Analysis of polychlorinated biphenyls, pyrethroid insecticides and fragrances in human milk using a laminar cup liner in the GC injector

 Since 1970 the State Laboratory of Basle City has been periodically analyzing human milk from the region (the latest in 1998/99) as a bioindicator for the environmental load of organochlorine pesticides [1, 2]. The analysis of human milk is very complex including several clean-up steps and is therefore time consuming. The focus is mainly on organochlorine pesticides, polychlorinated biphenyls (PCB), and nitro-musk compounds; analytes which are easily detectable with gas chromatography and electron capture detection (ECD). Our aim was to minimize the clean-up steps for the analysis of ECD sensitive substances. Furthermore, analytes insensitive to EC detection that require MS detection, such as polycyclic musk substitutes, were of interest. With the help of a specially designed GC liner in the vaporizing injector of the gas chromatograph, the laminar cup liner, we have considerably reduced the time and effort in the sample preparation. With the described clean-up procedure we analyzed 53 human milk samples from the region of Basle for PCB, pyrethrins, and pyrethroid insecticides and fragrances (nitro-musk compounds and polycyclic musk substitutes). While PCB showed a general downward trend in mean concentrations since 1980, residues of the polycyclic musk substitutes galaxolide and tonalide were detectable in almost every sample (e.g., 73 μg/kg fat of HHCB, 74 μg/kg fat of AHTN). Pyrethrins and pyrethroid insecticides were detected only at low concentrations between 0.03 and 0.46 mg/kg fat. Received: 28 September 1999 / Revised version: 2 May 2000     

Screening,optimization and kinetics of Jatropha curcas oil transesterification with heterogeneous catalysts

This work investigates the production of fatty acid methyl esters (FAME) from Jatropha curcas oil using a variety of heterogeneous catalysts: resins, zeolites, clays, hydrotalcites, aluminas and niobium oxide. For this purpose, a catalyst screening was first conducted in a batch reactor at the following operating conditions: oil to methanol molar ratio of 1:9, 6 h of reaction, 5 wt% catalyst, at 333 and 393 K. From the screening step, KSF clay and Amberlyst 15 catalysts were selected to carry out a 2³ full factorial central composite rotatable design so as to elucidate the effects of process variables on FAME yield. The optimum reaction conditions for both catalysts were found to be oil to methanol molar ratio of 1:12, 5 wt% of catalyst, 433 K and 6 h of reaction with a FAME yield of about 70 wt%. A kinetic study was then experimentally performed and a semi-empirical model was built to represent the experimental data. Finally, catalyst re-utilization in five successive batch experiments was evaluated at the optimized conditions.     

A Simplified Internet Routing Architecture

This paper studies the effect of disaggregation on the size of the routing table in the Internet’s Default Free Zone (DFZ). Current practises for traffic balancing and protection against prefix hijacking in the Internet are based in disaggregating prefixes that cause an increase in size of the Internet’s core routing table. I propose an algorithm to assess their effect on the table size of these techniques. This algorithm is applied on routing tables collected by the RIPE’s Routing Repository between January 2001 and February 2011. The results show that before 2010, the IPv4 addressing space was gradually getting more fragmented. This trend is slowing down since the beginning of 2010, possibly as the result of the economic downturn. In the second part of this paper, I propose an alternative architecture that allows local Traffic Engineering configurations but keeps their effects from spreading over the Internet and outline an implementation for this architecture on a Linux platform.     

Cognitive Radio Design on an MPSoC Reconfigurable Platform

Cognitive Radio has been proposed as a promising technology for solving today’s spectrum scarcity problem by means of dynamic spectrum access. The multiprocessor system-on-chip (MPSoC) reconfigurable platform is proposed as an enabling technology for cognitive radio. In this paper, we propose a design methodology based on task transaction level interface for the design of cognitive radio baseband on an MPSoC reconfigurable platform. The reconfiguration of a novel, low-complexity fast Fourier transform for orthogonal frequency-division multiplexing based Cognitive Radio is used as a design case to show the effectiveness of the methodology for modelling the dynamic behavior of Cognitive Radio and facilitating the platform implementation.

Composite gel-filled giant vesicles: Membrane homogeneity and mechanical properties

We further investigate the properties of composite Poly(NIPAM) (poly(N-isopropylacrylamide)) gel-filled giant vesicles, focusing here on i) the homogeneity of the membrane, ii) its coupling to the inner gel under strong suction pressures, and iii) the relation between the final elastic modulus of the vesicles and the amount of crosslinker in the pre-gel medium. We show that whereas the photo-polymerization process induces a decrease of the membrane homogeneity at the micrometer size range, the membrane still remains strongly coupled to the internal gel network. The vesicles studied here display average moduli in the range [0.5–25] kPa, confirming their potential as biomimetic mechanical systems.     

A model of self-limiting residual acid diffusion for pattern doubling

Pattern doubling by cross-linking of a spacer triggered by residual acid diffusion from a previously developed primary structure into the spacer is a possible option to create the necessary structure widths for the 32 nm node with current exposure technology by pattern doubling. A particular advantage of this process step would be the self-alignment to the primary structure, which would render a second exposure step unnecessary. In the paper, we present a new prototypical model of the bake step of this process and discuss the dependency of the desired behavior on parameters of the model.     

Compaction index of cement paste of normal consistency

Knowing the virtual packing densities of all the components in a mixture is necessary to calculate its granular packing density with the compressible packing model. The calculation of these virtual packing densities is based on real packing density measurements carried out according to specific operating modes, each one with a different compaction index K. For powders, the current method consists in adding water to powder in a mixer until obtaining a smooth paste (K = 6.7). But this method remains subjective since the degree of smoothness achieved is estimated by the operator. The objective of this work is to put forward a more rational alternative method based on tests of normal consistency used in cement plants. This paper presents experiments on binary mixtures (cement–mineral admixtures), with or without superplasticizer, which have resulted in a compaction index K = 4.8. Using these results, the amount of water (given in the technical data sheet) needed to obtain a normal consistency allows the calculation of virtual packing densities of standardized cements. However, if a superplasticizer is used it is necessary to carry out this test. Its saturation proportion can also be estimated with the test of normal consistency.     

Sensory profile,acceptability, and their relationship for diabetic/reduced calorie chocolates

The purpose of this study was to determine the sensory properties and acceptability of lab developed prototypes of conventional, diabetic (with no sugar), and diabetic/reduced calorie milk chocolates (no sugar and 25% calorie reduction) with high-intensity sweeteners, sucralose and stevioside, and partial fat replacement with whey protein concentrate (WPC). PLS was performed in order to relate sensory properties and consumer acceptability and to determine drivers of liking and disliking. There was no difference between conventional, diabetic and diabetic/reduced calorie milk chocolates for brightness, cocoa aroma, cocoa butter aroma, and cocoa flavor (p > 0.05). Acceptability was higher for sucrose substitution by sucralose than by stevioside and partial fat replacement reduced acceptability of flavor even more (p ? 0.05). Crucial attributes which determine consumer acceptability in samples are sweet aroma, melting rate, and sweetness, whereas bitterness, bitter aftertaste, adherence, and sandiness were drivers of disliking.