Does precontemplation represent a homogeneous stage category? A latent class analysis on German smokers.

The authors examined the subtype structure of smokers classified in the precontemplation stage of change within the transtheoretical model. From a general practice-based sample of 1,499 daily smoking patients from Germany (participation rate 80%), they used a subgroup of 929 smokers who were classified in the precontemplation stage and applied latent class analysis, using the pros and cons of nonsmoking and smoking cessation self-efficacy as the defining variables. Cross-sectional validation of the emerging classes was based on smoking behavior and processes of change variables. For longitudinal validation, generalized estimation equation analyses were used on motivational and abstinence criteria from 6-, 12-, 18-, and 24-month follow-ups. A 4-class model best represented the data. Three subtypes (labeled progressive, immotive, and disengaged pessimistic) were similar to clusters identified in U.S. studies. The 4th (disengaged optimistic), by contrast, was reminiscent of a type that had previously only emerged in a Dutch study. Cross-sectional and longitudinal validation results confirmed the distinctiveness and predictive power of the classes. The findings highlight the importance of tailoring interventions for smoking behavior change to the needs of different subgroups of precontemplating smokers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sliding wear of an unlubricated frictional combination of ductile metal and brittle abrasive

The concept of determining wear from hypotheses concerning shear effects in metal surface regions was applied to the sliding wear of a smooth elastoplastically deformable metal substance and a rough brittle abrasive. Interfacial layers or lubricating depositions on either surface were neglected. The form of the contact was modelled using random fields for the roughness profiles. The resulting intensities of wear may be compared with published experimental results. The wear intensity level was quantitatively determined. Dependence on the nominal pressure and properties of the rough abrasive is thus explained. Instead of hardness the compressive strength of abrasive peaks is the dominant characteristic parameter.     

Inter-observer variation in masked and unmasked images for quality evaluation of clinical radiographs

PURPOSE: To investigate the influence of masking on the inter-observer variation in image quality evaluation of clinical radiographs of chest and lumbar spine. BACKGROUND: Inter-observer variation is a big problem in image quality evaluation since this variation is often much bigger than the variation in image quality between, for example, two radiographic systems. In this study, we have evaluated the effect of masking on the inter-observer variation. The idea of the masking was to force every observer to view exactly the same part of the image and to avoid the effect of the overall 'first impression' of the image. A discussion with a group of European expert radiologists before the study indicated that masking might be a good way to reduce the inter-observer variation. METHODS: Five chest and five lumbar spine radiographs were collected together with detailed information regarding exposure conditions. The radiographs were digitised with a high-performance scanner and five different manipulations were performed, simulating five different exposure conditions. The contrast, noise and spatial resolution were manipulated by this method. The images were printed onto the film and the individual masks were produced for each film, showing only the parts of the images that were necessary for the image quality evaluation. The quality of the images was evaluated on ordinary viewing boxes by a large group of experienced radiologists. The images were examined with and without the masks with a set of image criteria (if fulfilled, 1 point; and not fulfilled, 0 point), and the mean score was calculated for each simulated exposure condition. RESULTS: The results of this study indicate that-contrary to what was supposed-the inter-observer variation increased when the images were masked. In some cases, especially for chest, this increase was statistically significant. CONCLUSIONS: Based on the results of this study, image masking in studies of fulfilment of image criteria cannot be recommended.     

Co-oxidation of carotene and crocin by soyabean lipoxygenase isoenzymes

Summary Three lipoxygenases that occur in soya beans were separated chromatographically. L-1 (optimum pH = 9.0), L-2 (pH 6.5), L-3 (pH 6.5). The velocities with which these enzymes co-oxidise-carotene or Crocin in the presence of linoleic acid or linoleyl sulphate weremeasured. The carotenoid turnover was related to each lipoxygenase activity.-carotene/linoleic acid = 55% (L-2), 43% (L-3), 6% (L-1), Crocin/linoleic acid = 17,8% (L-2), 14,3% (L-3), 3.3% (L-1), crocin/linoleyl sulphate = 24% (L-3), 4,2% (L-1).The relationship between the reaction rate of the Crocin bleaching and the concentrations of the enzyme, Crocin and linoleic acid was determined. To explain the differences between the pH-6.5 (L-2, L-3) and the alkaline (L-1) lipoxygenases it is supposed that L-2 and L-3 form specially active radicals that are able to co-oxidise polyenes. Both enzymes possess a hydrophobic bonding position, in the neighbourhood of the active site, for-carotene.

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Co-oxidation von Carotin und Crocin durch Lipoxygenase-Isoenzyme aus der Sojabohne

Zusammenfassung Drei in Sojabohnen vorkommende Lipoxygenasen wurden chromatographisch getrennt: L-1 (pH-Optimum 9,0), L-2 (pH 6,5), L-3 (pH 6,5). Gemessen wurden die Geschwindigkeiten mit denen diese Enzyme-Carotin oder Crocin in Gegenwart von Linolsäure oder Linoleylsulfat co-oxydieren. Die Carotinoid-Umsätze wurden auf die jeweilige Lipoxygenase-Aktivität bezogen.-Carotin/Linolsäure: 55% (L-2), 43% (L-3), 6% (L-1), Crocin/Linolsäure: 17,8% (L-2),14,3% (L-3),3,3% (L-1), Crocin/Linoleylsulfat: 24% (L-3), 4,2% (L-1).Für die Crocin-Bleichung wurde die Abhängigkeit der Reaktionsgeschwindigkeit von der Enzym-, Crocin- und Linolsäure-Konzentration bestimmt.Zur Erklärung der Unterschiede zwischen den pH 6,5- (L-2, L-3) und der alkalischen Lipoxygenase (L-1) wird angenommen: L-2 und L-3 bilden besonders aktiv Radikale, welche die Polyene co-oxydieren können. Beide Enzyme besitzen in der Nähe des aktiven Zentrums eine hydrophobe Bindungsstelle für das-Carotin.

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We are grateful to the Deutsche Forschungsgemeinschaft Bonn-Bad Godesberg for supporting this work.     

Process control of lightly salted wild and farmed Atlantic cod (Gadus morhua) by brine injection, brining, and freezing--a low field NMR study

The aim of this study was to use low-field nuclear magnetic resonance (NMR) and traditional chemical methods to investigate the physical and chemical differences in wild and farmed cod processed pre- and postrigor, and how these properties were affected by brine injection, brining, and freezing. In prerigor processed farmed or wild cod, brine injections followed by brining for 2 d, with brine concentrations up to 5.5% and 4%, respectively, were not sufficient to reach a muscle salt concentration of 2% as aimed for, while wild cod processed postrigor had sufficient salt uptake after the same processing. Low-field NMR gave valuable information about the differences in the muscle structure between wild and farmed cod as well as the state of the water in the muscle during brine injection, brining, and during rigor tension. Low-field NMR is, therefore, a valuable tool that can be used to optimize the salting and storing processes of lightly salted cod products from both wild and farmed cod. For farmed cod to be used in the production of lightly salted products further research is needed. Practical Application: Optimal processing of lightly salted cod products is important to the fish industry, due to an increasing market for this product in southern Europe. Farmed cod, which is seen as a potential steady raw material source for this production, differs considerably from its wild counterparts by having other chemical and physical muscle properties, such as lower water content and lower pH. With the processing procedures used today the farmed cod can, therefore, only be used in some of the products, where wild cod is currently used as raw material. It is, therefore, important that the processing of these products is optimized with regard to these differences in the raw material. This study gives a valuable contribution to further studies about optimal combinations of brine injections, brining, and freezing of pre- and postrigor processed farmed compared to wild cod.