Cholesterol synthesis and esterification in isolated enterocytes: Regulation by cholesterol and cholestyramine feeding

The purpose of the present study was to investigate the physiological control of the main regulatory enzymes of cholesterol metabolism in isolated enterocytes obtained from chick duodenum, jejunum and ileum. Cholesterol feeding resulted in an inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase and mevalonate 5-pyrophosphate decarboxylase, while cholestyramine feeding increased reductase activity in all the regions studied and decarboxylase activity only in duodenum. Cholesterol feeding markedly increased acyl-CoA:cholesterol acyltransferase, but the effects of cholestyramine were less clear. The effects on transferase activity cannot be due to differences in the availability of acyl-CoA as exogenous substrate as no significant differences were found in acyl-CoA hydrolase activity after any of the dietary treatments. The effects of cholesterol feeding were related to changes in the cholesterol content of epithelial cells, whereas in the case of cholestyramine this relationship was less apparent.     

Modern Applications of Electron Microscopy to Catalysis

The active sites of ultra-dispersed Pt/-Al₂O₃ catalysts are studied using high-resolution electron microscopy, Z-contrast and dark field. In addition we have calculated using a method based in density functional theory the electrostatic potential and charge distribution of the active sites. It is conclude that the most likely Pt clusters that are formed correspond to Pt₁₃ and Pt with icosahedral and decahedral structure. It is shown that this is consistent with the electron microscopy data.     

CRUDi framework proposal: financial industry application

The alignment of information systems with the business goals of an organisation, although a topic of great importance, is not always properly valued or taken into consideration. In general, managers have different opinions to chief information officers (CIOs) in relation to IS, especially with regard to their importance and value to the business and also in terms of investment needs. Here, we discuss and study new approaches to methods and tools for assessing the relative importance of each information system to business, focusing on the financial sector including banks and insurance companies. We suggest the introduction of new key indicators for better decision support and to identify investment priorities, and present results regarding the relative importance of each process to support the business strategy. The primary goal for the inherent research project is to analyse the main problems and difficulties encountered by IS and IT managers, featuring different players and how they relate. The main contributions of this work are the CRUDi framework as a tool to improve alignment between business and IS strategies and the CRUDi survey and its results qualifying the financial sector's opinion regarding the relative importance of processes and investments.     

Study of the thermomechanical and electrical properties of conducting composites containing natural rubber and carbon black

This work describes the preparation and characterization of composite materials obtained by the combination of natural rubber (NR) and carbon black (CB) in different percentages, aiming to improve their mechanical properties, processability, and electrical conductivity, aiming future applications as transducer in pressure sensors. The composites NR/CB were characterized through optical microscopy (OM), DC conductivity, thermal analysis using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMA), thermogravimetry (TGA), and stress–strain test. The electrical conductivity varied between 10^?9 and 10 S m^?1, depending on the percentage of CB in the composite. Furthermore, a linear (and reversible) dependence of the conductivity on the applied pressure between 0 and 1.6 MPa was observed for the sample with containing 80 wt % of NR and 20% of CB. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Different degrees of malnutrition and immunological alterations according to the aetiology of cirrhosis: a prospective and sequential study

Objectives

In this work we investigated how immunological dysfunction and malnutrition interact in alcoholic and viral aetiologies of cirrhosis.

Methods

To investigate the matter, 77 cirrhotic patients divided in three aetiologies [Alcohol, HCV and Alcohol + HCV) and 32 controls were prospectivelly and sequentially studied. Parameters of humoral immunity (Components 3 and 4 of seric complement and immunoglobulins A M, G and E) and of cellular immunity (total leukocytes and lymphocytes in peripheral blood, T lymphocytes subpopulations, CD4+ and CD8+, CD4+/CD8+ ratio and intradermic tests of delayed hypersensitivity), as well as nutrititional parameters: anthropometric measures, serum albumin and transferrin were evaluated.

Results

Multiple statistical comparisons showed that IgM was higher in HCV group; IgG was significantly elevated in both HCV and Alcohol + HCV, whereas for the Alcohol group, IgE was found at higher titles. The analysis of T- lymphocytes subpopulations showed no aetiologic differences, but intradermic tests of delayed hypersensitivity did show greater frequency of anergy in the Alcohol group. For anthropometric parameters, the Alcohol +HCV group displayed the lowest triceps skinfold whereas creatinine – height index evaluation was more preserved in the HCV group. Body mass index, arm muscle area and arm fat area showed that differently from alcohol group, the HCV group was similar to control.

Conclusion

Significant differences were found among the main aetiologies of cirrhosis concerning immunological alterations and nutritional status: better nutrition and worse immunology for HCV and vice-versa for alcohol.

     

Online FPS games: effect of router buffer and multiplexing techniques on subjective quality estimators

First Person Shooters are a genre of online games in which users demand a high interactivity, because the actions and the movements are very fast. They usually generate high rates of small packets which have to be delivered to the server within a deadline. When the traffic of a number of players shares the same link, these flows can be aggregated in order to save bandwidth. Certain multiplexing techniques are able to merge a number of packets, in a similar way to voice trunking, creating a bundle which is transmitted using a tunnel. In addition, the headers of the original packets can be compressed by means of standard algorithms. The characteristics of the buffers of the routers which deliver these bundled packets may have a strong influence on the network impairments (mainly delay, jitter and packet loss) which determine the quality of the game. A subjective quality estimator has been used in order to study the mutual influence of the buffer and multiplexing techniques. Taking into account that there exist buffers which size is measured in terms of bytes, and others measured in packets, both kinds of buffers have been tested, using different sizes. Traces from real game parties have been merged in order to obtain the traffic of 20 simultaneous players sharing the same Internet access. The delay and jitter produced by the buffer of the access router have been obtained using simulations. In general, the quality is expected to be reduced as the background traffic grows, but the results show an anomalous region in which the quality rises with the background traffic amount. Small buffers present better subjective quality results than bigger ones. When the total traffic amount gets above the available bandwidth, the buffers measured in bytes add to the packets a fixed delay, which grows with buffer size. They present a jitter peak when the offered traffic is roughly the link capacity. On the other hand, buffers which size is measured in packets add a smaller delay, but they increase packet loss for gaming traffic. The obtained results illustrate the need of knowing the characteristics of the buffer in order to make the correct decision about traffic multiplexing. As a conclusion, it would be interesting for game developers to identify the behaviour of the router buffer so as to adapt the traffic to it.     

Studies of distributed parameter systems: Decoupling the state-parameter estimation problem

The problem of state-parameter estimation is considered in terms of decoupling the estimation procedure. First, the theoretical preliminaries necessary for the mathematical statement of the problem are defined. Then using the extended Kalman filter (EKF) approach, the state and parameter are estimated by applying the solution techniques to a distributed parameter system. Next, the state estimation problem is decoupled from the parameter estimation problem and by using a numerical example, the advantage of this decoupling procedure is demonstrated. The numerical results show that convergence can be improved when this decoupling procedure is employed. The effect of the location of the measurements on the estimation problem is also analysed in this work. The results show that the convergence of the problem depends on the location as well as the number of measurements.     

Reciprocal Tree-Like Fractal Structures

Sometimes the complex structures of nature inspire human constructions. Gothic construction has shown that forces can cross space along intricate paths that may even be arbitrary if correctly dimensioned. In some way, ribbed structures are like trees where the branches conduct forces instead of sap; they operate as branches and trunks descending by fractal ways. Here we discuss reciprocal tree-like fractal structures and the difficulty in their design and erection and solutions for constructive details, as well as the possible analytical questions and automatic generation by means of proper software. The results are shown in the design of the Natural Interpretation Centre in Melilla where we have proposed two connected trees like shown at figures included below.     

Study of Ozonated Sunflower Oil Using 1H NMR and Microbiological Analysis

Prior studies have proven that ozonated vegetable oils present a high germicidal power. Ozonation of sunflower oil at different applied ozone dosage was carried out and peroxide and aldehydes indices along with antimicrobial activity were determined. The reaction products were identified using Proton Nuclear Magnetic Resonance Spectroscopy (¹H NMR). The principal signals intensity values were used for following the reaction course between ozone and sunflower oil. The reaction was following up to peroxide index values of 1202 mmol-equi/kg. The intensities of olefinic proton signals decreased with the gradual increase in ozone concentration but without disappearing completely. The Criegee ozonides obtained at 107.1 mg/g of ozone doses were approximately 3.9-fold higher than that at beginning of the reaction. The aldehyde protons were observed as a weak intensity signal in all the spectra. The signals belonging to olefinic protons from hydroperoxides appeared weak and increased with the increase in ozone doses. Signals from other oxygenated groups were assigned. The highest action spectrum of antimicrobial activity was obtained with the higher peroxide index. It was concluded that at higher applied ozone doses, the higher the antimicrobial activity potential of ozonized sunflower oil     

Evaporation of polymer-solvent mixtures

Summary The Stefan-Winkelmann diffusion technique has been used to determine vapor pressures of high boiling point compound-solvents mixtures. Data are reported at a temperature of 67°C for the mixtures polyphenyl ether (6 rings) — benzene and carbowax 1500 — benzene and at a temperature of 100°C for the mixtures polyphenyl ether (6 rings) — toluene and tricresylphosphate-toluene. The range of concentration is only limited by the appearance of a solid phase, and results are in good agreement with those determined by vapor pressure osmometry.Nomenclature A Vapour source - B Flowing gas phase - c Concentration, g-mol/cm³ - D_AB Molecular diffusion coefficient, cm₂/s - h_i Total interface depth, cm - K Parameter defined by equation (6), dimensionless - I Polymer or high boiling point compound - M_A Molecular weight - N_AZ Molar flux, g-mol/(cm₂) (s) - P_A Partial pressure at the interface, atm - P Total pressure, atm - R Gas constant, (atm) (cm₃) / (°K) (g-mol) - T Temperature, °K - t Time, s - Y_A Molar fraction at the interface, dimensionless - z_o Initial interface depth, cm - z_i Drop of the interface depth, cm - z Interface position Greek Letters _A Density of the liquid phase, g/cm³