The aroma of finnish wild raspberries, Rubus idaeus, L.

Summary Volatile components of fresh wild raspberries were studied by combined gas chromatographymass spectrometry. A total of 75 components were identified, corresponding to about 64 ppm of raspberry oil in the press juice. More than 40 compounds not reported previously as raspberry volatiles were detected. These included 5-methyl-4-hydroxy-3(2H)furanone, 2,5-dimethyl-4-hydroxy-3(2H)furanone, 2,5-dimethyl-4-methoxy-3(2H)furanone, and 11 terpenes. Two of the identified esters, ethyl 5-hydroxyoctanoate and ethyl 5-hydroxydecanoate, have not previously been identified in natural products. These esters are very unstable, forming the corresponding -lactones during processing of the berries.

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Das Aroma von finnischen wilden Himbeeren, Rubus idaeus, L.

Zusammenfassung Die flüchtigen Aromastoffe der wilden Himbeere wurden gaschromatographisch-massenspektrometrisch bestimmt. Insgesamt 75 Bestandteile wurden identifiziert, entsprechend einem Gehalt an ätherischem Öl von etwa 64 ppm. Mehr als 40 Komponenten wurden festgestellt, die bisher nicht in Himbeeren identifiziert worden sind. Zu diesen gehören 5-Methyl-4-hydroxy-3(2H)furanon, 2,5-Dimethyl-4-hydroxy-3(2H)furanon, 2,5-Dimethyl-4-methoxy-3(2H)furanon und 11 Terpene. Die zwei identifizierten Ester, nämlich 5-Hydroxyoctansäureethylester und 5-Hydroxydecansäureethylester, sind bisher in keinen natürlichen Produkten gefunden worden. Diese Ester sind sehr unstabil und wurden beim Verarbeiten der Beeren leicht zu den entsprechenden -Laktonen umgewandelt.

     

Effect of heat treating gel films on the formation of superhydrophobic boehmite flaky structures on austenitic stainless steel

The effect of heat treating gel films at different temperatures on the formation of the boehmite flaky structures on AISI 316 type austenitic stainless steel is investigated. After heating at different temperatures, the reactivity of the gel films with boiling water to form boehmite flakes was different, which resulted in different morphologies and different contact angle values after coating with hydrolyzed (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trimethoxysilane (FAS). When the gel film was heat treated from 200 to 600 °C, the resulting contact angle was above 150°, indicating superhydrophobic behavior. However, when the gel film was heat treated below 200 °C as well as at 700 and 800 °C, only some boehmite flakes were formed; when the gel film was heat treated at 900 °C, no boehmite flakes were observed. In these cases the surface roughness is insufficient for the superhydrophobicity. The formation condition of the boehmite flakes by reaction of the gel film with boiling water is also tentatively discussed.     

Copolymerization of propene with phenylnorbornene using ansa‐bridged metallocene catalysts

Propene was copolymerized with phenylnorbornene using methylaluminumoxane (MAO)‐activated metallocene dichlorides exhibiting different symmetry: C₂‐Symmetric rac‐ethylenebis(1‐ indenyl)zirconium dichloride ( 1 ), rac‐ dimethylsilylbis(1‐indenyl)zirconium dichloride ( 2 ), rac‐ethylenebis(1‐indenyl)hafnium dichloride ( 6 ), C_s‐symmetric isopropylidene(cyclopentadienyl‐9‐fluorenyl)zirconium dichloride ( 3 ), meso‐ethylenebis(1‐indenyl)zirconium dichloride ( 4 ), and C₁‐symmetric ethylene(1‐ fluorenyl‐1‐phenyl‐2‐indenyl)zirconium dichloride ( 5 ) were chosen to evaluate the influence of the symmetry in copolymerization reactions. Experiments were done as batch polymerizations to produce homogeneous copolymers. By this setup, blend formation was avoided. The copolymers were characterized by NMR, GPC, and DSC. Catalysts 1 and 2 were the most active to copolymerize random, amorphous, copolymers with good activity. C_s‐symmetric, 3 , showed decreased activity compared with 1 and 2 and produced a bimodal copolymer. Catalyst 4 showed even lower activity than that of 3 . The activity of the hafnium complex 6 , which produced a semicrystalline polymer with a high molecular weight (116,000 g/mol) was 320 kg/mol. Catalyst 1 produced the highest comonomer content (42%) in the copolymers measured by NMR. The least active catalyst was 5 (phenyl croup in the bridge), producing only 290 kg copolymer per mole of catalyst. All polymers had elevated glass transition temperatures compared to polypropylene. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2743–2752, 2002     

The ALSM algorithm — an improved subspace method of classification

The subspace methods of classification are decision-theoretic pattern recognition methods in which each class is represented in terms of a linear subspace of the Euclidean pattern or feature space. In most reported subspace methods, a priori criteria have been applied to improve either the class representation or the discriminatory power of the subspaces. Recently, construction of the class subspaces by learning has been suggested by Kohonen, resulting in an improved classification accuracy. A variant of the original learning rule is analyzed and results are given on its application to the classification of phonemes in automatic speech recognition.     

Determining the irradiance signal from an asymmetric source with directional detectors: application to calibrations of radiometers with diffusers

The energy transfer integral between radiating rectangular and detecting circular parallel plates having nonideal angular characteristics is solved for modeling the distance dependence of the irradiance signal. The equation derived for the irradiance signal, which is called the modified inverse-square law, depends on the position, shape, size, and angular characteristics of the light source and the detector. We apply the new model equation to the calibration of a spectroradiometer to determine accurately the distance offsets, which fix the positions of the effective receiving apertures of diffusers used in the entrance optics of spectroradiometers. Earlier measurement results, e.g., for solar UV irradiance, may include uncorrected effects and can be corrected reliably as diffuser offsets and other correction factors are determined with the modified inverse-square law. Simplifications of the modified inverse-square law for analyzing the distance offsets and the correction factors are studied. Simplified equations for the diffuser offset analysis may be used without losing the accuracy when the cosine response of the diffuser is reasonably good. However, for diffusers whose angular responsivities deviate much from the cosinusoidal angular responsivity, large approximation errors in the diffuser offset values may appear if the angular effects are not properly taken into account.     

Antibacterial effect of bioactive glasses on clinically important anaerobic bacteria in vitro

Bioactive glasses (BAGs) of different compositions have been studied for decades for clinical use and they have found many dental and orthopaedic applications. Particulate BAGs have also been shown to have antibacterial properties. This large-scale study shows that two bioactive glass powders (S53P4 and 13–93) and a sol–gel derived material (CaPSiO II) have an antibacterial effect on 17 clinically important anaerobic bacterial species. All the materials tested demonstrated growth inhibition, although the concentration and time needed for the effect varied depending on the BAG. Glass S53P4 had a strong growth-inhibitory effect on all pathogens tested. Glass 13–93 and sol–gel derived material CaPSiO II showed moderate antibacterial properties.     

Psychosocial dimensions of solving an indoor air problem

This investigation focuses on the psychological and social dimensions of managing and solving indoor air problems. The data were collected in nine workplaces by interviews (n = 85) and questionnaires (n = 375). Indoor air problems in office environments have traditionally utilized industrial hygiene or technical expertise. However, indoor air problems at workplaces are often more complex issues to solve. Technical questions are inter-related with the dynamics of the work community, and the cooperation and interaction skills of the parties involved in the solving process are also put to the test. In the present study, the interviewees were very critical of the process of solving the indoor air problem. The responsibility for coordinating the problem-managing process was generally considered vague, as were the roles and functions of the various parties. Communication problems occurred and rumors about the indoor air problem circulated widely. Conflicts were common, complicating the process in several ways. The research focused on examining different ways of managing and resolving an indoor air problem. In addition, reference material on the causal factors of the indoor air problem was also acquired. The study supported the hypothesis that psychosocial factors play a significant role in indoor air problems.     

Titanium dioxide coated cementitious materials for air purifying purposes: Preparation,characterization and toluene removal potential

This work presents promising results for air purification by heterogeneous photocatalysis on new titanium dioxide loaded cementitious materials. A set of eight concretes and plasters is enriched with TiO₂ photocatalyst by dip-coating and/or sol–gel methods.