Structural characterization of antimonide-based metamorphic buffer layers on (001) silicon substrate

The aim of the present study was the growth of antimony-based buffer layers with the lattice constant of InP on a GaP/Si pseudosubstrate by metal organic vapor phase epitaxy (MOVPE) and their structural investigation by atomic force microscopy (AFM), X-ray diffraction (XRD), and (scanning) transmission electron microscopy ((S)TEM). The purpose of these buffer layers was to overcome the lattice mismatch between Si and InP and to provide a smooth surface for the growth of n-doped (GaIn)As channel layers with a lattice constant of InP on a Si substrate. The growth of Sb-based buffer layers on GaP/Si pseudosubstrate is very challenging. The main problem was the island-like nucleation that occurs for Ga(PSb), Ga(AsSb) as well as GaSb on GaP/Si. The islands had different degrees of relaxation. The atomic resolution HAADF investigations have shown that the islands not only have Lomer but also 60° dislocations and 60° dislocation pairs at the interface. Additionally, they were relaxed by plastic relaxation due to the free surface as well as by the formation of stacking faults. It has been shown that the interface roughness increases for the ternary material system Ga(PSb)/GaP compared to the binary GaSb/GaP and is most severe for the Ga(AsSb)/GaP, where the group V atoms are completely exchanged from P to (AsSb). With increasing growth time, the sizes of the islands increased until they coalesced. The degree of relaxation increased with an increasing degree of coalescence. The density of stacking fault as well as threading dislocation densities were in the order of 10^10/cm^2. In addition, a low Sb-content layer that grew pseudomorphically onto GaP was observed for Ga(PSb) layers. The island-like nucleation of Ga(PSb) could neither be overcome by introducing a pseudomorphically grown Ga(PSb) interlayer with a low Sb-content between the metamorphic Ga(PSb) and the GaP layer nor by utilizing a flow rate modulated epitaxy. The most promising approach had been the introduction of an InP layer that showed a 2D-nucleation on the GaP/Si pseudosubstrate. If the growth conditions are optimized so that the relaxation of the layer will take place without the formation of lattice defects such as stacking faults or threading dislocations, the InP/GaP/Si pseudosubstrate will be a very promising growth template for the (GaIn)As channel layers

First Insights into Barriers and Facilitators from the Perspective of Persons with Multiple Sclerosis: A Multiple Case Study

Multiple Sclerosis (MS) is a complex, lifelong disease. Its effects span across different areas of life and vary strongly. In Switzerland, there is an intense discussion on how to optimize quality of care and patient safety. Patients should be more involved in the management of health care to improve the quality of care from the patient's perspective and form a more comprehensive perspective. This multiple-case study explores the question of how persons with MS experience and describe functioning related barriers, facilitating factors, and ethically relevant conflicts. To address this from a comprehensive perspective, the MS core set of the International Classification for Functioning, Disability, and Health (ICF) is used as theoretical framework. To explore barriers, facilitators, and relevant ethical issues, different narrative sources were used for thematic analysis and ICF coding: (a) MS transcripts from DIPEx interviews and (b) an autobiographical book of persons living with MS. Insights that were meaningful for daily practice and education were identified: (a) understanding the importance of environmental circumstances based on narrative sources; (b) understanding the importance of a person's individual life situation, and the ability to switch perspectives in the medical field; (c) respect for PwMS' individuality in health care settings; (d) creating meaningful relationships for disease management and treatment, as well as building trust. Keywords: DIPEx; ICF; ethics; multiple case study; multiple sclerosis; narration; patient experience; patient perspective; qualitative research methods; source analysis; thematic analysi

Zytokinmuster bei chronisch-entzündlichen Darmerkrankungen im Kindes- und Jugendalter

Die weltweit steigende Prävalenz chronisch entzündlicher Darmerkrankungen (CED) erhöht die Relevanz für eine frühzeitige und zielgerichtete Diagnostik und Therapie beim Morbus Crohn (MC) und der Colitis ulcerosa (CU). Die Differenzierung zwischen diesen beiden Hauptentitäten, welche bei teils sehr ähnlicher klinischer Symptomatik einen unterschiedlichen Verlauf zeigen und auch unterschiedliche Therapiestrategien erfordern, erweist sich vor allem zu Beginn der Erkrankung häufig als schwierig bis unmöglich. Bisher erfolgen die Verlaufsbeurteilung und Steuerung der Therapie unter Zuhilfenahme des fäkalen Calprotectins, einem relativ unspezifischen Biomarker, welcher mit der granulozytären Aktivierung im Gastrointestinaltrakt korreliert und somit die intestinale inflammatorische Aktivität widerspiegelt. Insbesondere bei pädiatrischen Patienten, bei welchen eine chronisch-entzündliche Darmerkrankung verglichen mit adulten Patienten mit mehr Komplikationen und weitreichenderen Folgen einhergeht, gilt es deshalb, einen möglichst wenig invasiven, spezifischen, sensitiven, kostengünstigen und gut verfügbaren Biomarker zu finden, welcher Diagnostik und Verlaufsbeurteilung erleichtern und somit eine frühzeitige individuelle Therapie ermöglichen kann. Zytokine sind Proteine, die im Körper eine wichtige Rolle im Rahmen der Kommunikation zwischen Zellen des Immunsystems innehaben, weswegen Erkenntnisse über Zytokinprofile ein besseres Verständnis der immunologischen Abläufe und der Pathogenese von Erkrankungen ermöglichen. Ziel der Studie war es aus diesem Grund, herauszufinden, ob Unterschiede in den Zytokinprofilen des MC und der CU bestehen, und inwiefern diese mit den bisher etablierten Biomarkern Calprotectin und C-reaktives Protein (CRP) sowie den klinischen Aktivitätsscores Pediatric Crohn's Disease Activity Index (PCDAI) und Pediatric Ulcerative Colitis Activity Index (PUCAI) korrelieren. Es wurden 23 MC- und 10 CU-Patienten der Kinder- und Jugendklinik am Universitätsklinikum des Saarlandes im Alter zwischen 9 und 19 Jahren in die Studie eingeschlossen, welchen im Rahmen von Routineuntersuchungen sowie krankheitsbedingten 2 Aufenthalten im Krankenhaus Blut entnommen wurde. Insgesamt wurden 145 Blutproben abgenommen, welche nach der Blutentnahme zentrifugiert und bis zur weiteren Verarbeitung aufbewahrt wurden. Zudem wurden das fäkale Calprotectin und das CRP bestimmt sowie je nach Krankheitsentität der PCDAI oder der PUCAI erhoben. Beim PCDAI und PUCAI handelt es sich um die beiden gebräuchlichsten Aktivitätsscores für den MC und die CU in der Pädiatrie. Beide Scores dienen der Abschätzung des Schweregrades der CED des jeweiligen Patienten und beinhalten Faktoren aus der Anamnese und klinischen Untersuchung sowie Laborwerte. Anhand von Literaturrecherche wurde ein möglichst breites Spektrum an Zytokinen im Serum untersucht: Wir untersuchten die proinflammatorischen Zytokine Interleukin-1α (IL-1α), Interleukin-1β (IL-1β), Interleukin-6 (IL-6), Interleukin-12p40 (IL-12p40), Interferon gamma-induced protein 10 (IP-10), Tumornekrosefaktor-α (TNF-α), Interferon-γ (IFN-γ), das antiinflammatorisch wirksame Interleukin-10 (IL-10) sowie die Chemokine Interleukin-8 (IL-8), Macrophage inflammatory protein-1α (MIP-1α), Monocyte chemotactic protein-1 (MCP-1), Monocyte chemotactic protein-3 (MCP-3) als auch die Wachstumsfaktoren Granulocyte colony-stimulating factor (G-CSF) und Granulocyte macrophage colony-stimulating factor (GM-CSF). Die Zytokine wurden mittels Multiplexanalyse (Luminex®) quantifiziert. Beim Vergleich der beiden Entitäten MC und CU zeigten sich das MIP-1α und das MCP-3 beim MC sowie das Calprotectin bei der CU signifikant erhöht. Bei isolierter Betrachtung der Aktivitätsphasen fanden wir das MCP-3 beim MC in der Remission verglichen mit dem Schub signifikant erhöht. Das Calprotectin war bei der CU im Schub verglichen mit der Remission signifikant erhöht. Ein Vergleich der beiden Aktivitätsphasen unabhängig von der Krankheitsentität ergab eine signifikante Erhöhung von IP-10 und CRP im Schub. Bei isolierter Betrachtung der Krankheitsentitäten zeigten sich signifikante Erhöhungen des IP-10 beim MC sowie des CRP bei der CU. Zusätzlich konnten wir zeigen, dass die Zytokine IL-8 und G-CSF sowie das CRP positiv mit dem PUCAI korrelieren. Des Weiteren fand sich unabhängig von Krankheitsentität und Aktivitätsphase ein positiver Zusammenhang zwischen den beiden Zytokinen IL-6 und G-CSF mit dem CRP sowie eine positive Korrelation zwischen den beiden Biomarkern CRP und Calprotectin. Weitere Untersuchungen sind notwendig, um den Verlauf der Zytokinspiegel im Krankheitsverlauf und in Abhängigkeit der Therapie noch besser zu charakterisieren. Hieraus könnten sich Hinweise auf die Pathogenese und auf neue Therapieansätze ergeben.The increasing prevalence of inflammatory bowel disease (IBD) worldwide increases the relevance for early and targeted diagnosis and therapy of Crohn's disease (CD) and ulcerative colitis (UC). The differentiation between these two main entities, which in some cases show a different course with very similar clinical symptoms and also require different therapeutic strategies, often proves to be difficult or even impossible, especially at the beginning of the disease. Till now, the assessment and management of the course of the disease is based on faecal calprotectin, a relatively unspecific biomarker that correlates with granulocyte activation in the gastrointestinal tract and thus reflects the intestinal inflammatory activity. Especially in paediatric patients, in whom chronic inflammatory bowel disease is associated with more complications and far-reaching consequences compared to adult patients, it is therefore important to find a biomarker that is as non-invasive, specific, sensitive, cost-effective and readily available as possible, which can facilitate diagnosis and assessment of the course of the disease and thus enable early individualized therapy. Cytokines are proteins that play an important role in communication between cells of the immune system. Therefore knowledge about cytokine profiles enables a better understanding of immunological processes and pathogenesis of diseases. Thus, the aim of the study was to find out whether there are differences in the cytokine profiles of CD and UC, and how they correlate with the established biomarkers calprotectin and C-reactive protein (CRP) as well as the clinical activity scores Paediatric Crohn's Disease Activity Index (PCDAI) and Paediatrics Ulcerative Colitis Activity Index (PUCAI). The study included 23 CD and 10 UC patients aged 9 to 19 years from the Children’s and Adolescent Clinic at Saarland University Hospital, from whom blood was collected during routine examinations and hospitalizations due to illness. A total of 145 blood samples were collected, which were centrifuged after blood collection and stored until further processing. In addition, faecal calprotectin and CRP were determined and, depending on the disease entity, PCDAI or PUCAI were collected. PCDAI and PUCAI are the two most common activity scores for the CD and the UC in paediatrics. Both scores are used to estimate the severity of the patient’s IBD and include factors from the patient’s medical history and clinical examination as well as laboratory scores. 4 Based on literature research, the broadest possible spectrum of cytokines in serum was examined: We examined the proinflammatory cytokines interleukin-1α (IL-1α), interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-12p40 (IL-12p40), interferon-gamma induced protein 10 (IP-10), tumour necrosis factor-α (TNF-α), interferon-γ (IFN-γ), the anti-inflammatory interleukin-10 (IL-10) and the chemokines interleukin 8 (IL-8), macrophage inflammatory protein-1α (MIP-1α), monocyte chemotactic protein-1 (MCP-1), monocyte chemotactic protein-3 (MCP-3) as well as the growth factors granulocyte colony-stimulating factor (G-CSF ) and granulocyte-macrophage colony-stimulating factor (GM-CSF). The cytokines were quantified by means of multiplex analysis (Luminex®). The comparison of the two entities CD and UC showed significant increases in MIP-1α and MCP-3 in CD and calprotectin in UC. In isolated observation of the activity phases we found a significant increase in MCP-3 in CD in remission compared to the relapse. The calprotectin was significantly increased in UC in relapse compared to remission. A comparison of the two activity phases, independent of the disease entity, revealed a significant increase in IP-10 and CRP in the relapse. In an isolated analysis of the disease entities significant increases in IP-10 in CD and CRP in UC were found. Additionally, we could show that the cytokines IL-8 and G-CSF as well as the CRP correlate positively with the PUCAI. Furthermore, we found a positive correlation between the two cytokines IL-6 and G-CSF with the CRP and a positive correlation between the two biomarkers CRP and calprotectin independent of disease entity and activity phase. Further investigations are necessary to better characterize the course of cytokine levels in the course of the disease and in dependence of the therapy. This could provide information on pathogenesis and lead to new therapeutic approaches

Magneto-optical behaviour of EuIn_2P_2

We report results of a magneto-optical investigation of the Zintl-phase compound EuIn$_2$P$_2$. The compound orders magnetically at $T_C$=24 K and exhibits concomitant large magnetoresistance effects. For $T\le$50 K and increasing magnetic fields we observe a transfer of spectral weight in $\sigma_1(\omega)$ from energies above 1 eV into the low-energy metallic component as well as into a mid-infrared signal centered at about 600 cm$^{-1}$. This latter absorption is reminiscent to what has been seen in a large variety of so-called Kondo materials and ascribed to excitations across the hybridization gap. The observed gain of Drude weight upon increasing magnetic field suggests an enhancement of the itinerant charge-carrier concentration due to the increasing magnetization, a phenomenon that was previously observed in other compounds which exhibit colossal magnetoresistive effects.Comment: 13 pages, 4 figure

In-situ Clean-up and OPLC Fractionation of Chamomile Flower Extract Searching Active Components by Bioautography

Bioassay-guided isolation of antibacterial components of chamomile flower methanol extract was performed by OPLC with on-line detection, fractionation combined with sample clean-up in-situ in the adsorbent bed after sample application. The antibacterial effect of the fractions and the separated compounds remained on the adsorbent layer (do not overrun during OPLC separation) was tested with direct bioautography (DB) against the bioluminescent Pseudomonas savastanoi pv. maculicola and Vibrio fischeri. The fractions with great biologically activity were analysed by SPME-GC-MS and LC-MS/MS and the two active uneluted compounds were characterized by OPLC-MS using interface. Mainly essential oil components, coumarins, flavonoids, phenolic acids and fatty acids were identified in the fractions

The Explicit Wake Parametrisation V1.0: a wind farm parametrisation in the mesoscale model WRF

We describe the theoretical basis, implementation, and validation of a new parametrisation that accounts for the effect of large offshore wind farms on the atmosphere and can be used in mesoscale and large-scale atmospheric models. This new parametrisation, referred to as the Explicit Wake Parametrisation (EWP), uses classical wake theory to describe the unresolved wake expansion. The EWP scheme is validated for a neutral atmospheric boundary layer against filtered in situ measurements from two meteorological masts situated a few kilometres away from the Danish offshore wind farm Horns Rev I. The simulated velocity deficit in the wake of the wind farm compares well to that observed in the measurements, and the velocity profile is qualitatively similar to that simulated with large eddy simulation models and from wind tunnel studies. At the same time, the validation process highlights the challenges in verifying such models with real observations