In situ visualization of large-scale turbulence simulations in Nek5000 with ParaView Catalyst

The Journal of Supercomputing - In situ visualization on high-performance computing systems allows us to analyze simulation results that would otherwise be impossible, given the size of the...     

Cores of swirling particle motion in unsteady flows

In nature and in flow experiments particles form patterns of swirling motion in certain locations. Existing approaches identify these structures by considering the behavior of stream lines. However, in unsteady flows particle motion is described by path lines which generally gives different swirling patterns than stream lines. We introduce a novel mathematical characterization of swirling motion cores in unsteady flows by generalizing the approach of Sujudi/Haimes to path lines. The cores of swirling particle motion are lines sweeping over time, i.e., surfaces in the space-time domain. They occur at locations where three derived 4D vectors become coplanar. To extract them, we show how to re-formulate the problem using the Parallel Vectors operator. We apply our method to a number of unsteady flow fields.     

Learning beyond finite memory in recurrent networks of spiking neurons

We investigate possibilities of inducing temporal structures without fading memory in recurrent networks of spiking neurons strictly operating in the pulse-coding regime. We extend the existing gradient-based algorithm for training feedforward spiking neuron networks, SpikeProp (Bohte, Kok, & La Poutré, 2002), to recurrent network topologies, so that temporal dependencies in the input stream are taken into account. It is shown that temporal structures with unbounded input memory specified by simple Moore machines (MM) can be induced by recurrent spiking neuron networks (RSNN). The networks are able to discover pulse-coded representations of abstract information processing states coding potentially unbounded histories of processed inputs. We show that it is often possible to extract from trained RSNN the target MM by grouping together similar spike trains appearing in the recurrent layer. Even when the target MM was not perfectly induced in a RSNN, the extraction procedure was able to reveal weaknesses of the induced mechanism and the extent to which the target machine had been learned.     

Source mass and positioning system for an accurate measurement of G

We report on a system of well-characterized source masses and their precision positioning system for a measurement of the Newtonian gravitational constant G using atoms as probes. The masses are 24 cylinders of 50 mm nominal radius, 150.2 mm nominal height, and mass of about 21.5 kg, sintered starting from a mixture of 95.3% W, 3.2% Ni, and 1.5% Cu. Density homogeneity and cylindrical geometry have been carefully investigated. The positioning system independently moves two groups of 12 cylinders along the vertical direction by tens of centimeters with a reproducibility of a few microns. The whole system is compatible with a resolution DeltaG/G<10(-4).     

Equilibria of iterative softmax and critical temperatures for intermittent search in self-organizing neural networks

Kwok and Smith (2005) recently proposed a new kind of optimization dynamics using self-organizing neural networks (SONN) driven by softmax weight renormalization. Such dynamics is capable of powerful intermittent search for high-quality solutions in difficult assignment optimization problems. However, the search is sensitive to temperature setting in the softmax renormalization step. It has been hypothesized that the optimal temperature setting corresponds to the symmetry-breaking bifurcation of equilibria of the renormalization step, when viewed as an autonomous dynamical system called iterative softmax (ISM). We rigorously analyze equilibria of ISM by determining their number, position, and stability types. It is shown that most fixed points exist in the neighborhood of the maximum entropy equilibrium w= (N(-1), N(-1), ..., N(-1)), where N is the ISM dimensionality. We calculate the exact rate of decrease in the number of ISM equilibria as one moves away from w. Bounds on temperatures guaranteeing different stability types of ISM equilibria are also derived. Moreover, we offer analytical approximations to the critical symmetry-breaking bifurcation temperatures that are in good agreement with those found by numerical investigations. So far, the critical temperatures have been determined only by trial-and-error numerical simulations. On a set of N-queens problems for a wide range of problem sizes N, the analytically determined critical temperatures predict the optimal working temperatures for SONN intermittent search very well. It is also shown that no intermittent search can exist in SONN for temperatures greater than one-half.     

Design,Synthesis and Biological Characterization of Histone Deacetylase 8 (HDAC8) Proteolysis Targeting Chimeras (PROTACs) with Anti-Neuroblastoma Activity

In addition to involvement in epigenetic gene regulation, histone deacetylases (HDACs) regulate multiple cellular processes through mediating the activity of non-histone protein substrates. The knockdown of HDAC8 isozyme is associated with the inhibition of cell proliferation and apoptosis enhancement in several cancer cell lines. As shown in several studies, HDAC8 can be considered a potential target in the treatment of cancer forms such as childhood neuroblastoma. The present work describes the development of proteolysis targeting chimeras (PROTACs) of HDAC8 based on substituted benzhydroxamic acids previously reported as potent and selective HDAC8 inhibitors. Within this study, we investigated the HDAC8-degrading profiles of the synthesized PROTACs and their effect on the proliferation of neuroblastoma cells. The combination of in vitro screening and cellular testing demonstrated selective HDAC8 PROTACs that show anti-neuroblastoma activity in cells.     

纳米定位测量机操作-测量结果

伊尔梅瑙工业大学过程测量和传感技术研究所研制了三维纳米定位和测量机(NPMM).阿贝无偏设计使得该机器异常精确.在整个25 mm×25 mm×5 mm的定位和测量域内,干涉测长系统分辨力可达0.1 nm,不确定度达5～10 nm.提供了纳米定位测量机的基本信息,介绍其操作模式,并给出了测量结果.     

Joining High Thickness Materials by Sewing – first Modelling Steps of the Stitched Place

Applied Composite Materials - Many textile products are using materials with higher thickness like foams, spacer fabrics and nonwoven materials in order to provide comfortable softness of the...     

Diagramme zur Auswertung der Johansen‐Formeln für einschnittige Holz‐ bzw. Holzwerkstoff‐Verbindungen

Diagrams to evaluate the Johansen‐formulas for single shear connections of timber or wood‐based panels. Metal dowel‐type fasteners are nowadays designed by using the Europe‐wide applied, but rather complex Johansen Theory, which is effectively used by means of computer programs. This however can yield a diminished overview. In this contribution the evaluation is done by use of diagrams, which should facilitate the application of the new design rules in addition or as an alternative to other methods.     

Parallel kinematics for nanoscale Cartesian motions

A novel design of high load capacity multiaxis positioning stages with an accuracy in the range of nanometers is presented. For strokes of some 10 mm with no play and high stiffness a general design principle supporting six Cartesian degrees of freedom has been developed using a new parallel kinematic topology based on trapezoidal arrangements. It was developed together with novel flexures and drives for synchrotron optics in ultrahigh vacuum at BESSY. The performance of the setup and its kinematic properties are described as well as high-resolution measurements of the six motions and their crosstalk. Applications of the design have been in daily operation since 1998. Since then, more than 30 derivates have been implemented with outstanding characteristics and excellent reliability.