Pigments protect the light harvesting proteins of chloroplast thylakoid membranes against digestion by gastrointestinal proteases

Chloroplast thylakoid membranes inhibit pancreatic lipase/colipase activity in vitro and, when included in food, induce satiety signals. As thylakoid membranes themselves are nutrients, containing lipids and proteins, it is of interest to study the digestion of thylakoids by enzymes of the gastrointestinal tract. Thylakoid membranes were treated with pepsin, trypsin, gastric and pancreatic juice at 37°C and the resulting enzymatic breakdown was analyzed by gel electrophoresis, electron microscopy and mass spectroscopy. In all cases, several of the proteins were degraded within half an hour, while the main parts of the pigment–protein complexes were resistant for hours. Oil emulsified thylakoids were more resistant towards the enzymatic breakdown. Electron microscopy demonstrated that, after treatments, the thylakoids still remained in a membrane vesicular form. The capacity of thylakoid membranes to inhibit the lipase/colipase activity was partly reduced in all cases. About 50% of the inhibition capacity remained after treatment with pancreatic juice when the thylakoids were present in an oil emulsion. Delipidated thylakoids and plasma membranes, which lack the photosynthetic pigments, were degraded rapidly by pancreatic juice. Conclusion: The pigments, closely bound to the trans-membrane helices of thylakoid membrane proteins protect these from digestion by pepsin, trypsin, gastric and pancreatic juice. This supports the notion that a substantial inhibition of lipase/colipase takes place during the first 2 h in the intestine resulting in a retardation and prolongation of lipolysis in vivo.     

The effect of postmortem processing treatments on quality attributes of raw Atlantic salmon (Salmo salar) measured by sensory and instrumental methods

The main objective of this study was to compare the effects of three different processing treatments on sensory attributes and instrumental quality measurements of raw Atlantic salmon (Salmo salar) fillets. Salmon was either pre-rigor filleted and restricted or allowed to contract (Vacuum-PRE and Contracted-PRE, respectively) or post-rigor filleted (POST). Sensory evaluation (appearance, flavour, texture) and instrumental quality measurements (colour, texture, fat, astaxanthin, liquid holding capacity) were performed at 5–7 days postmortem. Sensory evaluation revealed that Vacuum-PRE fillets had less desirable quality attributes than the other treatment groups, with higher scores for tenderness and whiteness and lower scores for hardness and colour intensity. The observed changes in fillet height between the treatment groups indicated that the immediate vacuum packaging of the Vacuum-PRE fillets had limited their contraction during rigor mortis development, resulting in the negative effects observed on quality. This implicates that the well-known positive effects of pre-rigor filleting regarding colour and texture can be reduced or even abolished if the fillets are restricted from contraction during rigor mortis development.     

Giant oil field decline rates and their influence on world oil production

The most important contributors to the world's total oil production are the giant oil fields. Using a comprehensive database of giant oil field production, the average decline rates of the world's giant oil fields are estimated. Separating subclasses was necessary, since there are large differences between land and offshore fields, as well as between non-OPEC and OPEC fields. The evolution of decline rates over past decades includes the impact of new technologies and production techniques and clearly shows that the average decline rate for individual giant fields is increasing with time. These factors have significant implications for the future, since the most important world oil production base – giant fields – will decline more rapidly in the future, according to our findings. Our conclusion is that the world faces an increasing oil supply challenge, as the decline in existing production is not only high now but will be increasing in the future.     

Preparation of lanthanum tungstate membranes by tape casting technique

Lanthanum tungstate materials have been reported to show exceptional mixed proton and electron conducting behaviour at elevated temperatures and making them attractive for dense hydrogen gas separation membranes. In this work preparation of planar asymmetric lanthanum tungstate membranes was addressed. For this purpose carbon black and rice starch pore formers were evaluated for optimum substrate gas permeability. It was found that carbon black pore former results in higher level of effective porosity. Stabilization of fine lanthanum tungstate powder in ethanol based solvent media was carried out to find out optimum surfactant quantity for tape casting slurry. By combining lanthanum tungstate tapes with and without pore former defect free asymmetric membranes were produced by conventional sintering.     

Global coal production outlooks based on a logistic model

A small number of nations control the vast majority of the world’s coal reserves. The geologically available amounts of coal are vast, but geological availability is not enough to ensure future production since economics and restrictions also play an important role. Historical trends in reserve and resource assessments can provide some insight about future coal supply and provide reasonable limits for modelling. This study uses a logistic model to create long-term outlooks for global coal production. A global peak in coal production can be expected between 2020 and 2050, depending on estimates of recoverable volumes. This is also compared with other forecasts. The overall conclusion is that the global coal production could reach a maximum level much sooner than most observers expect.     

Loss of safety assessment and the IEC 61508 standard

The standard IEC 61508 contains a lot of useful information and guidance for safety improvement regarding the use of safety systems. However, some of the basic concepts and methods for loss of safety quantification are somewhat confusing. This paper discusses the failure classification, the various contributions to the safety unavailability, and in particular the common cause failure (CCF) model presented in this standard. Suggestions for clarifications and improvements are provided. In particular, a new CCF model is suggested, denoted the Multiple Beta Factor model.     

A multivariate analysis of the early dropout process.

Performed principal-component factor analyses on patient input (demographic and pretherapy expectations), therapist input (demographic), and patient perspective therapy process variables that significantly differentiated 71 early dropout from 110 nondropout outpatients at 2 community mental health centers. At 1 setting results confirm (a) the presence of selection factors in the intake process whereby the more disturbed patients, who subsequently drop out, are assigned to lower level trained therapists and (b) the proposition that many patients unilaterally terminate despite the perception of the initial session as being an overall positive experience. Findings at the 2nd setting support the more traditionally held view of "dropout" as related to patient dissatisfaction with received services. Differences in the dropout process at the 2 settings were attributed to empirically demonstrated differences in the therapists' theoretical approach to the initial interview. The proclivity of earlier investigators to conceptualize dropouts as being characteristic of a single type of patient seems to be another unfounded homogeneity myth. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hamburger Composition and Microwave Heating Uniformity

ABSTRACT: The importance of recipe modifications on the microwave heating uniformity and dielectric properties of a hamburger was investigated in a household oven. Factorial design was used in the experimental setup, and data were evaluated by analysis of variance. Temperature was monitored by a fiberoptic device, infrared imaging, and thermocouples. Dielectric data of the hamburger components were measured by a cavity perturbation method. An analytical model for calculating microwave energy balance was developed and compared with experimental data, and numerical modeling was also used in the analysis, and the results were compared. Uneven heating is difficult to improve by recipe modifications only. The differences between the analytical and numerical modeling indicate that the uniformity of heating in relatively small loads is difficult to achieve.     

Interactive surface modelling, an implementation of an expert system for specification of surface roughness and topography

Making roughness a useful tool for obtaining optimally functional surfaces demands a high quality foundation for surface specifications. Erroneous specifications in many cases lead to costly production and perhaps nonfunctional surfaces. The Interactive Surface Modelling system, ISM, presented in this paper, addresses those problems with an approach where functional demands control the route from specification of parameters through manufacturing preparation to measurement of the machined surface. Here, the operator, be it the designer, the production engineer, or the quality control engineer, can interactively reason with the system to reach a suitable specification with the aid of integrated software in a PC-Windows environment controlled by an expert system software. The representation of the surface's 3D geometry then is a natural component. The access to depiction and literature references and standards is implemented together with the ability to serve the user with graphic feedback by generating synthetic surfaces from the specification made. The described features have been implemented in a prototype developed in cooperation between Volvo and Chalmers on two functional surfaces: cylinder liners and synthetic leather for the automotive industry. Problems with specifying correct roughness and topography actually have emerged when changes have been made of material or manufacturing process for an old and proven product. This has shown that knowledge is missing or incomplete about proper intervals for roughness parameter values for definition of the relationship between a surface's function and its parameters . The result is misunderstandings and errors. By letting ISM be a base for continuous updating and modification of knowledge, opportunities will be created for increased quality of surface roughness specifications through this systematic approach to the complex, expanding field of Surface Roughness and Surface Topography.