The fast and direct identification of possibly pathogenic microorganisms in air is gaining increasing interest due to their threat for public health, e. g. in clinical environments or in clean rooms of food or pharmaceutical industries. We present a new detection method allowing the direct recognition of relevant germs or bacteria via fluorescence-labeled antibodies within less than one hour. In detail, an air-sampling unit passes particles in the relevant size range to a substrate which contains antibodies with fluorescence labels for the detection of a specific microorganism. After the removal of the excess antibodies the optical detection unit comprising reflected-light and epifluorescence microscopy can identify the microorganisms by fast image processing on a single-particle level. First measurements with the system to identify various test particles as well as interfering influences have been performed, in particular with respect to autofluorescence of dust particles. Specific antibodies for the detection of Aspergillus fumigatus spores have been established. The biological test system consists of protein A-coated polymer particles which are detected by a fluorescence-labeled IgG. Furthermore the influence of interfering particles such as dust or debris is discussed.

To assess the risks associated with transport accidents involving solid LSA-II and LSA III materials a comprehensive experimental programme was conducted to quantify and characterise airborne release of radioactive particulate matter in transport and handling accidents with mechanical impact of varying severities and to determine the dependency from influencing parameters such as LSA material and packaging properties and size. The experimental approach combined well-controlled and very reproducible impact experiments with small scale specimens and drop tests of larger scale specimens from different heights up to 27m. In both cases the associated airborne release of particulate matter is determined by measuring the amount and aerodynamic particle size characteristics of released dust. The small scale tests revealed fundamental results on airborne release and size distribution which helped to design the test matrix of the large scale experiments, especially with brittle material. In the large scale tests, volumes of specimens were varied systematically up to 200L and the LSA material was contained either within packaging or without protective packaging in order to determine the influence of the packaging on the airborne release and to be able to extrapolate other configurations of package sizes and impact severities. The LSA surrogate materials were either concrete, used to immobilize radioactive wastes as representative brittle material, or appropriately chosen powders representing dispersible materials. Based on the experimental results it can be concluded that the requirements of the current IAEA Transport Regulations sufficiently limit potential radiological consequences from transport accidents with mechanical impact involving packages with LSA-II or LSA-III materials.

Automatic pollen recognition has been developed based on socalled gray-scale invariants, which characterise pollen grains independently from their position and orientation on the microscopic sample. Thus, pollen features can be extracted from the gray-scale images of transmitted light and fluorescence microscopy. In a first step, this approach is demonstrated with Ambrosia pollen of samples from a Burkard sampler, where pollen are collected from ambient air on a sticky tape mounted on a slowly rotating drum. Self-learning Support Vector Machines create a classification model from the gray-scale invariants of the particles on three Burkard samples from Mezzana (Ticino), Switzerland. Automatic pattern recognition is tested with 13 other samples from the period between July, 20th and September, 9th 2004. A recall of 77.3 % has been found for the automatic recognition of Ambrosia pollen, together with a precision of 84.0 % for this classification. Falsely negative classified objects can partly be ascribed to agglomerated pollen, the number of falsely positive classified objects can be reduced by a more specific classification mode. Automatic pollen recognition provides the basis for the development of a fully automated system that combines sampling, particle deposition onto a surface suitable for optical analysis, automatic preparation, microscopic imaging techniques, pattern recognition and the hourly output of number concentration of airborne pollen. Keywords: automatic pollen recognition, Ambrosia pollen, primary fluorescence, gray-scale invariants, Support Vector Machines, pattern recognition, pollen monitor, Burkard sampler, online- measurement Automatische Pollenerkennung – Entwicklungen und Perspektiven Die automatische Erkennung von Pollen wurde auf der Basis von so genannten Grauwert-Invarianten entwickelt, die Pollen unabhangig von ihrer Position und Orientierung auf der mikroskopischen Probe charakterisieren. Somit konnen Polleneigenschaften aus den mikroskopischen Graustufen-Bildern (Durchlicht und Fluoreszenz) abgeleitet werden. Zunachst wird dieser Ansatz am Beispiel von Ambrosia -Pollen auf Proben aus Burkardfallen demonstriert, in denen Pollen aus der Ausenluft auf einem Klebeband gesammelt werden, das auf einer langsam rotierenden Trommel befestigt ist. Selbstlernende Support-Vector-Machines erzeugen ein Klassifikationsmodell aus den Grauwert-Invarianten der Partikel von drei Burkardproben aus Mezzana (Tessin), Schweiz. Die automatische Mustererkennung wird an 13 weiteren Proben aus der Zeit zwischen dem 20. Juli und dem 9. September 2004 getestet. Fur die automatische Erkennung von Ambrosia -Pollen ergibt sich eine Erkennungsrate von 77,3 % bei einer Bestimmungsgenauigkeit von 84,0 % fur diese Klassifizierung. Falsch negativ klassifizierte Objekte konnen teilweise auf agglomerierte Pollen zuruckgefuhrt werden, die Zahl falsch positiv klassifizierter Objekte kann durch eine spezifischere Klassifikation reduziert werden. Die automatische Pollenerkennung bildet die Basis der Entwicklung eines voll automatisierten Systems, das Probenahme, Partikelabscheidung auf einer mikroskopierfahigen Oberflache, automatische Praparation, mikroskopische Abbildungstechniken, Mustererkennung und die stundliche Angabe der Anzahlkonzentration luftgetragener Pollen vereint. Stichworter: automatische Pollenerkenung, Ambrosia -Pollen, Eigenfluoreszenz, Grauwert-Invarianten, Support-Vector-Machines, Mustererkennung, Pollenmonitor, Burkardfalle, Online- Messung

Since the middle of the twentieth century there has been growing concern about air quality. Since the mid-1990th, new European framework directives relating to air quality gave rise to intense discussions about limit values for ambient exposure and their practical application. With respect to the impact on human health, particulate matter has to be differentiated by its aerodynamic diameter [1]. Particles with an aerodynamic diameter less than 10 μm, denoted as PM10, can enter the lower respiratory tract, i.e., the bronchial tubes in the lung. However, the pulmonary alveoli can only be reached by the finer particle fraction with an aerodynamic diameter less than 2.5 μm, denoted as PM2.5. A study by the World Health Organization (WHO) notes a correlation of ambient exposure of PM2.5 with mortality and cardiovascular diseases [2]. An increased risk of respiratory diseases correlated with ambient exposure to PM10 was also noted [3]. Beyond the determination of the total mass concentration of particulate matter, it is reasonable to focus on aerosol components owing to their broad spectrum of health impacts. While soot particles are alleged to be carcinogenic, the beneficial effect of airborne sea salt on respiratory diseases is clearly evident. Microscopy is a powerful tool for the differentiation of coarse particulate matter and allows a detailed analysis of air quality.

A fully automated system has been developed for microscope-based single particle analysis by extracting optical finger-prints from individual particles in ambient air samples. For this purpose, light microscopy was developed towards an objective measuring technique by employing a novel pattern recognition technique. Automated particle classification is based on so-called grey scale invariants, extracted from microscopic images of translucent, fluorescent and dark field microscopy. This information was bundled to a feature vector providing a kind of finger print for every particle. In a first step this approach was used for an automated recognition of allergen carriers such as pollen and fungal spores. A leave-one-out test gave a recognition rate of about 95% for 26 for the most frequent pollen species in central Europe. Because no pollen-specific code was used, the recognition software was also employed for an automated recognition of fungal spores without any change. Six of the most frequent airborne fungal spore genera in Central Europe were classified with a mean recognition rate of 93%. These results gave reason to a research project aiming at the development of a fully automated system. The instrument should combine (1) high-volume sampling of coarse particles >2.5 μm, (2) electrostatic precipitation of this fraction onto a surface suitable for optical analysis, (3) automatic preparation for microscopic single particle analysis, (4) imaging by various microscopic techniques, e.g. transmitted, fluorescence and dark field microscopy, (5) feature extraction by grey scale invariants, (6) classification by self-learning Support Vector Machines and (7) hourly output of number concentration of airborne pollen, fungal spores and other particles of interest. A first demonstrator is presented in early 2005. First field tests are planned for the first half of 2005. A commercialised device should be available as from 2007. The project is funded by the German Ministry of Education and Research.

RATIONALE:The Dutch VIGALL (virally mediated allergy) study investigates the role of viral upper respiratory tract infections (URTI) on maturation of the immune system and development of allergic disease.Here we investigate the prevalence of viral respiratory pathogens and changes in the immune response related to the age of children.METHODS: Hundred twenty-six infants were included at birth.Nasal brush samples were taken during routine visits every 6 months and during URTI up to the age of the two years.The type of virus, number of effector cells (macrophages, T-lymphocytes), and mediators cells (Th 1 and Th2 cytokine positive) in relation to the age of the child were determined.RESULTS: The most common viral pathogens during URTI were rhinovirus (-40%), RSV (~20%), and coronavirus (~10%).Surprisingly, 20% of infants without nasal symptoms were rhinovirns positive.Numbers of macrophages (CD68) in healthy controls remained constant with age, where the numbers increased during RSV or rhinovirus URTI.Numbers of T-lymphocytes (CD3) increased with age, both during viral infection and in healthy controls.Additionally, a decrease in numbers of IL-4 and IL-10 positive cells (Th2) was observed with increasing age of healthy controls, while the number of IL-12 positive cells (Th 1) remained constant.T-lymphocyte and IL-4 responses remained related to the age when adjusted for the number of respiratory infections.CONCLUSIONS: Our data show the maturation of the nasal immune system in children.Based on initial data we suggest that the maturation is ' age-related rather than infection-related.

An expansion- type Kelvin spectrometer has been designed and its performance has been shown to agree with the theoretical simulation within experimental uncertainty. In the intrinsically calibrated mode, number concentration as well as supersaturation can be determined from first principles and experimentally verified. In this mode, the number concentration uncertainty is about +/- 15%, and the supersaturation uncertainty is about +/- 20%. The concentration detection limit in this mode depends on the supersaturation and is limited by heat conduction from the walls. In the Mie scattering mode, the detection limit is about 30 cm(-3). It is capable of operating in a wide range of supersaturations using a variety of liquids.

The Respicon has been introduced as a sampler for health related measurements of airborne contaminants at workplaces. The instrument is aimed at simultaneous collection of three health related aerosol fractions: (a) the coarser inhalable fraction, defining the aerosol fraction that may enter the nose and mouth during breathing; (b) the intermediate thoracic fraction, defining the fraction that may penetrate beyond the larynx and so reach the lung; and (c) the finer respirable fraction, defining the fraction that may penetrate to gas exchange region of the lung. The instrument has a number of features attractive to occupational hygienists: in addition to providing the three aerosol fractions simultaneously, it is light and compact enough to be used as a personal sampler. yet can be a tripod mounted for area sampling, it can provide samples not only for gravimetric analysis but also microscopic and chemical analyses; and it is also available in a photometric direct-reading version. The instrument has previously been evaluated as an area sampler and, in this mode of operation, has shown reasonable accuracy in collecting respirable, thoracic and inhalable particles, the latter up to particle diameters of ca. 80 microm. Except for some scattered unpublished data there exist no systematic investigations in the Respicon's performance when used as a personal sampler in the industrial environment. In this paper, we will report on a study of side by side comparison of the Respicon with the IOM inhalable sampler, regarded as a reference instrument for the inhalable fraction. The main study was performed at six different workplaces in a nickel refinery. Statistical analysis of the gravimetrically-determined concentration data reveals consistently lower aerosol exposure values for the Respicon as compared to the IOM sampler. The data for the nickel workplaces are compared with findings from other studies. The results are interpreted in the light of the overall results and the possibility of introducing a correction factor is discussed.

This paper describes plans for two sets of experiments designed to evaluate the behavior of irradiated nuclear fuel to high-energy shock and collision impact environments. The first is the initiative of an international working group established to study the consequences of terrorist attacks on container systems used to store and transport radioactive materials. A related, but separate, study provides information on spent fuel behavior in high-energy collision impact situations to enhance the fidelity of risk assessments. Both sets of planned experiments include the same organizations and are pursued with similar test protocols. The international group involved with study of terrorist attack consequences includes representatives from France, Germany, the United Kingdom, and the United States. The two experimental programs would be conducted at laboratories in Germany and in the U.S.

Three particle size fractions of the airborne dust are defined in European and US standards for healthrelated dust measurements at the workplace: the respirable, the thoracic, and the inhalable fraction. In 1999 we introduced a novel instrument for personal, time-resolved concentration monitoring and sampling of these three fractions. The instrument combines inertial classification, filter sampling and photometric aerosol detection. It consists of a two-stage virtual impactor (cut-off diameters of 4 and 10 pin), three filters, and three light scattering photometers. The filter material can be chosen in order to meet the requirements of the respective analytical method: gravimetry, chemical, or microbiological analysis. In this paper we describe the instrument and we present recent data on calibration and validation tests as well as results of field measurements at real workplaces. The instrument fulfills the requirements of the European standards directly when operated as an area monitor. When the instrument is used as a personal monitor a constant correction factor has to be applied to the extrathoracic fraction of the dust collected by the sampler in order to achieve compatibility with the health related sampling standards. Examples from various field studies show that a large body of information is available from the measurements with this new instrument.

A computer-controlled spray-generating and spray-exposure unit called RHINOCON was designed and constructed to offer the possibility of depositing, for example, environmental or pharmaceutical aerosols at the air/liquid interface under realistic exposure conditions. Here, isolated human respiratory cells are chosen to simulate, as far as possible, the in vivo situation. The exposure unit is equipped to hold up to 6 commercially available pump-spray dispensers, which are prepared mechanically for exposure as described in the manufacturer's users' guide. A transwell insert containing the cells is placed opposite each dispenser in a special plate head first. After starting the program, the spray dispensers are shaken and actuated automatically. The spray is released into an air flow passing over the cells, where the spray droplets are deposited due to their inertia. After exposure, the inserts can easily be removed and processed to measure a variety of cell toxicity parameters, such as cell viability or cell metabolism. Validation of the experimental setup was performed in an initial set of experiments: (1) by determination of the deposited amount of nebulized test substance on transwell membranes, and (2) by investigation of the cellular reactions of a human respiratory epithelial cell line (HFBE 21) exposed to nebulized hydrogen peroxide or to standard medium as a reference control.

Three particle size fractions of airborne dust are defined in European and U.S. standards for health-related dust measurements at the workplace: the respirable, the thoracic, and the inhalable fraction. We developed a novel instrument for personal, time-resolved concentration monitoring and sampling of these three fractions. The instrument combines inertial classification, filter sampling, and photometric aerosol detection. It consists of a two-stage virtual impactor (cut-off diameters of 4 and 10 mu m), three filters, and three light scattering photometers. The virtual impactor serves as a particle size classifier and a coarse particle concentrator. This enrichment compensates for the decreasing particle mass-based photometric sensitivity with increasing particle diameter. The optical sensors are calibrated in-situ via the mass concentrations obtained gravimetrically from the filter samples. The device operates at a how rate of 3.1 1/min. There is strong agreement between the experimentally determined particle size-dependent collection efficiencies and the definition curves of the corresponding dust fractions. The size dependence of the sensitivity of the inertial concentrator and photometric detection units follow the definition curves qualitatively. Exposure data were obtained for different workplace environments characterized by temporally and spatially highly fluctuating concentrations. The field measurements have shown that the instrument is practicable under rough industrial conditions and that it enables a more comprehensive and more realistic characterization of the individual exposure of workers to health-endangering dusts than was previously possible.