Epitaxial growth and characterization of multi-layer site-controlled InGaAs quantum dots based on the buried stressor method

We report on the epitaxial growth, theoretical modeling, and structural as well as optical investigation of multi-layer, site-controlled quantum dots fabricated using the buried stressor method. This advanced growth technique utilizes the strain from a partially oxidized AlAs layer to induce site-selective nucleation of InGaAs quantum dots. By implementing strain-induced spectral nano-engineering, we achieve separation in emission energy by about 150 meV of positioned and non-positioned quantum dots and a local increase of the emitter density in a single layer. Furthermore, we achieve a threefold increase of the optical intensity and reduce the inhomogeneous broadening of the ensemble emission by 20% via stacking three layers of site-controlled emitters, which is particularly valuable for using the SCQDs in microlaser applications. Moreover, we obtain direct control over emission properties by adjusting the growth and fabrication parameters. Our optimization of site-controlled growth of quantum dots enables the development of photonic devices with enhanced light-matter interaction and microlasers with increased confinement factor and spontaneous emission coupling efficiency

Glycan-specific IgG anti-IgE autoantibodies are protective against allergic anaphylaxis in a murine model.

BACKGROUND IgE causes anaphylaxis in type-1 hypersensitivity diseases by activating degranulation of effector cells such as mast cells and basophils. The mechanisms that control IgE activity and prevent anaphylaxis under normal conditions are still enigmatic. OBJECTIVE We aimed to unravel how anti-IgE autoantibodies are induced and understand their role in regulating serum IgE level and allergic anaphylaxis. METHODS We immunized mice with different forms of IgE and tested anti-IgE autoantibody responses and their specificities. We then analysed the effect of those antibodies on serum kinetics and their in vitro and in vivo impact on anaphylaxis. Finally, we investigated anti-IgE autoantibodies in human sera. RESULTS Immunization of mice with IgE-immune complexes induced glycan-specific anti-IgE autoantibodies. The anti-IgE autoantibodies prevented effector cell sensitization, reduced total IgE serum levels, protected mice from passive and active IgE sensitization, and resulted in cross-protection against different allergens. Furthermore, glycan-specific anti-IgE autoantibodies were present in sera from allergic and non-allergic subjects. CONCLUSION In conclusion, we provide first evidence that in the murine model the serum level and anaphylactic activity of IgE may be down-regulated by glycan-specific IgG anti-IgE autoantibodies

The surface-associated exopolysaccharide of Bifidobacterium longum 35624 plays an essential role in dampening host proinflammatory responses and repressing local TH17 responses

The immune-modulating properties of certain bifidobacterial strains, such as Bifidobacterium longum subsp. longum 35624 (B. longum 35624), have been well described, although the strain-specific molecular characteristics associated with such immune-regulatory activity are not well defined. It has previously been demonstrated that B. longum 35624 produces a cell surface exopolysaccharide (sEPS), and in this study, we investigated the role played by this exopolysaccharide in influencing the host immune response. B. longum 35624 induced relatively low levels of cytokine secretion from human dendritic cells, whereas an isogenic exopolysaccharide-negative mutant derivative (termed sEPSneg) induced vastly more cytokines, including interleukin-17 (IL-17), and this response was reversed when exopolysaccharide production was restored in sEPSneg by genetic complementation. Administration of B. longum 35624 to mice of the T cell transfer colitis model prevented disease symptoms, whereas sEPSneg did not protect against the development of colitis, with associated enhanced recruitment of IL-17+ lymphocytes to the gut. Moreover, intranasal administration of sEPSneg also resulted in enhanced recruitment of IL-17+ lymphocytes to the murine lung. These data demonstrate that the particular exopolysaccharide produced by B. longum 35624 plays an essential role in dampening proinflammatory host responses to the strain and that loss of exopolysaccharide production results in the induction of local TH17 responses. IMPORTANCE: Particular gut commensals, such as B. longum 35624, are known to contribute positively to the development of mucosal immune cells, resulting in protection from inflammatory diseases. However, the molecular basis and mechanisms for these commensal-host interactions are poorly described. In this report, an exopolysaccharide was shown to be decisive in influencing the immune response to the bacterium. We generated an isogenic mutant unable to produce exopolysaccharide and observed that this mutation caused a dramatic change in the response of human immune cells in vitro. In addition, the use of mouse models confirmed that lack of exopolysaccharide production induces inflammatory responses to the bacterium. These results implicate the surface-associated exopolysaccharide of the B. longum 35624 cell envelope in the prevention of aberrant inflammatory responses

Role of the gene At1g64110 for the development of syncytia induced by Heterodera schachtii in Arabidopsis roots

Nematoden der Gattung Heterodera schachtii infizieren neben vielen anderen Pflanzen auch die Modellpflanze Arabidopsis thaliana. Der Schädling induziert in der Pflanzenwurzel den Aufbau eines Nährzellensystems (Synzytium), welches für die künftige Nährstoffversorgung des Nematoden dient. Vorhergehende Transkriptomanalysen von Synzytien haben offen gelegt, welche Gene im Nährzellensystem in ihrer Transkriptionsrate verändert werden. Ein stark hochreguliertes Gen, das Gen At164110, codiert für eine ATPase. Infektionsversuche von Heterodera schachtii an At1g64110 T-DNA Mutanten haben gezeigt, dass dieses Gen für die Entwicklung von Nematoden eine wichtige Rolle spielt. Ziel dieser Masterarbeit war es, transgene Arabidopsis Linien bereitzustellen, um eine Funktionsanalyse sowie eine Expressionsanlyse an dem Gen At1g64110 durchführen zu können. Für die Funktionsanalyse wurden künstliche Mikro-RNA Konstrukte mit gewebespezifischen Promotoren kombiniert, um das Gen zum einen in der gesamten Pflanze (Promotor CaMV) zum anderen nur im Synzytium (Promotor MIOX5, Promotor PDF2.1) runterzuregulieren. Die Konstrukte wurden erfolgreich in Arabidopsis transformiert und 15 verschiedene T1 Arabidopsis Linien für die Funktionsanalysen selektiert. Für die Expressionsanalyse wurden drei Promotor::GUS Konstrukte mit unterschiedlicher Promotor Länge hergestellt und erfolgreich in Arabidopsis transformiert. Eine vorläufige Analyse von zufällig ausgewählten T1 Arabidopsis Pflanzen hat eine transgene Promotoraktivität in Trichomen und Schoten gezeigt. 15 verschieden T1 Arabidopsis Linien wurden für weiterführende GUS Expressionsanalysen selektiert. Zusätzlich wurde die vorhergehende Transkriptomanalyse für das Gene At1g64110 über quantitative Real Time PCR (qRT PCR) bestätigt. Die qRT-PCR zeigte eine 97,2-fache Hochregulierung des Gens in 15 Tage alten Synzytien im Vergleich zu nicht infizierten Kontrollwurzeln. Außerdem wurde gefunden, dass das nahe verwandte Gen At5g52882 sehr große Ähnlichkeit zu At1g64110 aufwies, jedoch dafür keine GeneChip Daten vorhanden waren. In der Vermutung, dass auch dieses Gen im Synzytium stärker exprimiert werden könnte, wurde eine qRT-PCR durchgeführt. Die Analyse zeigte weder eine Hochregulierung noch eine Runterregulierung von At5g2882 in 15 Tage alten Synzytien im Vergleich zu nicht infizierten Kontrollwurzeln.The plant parasitic nematode Heterodera schachtii infects several crop species and also the model plant Arabidopsis thaliana. The parasites induce the formation of specific feeding structures (syncytia) in the plant roots that serve as their sole nutrient source. Previous transcriptome analysis has shown that many genes are up regulated and down regulated in syncytia. One of the strongly up regulated genes, At1g64110, codes for an ATPase. Infection tests of At1g64110 T-DNA mutants with Heterodera schachtii revealed that this gene is important for nematode development. The aim of this thesis was to prepare transgenic Arabidopsis lines for a functional analysis and for a expression analysis of At1g64110. For the functional analysis, artificial microRNA constructs with tissue specific promoters were created to silence the gene in the whole plant (promoter CaMV) and in syncytia (Promoter MIOX5, Promoter PDF2.1). The constructs were successfully transformed into Arabidopsis. 15 T1 Arabidopsis lines for each construct were isolated for further studies. For the expression analysis three promoter::GUS constructs with different length were created and also transformed into Arabidopsis. Preliminary analysis of randomly selected T1 Arabidopsis plants showed transgenic promoter activity in trichomes and siliques. 15 T1 Arabidopsis lines for each construct were isolated for further GUS expression analysis. Moreover, the previous transcriptome analysis for the gene At1g64110 was confirmed by quantitative real time PCR (qRT PCR) during this project. The qRT-PCR showed a 97.2-fold up regulation of the gene in 15 dpi (days post infection) syncytia in comparison to uninfected roots which is in line with the previous GeneChip data. The gene At5g52882 was found to be highly similar to the gene At1g64110, but as no transcriptome expression data were available for this gene a qRT-PCR was done. The analysis showed no change in expression levels of this gene in 15 dpi syncytia in comparison to normal roots.Stephan PlattnerZsfassung in dt. SpracheWien, Univ. für Bodenkultur, Masterarb., 2009(VLID)103158

The deadly broomstick: an unusual missile injury to the neck

A 51-year-old man was struck by the tip of a broomstick weighing 1000 g at the left side of the neck, upon which he collapsed. Intense but delayed cardiopulmonary resuscitation restored the circulation roughly 30 minutes after the incident. Upon admittance to a nearby hospital, an extensive hypoxic cerebral damage was diagnosed. Death due to the severe cerebral damage occurred 5 hours after the incident. An autopsy demonstrated a severe subcutaneous traumatization of the left side of the neck, with a hemorrhage compressing the carotid bifurcation. A prolonged excitation due to this ongoing compression of the baroreceptors in the carotid sinus was assumed to have led to a cardiac arrest. In this case report, the authors discuss the underlying pathophysiology of this potentially lethal and rare reflexogenic incident also known as the Hering reflex and discuss possible therapeutic measures

Polysaccharides from European Black Elderberry Extract Enhance Dendritic Cell Mediated T Cell Immune Responses

European black elderberry (Sambucus nigra L.) is a popular way to treat common colds or influenza infections. Mechanistically, this might be due to a direct antiviral effect or a stimulatory effect on the immune system of the host. Here, we evaluated the modulatory effects of black elderberry derived water extract (EC15) and its polysaccharide enriched fractions (CPS, BOUND, and UNBOUND) in comparison to a conventional alcoholic extract (EE25), regarding the phenotypical and functional properties of dendritic cells (DCs), which are essential cells to induce potent T cell responses. Interestingly, the water extract and its polysaccharide fractions potently induced DC maturation, while the ethanol extract did not. Moreover, the capacity to stimulate T cells by these matured DCs, as assessed using MLR assays, was statistically higher when induced by the water extracted fractions, compared to immature DCs. On the other hand, the ethanol extract EE25 did not induce T cell stimulation. Finally, the cytokine expression profiles of these DC—T cell cocultures were assessed and correlated well with increased T cell stimulation. Also, the expression of inflammatory cytokines, such as IL-6, TNF-α, and IFN-γ was highly increased in the presence of the elderberry water extract EC15, and the polysaccharide enriched CPS, BOUND, and UNBOUND fractions, but not by EE25. Thus, from these data, we conclude that the polysaccharides present in water-derived elderberry fractions induce potent immune-modulatory effects, which represents the basis for a strong immune-mediated response to viruses including influenza

Elevated body core temperature in medico-legal investigation of violent death

Pathologically elevated body core temperature, measured at the death scene, is an important finding in medico-legal investigation of violent deaths. An abnormally high rectal temperature at any death scene may point to an underlying pathology, the influence of certain drugs or a hidden cerebral traumatism, and death by suffocation which would remain undetected without further medico-legal investigations. Furthermore, hyperthermia and fever, if unrecognized, may result in an erroneous forensic estimation of time since death in the early postmortem period by the "Henssge method." By a retrospective study of 744 cases, the authors demonstrate that hyperthermia is a finding with an incidence of 10% of all cases of violent death. The main causes are: influence of drugs, malignant tumors, cerebral hypoxia as a result of suffocation, infections, and systemic inflammatory disorders. As a consequence it must be stated, that hyperthermia must be excluded in every medico-legal death scene investigation by a correct measurement of body core temperature and a comparison between the cooling rate of the body and the behavior of early postmortem changes, notably livor and rigor mortis

Polysaccharides from European Black Elderberry Extract Enhance Dendritic Cell Mediated T Cell Immune Responses

European black elderberry (Sambucus nigra L.) is a popular way to treat common colds or influenza infections. Mechanistically, this might be due to a direct antiviral effect or a stimulatory effect on the immune system of the host. Here, we evaluated the modulatory effects of black elderberry derived water extract (EC15) and its polysaccharide enriched fractions (CPS, BOUND, and UNBOUND) in comparison to a conventional alcoholic extract (EE25), regarding the phenotypical and functional properties of dendritic cells (DCs), which are essential cells to induce potent T cell responses. Interestingly, the water extract and its polysaccharide fractions potently induced DC maturation, while the ethanol extract did not. Moreover, the capacity to stimulate T cells by these matured DCs, as assessed using MLR assays, was statistically higher when induced by the water extracted fractions, compared to immature DCs. On the other hand, the ethanol extract EE25 did not induce T cell stimulation. Finally, the cytokine expression profiles of these DC—T cell cocultures were assessed and correlated well with increased T cell stimulation. Also, the expression of inflammatory cytokines, such as IL-6, TNF-α, and IFN-γ was highly increased in the presence of the elderberry water extract EC15, and the polysaccharide enriched CPS, BOUND, and UNBOUND fractions, but not by EE25. Thus, from these data, we conclude that the polysaccharides present in water-derived elderberry fractions induce potent immune-modulatory effects, which represents the basis for a strong immune-mediated response to viruses including influenza