progressive neurological illnesses. Pathological findings are also provided.

Methods:

Ten subjects were recruited from the PPND kindred; 5 affected and 5 unaffected. The subjects underwent clinical assessment, polysomnography, and wrist actigraphy. Available sleep‐relevant areas (pedunculopontine/laterodorsal tegmentum, nucleus basalis of Meynert, thalamus, and locus ceruleus) of affected subjects were analyzed postmortem.

Results:

The affected group's total sleep time was an average of 130.8 minutes compared to 403.6 minutes in the control group (p < 0.01). Initial sleep latency was significantly longer in affected subjects (range, 58–260 minutes vs 3–34 minutes). Affected subjects also had an increase in stage I sleep (8.5% vs 1%), and less stage III/IV sleep (8.5% vs 17%). At the time of autopsy, all cases had severe neuronal tau pathology in wake‐promoting nuclei, as well as decreases in thalamic cholinergic innervations. There was no difference in orexinergic fiber density in nucleus basalis of Meynert or locus ceruleus compared to controls.

Interpretation:

The PPND kindred showed severe sleep disturbance. Sleep abnormalities are common in neurodegenerative illnesses, but this is the first study of sleep disorders in PPND. Unlike most neurodegenerative conditions, PPND is characterized by decreased total sleep time, increased sleep latency, and decreased sleep efficiency, without daytime hypersomnolence. Ann Neurol 2011;69:1014–1025