Treatment Persistence and Switching Patterns of Adalimumab Biosimilar ABP 501 in European Patients with Rheumatologic Diseases

INTRODUCTION

ABP 501 was an adalimumab (ADA) biosimilar approved for treating immune-mediated inflammatory diseases (IMIDs) including rheumatoid arthritis (RA), psoriatic arthritis (PsA), and ankylosing spondylitis (AS). In this retrospective study, we aimed to examine the treatment patterns of ABP 501 among patients with these IMIDs using German and French pharmacy claims databases.

METHODS

Patients with RA, PsA, or AS who initiated ABP 501 between October 2018 and March 2020 and were observed continuously for ≥ 365 days both before and after ABP 501 initiation were included. Descriptive analyses of persistence and switch after ABP 501 discontinuation were conducted and reported for each disease cohort by prior use of ADA products (patients naïve to ADA or patients experienced with ADA).

RESULTS

Median (95% confidence interval) persistence on ABP 501 was 9.4 (8.6-10.3), 10.2 (9.0-11.7), and 12.1 (11.0-13.1) months in German patients, and 11.7 (9.9-13.3), 7.1 (5.8-8.4), and 10.8 (9.6-11.9) months in French patients for RA, PsA, and AS, respectively. For patients who switched from ABP 501 to another targeted therapy during the first 12 months of follow-up, switching patterns varied between patients naïve to ADA and patients experienced with ADA in both Germany and France, with patients naïve to ADA switching most frequently to other targeted therapies including non-ADA tumor necrosis factor inhibitor (TNFi), non-TNFi biologic, or Janus Kinase inhibitor (JAKi) and patients experienced with ADA switching most frequently back to ADA reference product (RP).

CONCLUSIONS

Across three rheumatologic diseases, about half of patients persisted on ABP 501 at the end of 12 months after treatment initiation in both Germany and France. Patients experienced with ADA were more likely to switch back to ADA RP, regardless of indication and country, suggesting a possible nocebo effect. Future studies are warranted to understand reasons of discontinuation and switching.

Treatment persistence and switching patterns of ABP 501 in European patients with inflammatory bowel disease

Background

Approval of the adalimumab (ADA) biosimilar ABP 501 for inflammatory bowel disease (IBD) indications was based on the principle of extrapolation, without indication-specific clinical trial data.

Objectives

To evaluate the real-world treatment patterns of ABP 501 in patients with IBD.

Design

Retrospective analysis of pharmacy claims data from Germany and France.

Methods

Continuously insured adult IBD patients who initiated ABP 501 between October 2018 and March 2020 were included. Treatment persistence, adherence, and post-ABP 501 switching patterns were evaluated for two mutually exclusive groups: ADA-naïve patients (i.e. no baseline use of ADA products) and ADA-experienced patients (i.e. previously treated with ADA products).

Results

A total of 3362 German patients and 733 French patients were included, with 54.4% and 65.3% being ADA-naïve patients, respectively. Median persistence (95% CI) on ABP 501 was 10.9 months (9.8-11.6) in ADA-naïve patients and 14.2 months (12.7-15.2) in ADA-experienced patients in Germany; for the French cohort, ADA-naïve and -experienced patients had median persistence of 12.8 months (10.2-14.7) and 11.5 months (8.8-14.4), respectively. During the first 12 months of ABP 501 initiation, 53.7% of German patients and 51.0% of French patients were adherent to the therapy. About 20% of patients in both countries switched from ABP 501 to another targeted therapy. In the German cohort, ADA-naïve patients most frequently switched to non-tumor necrosis factor inhibitor biologics, but ADA-experienced patients most commonly switched to reference product (RP); in the French cohort, patients most often switched to RP regardless of prior exposure to ADA products.

Conclusion

About 50% of patients persisted on and were adherent to ABP 501 therapy during the first 12 months after treatment initiation in two large European countries. Post-ABP 501, switching patterns varied between countries, indicating diversified treatment practices warranting further research on reason(s) for switching and potential overall treatment outcomes.

Health Care Situation in the Treatment of Uncontrolled GINA Step 4/5 Patients in Germany

Purpose

It has been estimated that, in 2019, 54,000 patients in Germany had uncontrolled GINA step 4/5 asthma. In the current study we analyzed which health care providers were involved in the management of these patients and their role in disease phenotyping.

Patients and Methods

The year 2019 was retrospectively analyzed using the IQVIATM LRx, a longitudinal anonymized prescription database, and the electronic, anonymized medical records database, the IQVIA Disease Analyzer.

Results

Of 54,000 uncontrolled GINA step 4/5 asthma patients in Germany, 52% had consulted both general practitioners (GPs) and pulmonologists, and 48% were seen exclusively by a GP. Of these 54,000 patients, 45% were being prescribed and were thus overusing short-acting β2-agonists (SABAs) and oral corticosteroids (OCS) for ≥2 years, 26% for ≥3 years, and 16% for ≥4 years. In most regions, pulmonologists saw one of their uncontrolled GINA step 4/5 asthma patients per week. Laboratory tests from consultations with a GP were available for only 10% of patients referred to a pulmonologist. In 50% of uncontrolled asthma patients treated according to GINA step 4/5, these were initiated by the pulmonologist, and 34% received laboratory testing within the first year (in GINA step 4/5 asthma, the numbers are 20% and 18%, respectively).

Conclusion

Fifty percent of uncontrolled asthma patients treated according to GINA step 4/5 were regularly seen by pulmonologists, who performed most of the phenotyping confirming their importance in the management of severe, uncontrolled asthma in Germany. To understand treatment pathways for these patients, further studies are needed.

Dominance of benthic fluxes in the oceanic beryllium budget and implications for paleo-denudation records

The ratio of atmosphere-derived ¹⁰Be to continent-derived ⁹Be in marine sediments has been used to probe the long-term relationship between continental denudation and climate. However, its application is complicated by uncertainty in ⁹Be transfer through the land-ocean interface. The riverine dissolved load alone is insufficient to close the marine ⁹Be budget, largely due to substantial removal of riverine ⁹Be to continental margin sediments. We focus on the ultimate fate of this latter Be. We present sediment pore-water Be profiles from diverse continental margin environments to quantify the diagenetic Be release to the ocean. Our results suggest that pore-water Be cycling is mainly controlled by particulate supply and Mn-Fe cycling, leading to higher benthic fluxes on shelves. Benthic fluxes may help close the ⁹Be budget and are at least comparable to, or higher (~2-fold) than, the riverine dissolved input. These observations demand a revised model framework, which considers the potentially dominant benthic source, to robustly interpret marine Be isotopic records.

Coastal El Niño triggers rapid marine silicate alteration on the seafloor

Marine silicate alteration plays a key role in the global carbon and cation cycles, although the timeframe of this process in response to extreme weather events is poorly understood. Here we investigate surface sediments across the Peruvian margin before and after extreme rainfall and runoff (coastal El Niño) using Ge/Si ratios and laser-ablated solid and pore fluid Si isotopes (δ³⁰Si). Pore fluids following the rainfall show elevated Ge/Si ratios (2.87 µmol mol^-1) and δ³⁰Si values (3.72‰), which we relate to rapid authigenic clay formation from reactive terrigenous minerals delivered by continental runoff. This study highlights the direct coupling of terrestrial erosion and associated marine sedimentary processes. We show that marine silicate alteration can be rapid and highly dynamic in response to local weather conditions, with a potential impact on marine alkalinity and CO₂-cycling on short timescales of weeks to months, and thus element turnover on human time scales.

Environmental changes affect the microbial release of hydrogen sulfide and methane from sediments at Boknis Eck (SW Baltic Sea)

Anthropogenic activities are modifying the oceanic environment rapidly and are causing ocean warming and deoxygenation, affecting biodiversity, productivity, and biogeochemical cycling. In coastal sediments, anaerobic organic matter degradation essentially fuels the production of hydrogen sulfide and methane. The release of these compounds from sediments is detrimental for the (local) environment and entails socio-economic consequences. Therefore, it is vital to understand which microbes catalyze the re-oxidation of these compounds under environmental dynamics, thereby mitigating their release to the water column. Here we use the seasonally dynamic Boknis Eck study site (SW Baltic Sea), where bottom waters annually fall hypoxic or anoxic after the summer months, to extrapolate how the microbial community and its activity reflects rising temperatures and deoxygenation. During October 2018, hallmarked by warmer bottom water and following a hypoxic event, modeled sulfide and methane production and consumption rates are higher than in March at lower temperatures and under fully oxic bottom water conditions. The microbial populations catalyzing sulfide and methane metabolisms are found in shallower sediment zones in October 2018 than in March 2019. DNA-and RNA profiling of sediments indicate a shift from primarily organotrophic to (autotrophic) sulfide oxidizing Bacteria, respectively. Previous studies using data collected over decades demonstrate rising temperatures, decreasing eutrophication, lower primary production and thus less fresh organic matter transported to the Boknis Eck sediments. Elevated temperatures are known to stimulate methanogenesis, anaerobic oxidation of methane, sulfate reduction and essentially microbial sulfide consumption, likely explaining the shift to a phylogenetically more diverse sulfide oxidizing community based on RNA.

Smaller fish species in a warm and oxygen-poor Humboldt Current system

Climate change is expected to result in smaller fish size, but the influence of fishing has made it difficult to substantiate the theorized link between size and ocean warming and deoxygenation. We reconstructed the fish community and oceanographic conditions of the most recent global warm period (last interglacial; 130 to 116 thousand years before present) by using sediments from the northern Humboldt Current system off the coast of Peru, a hotspot of small pelagic fish productivity. In contrast to the present-day anchovy-dominated state, the last interglacial was characterized by considerably smaller (mesopelagic and goby-like) fishes and very low anchovy abundance. These small fish species are more difficult to harvest and are less palatable than anchovies, indicating that our rapidly warming world poses a threat to the global fish supply.

MACC1 regulates clathrin-mediated endocytosis and receptor recycling of transferrin receptor and EGFR in colorectal cancer

Metastasis Associated in Colon Cancer 1 (MACC1) is a novel prognostic, predictive and causal biomarker for tumor progression and metastasis in many cancer types, including colorectal cancer. Besides its clinical value, little is known about its molecular function. Its similarity to SH3BP4, involved in regulating uptake and recycling of transmembrane receptors, suggests a role of MACC1 in endocytosis. By exploring the MACC1 interactome, we identified the clathrin-mediated endocytosis (CME)-associated proteins CLTC, DNM2 and AP-2 as MACC1 binding partners. We unveiled a MACC1-dependent routing of internalized transferrin receptor towards recycling. Elevated MACC1 expression caused also the activation and internalization of EGFR, a higher rate of receptor recycling, as well as earlier and stronger receptor activation and downstream signaling. These effects are limited by deletion of CME-related protein interaction sites in MACC1. Thus, MACC1 regulates CME and receptor recycling, causing increased growth factor-mediated downstream signaling and cell proliferation. This novel mechanism unveils potential therapeutic intervention points restricting MACC1-driven metastasis.

Real-world use of talimogene laherparepvec in Germany: a retrospective observational study using a prescription database

Aim: There is a growing body of data on real-world use of talimogene laherparepvec (T-VEC). We aimed to characterize real-world T-VEC use using a nationally representative German prescription database covering 60% of prescriptions reimbursed. Patients & methods: A retrospective analysis was conducted using the German IMS^® LRx prescription database, analyzing patients aged ≥18 years with an initial T-VEC prescription at 10⁶ plaque-forming units (PFU)/ml and ≥1 subsequent prescription at 10⁸ PFU/ml. Median time on T-VEC treatment, patient characteristics and patterns of T-VEC use were described. Results: Of 127 patients prescribed T-VEC, 72 patients (57%) met study criteria. About two-thirds of these patients initiated T-VEC in 2017. Median age at T-VEC initiation was 74 years (range: 44 to 91). Most prescriptions (88%) were dispensed from hospitals. At study end, 26 (36%) patients remained on T-VEC; 46 (64%) had ended treatment. Median duration of T-VEC treatment for all patients was 18.7 weeks (95% CI: 15.3-26.9) and was longer among those who initiated treatment in 2017 versus 2016 (26.7 vs 15.6 weeks, respectively). Median volume administered for the first 10⁶ PFU/ml and second 10⁸ PFU/ml was 4 ml; the volume decreased for subsequent administrations (2 ml by the eighth administration and 1 ml by the 16th administration). Conclusion: This real-world prescription database study showed that patients who initiated treatment in 2017 had a treatment duration in clinical practice that corresponded with the European Summary of Product Characteristics guideline of continuing T-VEC for ≥6 months. Additional long-term data linking drug use with clinical outcomes are needed.

Two C++ libraries for counting trees on a phylogenetic terrace

Motivation

The presence of terraces in phylogenetic tree space, i.e. a potentially large number of distinct tree topologies that have exactly the same analytical likelihood score, was first described by Sanderson et al. However, popular software tools for maximum likelihood and Bayesian phylogenetic inference do not yet routinely report, if inferred phylogenies reside on a terrace, or not. We believe, this is due to the lack of an efficient library to (i) determine if a tree resides on a terrace, (ii) calculate how many trees reside on a terrace and (iii) enumerate all trees on a terrace.

Results

In our bioinformatics practical that is set up as a programming contest we developed two efficient and independent C++ implementations of the SUPERB algorithm by Constantinescu and Sankoff (1995) for counting and enumerating trees on a terrace. Both implementations yield exactly the same results, are more than one order of magnitude faster, and require one order of magnitude less memory than a previous thirrd party python implementation.

Availability and implementation

The source codes are available under GNU GPL at https://github.com/terraphast.

Supplementary information

Supplementary data are available at Bioinformatics online.

Recovery of High-Energy Photoelectron Circular Dichroism through Fano Interference

It is commonly accepted that the magnitude of a photoelectron circular dichroism (PECD) is governed by the ability of an outgoing photoelectron wave packet to probe the chiral asymmetry of a molecule. To be able to accumulate this characteristic asymmetry while escaping the chiral ion, photoelectrons need to have relatively small kinetic energies of up to a few tens of electron volts. Here, we demonstrate a substantial PECD for very fast photoelectrons above 500 eV kinetic energy released from methyloxirane by a participator resonant Auger decay of its lowermost O 1s excitation. This effect emerges as a result of the Fano interference between the direct and resonant photoionization pathways, notwithstanding that their individual effects are negligibly small. The resulting dichroic parameter has an anomalous dispersion: It changes its sign across the resonance, which can be considered as an analogue of the Cotton effect in the x-ray regime.

Cold atmospheric pressure plasma for treatment of chronic wounds: drug or medical device?

OBJECTIVE

The use of cold atmospheric pressure plasma (CAPP) as a new therapeutic option to aid the healing of chronic wounds appears promising. Currently, uncertainty exists regarding their classification as medical device or medical drug. Because the classification of CAPP has medical, legal, and economic consequences as well as implications for the level of preclinical and clinical testing, the correct classification is not an academic exercise, but an ethical need.

METHOD

A multidisciplinary team of physicians, surgeons, pharmacists, physicists and lawyers has analysed the physical and technical characteristics as well as legal conditions of the biological action of CAPP.

RESULTS

It was concluded that the mode of action of the locally generated CAPP, with its main active components being different radicals, is pharmacological and not physical in nature.

CONCLUSION

Depending on the intended use, CAPP should be classified as a drug, which is generated by use of a medical device directly at the point of therapeutic application.

Symmetry breakdown of electron emission in extreme ultraviolet photoionization of argon

Short wavelength free-electron lasers (FELs), providing pulses of ultrahigh photon intensity, have revolutionized spectroscopy on ionic targets. Their exceptional photon flux enables multiple photon absorptions within a single femtosecond pulse, which in turn allows for deep insights into the photoionization process itself as well as into evolving ionic states of a target. Here we employ ultraintense pulses from the FEL FERMI to spectroscopically investigate the sequential emission of electrons from gaseous, atomic argon in the neutral as well as the ionic ground state. A pronounced forward-backward symmetry breaking of the angularly resolved emission patterns with respect to the light propagation direction is experimentally observed and theoretically explained for the region of the Cooper minimum, where the asymmetry of electron emission is strongly enhanced. These findings aim to originate a better understanding of the fundamentals of photon momentum transfer in ionic matter.

Note: Soft X-ray transmission polarizer based on ferromagnetic thin films

A transmission polarizer for producing elliptically polarized soft X-ray radiation from linearly polarized light is presented. The setup is intended for use at synchrotron and free-electron laser beamlines that do not directly offer circularly polarized light for, e.g., X-ray magnetic circular dichroism (XMCD) measurements or holographic imaging. Here, we investigate the degree of ellipticity upon transmission of linearly polarized radiation through a cobalt thin film. The experiment was performed at a photon energy resonant to the Co L₃-edge, i.e., 778 eV, and the polarization of the transmitted radiation was determined using a polarization analyzer that measures the directional dependence of photo electrons emitted from a gas target. Elliptically polarized radiation can be created at any absorption edge showing the XMCD effect by using the respective magnetic element.

Piscirickettsia salmonis infection in cultured lumpfish (Cyclopterus lumpus L.)

A Piscirickettsia salmonis infection was diagnosed in lumpfish (Cyclopterus lumpus L.) juveniles held in a marine research facility on the west coast of Ireland. The main clinical signs and pathology included marked ascites, severe multifocal liver necrosis and severe diffuse inflammation and necrosis of the exocrine pancreas and peri-pancreatic adipose tissue. Numerous Piscirickettsia-like organisms were observed by histopathology in the affected organs, and the bacterial species was characterized by molecular analysis. Sequencing of the partial 16S rDNA gene and internal transcribed spacer region showed the lumpfish sequences to be closely related to previously identified Atlantic salmon (Salmo salar L.) sequences from Ireland. To the authors' knowledge, this is the first detection of P. salmonis in lumpfish worldwide. The infection is considered potentially significant in terms of lumpfish health and biosecurity.

First record of Tetramicra brevifilum in lumpfish (Cyclopterus lumpus, L.)

A microsporidian species with 98.3-98.4% nucleotide identity to Tetramicra brevifilum (Journal of Fish Diseases, 3, 1980, 495) was diagnosed in lumpfish (Cyclopterus lumpus, L.) broodstock held at a breeding and rearing facility in western Ireland. The fish were wild-caught from the west coast of Ireland, and the first case was diagnosed one year after capture. Clinical signs included severe bloating, lethargy, exophthalmos, anorexia, white patches on the cornea and externally visible parasitic cysts on skin and fins. Necropsy revealed severe ascites, white nodules and vacuoles in all the internal organs and partial liquefaction of the skeletal muscle. On histological examination, microsporidian xenomas were observed in all internal organs, the skin, skeletal muscle, gills and the eyes. The microsporidian species was identified by molecular analysis and transmission electron microscopy. This is the first record of T. brevifilum infecting lumpfish, and the disease is considered to be of potential significance to the rising aquaculture industry of this species.

Dendritic cell-mediated survival signals in Eμ-Myc B-cell lymphoma depend on the transcription factor C/EBPβ

The capacity of dendritic cells (DCs) to regulate tumour-specific adaptive immune responses depends on their proper differentiation and homing status. Whereas DC-associated tumour-promoting functions are linked to T-cell tolerance and formation of an inflammatory milieu, DC-mediated direct effects on tumour growth have remained unexplored. Here we show that deletion of DCs substantially delays progression of Myc-driven lymphomas. Lymphoma-exposed DCs upregulate immunomodulatory cytokines, growth factors and the CCAAT/enhancer-binding protein β (C/EBPβ). Moreover, Eμ-Myc lymphomas induce the preferential translation of the LAP/LAP* isoforms of C/EBPβ. C/EBPβ(-/-) DCs are unresponsive to lymphoma-associated cytokine changes and in contrast to wild-type DCs, they are unable to mediate enhanced Eμ-Myc lymphoma cell survival. Antigen-specific T-cell proliferation in lymphoma-bearing mice is impaired; however, this immune suppression is reverted by the DC-restricted deletion of C/EBPβ. Thus, we show that C/EBPβ-controlled DC functions are critical steps for the creation of a lymphoma growth-promoting and -immunosuppressive niche.

[Heart involvement in Friedreich's ataxia]

Friedreich's ataxia is a rare hereditary disease and although the gene defect has already been identified as a deficiency of the mitochondrial protein frataxin, the pathophysiology is still unknown. Although a multisystem disorder organ involvement is predominantly neurological. Besides the characteristic features of spinocerebellar ataxia the heart is frequently also affected. Cardiac involvement typically manifests as hypertrophic cardiomyopathy, which can progress to heart failure and death. So far most research has focused on the neurological aspects and cardiac involvement in Friedreich's ataxia has not been systematically investigated. Thus, a better understanding of the progression of the cardiomyopathy, cardiac complications and long-term cardiac outcome is warranted. Although no specific treatment is available general cardiac therapeutic options for cardiomyopathy should be considered. The current review focuses on clinical and diagnostic features of cardiomyopathy and discusses potential therapeutic developments for Friedreich's ataxia.

Angular momentum sensitive two-center interference

In quantum mechanics the Young-type double-slit experiment can be performed with electrons either traveling through a double slit or being coherently emitted from two inversion symmetric molecular sites. In the latter one the valence photoionization cross sections of homonuclear diatomic molecules were predicted to oscillate over kinetic energy almost 50 years ago. Beyond the direct proof of the oscillatory behavior of these photoionization cross sections σ, we show that the angular distribution of the emitted electrons reveals hitherto unexplored information on the relative phase shift between the corresponding partial waves through two-center interference patterns.

Crystal Structure Determination of the Nonclassical 2-Norbornyl Cation

After decades of vituperative debate over the classical or nonclassical structure of the 2-norbornyl cation, the long-sought x-ray crystallographic proof of the bridged, nonclassical geometry of this prototype carbonium ion in the solvated [C7H11]+[Al2Br7]–• CH2Br2salt has finally been realized. This achievement required exceptional treatment. Crystals obtained by reacting norbornyl bromide with aluminum tribromide in CH2Br2undergo a reversible order-disorder phase transition at 86 kelvin due to internal 6,1,2-hydride shifts of the 2-norbornyl cation moiety. Cooling with careful annealing gave a suitably ordered phase. Data collection at 40 kelvin and refinement revealed similar molecular structures of three independent 2-norbornyl cations in the unit cell. All three structures agree very well with quantum chemical calculations at the MP2(FC)/def2-QZVPP level of theory.

[The new OCT generation offers deep insights: imaging of the choroid using the Cirrus OCT]

BACKGROUND

Until now depiction of the choroid using time domain optical coherence tomography (OCT) (Stratus III) was barely possible. Visualization of choroidal perfusion was carried out using indocyanine green angiography (ICGA). The spectral-domain OCT, such as Cirrus OCT (C-OCT) is able to image the choroid better because it offers higher resolution, increased penetration depth of the scan beam and faster acquisition of A-scan data. The aim of the study was to evaluate the potential of choroidal imaging in patients suffering from macular disease.

METHODS

The advanced visualization tool of C-OCT was primarily used and converted to a z-axis topography. Because of a special algorithm developed by our team, targeted imaging of the choroidal vessels was possible through the scanned two dimensional retinal areas. This image offers an extended image of choroidal vessels (large and small vessels) in several levels. In total 20 patients eyes (n = 15 with various macular diseases and n = 5 normal conditions) who underwent C-OCT and ICG angiography (HRA 2) were chosen to participate in this special algorithm. A precise correlation of ICG and choroid OCT in a semitransparent manner was carried out.

RESULTS

The first prototype of the recognition software prototype produced clear imaging of the choroid in 100% of cases but only in 55% in the macular region depending on the extent of macular disease. Limitations were low signal intensity and penetration depth as well as a poorly defined retinal pigment epithelium (RPE) and choriocapillaris especially in macular diseases of the RPE layer. After a black and white conversion in OCT using the software it was possible in all cases to integrate the choroidal OCT with the ICG angiogram in a semitransparent manner. This confirms that the choroidal vessels in C-OCT correlated identically with the ICG angiography. In contrast to the ICG where the contrast agent in the vessel emits a signal, the choroidal vessels are visible due to different reflectivity in the merging tissue.

CONCLUSIONS

These investigations showed that non-invasive topographic imaging of the choroid using spectral domain OCT, such as Cirrus OCT is now possible. Distinguishability of smaller vessels was excellent. The ICG (perfusion) and C-OCT (morphology) methods are two very different vessel imaging techniques. The integration of both methods is possible. The clinical relevance of the new image information still has to be researched.

Study of threading dislocation density reduction in AlGaN epilayers by Monte Carlo simulation of high-resolution reciprocal-space maps of a two-layer system

High-resolution X-ray diffraction in coplanar and noncoplanar geometries has been used to investigate the influence of an SiNxnano-mask in the reduction of the threading dislocation (TD) density of high-quality AlGaN epitaxial layers grown on sapphire substrates. Our developed model, based on a Monte Carlo method, was applied to the simulation of the reciprocal-space maps of a two-layer system. Good agreement was found between the simulation and the experimental data, leading to an accurate determination of the dislocation densities as a function of the overgrowth layer thickness. The efficiency of the SiNxnano-mask was defined as the ratio of the TD densities in the AlGaN layers below and above the mask. A significant improvement in the AlGaN layer quality was achieved by increasing the overgrowth layer thickness, and a TD density reduction scaling law was established.

[EYECUBE as 3D multimedia imaging in macular diagnostics]

BACKGROUND

In the new generation of EYECUBE devices, the angiography image and the OCT are included in a 3D illustration as an integration. Other diagnostic procedures such as autofluorescence and ICG can also be correlated to the OCT. The aim was to precisely classify various two-dimensional findings in relation to each other.

METHOD

The new generation of OCT devices enables imaging with a low incidence of motion artefacts with very good fundus image quality - and with that, permits a largely automatic classification. The feature enabling the integration of the EYECUBE was further developed with new software, so that not only the topographic image (red-free, autofluorescence) can be correlated to the Cirrus OCT, but also all other findings gathered within the same time frame can be correlated to each other. These were brightened and projected onto the cube surface in a defined interval. The imaging procedures can be selected in a menu toolbar. Topographic volumetry OCT images can be overlayed. The practical application of the new method was tested on patients with macular disorders.

RESULTS

By lightening up the results from various diagnostic procedures, it is possible of late to directly compare pathologies to each other and to the OCT results. In all patients (n = 45 eyes) with good single-image quality, the automated integration into the EYECUBE was possible (to a great extent). The application is not dependent on a certain type of device used in the procedures performed.

CONCLUSIONS

The increasing level of precision in imaging procedures and the handling of large data volumes has led to the possibility of examining each macular diagnostics procedure from the comparative perspective: imaging (photo) with perfusion (FLA, ICG) and morphology (OCT). The exclusion of motion artefacts and the reliable scan position in the course of the imaging process increases the informative value of OCT.

FC26-05 - Differences in depression symptoms between RTMS responders and rTMS non-responders in a sample of tinnitus affected people

Introduction

The clinic of psychiatry and psychotherapy and the clinic of otolaryngology of the clinic of Nuremberg offer an interdisciplinary consultation for patients suffering from tinnitus aurium and comorbid major depression and/or insomnia.

Objectives

Prediction variables are needed regarding the treatment of subjective ear noises by low frequency rTMS.

The aim of the present study was to examinea)

Methods

From June 2008 to July 2010 109 outpatients with chronic tinnitus were treated with rTMS (1 Hz, 2000 impulses, intensity 110% motor-treshold, 10 proceedings, stimulation of left auditory cortex). Prior to and afterwards the proceedings clinical assessment regarding the severity of tinnitus (TQ) and depressive symptoms (BDI II, MADRS) took place.

Results

Response to rTMS was defined as reduction in the TQ score of ≥ 5 points (54 responder, 18 female, 36 male; 55 non-responder, 16 female, 39 male). The samples did not differ in age (MR = 56,4, SDR = 13,3; MNR = 57,3, SDNR = 12,2). The subsamples differed significantly regarding depression symptoms before rTMS, as non-responder being more depressive than rTMS-responder (table 1; MADRS: p = 0.008 **; BDI II: p = 0.01**).

Furthermore there is a significant interaction between BDI and the response/non-response criterion indicating a higher decrease of depression symptoms in rTMS responders.

Excitation and De-Excitation Mechanisms of Rare-Earth Ions in III-V Compounds: Optically Detected Microwave-Induced Impact Ionization of Yb Dopant in Inp

The excitation mechanisms of rare-earth dopants in III-V semiconductors are being reviewed. The discussion is focused on ytterbium-doped InP crystals for which a particularly large amount of experimental data has been gathered. Here, the results obtained recently by optically detected microwave-induced impact ionization are being examined in detail. On the basis of the experimental findings it is argued that the intrashell luminescence is excited by an intermediate state involving binding of an exciton. Direct evidence for the existence of such a state, of pseudoacceptor type, will be given. The nonradiative recombination channel responsible for the fast decay of Yb luminescence will also be discussed and, for the first time, evidence for an Auger process will be presented. It will also be shown that the nonradiative channel may be effectively blocked by impact ionization of a participating carrier.

Near-Bandgap Photoluminescence Decay Time in GaN Epitaxial Layers Grown on Sapphire

Using picosecond time-resolved photoluminescence we have studied the decay time of excess carriers in GaN epitaxial layers over a wide range of temperatures from 4 K up to 400 K. At low temperature, a thermal dissociation of donor-bound excitons is observed. At higher temperatures up to room temperature, the luminescence decay at moderate excitation is governed by trapping of photogenerated electrons in ionized shallow donor levels. Using measured luminescence intensities to determine the quantum efficiency, we obtain the radiative lifetime of free excitons from low temperature up to room temperature. We use these data to determine the radiative recombination coefficient and the interband momentum matrix element.

Movpe of Rare Earth Doped III-V Semiconductors

Different III-V compound semiconductors have been doped with the rare earth (RE) elements Yb, Er, and Tm using atmospheric pressure metalorganic vapor phase epitaxy. Best results have been obtained using the novel metalorganic compounds tris-isopropyl-cyclopentadienyl-RE as precursors which have an acceptable vapor pressure and can be used as liquids at bubbler temperatures of 60°-90°C. Only Yb has been found to occupy a regular lattice site in InP, whereas the other RE show complex optical spectra because of their incorporation in form of different centers and clusters.

Influence of Surface Defects on the Characteristics of GaN Schottky Diodes

We have studied the fabrication of Pt/Au Schottky diodes on n-type GaN. We show that the electrical characteristics of the diodes are strongly dependent on the surface chemical treatment before the metal deposition. Lowest leakage currents were obtained by the use of a HC1 solution. We also show that annealing the diode at a moderate temperature (400°C) leads to reduced reverse currents. In order to explain these results, we measured the density of deep levels in the Schottky diode depletion region before and after the annealing process. We did not observe any significant difference in the bulk density of defects due to the anneal. We also studied the temperature dependence of the reverse currents and found a low activation energy. Our results are interpreted in terms of electrical defects at the metal-GaN surface.

Effects of Piezoelectric Fields in GaInN/GaN and GaN/AlGaN Heterostructures and Quantum Wells

The effects of piezoelectric fields on the static and dynamic optical properties of GaInN/GaN and GaN/AIGaN double heterostructures and single quantum wells are studied by time-resolved photoluminescence. We find a strong increase of the luminescence decay time of the dominating transition with well thickness by several orders of magnitude. For well thicknesses larger than about 5 nm, two emission lines with strongly differing decay times are observed, which are attributed to spatially direct and indirect transitions. Our experimental findings are consistently explained by a quantitative model based on the piezoelectric fields in strained wurtzite quantum wells.

Mechanisms of Strain Reduction in GaN and AlGaN/GaN Epitaxial Layers

We have investigated Al0.12Ga0.88N layers with and without a 1 µm GaN buffer, grown on the c-face of α – Al2O3 substrate with an intermediate AlN nucleation layer grown by LP-MOVPE. We used spatially resolved cathodoluminescence spectroscopy at a temperature of 8K to investigate the strain and the homogeneity of composition that can be determined from the energy of the luminescence peak. The larger thermal expansion coefficient of the sapphire in comparison to the nitrides leads to a biaxial compressive strain of the upper GaN layer when cooling down from growth temperature. For AlGaN layers directly grown on the nucleation layer this cannot be confirmed. The layer stays relaxed and fluctuations in the aluminium composition of 0.4% can be observed. When growing an intermediate GaN buffer, the AlGaN layer gets tensilely strained. This strain is of elastic nature and microcracks can be observed preferentially at the edges due to the smaller lattice constant of AlGaN in comparison to GaN. Even detaching of the AlGaN layers grown on the buffer can be observed. In the regions without cracks the layers are quite homogeneous. A deformation potential of (19±4)eV was estimated for Al0.12Ga0.88N.

Metalorganic vapor phase epitaxial growth of GaInN/GaN hetero structures and quantum wells

GaInN/GaN heterostructures and quantum wells have been grown by low pressure metalorganic vapor phase epitaxy on sapphire using an AIN nucleation layer. We found a significant In incorporation only for growth temperatures of 700°C, although still very high In/Ga ratios in the gas phase had to be adjusted. The In content could be increased by reducing the H2/N2 flow ratio in the main carrier gas. GaInN layers typically show two lines in low temperature photoluminescence which are identified as excitonic-like (high energy peak) and impurity-related-like (low energy) by time-resolved spectroscopy. Quantum wells with a thickness between 8 and 0.5 nm showed only one emission line. The peak of the thinnest wells shows excitonic-like behaviour, whereas we found a smooth transition to an impurity-related-like type with increasing thickness. By scanning transmission electron microscopy studies we found indications for composition fluctuations in these thicker quantum wells which may cause localization effects for the excitons and thus be responsible for the observed optical spectra.

Yellow Luminescence and Associated Odmr in Movpe Gan: A Comparison of Defect Models

Two positive ODMR resonances are commonly observed on a luminescence band in GaN at 2.2 eV, one identified as a shallow donor, the other currently unidentified. We here report a study of their dependencies on a variety of experimental parameters, including microwave modulation frequency, microwave power, photoexcitation power and photoexcitation energy. ODMR simulations using two theoretical models are compared to experimental results which are consistent with spin-dependent recombination between the two defects, assuming the donor has a spin-lattice relaxation time shorter than the spin-dependent recombination lifetime. The photoexcitation energy dependence suggests that the spin-dependent recombination associated with the 2.2 eV band is not the same recombination that is responsible for the luminescence. This supports the two stage model put forth by Glaser et al. for the luminescence process.

[Optical coherence tomography for macula diagnostics. Review of methods and standardized application concentrating on diagnostic and therapy control of age-related macula degeneration]

BACKGROUND

Optical coherence tomography (OCT) has gained increasing relevance for follow-up after the treatment of macular diseases especially after anti-VEGF therapy. Therefore it seemed reasonable to develop standardized evaluation strategies and OCT examination guidelines for Stratus OCT III.

MATERIALS AND METHODS

Basic guidelines for the Stratus OCT III examination of macular diseases were developed. The first part contains basic advice for the OCT examination with respect to the examiner, patients, image quality, movement artefacts, algorithms, archiving and interpretation of OCT images. The second part consists of the relevance and indications for OCT examination especially in age-related macular degeneration (AMD), subgroups of AMD and follow-up after treatment. The third part demonstrates a brief outlook on future developments, such as the digital integration method (DIM), which provides identical scan localization in follow-up and eliminates any movement artefacts.

CONCLUSION

The application of standardized routine scanning and analysis protocols in Stratus OCT III for macular diseases and follow-up examinations provides an optimized, time-saving and comparable use of OCT. Therefore, the relevance and quality of OCT is increased for routine use in outpatient departments, hospitals and also for clinical studies.

Walter Krösche (1882-1957) and the Mannich reaction

Walter Krösche was the Ph.D. student of Carl Mannich, with whom the latter published the school forming paper where the first 'Mannich reaction' has been described. For the first time biographic details and photos of Krösche are published here in a short biographic sketch.