Exotic Spaces in Quantum Gravity I: Euclidean Quantum Gravity in Seven Dimensions

It is well known that in four or more dimensions, there exist exotic manifolds; manifolds that are homeomorphic but not diffeomorphic to each other. More precisely, exotic manifolds are the same topological manifold but have inequivalent differentiable structures. This situation is in contrast to the uniqueness of the differentiable structure on topological manifolds in one, two and three dimensions. As exotic manifolds are not diffeomorphic, one can argue that quantum amplitudes for gravity formulated as functional integrals should include a sum over not only physically distinct geometries and topologies but also inequivalent differentiable structures. But can the inclusion of exotic manifolds in such sums make a significant contribution to these quantum amplitudes? This paper will demonstrate that it will. Simply connected exotic Einstein manifolds with positive curvature exist in seven dimensions. Their metrics are found numerically; they are shown to have volumes of the same order of magnitude. Their contribution to the semiclassical evaluation of the partition function for Euclidean quantum gravity in seven dimensions is evaluated and found to be nontrivial. Consequently, inequivalent differentiable structures should be included in the formulation of sums over histories for quantum gravity.Comment: AmsTex, 23 pages 5 eps figures; replaced figures with ones which are hopefully viewable in pdf forma

Monitoring method for carbon nanotubes (CNT): Personal sampler and corresponding reading device

At present, CNT and other nanofiber materials in air can only be detected by deposition on a substrate and the use of off-line imaging analysis such as scanning electron microscopy. The majority of techniques suitable for the quasi- real-time measurement of engineered nanoparticles such as electrical low pressure impactor, condensation particle counter, optionally combined with a scanning mobility particle sizer (SMPS) can not distinguish between nanoparticles in general and airborne nanofibres in particular. In common workplace settings the considerable background of fine and ultrafine particles thus poses a challenge for these instruments. Furthermore, a true portability of the present devices is not given due to their size and power consumption. However, there is an urgent need due to the expected toxicity of nanofibres to control workplace environments with a robust and mobile device to ensure the safety of the working personnel as soon as possible. To meet these challenges, a suitable personal sampler together with a corresponding reading device is under development in the NANODEVICE-project, funded by the European Commission under grant agreement FP7-211464-2. A pre-prototype personal sampler for CNT sampling, the used Raman-spectroscopic inspection of deposited CNTs and a possible approach in determining the qualitative presence of CNTs will be shown. Additionally, it seems even possible to distinguish between carbon nanofibers from different manufacturers based on Raman spectroscopy and data analysis

Reactive oxygen species in phagocytic leukocytes

Phagocytic leukocytes consume oxygen and generate reactive oxygen species in response to appropriate stimuli. The phagocyte NADPH oxidase, a multiprotein complex, existing in the dissociated state in resting cells becomes assembled into the functional oxidase complex upon stimulation and then generates superoxide anions. Biochemical aspects of the NADPH oxidase are briefly discussed in this review; however, the major focus relates to the contributions of various modes of microscopy to our understanding of the NADPH oxidase and the cell biology of phagocytic leukocytes

Rendering Identity: Normativity in Conventional Contemporary Queer Documentary

Depictions of queer subjects in documentary filmmaking predominantly emphasize the promotion of queer visibility and activist rhetorics. Limited research and discourse has been executed, practically or academically, to explore documentary form as holding potential to contribute to subversive renderings of contemporary queer experience. The following thesis outlines possible basis for reconsidering contemporary queer filmmaking through the disposition of current documentary production limitations. This includes synthesizing tenets of queer theory and film theory to support the potential applications of queer documentary and recommending a premise for subversive documentary principles to better express contemporary queerness. The primary issue confronted is the capacity in which filmmakers seeking to create queer content, and more specifically content that embodies queerness’ radical fluidity, within the confines of a formulaic medium

Effects of conceptual antigenicity and strain specificity on the accumulation of metrial gland cells in the murine placental labyrinth. Abstr.

Special techniques algorithms are worked out, such as MSA, preparation of management plans, SPC in the preparation of manufacturing automotive components that improve its effectiveness

Section: Cell physiology Dynamics of rat entorhinal cortex layer II/III cells: characteristics of membrane potential resonance at rest predict oscillation properties near threshold

Abstract Neurons generate intrinsic subthreshold membrane potential oscillations (MPOs) under various physiological and behavioural conditions. These oscillations influence neural responses and coding properties on many levels. On the single-cell level, MPOs modulate the temporal precision of action potentials; they also have a pronounced impact on large-scale cortical activity. Recent studies have described a close association between the MPOs of a given neuron and its electrical resonance properties. Using intracellular sharp micro-electrode recordings we examine both dynamical characteristics in layers II and III of the entorhinal cortex (EC). Our data from EC-layer-II stellate cells show strong membrane potential resonances and oscillations, both in the range of 5-15 Hz. At the resonance maximum, the membrane impedance can be more than twice as large as the input resistance. In EC-layer-III cells, MPOs could not be elicited, and frequency-resolved impedances decay monotonically with increasing frequency or has only a small peak followed by a subsequent decay. To quantify and compare the resonance and oscillation properties, we use a simple mathematical model that includes stochastic components to capture channel noise. Based on this model we demonstrate that electrical resonance is closely related though not equivalent to the occurrence of sag-potentials and MPOs. MPO frequencies can be predicted from the membrane impedance curve for stellate cells. The model also explains the broad-band nature of the observed MPOs. This underscores the importance of intrinsic noise sources for subthreshold phenomena and rules out a deterministic description of MPOs. In addition, our results show that the two identified cell classes in the superficial EC layers, which are known to target different areas in the hippocampus, also have different preferred frequency ranges and dynamic characteristics. Intrinsic cell properties may thus play a major role for the frequency-dependent information flow in the hippocampal formation.

Isoprenylcysteine carboxyl methyltransferase facilitates glucose-induced Rac1 activation, ROS generation and insulin secretion in INS 832/13 β-cells

Isoprenylcysteine carboxyl methyltransferase (ICMT) catalyzes the post-translational methylation of C-terminal cysteines of isoprenylated proteins, including small G-proteins and the γ-subunits of heterotrimeric G-proteins. It is widely felt that carboxymethylation promotes efficient membrane association of the methylated proteins and specific protein-protein interactions. In the current study, we tested the hypothesis that ICMT-mediated carboxymethylation of specific proteins (e.g., Rac1) plays a regulatory role in glucose-stimulated insulin secretion (GSIS). Western-blot analysis indicated that ICMT is expressed and predominantly membrane associated in INS 832/13 β-cells. siRNA-mediated knockdown of endogenous expression of ICMT markedly attenuated glucose, but not KCl-induced insulin secretion. These findings were further supported by pharmacological observations, which suggested a marked reduction in glucose-, but not KCl-stimulated insulin secretion by acetyl farnesyl cysteine (AFC), a selective inhibitor of ICMT. In addition, glucose-induced Rac1 activation, a hallmark signaling step involved in glucose-stimulated insulin secretion, was markedly inhibited following pharmacological (AFC) or molecular biological (siRNA-ICMT) inhibition of ICMT. Lastly, we also noticed a marked reduction in glucose-induced acute increase in the generation of reactive oxygen species in INS 832/13 cells pre-treated with AFC or transfected with siRNA-ICMT. Together, these data suggest that ICMT regulates glucose-induced Rac1 activation, generation of reactive oxygen species and insulin secretion in pancreatic β-cells