rhAPC reduces the endothelial cell permeability via a decrease of contractile tensions induced by endothelial cells

All cells generate contractile tension. This strain is crucial for mechanically controlling the cell shape, function and survival. In this study, the CellDrum technology quantifying cell's (the cellular) mechanical tension on a pico-scale was used to investigate the effect of lipopolysaccharide (LPS) on human aortic endothelial cell (HAoEC) tension. The LPS effect during gram-negative sepsis on endothelial cells is cell contraction causing endothelium permeability increase. The aim was to finding out whether recombinant activated protein C (rhAPC) would reverse the endothelial cell response in an in-vitro sepsis model. In this study, the established in-vitro sepsis model was confirmed by interleukin 6 (IL-6) levels at the proteomic and genomic levels by ELISA, real time-PCR and reactive oxygen species (ROS) activation by florescence staining. The thrombin cellular contraction effect on endothelial cells was used as a positive control when the CellDrum technology was applied. Additionally, the Ras homolog gene family, member A (RhoA) mRNA expression level was checked by real time-PCR to support contractile tension results. According to contractile tension results, the mechanical predominance of actin stress fibers was a reason of the increased endothelial contractile tension leading to enhanced endothelium contractility and thus permeability enhancement. The originality of this data supports firstly the basic measurement principles of the CellDrum technology and secondly that rhAPC has a beneficial effect on sepsis influenced cellular tension. The technology presented here is promising for future high-throughput cellular tension analysis that will help identify pathological contractile tension responses of cells and prove further cell in-vitro models.     

Electrical-contact-free readout of the response of superconductive bolometer arrays using thermal cross talk

We utilized and investigated the unique dependence of the magnitude and phase of the response on thermal cross talk between bolometer pixels in an array to measure the response of the devices through fewer monitoring devices. We show the feasibility of the proposed readout technique by use of two source pixels in an array, as the image-mapping devices, and one optically shielded pixel as the readout device. While the sensing pixels were electrical-contact free, the readout device was current biased in 4-probe current-bias configuration. Both the phase and the magnitude of the response due to the cross talk in the array were found to be strongly dependent on the modulation frequency and the distance between the sensing and the readout pixels. A series of measurements were designed to extract the response of each single-sensing pixel. By combining the measured data, the response of individual pixels could be extracted through the interpolation of the mapped responses.     

Effect of aerosol microphysical properties on polarization of skylight: sensitivity study and measurements

We analyze the sensitivity of the degree of linear polarization in the Sun's principal plane as a function of aerosol microphysical parameters: the real and imaginary parts of the refractive index, the median radius and geometric standard deviation of the bimodal size distribution (both fine and coarse modes), and the relative number weight of the fine mode at a wavelength of 675 nm. We use Mie theory for single-scattering simulations and the doubling-adding method with the inclusion of polarization for multiple scattering. It is shown that the behavior of the degree of linear polarization is highly sensitive to both the small mode of the bimodal size distribution and the real part of the refractive index of aerosols, as well as to the aerosol optical thickness; whereas not all parameters influence the polarization equally. A classification of the importance of the input parameters is given. This sensitivity study is applied to an analysis of ground-based polarization measurements. For the passive remote sensing of microphysical and optical properties of aerosols, a ground-based spectral polarization measuring system was built, which aims to measure the Stokes parameters I, Q, and U in the visible (from 410 to 789 nm) and near-infrared (from 674 to 995 nm) spectral range with a spectral resolution of 7 nm in the visible and 2.4 nm in the near infrared. We compare polarization measurements taken with radiative transfer simulations under both clear- and hazy-sky conditions in an urban area (Cabauw, The Netherlands, 51.58 degrees N, 4.56 degrees E). Conclusions about the microphysical properties of aerosol are drawn from the comparison.     

A software‐based method for ergonomic posture assessment in automotive preproduction planning: Concordance and difference in using software and personal observation for assessments

This article describes the pilot study for testing a system for ergonomic posture assessment. 1 The software‐based approach for ergonomic assessment is based on motion capturing work tasks using realistic mock‐ups of the assembly environment. The approach for ergonomic assessment reduces the expenditure of time for evaluation. This may lead to considerable ergonomic aspects during the early stages of production planning. A comparative test between human observers and the software system was carried out. The test of the system focuses on correct recognition of postures from the motion data and compares the computer‐based evaluation with the results of a manual analysis carried out by a human observer. The tests indicate sufficient results for the automated assessment, especially for the arm and leg postures. But there is still some potential for further improvement of the recognition accuracy of the back postures. © 2011 Wiley Periodicals, Inc.     

Soft X-ray lithography of high aspect ratio SU8 submicron structures

SU8 submicron structures with an aspect ratio of more than 50 are made by soft X-ray lithography using modified spectra of the synchrotron radiation at the ANKA LITHO-1 beamline, which includes a chromium mirror. The X-ray spectrum is additional shaped by a beam stop and a filter to a narrow band in order to reduce the influence of diffraction and photoelectrons. The exposure determination is based on the measured threshold doses for used SU-8 resist layers as well as on the calculated diffractive distribution of an absorbed power. Post-exposure bake of the resist is performed at low temperature and low pressure to avoid changes of the structural size because of shrinkage due to temperature changes and to eliminate a “skin” layer at the top of the resist. SU8 structures with lateral dimensions of 1 μm and heights from 50 to 80 μm have been fabricated defect free with the optimized process.     

Experience of automation failures in training: effects on trust,automation bias,complacency and performance

This work examined the effects of operators’ exposure to various types of automation failures in training. Forty-five participants were trained for 3.5 h on a simulated process control environment. During training, participants either experienced a fully reliable, automatic fault repair facility (i.e. faults detected and correctly diagnosed), a misdiagnosis-prone one (i.e. faults detected but not correctly diagnosed) or a miss-prone one (i.e. faults not detected). One week after training, participants were tested for 3?h, experiencing two types of automation failures (misdiagnosis, miss). The results showed that automation bias was very high when operators trained on miss-prone automation encountered a failure of the diagnostic system. Operator errors resulting from automation bias were much higher when automation misdiagnosed a fault than when it missed one. Differences in trust levels that were instilled by the different training experiences disappeared during the testing session.

Practitioner Summary: The experience of automation failures during training has some consequences. A greater potential for operator errors may be expected when an automatic system failed to diagnose a fault than when it failed to detect one.     

Model development guidelines for UML-RT: conventions,patterns and antipatterns

Software development guidelines are a set of rules which can help improve the quality of software. These rules are defined on the basis of experience gained by the software development community over time. This paper discusses a set of design guidelines for model-based development of complex real-time embedded software systems. To be precise, we propose nine design conventions, three design patterns and thirteen antipatterns for developing UML-RT models. These guidelines have been identified based on our analysis of around 100 UML-RT models from industry and academia. Most of the guidelines are explained with the help of examples, and standard templates from the current state of the art are used for documenting the design rules.     

Cellular Molybdenum Silicide/Silicon Carbide Composites from Stems of Maize

Biomimicking of woods has been conducted extensively in the past. In this work, the unique microstructural feature of maize stems has been explored. These stems appear to be promising precursor materials for producing fiber-reinforced composites with unique anisotropic properties. A unique melt infiltration technique has been adopted to mineralize this structure into ceramic composites. The cellular morphology of the precursor stem was retained in the final composite. SiC–Si and MoSi₂–SiC cellular composites were obtained by infiltration with Si and Si–MoSi₂–Al mixture, respectively. It has been found that a small (2 wt%) addition of aluminum in the infiltrating mixture can help in attaining a homogeneous distribution of MoSi₂ in the SiC cellular matrix.     

A method for robustness analysis of controlled nonlinear systems

This paper presents an approach to analyzing robustness properties of nonlinear systems under feedback control. The core idea is to apply numerical bifurcation analysis to the closed-loop process, using the controller/observer tuning parameters, the set points, and parameters describing model uncertainty (parametric as well as unmodeled dynamics) as bifurcation parameters. By analyzing the Hopf bifurcation and saddle-node bifurcation loci with respect to these parameters, bounds on the controller tuning are identified which can serve as a measure for the robustness of the controlled system. These bounds depend upon the type as well as the degree of mismatch that exists between the plant and the model used for controller design.The method is illustrated by analyzing three control systems which are applied to a continuously operated stirred tank reactor: a state feedback linearizing controller and two output feedback linearizing controllers. While model uncertainty has only a minor effect on the tuning of the state feedback linearizing controller, this does not represent a very realistic scenario. However, when an observer is implemented in addition to the controller and an output feedback linearizing scheme is investigated, it is found that the plant-model mismatch has a much more profound impact on the tuning of the observer than it has on the controller tuning. In addition, two observer designs with different level of complexity are investigated and it is found that a scheme which makes use of additional knowledge about the system will not necessarily result in better stability properties as the level of uncertainty in the model increases. These investigations are carried out using the robustness analysis scheme introduced in this paper.     

Replication of sub-100 nm structures using h- and s-PDMS composite stamps

Soft-UV-NIL as replication technique was used to replicate sub-100 nm structures. The aim of this work is the stamp production and the replication of structures with dimensions smaller than 100 nm in a simple manner. Composite stamps composed of two layers, a thin hard PDMS layer supported by a thick soft PDMS (s-PDMS) layer are compared to common s-PDMS stamps regarding the resolution by using a Siemens star (star burst pattern) as test structure. The master is fabricated by electron beam lithography in a 140 nm thick PMMA resist layer. The stamp is molded directly from the structured resist, without any additional anti sticking treatment. Therefore the resist thickness determines the aspect ratio, which is 1.5 at the resolution limit. The replication is done in a UV-curing cycloaliphatic epoxy material. The employed test structure provides good comparability, the resolution limit at a glance, and it integrates a smooth transition from micro- to nanostructures. Therefore it is a capable structure to characterize the UV-NIL.