We investigate the influence of pumping (i.e. population inversion) of the nonlinear material on the optical bistability of semiconductor microresonators, the reduction of sustaining power for bright ...and dark solitons by pumping, and the influence of pumping on dynamics of solitons and the background on which they exist. Reduction of soliton sustaining power by a factor of 300 is observed for dark solitons and the role played by material transparency and laser threshold is clarified.
The present study describes modifications to an existing bioautographic method for detecting genotoxic substances on thin-layer chromatography (TLC) plates by using the umu assay. It will be shown ...that the complex procedure that is described in the literature can be significantly simplified. Using the modified method, it is possible to detect 0.3 ng of the genotoxic substance 4-nitroquinoline-N-oxide. With 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal), a suitable substrate for environmental samples for the detection of the resulting β-galactosidase was found. Experiments showed, in contrast, that indirectly genotoxic substances could not thus far be identified on the TLC plate with overlayer bioautography.
We describe the multi-purpose Monte-Carlo event generator WHIZARD for the simulation of high-energy particle physics experiments. Besides the presentation of the general features of the program like ...SM physics, BSM physics, and QCD effects, special emphasis will be given to the support of the most accurate simulation of the collider environments at hadron colliders and especially at future linear lepton colliders. On the more technical side, the very recent code refactoring towards a completely object-oriented software package to improve maintainability, flexibility and code development will be discussed. Finally, we present ongoing work and future plans regarding higher-order corrections, more general model support including the setup to search for new physics in vector boson scattering at the LHC, as well as several lines of performance improvements.
Abstract The caudal anterior cingulate cortex (cAC) is an essential component of the circuitry involved in acquisition of forebrain-dependent trace eyeblink conditioning. Lesions of the cAC prevent ...trace eyeblink conditioning Weible AP, McEchron MD, Disterhoft JF (2000) Cortical involvement in acquisition and extinction of trace eyeblink conditioning. Behav Neurosci 114(6):1058–1067. The patterns of activation of cAC neurons recorded in vivo suggest an attentional role for this structure early in training Weible AP, Weiss C, Disterhoft JF (2003) Activity profiles of single neurons in caudal anterior cingulate cortex during trace eyeblink conditioning in the rabbit. J Neurophysiol 90(2):599–612. The goal of the present study was to identify connections of the portion of the rabbit cAC previously demonstrated to be involved in trace eyeblink conditioning, using the neuronal tract tracer wheat germ agglutinin conjugated to horseradish peroxidase, to better understand how the cAC contributes to the process of associative learning. Reciprocal connections with the claustrum provide a route for the transfer of sensory information between the cAC and neocortical and allocortical regions also involved in learning. Connections with components of the basal forebrain cholinergic system are described, with relevance to the proposed attentional role of the cAC. Reciprocal and unidirectional connections were in evidence in multiple thalamic regions, including the medial dorsal nucleus, which have been implicated in a variety of conditioning paradigms. Anterograde connections with the caudate and lateral pontine nuclei provide access to forebrain motor and brainstem sensory circuitry, respectively. The relevance of these connections to acquisition of the trace conditioned reflex is discussed.
In many systems with moving contacts spatially periodic wear patterns related to structural resonances emerge. Often, however, the structural properties of the sliding system vary periodically with ...position. Based on a generic minimal model the present work investigates the effect of a spatially periodic structural stiffness on wear pattern generation. Linear stability of the resulting wear dynamics is analysed using spatial Floquet analysis. It turns out that the emergence of wear patterns by instability can in general not be evaluated through stability analysis based on spatially local parameters alone. A spatially periodic stiffness can stabilize the system, depending on the wavelength and the amplitude of the spatially periodic parameter variation. The relevance of the effect is discussed and open points are addressed.
The ability to purify to homogeneity a population of hepatic progenitor cells from adult liver is critical for their characterization prior to any therapeutic application. As a step in this ...direction, we have used a bipotential liver cell line from 14 days postcoitum mouse embryonic liver to compile a list of cell surface markers expressed specifically by liver progenitor cells. These cells, known as bipotential mouse embryonic liver (BMEL) cells, proliferate in an undifferentiated state and are capable of differentiating into hepatocyte‐like and cholangiocyte‐like cells in vitro. Upon transplantation, BMEL cells are capable of differentiating into hepatocytes and cholangiocytes in vivo. Microarray and Gene Ontology (GO) analysis of gene expression in the 9A1 and 14B3 BMEL cell lines grown under proliferating and differentiating conditions was used to identify cell surface markers preferentially expressed in the bipotential undifferentiated state. This analysis revealed that proliferating BMEL cells express many genes involved in cell cycle regulation, whereas differentiation of BMEL cells by cell aggregation causes a switch in gene expression to functions characteristic of mature hepatocytes. In addition, microarray data and protein analysis indicated that the Notch signaling pathway could be involved in maintaining BMEL cells in an undifferentiated stem cell state. Using GO annotation, a list of cell surface markers preferentially expressed on undifferentiated BMEL cells was generated. One marker, Cd24a, is specifically expressed on progenitor oval cells in livers of diethyl 1,4‐dihydro‐2,4,6‐trimethyl‐3,5‐pyridinedicarboxylate‐treated animals. We therefore consider Cd24a expression a candidate molecule for purification of hepatic progenitor cells.
Disclosure of potential conflicts of interest is found at the end of this article.
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