We assess the cost and technical feasibility of extending the Very Large Telescope Interferometer (VLTI) through the addition of four 8 m-class Unit Telescopes (UTs), an upgrade we refer to as the new generation VLTI (ngVLTI). Such an upgrade would provide a dense and homogeneous uv coverage with baselines up to 220 m, enabling true imaging at milliarcsecond angular resolution across science cases ranging from Solar System bodies to distant active galactic nuclei. Because each image is reconstructed at a single wavelength, repeating the reconstruction across the spectral channels of the instrument would deliver spectral-imaging cubes – a qualitatively new capability for the VLTI, bringing it close to the imaging power of ALMA at near-infrared wavelengths. Motivated by this scientific case, we examine a compact telescope concept consisting of a fast (f/0.64), segmented, parabolic primary mirror feeding a subterranean coudé focus compatible with the existing VLTI infrastructure. We summarise the optical design, which achieves diffraction-limited performance over a 1 arcmin field of view and a well-matched reimaged pupil, discuss the mechanical trade-offs behind the choice of a 60-segment, 1.2 m primary – a mirror mass of 13.5 tons and an altitude moving mass of 50 tons – and quantify the gravitational flexure of the telescope structure and its resulting optical sensitivity as a function of pointing elevation. We then present a back-of-the-envelope cost estimate of order 80 MEuro per telescope (2026 prices), broken down into the segmented primary, adaptive secondary, coudé train, mount, enclosure, and ancillary instrumentation. The proposed upgrade appears both cost-competitive and technically achievable, offering a long-term perspective for Paranal Observatory in the ELT era.
BACKGROUND:Seizure frequency and cognitive function are common parameters in assessing epilepsy surgery outcomes. However, psychobehavioral outcomes, such as symptoms of depression and quality of life (QOL), have not found equal attention yet. OBJECTIVE:To assess the effect of seizure frequency, the extent of resection, and cognitive function on the psychobehavioral outcome of patients after temporal lobe surgery for pharmacoresistant epilepsy. METHODS:We retrospectively reviewed all consecutive patients who underwent surgery for intractable temporal lobe epilepsy between 09/2015 and 07/2019. We examined seizure outcome, surgical plan, resection volume, cognitive functions, and psychobehavioral outcome. RESULTS:This study included 77 patients (31 males, 46 females) who underwent temporal lobe surgery. One year after surgery, 53 patients (68.8 %) were completely seizure-free (Engel IA) and 92.2 % of patients showed a worthwhile improvement in seizure frequency (Engel I-III). Resection volume was significantly negatively correlated with QOL (r = - 0.284, p = 0.041). However, after controlling for the effect of seizure outcome, no significant correlation remained. Patients with a worthwhile improvement in seizure frequency showed significantly fewer symptoms of depression (p = 0.024) and a significantly higher QOL (p = 0.012) one year after surgery. The differences in symptoms of depression (p = 0.044) and QOL (p = 0.030) between patients with and without improvements in seizure frequency remained significant after controlling for the effect of resection volume. After procedures sparing the amygdala and hippocampus (neocortical resection), patients presented significantly fewer symptoms of depression (p = 0.044) and significantly better QOL (p = 0.008) than patients after procedures involving mesial-temporal structures, independent of the resection volume, and after controlling for the side of the procedure (dominant vs. non-dominant). After also controlling for seizure outcome, the difference remained for QOL (p = 0.014) but not for symptoms of depression. CONCLUSIONS:A patient's emotional well-being one year after surgery for pharmacoresistant temporal lobe epilepsy strongly depends on their seizure outcome. As an individual factor, the extent of neocortical resection negatively affects postsurgical emotional well-being, but a favorable seizure outcome outweighs this effect, independent of the resection volume. A favorable seizure outcome even outweighs the negative effects of procedures involving mesial-temporal structures on symptoms of depression.
The development of new high temperature materials for coatings as well as structural components is an important topic to contribute to a higher efficiency and sustainability of e.g. gas turbine engines. One promising new class of high temperature materials are NiAl-based alloys. Within this study, the microstructure and microhardness of NiAl-Ta-Cr alloys with varying Cr and Ta content were investigated. Graded specimens were fabricated by laser-based directed energy deposition utilizing an in situ alloying approach by mixing elemental Ta and Cr as well as pre-alloyed NiAl powder. Thermodynamic calculations were performed to design the alloy compositions beforehand. Inductive preheating of the substrate was used to counter the challenge of cracking due to the high brittleness. The results show that the cracking decreases with increasing preheating temperature. However, even at 700 °C, the cracking cannot be fully eliminated. Scanning electron microscopy, X-ray diffraction and electron backscatter diffraction revealed the formation of the phases B2-NiAl, A2-Cr and C14-NiAlTa within NiAl-Ta and NiAl-Cr alloys. For NiAl-Ta-Cr compositions, deviations regarding the phase formation between calculation and experiment were observed. Maximum hardness values were achieved within the NiAl-Ta and NiAl-Ta-Cr systems for the eutectic compositions at 14 at.-% Ta with maximum values above 900 HV0.1.
This contribution addresses the complete process chain of an annular aerospike breadboard engine fabricated by laser powder bed fusion using the nickel-based superalloy Inconel® 718. In order to qualify the material and process for this high-temperature application, an extensive material characterization campaign including density and roughness measurements, as well as tensile tests at room temperature, 700, and 900 °C, was conducted. In addition, various geometric features such as triangles, ellipses, and circular shapes were generated to determine the maximum unsupported overhang angle and geometrical accuracy. The results were taken into account in the design maturation of the manifold and the cooling channels of the aerospike breadboard engine. Postprocessing included heat treatment to increase mechanical properties, milling, turning, and eroding of interfaces to fulfill the geometrical tolerances, thermal barrier coating of thermally stressed surfaces for better protection of thermal loads, and laser welding of spike and shroud for the final assembly as well as quality assurance. This contribution goes beyond small density cubes and tensile samples and offers details on the iterations necessary for the successful printing of large complex shaped functional parts. The scientific question is how to verify the additive manufacturing process through tensile testing, simulation, and design iterations for complex geometries and reduce the number of failed prints.
PURPOSE: To evaluate formulas for intraocular lens (IOL) calculation in silicone oil (SO)-filled eyes. DESIGN: Retrospective, consecutive case series.METHODS: We conducted our study at the Department many, and included SO-filled eyes that received SO removal combined with phacoemulsification and IOL implantation. Preoperative assessments included biometry (IOLMaster 700; Carl Zeiss Meditec). To evaluate the measurements, we compared the mean prediction error, and mean and median absolute prediction error of 8 different formulas.RESULTS: A total of 90 eyes matched our inclusion criteria. The median absolute error was lowest in the Barrett Universal II formula (0.43 diopters [D] +/- 0.75) followed by Kane (0.44 D +/- 0.75), Hill-radial basis function (0.47 D +/- 0.74), Holladay II (0.47 D +/- 0.77), Sanders Retzlaff Kraff/theoretical (0.51 D +/- 0.74), Holladay I (0.51 D +/- 0.76), and Haigis and Hoffer Q (0.52 D +/- 0.74 each). Regarding eyes within +/- 0.5 D Barrett Universal II (57.8%, 52 eyes) performed best, again followed by Kane (56.7%, 51 eyes) and Hill-radial basis function (54.4%, 49 eyes).CONCLUSION: Using modern formulas for IOL calculation in oil-filled eyes improves predictability but still not as good as in unoperated eyes. This issue is created by the change in refractive index due to the SO fill and therefore a lower precision of axial length measurement and 2022;244: 166-174. (c) 2022 Published by Elsevier Inc.)
Recently, the additive manufacturing (AM) technology laser metal deposition (LMD) has gained a lot of attention for processing crack prone high temperature materials such as nickel‐based superalloys or intermetallics. A feasibility study on LMD of a graded transition from binary ß‐NiAl to Ni50Al42Ta8 is presented with the aim to show the possibility of manufacturing ß‐NiAl‐based structures with a spatially resolved microstructure and subsequently tailored mechanical properties. For achieving this, the alloys Ni50Al50 and Ni50Al42Ta8 are coinjected into the process zone and the powder feeding rates are adapted in a layerwise manner. Due to preheating temperatures of up to 1000 °C, the transition can be manufactured with high relative density and a low degree of cold cracking. Scanning electron microscopy of the transition zone shows the formation of a fine dendritic microstructure consisting of ß‐NiAl dendritic and NiAlTa interdendritic regions. Large area energy‐dispersive X‐ray analysis reveals a gradient in NiAlTa Laves phase content with increasing build height. The observed volume fraction of Laves phase corresponds well to reported values from cast ingots. Finally, hardness measurements along the build‐up direction show an increase in hardness from 300 HV0.1 to 680 HV0.1 indicating a tremendous increase in tensile strength.
Abstract. Low-cost sensors are considered as exhibiting great potential to complement classical air quality measurements in existing monitoring networks. However, the use of low-cost sensors poses some challenges. In this study, the behavior and performance of electrochemical sensors for NO and NO2 were determined over a longer operating period in a real-world deployment. After careful calibration of the sensors, based on co-location with reference instruments at a rural traffic site during six months and by using robust linear regression and random forest regression, the coefficient of determination of both types of sensors were high (R2 > 0.9) and the root mean square error (RMSE) of NO and NO2 sensors were about 6.8 ppb and 3.5 ppb, respectively, for 10-minute mean concentrations. The RMSE of the NO2 sensors, however, more than doubled, when the sensors were deployed without re-calibration for a one-year period at other site types (including urban background locations), where the range and the variability of air pollutant concentrations differed from the calibration site. This indicates a significant effect of the re-location of the sensors on the quality of their data. During deployment, we found that the NO2 sensors are capable of distinguishing general pollution levels, but they proved unsuitable for accurate measurements, mainly due to significant biases. In order to investigate the long-term stability of the original calibration, the sensors were re-installed at the calibration site after deployment. Surprisingly, the coefficient of determination and the RMSE of the NO sensor remained almost unchanged after more than one year of operation. In contrast, the performance of the NO2 sensors clearly deteriorated as indicated by a higher RMSE (about 7.5 ppb, 10-minute mean concentrations) and a lower coefficient of determination (R2 = 0.59).
Purpose: To describe the patients' characteristics, surgical ratio, and outcomes following epilepsy surgery at the newly established Epilepsy Center Frankfurt Rhine-Main. Methods: We retrospectively studied the first 100 consecutive patients, including adult (n = 77) and pediatric (n = 23) patients, with drug-resistant epilepsy who underwent resective or ablative surgical procedures at a single, newly established epilepsy center. Patient characteristics, seizure and neuropsychological outcomes, histopathology, complications, and surgical ratio were analyzed. Results: The mean patient age was 28.8 years (children 10.6 years, adults 34.2 years). The mean epilepsy duration was 11.9 years (children 3.9 years, adults 14.3 years), and the mean follow-up was 1.5 years. At the most recent visit, 64% of patients remained completely seizure free [Engel IA]. The rates of perioperative complications and unexpected new neurological deficits were 5%, each. The proportion of patients showing deficits in one or more cognitive domains increased six months after surgery and decreased to presurgical proportions after two years. Symptoms of depression were significantly decreased and quality of life was significantly increased after surgery. The surgical ratio was 25.3%. Conclusion: Similar postsurgical outcomes were achieved at a newly established epilepsy center compared with long-standing epilepsy centers. The lower time to surgery may reflect a general decrease in time to surgery over the last decade or the improved accessibility of a new epilepsy center in a previously underserved area. The surgical ratio was not lower than reported for established centers. (C) 2020 Elsevier Inc. All rights reserved.
Purpose To compare the effective lens position (ELP), anterior chamber depth (ACD) changes, and visual outcomes in patients with and without pseudoexfoliation syndrome (PEX) after cataract surgery. Design Prospective, randomized, fellow-eye controlled clinical case series. Methods This prospective comparative case series enrolled 56 eyes of 56 consecutive patients with (n = 28) or without PEX (n = 28) and clinically significant cataract who underwent standard phacoemulsification and were implanted with single-piece acrylic posterior chamber intraocular lenses (IOLs). The primary outcome parameters were the ACD referring to the distance between the corneal anterior surface and the lens anterior surface, which is an indicator of the postoperative axial position of the IOL (the so-called ELP) and distance corrected visual acuity (DCVA). Results Before surgery, the ACD was 2.54 ± 0.42 mm in the PEX group and 2.53 ± 0.38 mm in the control group (p = 0.941). Postoperatively, the ACD was 4.29 ± 0.71 mm in the PEX group and 4.33 ± 0.72 mm in the normal group, respectively (p = 0.533). There was no significant difference in ACD changes between groups (PEX group: 1.75 ± 0.74 mm, control group: 1.81 ± 0.61 mm, p = 0.806) and DCVA pre- (p = 0.469) and postoperatively (PEX group: 0.11 ± 0.13 logMAR, control group: 0.09 ± 0.17 logMAR, p = 0.245) between groups. Conclusion Preoperative and postoperative ACD, as an indicator of ELP, between PEX eyes and healthy eyes after cataract surgery showed no significant difference. Phacoemulsification induced similar changes in eyes with PEX compared to healthy eyes.
PURPOSE: The study was performed to evaluate the refractive and visual outcome of patients with misaligned toric intraocular lenses (IOLs) after operative realignment, with and without back-calculation of the toric axis after implantation of the IOL. DESIGN: Institutional, retrospective case-control study. METHODS: This is a retrospective case series of 39 patients who underwent a second operation to realign a misaligned toric IOL from August 2013 to December 2019 at the Department of Ophthalmology, Goethe University, Frankfurt, Germany. Ideal toric axis was calculated using the back-calculator astigmatismfix.com. RESULTS: The study consists of 39 treated eyes (20 [51%] right eyes). The toric IOLs showed a postoperative misalignment of 25.69 +/- 26.068. Postrotational, uncorrected distance visual acuity (UDVA) improved from 0.39 +/- 0.29 logMAR to 0.27 +/- 0.18 logMAR. Refractive outcome showed a reduction of residual sphere and cylinder. The postoperative UDVA when performing alignment to the preoperative calculated axis (51%) was 0.24 +/- 0.16 logMAR with a cylinder of 0.90 +/- 0.90 diopter (D). In the group with alignment to a back-calculated axis (49%), the UDVA was 0.32 +/- 0.20 logMAR with a cylinder of 0.76 +/- 0.72 D. High cylinder power IOLs (>= 2 D) showed a higher decrease in residual cylinder when back-calculation was performed than low cylinder power IOLs (<2 D) (27% vs 9%). The mean spherical equivalent prediction error of the backcalculator was 0.54 +/- 0.55 D. CONCLUSION: Realignment of misaligned toric IOLs improves visual acuity and reduces residual refractive errors. Especially for high cylinder power IOLs, better refractive outcome can be seen when performing a back-calculation before realignment. (C) 2020 Published by Elsevier Inc.
The additive manufacturing (AM) technique, laser metal deposition (LMD), combines the advantages of near net shape manufacturing, tailored thermal process conditions and in situ alloy modification. This makes LMD a promising approach for the processing of advanced materials, such as intermetallics. Additionally, LMD allows the composition of a powder blend to be modified in situ. Hence, alloying and material build-up can be achieved simultaneously. Within this contribution, AM processing of the promising high-temperature material β-NiAl, by means of LMD, with elemental powder blends, as well as with pre-alloyed powders, was presented. The investigations showed that by applying a preheating temperature of 1100 °C, β-NiAl could be processed without cracking. Additionally, by using pre-alloyed, as well as elemental powders, a single phase β-NiAl microstructure can be achieved in multi-layer build-ups. Major differences between the approaches were found within substrate near regions. For in situ alloying of Ni and Al, these regions are characterized by an inhomogeneous elemental distribution in a layerwise manner. However, due to the remelting of preceding layers during deposition, a homogenization can be observed, leading to a single-phase structure. This shows the potential of high temperature preheating and in situ alloying to push the development of new high temperature materials for AM.
Background: Diabetes prevalence is constantly rising, involving the eyes with damage including development of diabetic macular oedema. Since 2012, intravitreal anti-vascular endothelial growth factor medication is available for diabetic macular oedema treatment. Endocrinological studies have shown that fewer women are affected by diabetes. However, when affected, they exhibit more severe diabetic complications than men. We have investigated gender-related differences in diabetic macular oedema and outcome in an ophthalmological tertiary referral hospital. Methods: We included 88 patients (54 males and 34 females) with 112 eyes (68 male and 44 female) having clinically significant diabetic macular oedema, treated with anti-vascular endothelial growth factor medication. A 1 year follow-up was performed in all patients (visual acuity and optical coherence tomography). Previous retinal surgery was an exclusion criterion, as were other retinal pathologies. Results: The mean visual acuity and mean central retinal thickness at baseline were 0.53 logMAR (male 0.49 and female 0.595) and 469 μm (male 452 μm and female: 494 μm), respectively. After 360 days, mean visual acuity changed by −0.07 (±0.36) logMAR (male −0.11 and female +0.01) and mean central retinal thickness changed by −119 μm (male −113 μm and female −127 μm). For visual acuity, a significant difference was noted at baseline ( p = 0.02) and at 1 year ( p < 0.001). Males received 5.6 injections and females received 5.68 injections in 1 year. Conclusion: Our study showed that female patients with diabetic macular oedema were diagnosed with and treated for diabetic macular oedema at a stage when visual acuity and optical coherence tomography were worse than those in their male counterparts. This gender difference could not be reduced, despite similar numbers of injections. Female diabetic patients should therefore be assessed early for ophthalmological pathologies.
Natural estrogens act as endocrine disruptors. However, the fate of livestock farming derived natural estrogens (17α-estradiol, 17β-estradiol, estrone, and estriol) in slurry is not well understood. In this study, we assessed the effects of on farm-storage on natural estrogen concentrations in slurry. Furthermore, we monitored pig and cattle slurry pits from major agricultural areas in Switzerland and determined natural estrogen concentrations therein. They were relatively stable over time, and mean concentrations ranged from 138 to 861 and 54 to 244 ng/L for cattle and pig slurries, respectively. 17α-Estradiol and estriol were the most prevalent estrogens in cattle and pig slurries, respectively. Based on livestock numbers, agricultural area, and estrogen concentrations in slurry, the estimated annual load of total natural estrogens applied on agricultural area amounted to 36 mg/ha. Our results indicate that slurry application is a relevant source of natural estrogens in the environment.
The European Southern Observatory (ESO) is managing the Extremely Large Telescope (ELT) system performance and budgets. The Telescope Main Structure, Hosted Optical Units and Scientific Instruments are designed and built outside ESO by contractors and consortia. Within this scope, system simulations are performed including the coupling between the Telescope Main Structure and its Hosted Units. Both dynamic couplings relevant for control-structure interaction, seismic loads, and micro-vibrations as well as quasi-static deflections are included in these simulations. This paper explains the modeling approach and the first simulation results.
Cantilever components such as balconies produce thermal bridges, and therefore it is standard practice to isolate them in the connection area with the Schock Isokorb (R) load-bearing thermal insulation element. Normal live loads cause deformations and vibrations to occur in the balcony slab that are further influenced by the choice of connection element. This article shows the effect of Schock Isokorb (R) on the natural frequency of the balcony slab and thus also on its vibration behaviour, based on investigations at the Materials Testing and Research Institute (MPA Karlsruhe). Additionally, product-related torsion spring strength values are derived depending on materials such as stainless-steel or glass-fibre reinforcement, and the corresponding calculation formula is validated. The stiffness values determined from this can be used in serviceability checks within FE programs. This offers designers the possibility of a precise deformation calculation during structural modelling.
The SARS-CoV-2 pandemic poses major challenges for the entire medical care system. Especially in maximum care clinical facilities, a higher exposure to potentially infectious patients or positively tested COVID-19 patients is to be expected. A hospital facility concept was developed in the Department of Ophthalmology, Goethe University, Frankfurt am Main, Germany with the aim of achieving maximum patient safety with maximum employee protection. The current infection control hygiene recommendations of the Robert Koch Institute (RKI), the leading specialist association, were taken into consideration along with the existing hospital hygiene plan of the University Hospital Frankfurt am Main. Incorporated into the developmental process were the Institute for Medical Microbiology and Hospital Hygiene, the occupational medical service department and the board of the University Hospital Frankfurt am Main. The operational concept with individualized measures ensures that (i) the care of outpatients; (ii) the performance of outpatient operations; (iii) and the care of admitted patients and patients undergoing surgery are also guaranteed during the COVID-19 pandemic. All measures have been documented in writing in the clinic's internal quality manual and are thus accessible to all employees. The concept is regularly checked for functionality, so-called stress tests and hygiene inspections are carried out and improvements are made as necessary.
Many mineral P fertilizers contain toxic uranium (U) in high concentrations. When the fertilizers are applied to agricultural sites, U can either accumulate in the soil or leach to ground and surface waters. We analyzed the U fluxes at three arable and three grassland agricultural sites on the Swiss plateau for 1 year. We calculated all inputs and outputs to the soils, modeled the speciation of U in the soil solution and investigated the possible leaching of U along preferential flow paths. We found that all sites showed positive U budgets (+0.9–6.6 g ha–1 y–1), indicating an accumulation of U. However, the accumulation of U was low and a doubling of U concentration in the surface soil would need 850–2,660 years assuming today’s U fluxes. Mineral P fertilizers were the quantitatively most important input, followed by manure application and mineral weathering (only important in the soils developed on limestone). While at sites with slightly acidic pH only little U (<0.01 μg L–1) was leached, the U leaching increased at neutral pH values, because of the formation of carbonato-U complexes. In all soil solutions, the U concentrations (≤0.8 μg L–1) were below legal threshold values and comparable to local drinking and surface waters. We found no indication for enhanced U leaching along preferential flow paths.