Trypsin inhibitory activity of raw soya bean after incubation with rumen fluid

Four soya bean (Glycine max Merr) inbreds, two of which (Williams 82 and Amsoy 71) capable of synthesising the Kunitz trypsin inhibitor (high trypsin inhibitory activity (TIA)) and two (L81–4590 and L83–4387), nearly isogenic to the former but lacking this particular function (low TIA) were used. In-vitro trials were performed to evaluate the residual TIA of flours incubated with runem fluid and the possible effect of proteinase inhibitors on rumen microbial fermentation, estimated by gas production. Only a slow fall in TIA was observed after short incubation times (5–10% at 2 h and 10–18% at 6 h), but after this period the rate of decline of TIA accelerated to give residual TIA of about 50% after 12 h and undetectable values after 48 h. Significant differences between genetic backgrounds were observed only at 2 h, when the Williams 82 background had a faster initial loss of TIA (89.1 versus 97.5% of the original activity, P < 0.01). Different patterns of TIA degradation were observed according to the presence/absence of the Kunitz inhibitor: inbreds lacking the Kunitz inhibitor initially had a higher residual TIA (95.9 versus 90.7%, P < 0.01) while at 12 and 24 h the residual TIA was considerably lower with respect to the other inbreds (45.4 versus 60.8 and 10.7 versus 20.4, respectively, P < 0.01). Gas production after 2 and 6 h of incubation was similar across treatments, whereas slightly but consistently more (P < 0.05) gas was produced at longer incubation times for inbreds lacking the Kunitz inhibitor. The results indicated that the proteinase inhibitors contained in raw soya bean are degraded at a much slower rate than previous nylon bag studies have suggested and that the presence of the Kunitz inhibitor leads to a higher residual TIA after rumen degradation and slightly lower microbial gas production.     

A coincidence system for radionuclide standardization using surface barrier detectors

A system for the standardization of alpha-gamma or electron-X radionuclide emitters is described. The system consists of one or two surface barrier detectors for alpha or electron detection which are coupled to thin-window NaI(Tl) crystals suitable for low-energy X- or gamma-ray detection. The performance of the system has been verified by the standardization of ²⁴¹Am, ¹³⁷Cs and ¹⁰⁹Cd solutions. The activity has been obtained using the extrapolation method applied to the 4π -γ and 2π e-X coincidence techniques. The surface barrier detection efficiency was varied by placing absorbers over the radioactive source or by changing the source-to-detector distance. The results were compared to those obtained using conventional absolute systems based on gas-flow and pressurized 4π proportional counters, or using radioactive solutions standardized in international comparisons sponsored by the Bureau International des Poids et Mesures, France. The expected and measured activities agreed within the experimental uncertainties, which were: 0.2% for ²⁴¹Am, 0.7% for ¹³⁷Cs and 0.6% for ¹⁰⁹Cd.     

Two models of multiple sclerosis: Experimental allergic encephalomyelitis (EAE) and theiler's murine encephalomyelitis virus (TMEV) infection. A pathological and immunological comparison

Theiler's murine encephalomyelitis virus (TMEV) infection and experimental allergic encephalomyelitis (EAE) are considered among the best models of human multiple sclerosis (MS). In both models, clinical disease is characterized by paralysis, while pathological changes consist of inflammatory demyelination. In both models there is a genetic influence on susceptibility/resistance to the development of disease. This has been thoroughly studied in TMEV infection, and it has been found to depend on both major histocompatibility complex (MHC) and non-MHC genes. At least four genes have been so far identified. Because of this genetic influence, some strains of mice are more susceptible to both clinical and pathological changes than others, and susceptibility appears to best correlate with the ability of a certain murine strain to develop a delayed-type hypersensitivity (DTH) response to viral antigens. We have also observed that even among mice which are equally susceptible clinically, striking differences may be seen under pathological examination. These consist of different gradients of severity of inflammation, particularly in regards to the macrophage component. There is an inverse relationship between the number of macrophages, and their length of stay in the CNS, and the ability of mice to remyelinate their lesions. The most severe lesions are in SJL/J mice, and remyelination in this strain is extremely poor. The least severe lesions in terms of macrophage invasion are in strains such as NZW and RIIIS/J, and these are able to remyelinate lesions very successfully. Murine chronic relapsing EAE (CR-EAE) shows pathological changes in many ways similar to those in TMEV-infected SJL/J mice, although less severe in terms of degrees of macrophage infiltration and tissue destruction. Mice with CR-EAE have a correspondingly limited ability to remyelinate their lesions. In both models the pathology appears to be mediated through a DTH response. However, while in EAE the DTH response is clearly against neuroantigens, the response in TMEV infection is against the virus itself. The end result in both models would be that of myelin destruction through a lymphotoxincytokine-mediated mechanism. The importance of the DTH response in both models is well illustrated by the effects of tolerance induction in EAE and TMEV infection to neuroantigens and virus, respectively. These are important models of human MS, since the current hypothesis is that a viral infection early in life, on the appropriate genetic background, may trigger a secondary misdirected immune response which could be directed either against myelin antigens and/or possible persistent virus(es). © 1995 Wiley-Liss, Inc.     

Protection of fixed service receivers from the interference produced by the non‐geostationary satellites in a fixed satellite service network: a statistical interference analysis

Until 1997, the power flux density (pfd) limits applicable to fixed satellite service (FSS) satellite transmitters to protect fixed service (FS) receivers operating in the same frequency band were those in Article 21 of the radio regulations. They were developed assuming that potentially interfering satellites in the FSS would only operate in the GSO. The need to revise these limits to allow for the protection of FS receivers from interference generated by non‐geostationary satellites has led to several studies, most of them based on the non‐realistic assumption that every visible satellite in a NGSO constellation produces the maximum allowed pfd level at the FS receive station location. To provide a quantitative indication of how pessimistic this assumption is, this paper considers a more realistic model in which the pfd entries reaching a given FS receiver location are characterized by statistically independent random variables. The probability density functions of these random variables depend on the operational characteristics of the NGSO network. The obtained results have also shown the need to consider some of the operational characteristics of NGSO satellite networks when evaluating the interference produced by their satellites. If these operational characteristics are not taken into account in the calculations, higher values of interference, that do not reflect the real interference environment, are obtained. Copyright © 2002 John Wiley & Sons, Ltd.     

High-Level Timed Petri Nets as a kernel for executable specifications

One of the goals of the IPTES environment is to provide a highly usable and formally based specification support environment for real-time applications. Therefore the environment is built upon a formal language that provides a sound, and mathematically well-defined kernel for IPTES. The language provides a means for formulating unambiguous specifications that can be formally verified at any stage of the project. The ability of verifying the specifications from the early stages of the project is very important for revealing errors when their correction can be done at a much lower cost compared with the cost of removing the same errors in later phases.The formal kernel of IPTES is a class of high-level Petri nets, called HLTPNs (High-Level Timed Petri Nets), that allow specifications to be executed, simulated, tested and formally proved.HLTPNs come in two forms: the internal form (HLTPN _i ) and the abstract form (HLTPN _a ).HLTPN _i may be viewed as the machine language of the abstract machine underlying the IPTES environment.HLTPN _a provides a higher-level intermediate notation that allows to deal explicitly with aspects related to scheduling of the modeled system.This material is based upon work supported by the esprit project IPTES and by CNR—Progetto Finalizzato Sistemi Informatici e Calcolo Parallelo.     

Tables and graphs for designing digital Cheby?shev filters

The authors draw attention to the availability of numerical tables and graphs for design by the conventional deduction of the z transform from a given squared magnitude function.     

Initial Brazilian experience with short-duration in-center daily hemodialysis

The whole initial Brazilian experience with short-duration in-center daily hemodialysis is summarized here. The study was performed at a time when low-flux membrane and nonproportional dialysis represented the standard dialysis treatment in Brazil. Five patients were treated for 2 years. The subject is developed in a way to narrate the efforts to set the research project and summarize the findings, meeting presentations, and publications that derived from the project. At the end of the study, the main benefits observed consisted of alleviation of the end-stage renal disease anemia; reduction of the frequency of complications during dialysis sessions; a lower degree of azotemia; easier blood pressure control; and improvements in acid-base status, mineral metabolism and bone disease, nutrition, and quality of life.     

Modeling segmentation of a visual scene via neural oscillators: fragmentation, discovery of details and attention

The present study analyses the problem of binding and segmentation of a visual scene by means of a network of neural oscillators, laying emphasis on the problems of fragmentation, perception of details at different scales and spatial attention. The work is based on a two-layer model: a second layer of Wilson-Cowan oscillators is inhibited by information from the first layer. Moreover, the model uses a global inhibitor (GI) to segment objects. Spatial attention consists of an excitatory input, surrounded by an inhibitory annulus. A single object is identified by synchronous oscillatory activity of neural groups. The main idea of this work is that segmentation of objects at different detail levels can be achieved by linking parameters of the GI (i.e. the threshold and the inhibition strength) with the dimension of the zone selected by attention and with the dimension of the smaller objects to be detected. Simulations show that three possible kinds of behavior can be attained with the model, through proper choice of the GI parameters and attention input: (i) large objects in the visual scene are perceived, while small details are suppressed; (ii) large objects are perceived, while details are assembled together to constitute a single 'noise term'; (iii) if attention is focused on a smaller area and the GI parameters modulated accordingly (i.e. the threshold and attention strength are reduced) details are individually perceived as separate objects. These results suggest that the GI and attention may represent two concurrent aspects of the same attentive mechanism, i.e. they should work together to provide flexible management of a visual scene at different levels of detail.     

Impact of the hypocaloric diet using food substitutes on the body weight and biochemical profile

Recent studies using balanced hypocaloric diets with food substitutes in some meals, have presented positive results. There are no studies with the Brazilian population on the efficacy of using food substitute, together with a hypocaloric diet. Main objective of this study was to verify the effects of a hypocaloric diet using food substitutes as meal replacement on the body weight, lipid profile, and glucose and insulin plasma levels. Seventy eight subjects of both genders were selected, 20-50 years old, and a body weight index between 25 kg/m2 and 35 kg/m2. The study lasted for six months and it was divided in 2 phases of three months each- mass reduction for 3 months and 3 months for maintenance. The sample was randomly divided in two groups: Group A (control- 3 months of general nutritional and physical orientation followed by 3 months with 1 meal replacement) and Group B (intervention- 2 meals replacement a day plus nutritional and physical orientation for 3 months followed by 3 months with 1 meal replacement). Anthropometric measurements, percent body fat (%BF), biochemical profile and intake survey were performed at moments 0, 3 and 6 months. Both groups showed a significant decrease in %BF, weight, and consequently in their BMI, in the third and sixth month of follow up. However, weight loss in group B was higher than in group A. At the end of the treatment, 0 and 25.0% of the patients of the group A and B, respectively, presented a weight loss higher than 10% of the initial weight. Comparing the triglycerides, LDL-cholesterol and glucose levels, between the beginning and after the three and six months of treatment, there was a significant reduction in the individuals only in group B. In conclusion, the use of food substitutes as meal replacement, together with a balanced, hypocaloric diet, proved to be efficient in weight loss for Brazilian overweighed individuals.