A column centrifugation method for the reconstitution in liposomes of the mitochondrial F0F1 ATP synthase/ATPase

A method for reconstitution of membrane proteins into unilamellar liposomes is described. The model enzyme was the F0F1 ATP synthase from mitochondria when in complex or free from its inhibitor protein. The enzymes were first solubilized with either of two detergents, i.e., n-dodecyl-beta-D maltoside or lauryldimethylamine oxide. After solubilization, the enzymes were passed through a column of Sepharose-AH using an ADP/sodium cholate selective elution buffer. The enzymes recovered from the column were subsequently passed through a centrifuge column of Sephadex G-50 fine. The eluate contained liposomes in which the F0F1 complex (with and without inhibitor protein) had been reconstituted. The reconstituted enzymes were capable of hydrolyzing ATP with formation of electrochemical H+ gradients. They also catalyzed the ATP-Pi exchange reactions. Thus the F0F1 complex which is formed by 18 subunits can be rapidly reconstituted into liposomes in a fully functional state. Moreover the data show that the interactions between the enzyme and its inhibitor protein are not perturbed in the reconstitution procedure.     

Solution of temperature fields in hydrodynamics bearings by the numerical network method

Solution to the 2-D steady-state nonlinear heat conduction equation, involving cylindrical coordinates, applied to a plain bearing by a simple and versatile numerical technique based on network method is presented in this work. These advantages of the technique are necessary for the status evaluation of industrial machines during operation because time and computing resources are limited. The pressure field in the fluid is previously solved from the Reynolds equation by finite element method. The main difficulty is associated with the exponential dependency of the viscosity on temperature. The proposed model is very efficient and requires negligible computing times. Solutions are very close to the experimental and numerical results of other researchers.     

Hull-less Barley Varieties: Storage Proteins and Amino Acid Distribution in Relation to Nutritional Quality

Barley (Hordeum vulgare L.) has had an important impact on human nutrition. Hull-less barley is a genetically improved type that has been widely used in recent years. Six Brazilian hull-less barley varieties (IAC-IBON 214-82; IAC 8612-421; IAC 8501-31; IAC 8501-12; IAPAR 39-ACUMAI; IAC 8501-22) were analyzed for storage protein constituents, amino acid contents, and similarity among the hull-less barley varieties. Albumins, globulins, prolamins I and II, and glutelins were extracted and separated by SDS-PAGE. The total protein amino acid contents of the flour were also determined for each variety by TLC and HPLC. Variations in intensity and appearance and disappearance of protein bands were observed among the varieties suggesting genetic variability. However, the amino acid profile did not indicate any major variations in the amino acid concentrations. The high lysine and threonine total concentrations detected in the seeds of the hull-less barley varieties encouraged an investigation into the regulation of amino acid metabolism and storage protein synthesis.     

Infrared and ultraviolet–visible spectroscopic studies of silica, [(Cp)2ZrCl2] and trimethylaluminum interactions

Infrared and UV–vis studies of metallocene immobilization on silica are reported here. The results have indicated changes in the Zr coordination sphere of metallocene depending on the immobilization route used. The reaction of [(Cp)₂ZrCl₂] with silica formed [(Cp)₂ZrCl]⁺[SiO]⁻ species. The same metallocene, reacting with TMA modified silica, formed monomethylated and dimethylated species by the substitution of chloro for methyl ligands, stabilized on the surface by interaction with “MAO-like” species (methylaluminoxane, MAO). These monomethylated and dimethylated cationic zirconium species are the active centers for the polymerization reaction. Different order of TMA addition in the silica modification step generated surface species of a similar nature, differing in their relative quantities. The highest amount of these active species was obtained when the support was added to the TMA solution rather than adding the TMA solution to the silica support. This was the most significant parameter affecting catalytic activity in ethylene polymerization.     

First experiences with the modelling and simulation package MIRACLES applied to a picture archiving and communication system (PACS) in a clinical environment

Since the construction of picture archiving and communication systems (PACS) appears to be extremely difficult, computer modelling and simulation are used as decision support tools. The package MIRACLES (Medical Image Representation, Archiving and Communication Learned from Extensive Simulation) has been developed at BAZIS in order to support the construction of simulation models of image information systems. This article discusses the application of MIRACLES to a prototypical PACS as being installed in a clinical environment. Attention is focussed to the required system analysis and difficulties which arose during the construction of the simulation model. The emphasis is on the presentation of the results of the simulation study, which show that simulation can be fruitfully used to predict, to analyse and to assist in solving performance problems. The simulation study confirmed assumptions and suppositions concerning both the system performance itself and strategies to improve the performance. The study also resulted in a number of concrete recommendations which might be useful for the set-up of the prototypical PACS.     

An algorithm for solving multi-point boundary value problems

We describe a method for computing solutions of multi-point boundary value problems, where the polychotomic structure of the underlying solution space is specifically exploited. After the system is integrated in a multiple shooting way, the resulting linear system is solved by a special decoupling algorithm that takes into account the fact that the dichotomy on each interval is potentially different (in contrast to the two point case). A number of examples sustains the theory.     

Modeling Power Supply Noise in Delay Testing

Excessive power supply noise during test can cause overkill. This article discusses two models for supply noise in delay testing and their application to test compaction. The proposed noise models avoid complicated power network analysis, making them much faster than existing power noise analysis tools. can cause performance degradation and     

Effect of the Extraction of a Hemagglutinin on the Nutritive Value of Amaranthus leucocarpus Seeds

Hemagglutinins present in Amaranthus leucocarpus seed meal were extracted with saline buffer and nutritive value was estimated by PER, NPR as well as Digestible Energy Consumption Evaluations. Protein digestibility was determined both in vitro and in vivo. Trypsin inhibitor activity was also determined. Saline-extracted Amaranth meal had significantly higher PER and NPR values than whole meal (p<0.05). There were no significant differences in digestible energy (Kcal/day/ animal) and protein consumption (g/day/animal) between diets (p<0.05). A. leucocarpus improves in nutritive value after the saline extraction procedures and has a good potential as a complementary food due to its lysine content. In addition purified agglutinin may be a useful biochemical.     

Income, Time Effects and Direct Preferences in a Multimodal Choice Context: Application of Mixed RP/SP Models with Non-Linear Utilities

Transport problems typically involve at least two types of constraints, on income and on time. Therefore, the indirect utility function depends either on the income available after having subtracted the cost of the discrete alternative and on the free time left after having worked and travelled by each competing option. In the typical linear-in-the-attributes and in-the-parameters specification, that represents the first grade approximation of the indirect utility function, the effect of income and time constraints cancel out and only the cost and time of the alternatives matter in the comparison between them. From a microeconomic point of view this is equivalent to assume that income and time effects could be disregarded; which is not always the case. To account for these effects the utility function should include second order attributes; however, in non-linear utility functions it may not be easy to distinguish among several effects that could be relevant: direct preferences for good and leisure, and simple interactions between attributes other than income and time effects. This paper analyses these effects from a theoretical point of view focusing on the possible confounding problem in detecting income and time effects. We use a dataset collected for a modal choice context and containing both revealed and stated preference data, and estimate several NL models examining the effect of the different second-order terms on detecting income and time effects. We compared specifications including square cost and time attributes, interactions between time and cost, cost divided by the income available to be spent on free time, and time multiplied by free time. Our results confirm the strong effect of direct preferences for goods and leisure time on choice, and the potential confounding effect between quadratic attributes and other non-linear omitted terms. Finally, we also found that care should be taken in highlighting income and time effects using mixed data sources, since confounding effects can occur when non-linearities are accounted for in both data sets.