Fast response time fiber optical pH and oxygen sensors

While fluorescence-based fiber optic sensors for measuring both pH and oxygen concentration (O2) are well known, current sensors are often limited by their response time and drift, which limits the use of existing fiber optic sensors of this type in wider applications, for example in physiology and other fields. Several new fiber optical sensors have been developed and optimized, with respect to key features such as tip shape and coating layer thickness. In this work, preliminary results on the performance of a suite of pH sensors with fast response times, < 3 second and oxygen sensors (O2) with response times < 0.2 second. The sensors have been calibrated and their performance analyzed using the Henderson–Hasselbalch equation (pH) and classic Lehrer-model (O2)

Constructive problem solving : a model construction approach towards configuration

In this paper we give a formalisation of configuration as the task to construct for a given specification, which is understood as a finite set of logical formulas, a model that satisfies the specification. In this approach, a specification consists of two parts. One part describes the domain, the possible components, and their interdependencies. The other part specifies the particular object that is to be configured. The language that is used to represent knowledge about configuration problems integrates three sublanguages that allow one to express constraints, to build up taxonomies, and to define rules. We give a sound calculus by which one can compute solutions to configuration problems if they exist and that allows one to recognize that a specification is inconsistent. In particular, the calculus can be used in order to check whether a given configuration satisfies the specification

Steric control of regiochemistry in the reactions of methyl substituted pentadienyl cations with isobutene

The dienylic chlorides 1–5 react with isobutene in the presence of zinc chloride/ether in dichloromethane to give the acyclic adducts 6–10 in 64–91% yield. The orientation effects are in contrast to the predictions of perturbational molecular orbital theory and can be explained on the basis of steric effects

Fast approximate calculation of valid domains in a satisfiability-based product configurator

Calculating valid domains is an important feature of an interactive product configurator. Since it is an NP hard problem, it is necessary (for large real-world instances) to calculate valid domains only approximately in order to keep the response time low. In this paper, we present a new fast and accurate approximation algorithm to calculate the valid domains in a satisfiability based interactive product configurator. The algorithm is based on building a full implication graph during unit propagation and performing a search in that implication graph in order to approximate whether a domain value is valid. We experimentally compared our new algorithm to the algorithm used by the commercial SAT-based configurator CAS Merlin and measured speedups of up to 18-fold while maintaining the same accuracy

M+D: conceptual guidelines for compiling a materials library

This article proposes to present a study conducted by the Raw Materials research group, the results of which comprise the conceptual guidelines for compiling an M+D material library. The study includes the topic, materials and design taking the impact of the changes that came into being in the post industrial era on project methodologies and the search for information regarding materials. Taking into account the importance and complexity that these relationships have taken on currently, we have studied the issue of materials based on Manzini (1983) and Ashby and Johnson (2002). Afterward different databases and materials libraries located in the Brazil, the United States, France and Italy geared toward design professionals and students were analyzed to understand what information and means of access to them were available. The project methodologies were approached based on Löbach (1991), Bürdeck (1994), Schulmann (1994), Baxter (1998), Dantas (1998 and 2005) and Papanek (1995 and 2000). This study sought to identify the key elements of the role of materials in the project process today, to serve as a parameter for the analysis of the models studied. A comparative analysis of the models investigated enabled identification of positive and negative aspects to adapt to the needs previously mentioned and identify conceptual guidelines for compiling a collection of materials for use in design projects. Keywords: Design, Materials, Project Methodology, Library</p

Transcriptional Targeting of B Cells for Induction of Peripheral CD8 T Cell Tolerance

Abstract Several mechanisms are in place to neutralize autoimmune CD8 T cells by tolerance induction. Developing self-specific CD8 T cells are eliminated in the thymus by Ag-presenting epithelial and dendritic cells (DCs). However, CD8 T cells escaping thymic central tolerance can also be inactivated by tolerance mechanisms in peripheral organs. In contrast to DCs, the role of B cells in generating CD8 T cell tolerance is not well-characterized. To investigate this question in more detail, we transcriptionally targeted Ag to B cells using B cell-specific retroviral vectors in vivo. Although Ag expression could be detected in B cells of thymus, lymph nodes, and spleen, B cells were unable to induce central tolerance of CD8 thymocytes. In contrast, in peripheral organs, we could identify clonal deletion and functional inhibition (anergy) of CD8 T cells as tolerance-inducing mechanisms. Although Ag expressed by B cells was acquired and cross-presented by DCs, B cells were also sufficient to tolerize CD8 T cells directly. These findings suggest exploitation of B cells for Ag-specific immunotherapy of CD8 T cell-mediated autoimmune diseases

Echoes of a decaying planetary system: the gaseous and dusty disks surrounding three white dwarfs

We have performed a comprehensive ground-based observational program aimed at characterizing the circumstellar material orbiting three single white dwarf stars previously known to possess gaseous disks. Near-infrared imaging unambiguously detects excess infrared emission towards Ton 345 and allows us to refine models for the circumstellar dust around all three white dwarf stars. We find that each white dwarf hosts gaseous and dusty disks that are roughly spatially coincident, a result that is consistent with a scenario in which dusty and gaseous material has its origin in remnant parent bodies of the white dwarfs' planetary systems. We briefly describe a new model for the gas disk heating mechanism in which the gaseous material behaves like a "Z II" region. In this Z II region, gas primarily composed of metals is photoionized by ultraviolet light and cools through optically thick allowed Ca II-line emission.Comment: 43 pages, 9 tables, 9 figures. Accepted to Ap

Saharan dust and ice nuclei over Central Europe

Surface measurements of aerosol and ice nuclei (IN) at a Central European mountain site during an episode of dust transport from the Sahara are presented. Ice nuclei were sampled by electrostatic precipitation on silicon wafers and were analyzed in an isothermal static vapor diffusion chamber. The transport of mineral dust is simulated by the Eulerian regional dust model DREAM. Ice nuclei and mineral dust are significantly correlated, in particular IN number concentration and aerosol surface area. The ice nucleating characteristics of the aerosol as analyzed with respect to temperature and supersaturation are similar during the dust episode than during the course of the year. This suggests that dust may be a main constituent of ice nucleating aerosols in Central Europe