Characterisation of natural organic matter from the Nordic typing project water samples by chemometric analysis of their near infrared spectral profiles

Natural organic matter (NOM) from nine different water sources located in the southern part of Norway selected for the “NOM typing project” was characterised by using near infrared spectroscopy and multivariate data analysis.

The near infrared profiles of these NOM samples were corrected for multiple scattering effect and differentiated twice before subjecting them for multivariate data analysis. The preprocessed profiles were first subjected to multivariate calibration using partial least squares (PLS) technique against earlier determined values of four different biopolymer input (carbohydrates, N-acetyl amino sugars, proteins and polyhydroxy aromatics) of the NOM as dependent variables. The profiles were then classified using principal component analysis (PCA).

The PLS calibration models obtained demonstrate that the biopolymer input of the NOM samples can be predicted with acceptable precision.

The PCA reveals that the samples fall into three different groups. This classification agrees with earlier classifications carried out by using variables that were determined by alternative expensive and time-consuming analytical techniques.     

An addressable 256×256 photodiode image sensor array with an 8-bit digital output

We have constructed an addressable 256 × 256 photodiode sensor array together with an 8-bit ADC (analog-to-digital converter) on the same chip. Such a digital camera is easy to connect to a computer where also the flexibility of the computer can be used to control the camera output. The sensor has been constructed in two versions. The first version was implemented with a 256-column parallel-bit-slice image processor on the same die in a commercial project and the second as a separate addressable digital image sensor. The sensor was functionally fabricated using 1.6 µm design rules in a 1.2 µm CMOS process where it required a total area of 96 mm².     

Isocyanates,aminoisocyanates and amines from fires—a screening of common materials found in buildings

Isocyanates, aminoisocyanates and amines were quantified from the combustion of 24 different materials or products typically found in buildings. Small‐scale combustion experiments were conducted in the cone calorimeter, where generally well‐ventilated combustion conditions are attained. Measurements were further made in two different full‐scale experiments. Isocyanates and amino‐compounds were sampled using an impinger‐filter sampling system with a reagent solution of di‐n‐butylamine in toluene. Filter and impinger solution were analysed separately using LC‐MS technique. Further the particulate distribution in the smoke gases was determined by impactor technique, and selected gaseous compounds quantified by FTIR. It was found in the small‐scale that isocyanates were produced from the majority of the materials tested. The highest concentration was found for glass wool insulation, and further high concentrations were found for PUR products, particleboard, nitrile rubber and melamine. Lower concentrations were found for wood and cable‐products. Amino‐isocyanates and amines were generally found from PUR products only. The distribution of isocyanates between the particulate‐ and fluid phases varied for the different materials and a tendency to enrichment of particles was seen for some of the materials. Further, when comparing the potential health hazard between isocyanates and other major fire gases (based on NIOSH IDLH‐values) it was found that isocyanates in several cases represented the greatest hazard. Copyright © 2003 John Wiley & Sons, Ltd.     

An ESDIRK method with sensitivity analysis capabilities

A new algorithm for numerical sensitivity analysis of ordinary differential equations (ODEs) is presented. The underlying ODE solver belongs to the Runge–Kutta family. The algorithm calculates sensitivities with respect to problem parameters and initial conditions, exploiting the special structure of the sensitivity equations. A key feature is the reuse of information already computed for the state integration, hereby minimizing the extra effort required for sensitivity integration. Through case studies the new algorithm is compared to an extrapolation method and to the more established BDF based approaches. Several advantages of the new approach are demonstrated, especially when frequent discontinuities are present, which renders the new algorithm particularly suitable for dynamic optimization purposes.     

The Sounds of Two Landscape Settings: auditory concepts for physical planning and design

Sonic aspects relevant to landscape architects and planners are examined in order to show that soundscapes can be acknowledged and developed as an aesthetic resource for sustainable development. This auditory approach aims at an inter-sensory understanding of human perception and its significance for the design of physical environments. Two settings--a pasture landscape and a city garden--were studied by skilled listeners on site. They contributed to a preliminary terminology for the design of sonic environments, sonotopes. Clarity emerged as one cardinal principle for auditory refuges, and it was found to be related to the balance of particular sonic features and their background sounds. A figure/ground model described these proportions. The distances to sonic events and the tempo of sonotopes defined refuges. Sonic events mirrored the land use and constituted acoustic space according to the distribution of sound sources. Distant sources were suggested as a practical pointer and design tool for overall conditions together with tempo, which is described as the pace of interplay of figures that fade in and out of a background.     

Characterisation of anthocyanins in red cabbage using high resolution liquid chromatography coupled with photodiode array detection and electrospray ionization-linear ion trap mass spectrometry

The aim of this work was to analyse and tentatively identify anthocyanin species in red cabbage using HPLC/DAD-ESI/Qtrap MS. The extraction was realized by using a pressurized liquid technique and the separation of the pigments was achieved by a high resolution liquid chromatography system with a 1.8 μm particles C-18 column. Photodiode array detection was employed to determine the UV/Vis spectral characteristic of the pigments. Electrospray ionization-linear ion trap mass spectrometry allowed the specific determination of the fragmentation patterns of the anthocyanins, by performing different ion scan modes. Twenty four anthocyanins were separated and identified, all having cyanidin as aglycon, represented as mono- and/or di-glycoside, and acylated, or not, with aromatic and aliphatic acids. Nine anthocyanins were identified for the first time in red cabbage.     

Uracil in human DNA from subjects with normal and impaired folate status as determined by high-performance liquid chromatography-tandem mass spectrometry.

A sensitive and selective method for determination of the uracil content in human DNA was first developed on the basis of high-performance liquid chromatography-tandem mass spectrometry. Uracil was excised from DNA using uracil DNA glycosylase. The released uracil was derivatized with 4-bromomethyl-7-methoxycoumarin, thereby forming bis-N,N'-(4-methylene-7-methoxycoumaryl)-uracil (uracil-MMC). 15N2-Uracil was used as an internal standard. The analytes were separated on an Adsorbsphere XL ODS column. A SCIEX API III tandem mass spectrometer equipped with a turbo ion-spray interface was used as the detector. Multiple reaction monitoring using the parent --> product ion combinations of m/z 489 --> 232 and 491 --> 233 were used to detect uracil-MMC and the internal standard, respectively. The detection limit for this assay is <1.0 x 10(-10) mol/L uracil, and the linearity is from 1.0 x 10(-10) to 2.5 x 10(-6) mol/L. The method was used for determination of uracil in human DNA. Our data show that the uracil levels in human DNA isolated from peripheral white blood cells did not differ between subjects with folate deficiency and subjects with normal red cell folate levels.     

Methods for Checking the Consistency of Precedence Constraints

Precedence constraints appear in mathematical models from many different fields of application and the problem of determining whether or not a set of such constraints is consistent is of rather general interest. This paper describes a number of different approaches to this problem. For each approach a survey of existing algorithms is given. An efficient algorithm, especially designed for checking the consistency of activity networks, is developed by the combination of recent graph algorithms with ideas published in the early 60's. The time of computation for this algorithm grows linearly with the number of constraints and it is faster than any other published algorithm when applied to digraphs of a certain structure.     

Design of a General‐Purpose European Compound Screening Library for EU‐OPENSCREEN

This work describes a collaborative effort to define and apply a protocol for the rational selection of a general‐purpose screening library, to be used by the screening platforms affiliated with the EU‐OPENSCREEN initiative. It is designed as a standard source of compounds for primary screening against novel biological targets, at the request of research partners. Given the general nature of the potential applications of this compound collection, the focus of the selection strategy lies on ensuring chemical stability, absence of reactive compounds, screening‐compliant physicochemical properties, loose compliance to drug‐likeness criteria (as drug design is a major, but not exclusive application), and maximal diversity/coverage of chemical space, aimed at providing hits for a wide spectrum of drugable targets. Finally, practical availability/cost issues cannot be avoided. The main goal of this publication is to inform potential future users of this library about its conception, sources, and characteristics. The outline of the selection procedure, notably of the filtering rules designed by a large committee of European medicinal chemists and chemoinformaticians, may be of general methodological interest for the screening/medicinal chemistry community. The selection task of 200K molecules out of a pre‐filtered set of 1.4M candidates was shared by five independent European research groups, each picking a subset of 40K compounds according to their own in‐house methodology and expertise. An in‐depth analysis of chemical space coverage of the library serves not only to characterize the collection, but also to compare the various chemoinformatics‐driven selection procedures of maximal diversity sets. Compound selections contributed by various participating groups were mapped onto general‐purpose self‐organizing maps (SOMs) built on the basis of marketed drugs and bioactive reference molecules. In this way, the occupancy of chemical space by the EU‐OPENSCREEN library could be directly compared with distributions of known bioactives of various classes. This mapping highlights the relevance of the selection and shows how the consensus reached by merging the five different 40K selections contributes to achieve this relevance. The approach also allows one to readily identify subsets of target‐ or target‐class‐oriented compounds from the EU‐OPENSCREEN library to suit the needs of the diverse range of potential users. The final EU‐OPENSCREEN library, assembled by merging five independent selections of 40K compounds from various expert groups, represents an excellent example of a Europe‐wide collaborative effort toward the common objective of building best‐in‐class European open screening platforms.