1,007 research outputs found
Some distance bounds of branching processes and their diffusion limits
We compute exact values respectively bounds of "distances" - in the sense of
(transforms of) power divergences and relative entropy - between two
discrete-time Galton-Watson branching processes with immigration GWI for which
the offspring as well as the immigration is arbitrarily Poisson-distributed
(leading to arbitrary type of criticality). Implications for asymptotic
distinguishability behaviour in terms of contiguity and entire separation of
the involved GWI are given, too. Furthermore, we determine the corresponding
limit quantities for the context in which the two GWI converge to Feller-type
branching diffusion processes, as the time-lags between observations tend to
zero. Some applications to (static random environment like) Bayesian decision
making and Neyman-Pearson testing are presented as well.Comment: 45 page
Species-specific evolution of immune receptor tyrosine based activation motif-containing CEACAM1-related immune receptors in the dog
Background: Although the impact of pathogens on the evolution of the mammalian immune system is still under debate, proteins, which both regulate immune responses and serve as cellular receptors for pathogens should be at the forefront of pathogen-driven host evolution. The CEA ( carcinoembryonic antigen) gene family codes for such proteins and indeed shows tremendous species-specific variation between human and rodents. Since little is known about the CEA gene family in other lineages of placental mammals, we expected to gain new insights into the evolution of the rapidly diverging CEA family by analyzing the CEA family of the dog. Results: Here we describe the complete CEA gene family in the dog. We found that the gene coding for the ITIM-bearing immunoregulatory molecule CEACAM1 gave rise to a recent expansion of the canine CEA gene family by gene duplication, similar to that previously found in humans and mice. However, while the murine and human CEACAMs (carcinoembryonic antigen-related cell adhesion molecules) are predominantly secreted and GPI-anchored, respectively, in the dog, most of the CEACAMs represent ITAM-bearing transmembrane proteins. One of these proteins, CEACAM28, exhibits nearly complete sequence identity with the ligand-binding N domain of CEACAM1, but antagonizing signaling motifs in the cytoplasmic tail. Comparison of nonsynonymous and synonymous substitutions indicates that the CEACAM28 N domain is under the strongest purifying selection of all canine CEACAM1-related CEACAMs. In addition, CEACAM28 shows a similar expression pattern in resting immune cells and tissues as CEACAM1. However, upon activation CEACAM28 mRNA and CEACAM1 mRNA are differentially regulated. Conclusion: Thus, CEACAM1 and CEACAM28 are the first paired immune receptors identified within the CEA gene family, which are expressed on T cells and are most likely involved in the fine-tuning of T cell responses. The direction of gene conversion accompanied by purifying selection and expression in immune cells suggests the possibility that CEACAM28 evolved in response to selective pressure imposed by species-specific pathogens
Measurement of motherinfant interactions and the home environment in a European setting: preliminary results from a cross-cultural
Background: Infant development is adversely affected in the context of postnatal depression. This relationship may be mediated by both the nature of early motherinfant interactions and the quality of the home environment.
Aim: To establish the usefulness of the Global Ratings Scales of MotherInfant Interaction and the InfantToddler version of the Home Observation for the Measurement of the Environment (ITHOME), and to test expected associations of the measures with characteristics of the social context and with major or minor depression.
Method: Both assessments were administered postnatally in four European centres; 144 mothers were assessed with the Global Ratings Scales and 114 with the ITHOME. Affective disorder was assessed by means of the Structured Clinical Interview for DSMIV Disorders.
Results: Analyses of motherinfant interaction indicated no main effect for depression but maternal sensitivity to infant behaviour was associated with better infant communication, especially for women who were not depressed. Poor overall emotional support also reduced sensitivity scores. Poor support was also related to poorer ITHOME scores, but there was no effect of depression.
Conclusions: The Global Ratings Scales were effectively applied but there was lessCIHR184pub152
Use of Cyclic Simple Shear Testing in Evaluation of the Deformation Potential of Liquefiable Soils
In recent years, a significant research effort has been focused on assessing the performance of structures founded on potentially liquefiable materials. While significant progress has been made on predictive tools for cases in which large deformations are likely, the ability to accurately and reliably predict small to moderate lateral deformations (\u3c1m) has proven more elusive. As a result, there is a universal need for high quality, element-level laboratory test data to calibrate and validate constitutive laws and numerical models for predicting the deformation of soil with limited liquefaction potential. To address this increasingly urgent need, a comprehensive cyclic simple shear testing program on liquefiable sands has been undertaken using the UC Berkeley Bi-directional Simple Shear Device. Many of the tests performed have new and innovative aspects that can provide information and insight into the behavior of soils showing limited deformation potential. Descried in this paper are results from a Kα test series, which replicates sloping ground conditions, and a newly developed and innovative “fabric” test series, which examines the influence of previous loading history on soil fabric and behavior
Metabolic characterization of directly reprogrammed renal tubular epithelial cells (iRECs)
Fibroblasts can be directly reprogrammed to induced renal tubular epithelial cells (iRECs) using four transcription factors. These engineered cells may be used for disease modeling, cell replacement therapy or drug and toxicity testing. Direct reprogramming induces drastic changes in the transcriptional landscape, protein expression, morphological and functional properties of cells. However, how the metabolome is changed by reprogramming and to what degree it resembles the target cell type remains unknown. Using untargeted gas chromatography-mass spectrometry (GC-MS) and targeted liquid chromatography-MS, we characterized the metabolome of mouse embryonic fibroblasts (MEFs), iRECs, mIMCD-3 cells, and whole kidneys. Metabolic fingerprinting can distinguish each cell type reliably, revealing iRECs are most similar to mIMCD-3 cells and clearly separate from MEFs used for reprogramming. Treatment with the cytotoxic drug cisplatin induced typical changes in the metabolic profile of iRECs commonly occurring in acute renal injury. Interestingly, metabolites in the medium of iRECs, but not of mIMCD-3 cells or fibroblast could distinguish treated and non-treated cells by cluster analysis. In conclusion, direct reprogramming of fibroblasts into renal tubular epithelial cells strongly influences the metabolome of engineered cells, suggesting that metabolic profiling may aid in establishing iRECs as in vitro models for nephrotoxicity testing in the future
Tests on fast heating for the regeneration process of ITER cryopumps
Tests zum schnellen Heizen fĂĽr die Regeneration von ITER-Kryopumpen
Im Rahmen des \u27European Fusion Technology Programme\u27 werden Arbeiten zur Entwicklung einer Primärvakuumpumpe für den ITER-Reaktor durchgeführt. Weil das in den Pumpen akkumulierte Tritiuminventar begrenzt werden muß, sind kurze Pumpzyklen nötig. Somit ergeben sich für die diskontinuierlich arbeitenden Kryopumpen Regenerationszeiten von nur ca. 4 min; davon stehen für die Heizung von LHe-Temperatur (4.2 K) auf LN2-Temperatur (77 K) etwa 60 s zur Verfügung.
In Komponententests wurden dazu schnelle Heiztechniken getestet. Die Versuche fanden in der Anlage TITAN statt. Wie im ursprünglichen Konzept festgelegt, wurde als Testgegenstand ein aus 7 Strömungskanälen bestehendes LHe-gekühltes Panel in \u27quilted design\u27 (500x350 mm2) verwendet. Im weiteren Planungsfortschritt ergab sich inzwischen, daß Panels mit weniger Kanälen ausreichen. Das Testpanel wurde in einer Umgebung bei LN2-Temperatur eingebaut, die als erste Pumpstufe wirkt. Nach dem Erstellen einer Vorstudie wurden ausführliche Testreihen mit drei verschiedenen Heizverfahren durchgeführt.
Zunächst wurde die schnelle Erwärmung mit Infrarotstrahlung untersucht. Hier erwies sich die Ankopplung als zu schwach und die thermische Trägheit der Heizstäbe als zu groß, um kurze Regenerationszyklen zu gewährleisten.
Gute Ergebnisse wurden zum einen bei erzwungener Strömung mit warmem He-Gas in den Kühlkanälen des Panels erzielt. Dabei wurden Durchsätze bis etwa 5.5 g/s bei erhöhten Drücken bis etwa 13 bar gefahren. Abhängig von der Position des Meßfühlers wurden typische Aufheizzeiten unter 50 s ermittelt.
Zum anderen wurde die schnelle Erwärmung durch Widerstandsheizelemente erzeugt, die direkt auf der Paneloberfläche angebracht waren. Die elektrische Leistung betrug maximal etwa 3 kW. Es konnte gezeigt werden, daß schon mit einer reduzierten Heizleistung von 2 kW problemlos Heizzeiten kleiner 30 s erreicht werden.
Die Untersuchungen belegen, daß die schnelle Regeneration von ITER-Kryopanels bei Verwendung geeigneter Heizmethoden technisch problemlos zu bewerkstelligen ist. Die elektrische Methode verbindet eine hohe Flexibilität mit einer sehr guten Regelbarkeit
Deregulation of the CEACAM Expression Pattern Causes Undifferentiated Cell Growth in Human Lung Adenocarcinoma Cells
CEACAM1, CEA/CEACAM5, and CEACAM6 are cell adhesion molecules (CAMs) of the carcinoembryonic antigen (CEA) family that have been shown to be deregulated in lung cancer and in up to 50% of all human cancers. However, little is known about the functional impact of these molecules on undifferentiated cell growth and tumor progression. Here we demonstrate that cell surface expression of CEACAM1 on confluent A549 human lung adenocarcinoma cells plays a critical role in differentiated, contact-inhibited cell growth. Interestingly, CEACAM1-L, but not CEACAM1-S, negatively regulates proliferation via its ITIM domain, while in proliferating cells no CEACAM expression is detectable. Furthermore, we show for the first time that CEACAM6 acts as an inducer of cellular proliferation in A549 cells, likely by interfering with the contact-inhibiting signal triggered by CEACAM1-4L, leading to undifferentiated anchorage-independent cell growth. We also found that A549 cells expressed significant amounts of non-membrane anchored variants of CEACAM5 and CEACAM6, representing a putative source for the increased CEACAM5/6 serum levels frequently found in lung cancer patients. Taken together, our data suggest that post-confluent contact inhibition is established and maintained by CEACAM1-4L, but disturbances of CEACAM1 signalling by CEACAM1-4S and other CEACAMs lead to undifferentiated cell growth and malignant transformation
Unconventional motional narrowing in the optical spectrum of a semiconductor quantum dot
Motional narrowing refers to the striking phenomenon where the resonance line
of a system coupled to a reservoir becomes narrower when increasing the
reservoir fluctuation. A textbook example is found in nuclear magnetic
resonance, where the fluctuating local magnetic fields created by randomly
oriented nuclear spins are averaged when the motion of the nuclei is thermally
activated. The existence of a motional narrowing effect in the optical response
of semiconductor quantum dots remains so far unexplored. This effect may be
important in this instance since the decoherence dynamics is a central issue
for the implementation of quantum information processing based on quantum dots.
Here we report on the experimental evidence of motional narrowing in the
optical spectrum of a semiconductor quantum dot broadened by the spectral
diffusion phenomenon. Surprisingly, motional narrowing is achieved when
decreasing incident power or temperature, in contrast with the standard
phenomenology observed for nuclear magnetic resonance
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