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At least 343 records · Page 19Linked to original sources
PubMed1995

Effect of food and oral simulating fluids on structure of adhesive composite systems.

This work evaluates the degradation of three adhesive/composite systems (Tenure/Marathon One. Scotchbond Multi-Purpose/Z100 and Optibond/Herculite XRV) upon immersion in 75% ethanol solution and in an artificial saliva (Moi-Stir). Shear bond strength (SBS) and diametral tensile strength (DTS) specimens were employed for this study. For the SBS specimens, the bonded interface and composite were exposed to food and oral simulating fluids at 37 degrees C for up to 30 days. A similar control series was stored in air. DTS specimens were stored in 75% ethanol at 37 degrees C for up to 30 days. The SBS specimens were sheared to failure. Small quantities of bonding resin were removed from the tooth side of the fractured surface and from the non-fractured fractured end of the composite for Fourier transform infrared microscopic evaluation. Similar scrapings were taken from DTS specimen surfaces. The infrared absorbance intensity (AI) of the major peaks was measured as a function of storage time and ratioed against the aromatic C = C (1609.4 cm-1) peak. The data were analysed using ANOVA and the Tukey LSD test. The AI of major peaks was similar for the materials stored either in air or in Moi-Stir for all testing periods. Storage in ethanol caused the AI of aliphatic C = C (1638 cm-1) and of O-H (approximately 3500 cm-1) bonds to significantly decrease (30-50%) for specimens of bonding resin while the AI of C = O bonds (1730 cm-1) increased (60-120%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adhesives↗
PubMed1980

[Syndromes of food hypermotivation in hyperactivity of lateral hypothalamic structures in rabbits].

In experiments on freely moving rabbits a focus of hyperactivity in the initiative centers of food motivation was created by means of blocking the inhibitory mechanisms in the lateral hypothalamus (LH) exposed to tetanus toxin (group I) or chronic electric stimulation (group II). The evoked syndromes were marked by intensity of food hypermotivation. The syndrome provoked by injection of tetanus toxin was characterized by an extremely rapid development, pronounced symptomatology of hyperphagia and severe progress. Concurrently, a pronounced epileptiform activity was recorded in LH, thus indicating the formation of a generator of pathologically enhanced excitation in the "pacemakers" of food motivation. The animals showed completely altered mechanisms of an adequate correction on the behaviour, depending on the results obtained. The syndrome provoked by chronic electric stimulation of LH was characterized by a slower formation and favourable course with a relatively weak epileptiform activity recorded in LH. Food hypermotivation was also demonstrated by the rabbits in the late periods after the commencement of electric stimulation; the adaptive pattern of the animals' behaviour remained unchanged. Occurence of the two syndromes of food hypermotivation is related to the formation of the excitation genertors that differ in the intensity of excitation they produce.

Animals↗
PubMed2004

Who dominates whom in the ecosystem? Energy flow bottlenecks and cascading extinctions.

In this paper, we investigate the problem of secondary extinction in food webs through the use of dominator trees, network topological structures that reduce food webs to linear pathways that are essential for energy delivery. Each species along these chains is responsible for passing energy to the taxa that follow it, and, as such, it is indispensable for their survival; because of this it is said to dominate them. The higher the number of species a node dominates, the greater the impact resulting from its removal. By computing dominator trees for 13 well-studied food webs we obtained for each of them the number of nodes dominated by a single species and the number of nodes that dominate each species. We illustrate the procedure for the Grassland Ecosystem showing the potential of this method for identifying species that play a major role in energy delivery and are likely to cause the greatest damage if removed. Finally, by means of two indices that measure error and attack sensitivity, we confirm a previous hypothesis that food webs are very robust to random loss of species but very fragile to the selective loss of the hubs.

Animals↗
PubMed1999

Food safety control in the Republic of Korea.

With the increased globalization of the food trade, the work of the World Trade Organization has led to the greater recognition and use of the concept of equivalence. Use of this concept, however, requires countries to be aware of the national controls applied in other countries. This article provides an overview of the current system in use in the Republic of Korea. It outlines the administrative systems employed to maintain food safety that includes the recent establishment of the Korea Food and Drug Administration. It provides details of the legislative structure, including the Food Sanitation Act of 1986 (and its recent amendment) and related regulations. Certain nongovernmental bodies are also described. The article concludes by recognizing that modern food safety problems require concerted action, both nationally and internationally.

Food↗
PubMed1975

Structural and hormonal alterations in the gastrointestinal tract of parenterally fed rats.

This study examines the effect of prolonged absence of oral food intake on structural parameters of the gastrointestinal tract in rats maintained nutritionally by intravenous feeding for up to 3 weeks. During this time, their body weights increased by 22%. Controls fed a nearly isocaloric oral diet were sham operated and harnessed in the same manner as their parenterally fed counterparts. Parenteral feeding resulted in a significant decrease in the weights (per 100 g body weight) of the oxyntic gland area of the stomach, small intestine, and pancreas. The weights of the spleen, testes, kidneys, and antral region of the stomach were unaltered. In the small intestine there was a significant loss of DNA and a near doubling of the RNA:DNA ratio in the parenterally fed animals. In the absence of an oral diet antral gastrin levels decreased to one-thirtieth of the control level. The following conclusions are suggested by these results. First, the oral intake and/or physical presence of food within the gastrointestinal tract are necessary for structural maintenance of some tissues of that tract. Second, the disproportionate decrease in weight that occurs in certain tissues is apparently unrelated to the absence of nutrients which might normally be utilized directly from the lumen. Third, maintenance of normal tissue stores of the hormone, gastrin, is dependent on stimuli provided by oral ingestion and the presence of food in the gastrointestinal tract.

Animals↗
PubMed1998

Gender, socioeconomic status and family status as determinants of food behaviour.

This study examines social structural and family status factors as determinants of food behaviour. The data were derived from the FINMONICA Risk Factor Survey, collected in Finland in spring 1992. A multidimensional framework of the determinants of food behaviour was used, including social structural position, family status and gender. The associations between the determinants of food behaviour were estimated by multivariate logistic regression models, adjusted for age and regional differences. Food behaviour was measured by an index including six food items which were chosen based on Finnish dietary guidelines. In general, women's food behaviour was more in accordance with the dietary guidelines than that of men. The pattern of association between educational level and food behaviour was similar for both genders, but slightly stronger for men than women. Employment status was associated only with women's food behaviour, but the tendency was the same for men. Marital status was associated with men's as well as women's food behaviour. The food behaviour of married men and women was more in line with the dietary guidelines than the food behaviour of those who had been previously married. Parental status, however, was only associated with women's food behaviour, that is, the food behaviour of women with young children was more closely in line with the dietary guidelines than that of the rest of the women.

Adult↗
PubMed2003

Food retailing and food service.

The food retailing and food service sector is not only an important component of the food marketing channel but is also vital to the United States economy, accounting for more than 7% of the United States gross domestic product in 2001. The business of food retailing and food service is undergoing salient change. The authors argue that the singular force driving this change is the consumer. To understand the linkages in the food marketing channel, this article provides information on the farm-to-retail price spread and the economic forces that influence their magnitude. Examples are given of farm-to-retail price spreads for red meat and dairy industries. In addition, the economics behind the provision of retail services and the growth of the food service industry are discussed. Further, the authors demonstrate that the structure of the food market channel is consumer driven, and present three characteristics of convenience (preparation, delivery, and service) and identify four food distribution channels in terms of convenience (complete convenience, traditional food service, consumer direct, and traditional retail).

Animals↗
PubMed1991

Structure-function analysis of stimulation of food intake by neuropeptide Y: effects of receptor agonists.

Neuropeptide Y (NPY) is a potent natural orexigenic signal in the rat. In this study, we have compared the effects of several COOH-terminal fragments of NPY and NPY receptor agonists on cumulative food intake in male rats. Rats were implanted with permanent cannulae either into the third cerebroventricle or paraventricular nucleus (PVN). NPY1-36 and various COOH-terminal fragments of NPY, two agonist analogues [Leu31, Pro34]NPY and NPY 1-4-Aca (epsilon-amino-caproic acid)-25-36, were administered intracerebroventricularly (ICV) or directly into the PVN, and the cumulative 2-h food intake response was compared. We observed that peptides that were effective by ICV were also effective when administered into the PVN, but smaller amounts of the peptides were required after PVN injection to evoke an equivalent food intake response. Injection of NPY1-36 induced a dose-dependent increment in food intake. Surprisingly, deletion of NH2-terminal tyrosine residue did not adversely affect feeding behavior. In fact, NPY2-36 was consistently more effective than NPY1-36; the enhancement in feeding by NPY2-36 was dose-related and was higher than evoked by NPY1-36 at each dose tested. Further serial deletion of aminoacids at NH2-terminal resulted in complete loss of activity. In addition, NPY agonist analogue, NPY 1-4-Aca-25-36, failed to stimulate feeding. However, NPY Y1 receptor agonist, [Leu31, Pro34]NPY, but not Y2 receptor agonist, NPY13-36, stimulated feeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2004

Structural, biological, and evolutionary relationships of plant food allergens sensitizing via the gastrointestinal tract.

The recently completed genome sequence of the model plant species Arabidopsis has been estimated to encode over 25,000 proteins, which, on the basis of their function, can be classified into structural and metabolic (the vast majority of plant proteins), protective proteins, which defend a plant against invasion by pathogens or feeding by pests, and storage proteins, which proved a nutrient store to support germination in seeds. It is now clear that almost all plant food allergens are either protective or storage proteins. It is also becoming evident that those proteins that trigger the development of an allergic response through the gastrointestinal tract belong primarily to two large protein superfamilies: (1) The cereal prolamin superfamily, comprising three major groups of plant food allergens, the 2S albumins, lipid transfer proteins, and cereal alpha-amylase/trypsin inhibitors, which have related structures, and are stable to thermal processing and proteolysis. They include major allergens from Brazil nut, peanuts, fruits, such as peaches, and cereals, such as rice and wheat; (2) The cupin superfamily, comprising the major globulin storage proteins from a number of plant species. The globulins have been found to be allergens in plant foods, such as peanuts, soya bean, and walnut; (3) The cyteine protease C1 family, comprising the papain-like proteases from microbes, plants, and animals. This family contains two notable allergens that sensitize via the GI tract, namely actinidin from kiwi fruit and the soybean allergen, Gly m Bd 30k/P34. This study describes the properties, structures, and evolutionary relationships of these protein families, the allergens that belong to them, and discusses them in relation to the role protein structure may play in determining protein allergenicity.

Allergens↗
PubMed2005

Use of carbon and nitrogen stable isotope ratios to assess the effects of environmental contaminants on aquatic food webs.

In this study, the value of carbon (delta13C) and nitrogen (delta15N) stable isotope ratios were determined in nymphs of a top-predator, the common backswimmer (Notonecta glauca L.), collected in 18 m3 outdoor freshwater mesocosms used to assess the fate and ecotoxicological effects of a diphenyl ether herbicide, fomesafen, applied alone or in combination with Agral 90 (mixture of polyethoxylated derivatives of nonylphenol). Both treatments had a negative effect on delta13C values which may reflect changes in carbon fluxes across food webs in the treated ponds associated with a shift in phytoplankton structure. A decrease in delta15N values was observed in the nymphs collected in mixture-treated ponds, which was presumably due to an increase in the abundance of rotifers and Chironominae larvae in these ponds. These preliminary results indicate that stable isotope ratios may be used as shortcuts to detect qualitative or quantitative shifts in the structure of aquatic food webs caused by pollutants.

Animals↗
PubMed2006

A kinetic inhibition mechanism for maintenance.

To fulfil their maintenance costs, most species use mobile pools of metabolites (reserve) in favourable conditions, but can also use less mobile pools (structure) under food-limiting conditions. While some empirical models always pay maintenance costs from structure, the presence of reserve inhibits the use of structure for maintenance purposes. The standard dynamic energy budgets (DEB) model captures this by simply supplementing all costs that could not be paid from reserve with structure. This is less realistic at the biochemical level, and involves a sudden use of structure that can complicate the analysis of the model properties. We here propose a new inhibition formulation for the preferential use of reserve above structure in maintenance that avoids sudden changes in the metabolites use. It is based on the application of the theory for synthesizing units, which can easily become rather complex for demand processes, such as the maintenance. We found, however, a simple explicit expression for the use of reserve and structure for maintenance purposes and compared the numerical behaviour with that of a classical model in oscillating conditions, by using parameters values from a fit of the models to data on yeasts in a batch culture. We conclude that our model can better handle variable environments. This new inhibition formulation has a wide applicability in modelling metabolic processes.

Adaptation, Physiological↗
PubMed2004

Rapid income growth adversely affects diet quality in China--particularly for the poor!

To study the impact of income change--specifically rapid income growth--on diet behavior over time and by socioeconomic level, we used data from a prospective study of China begun in 1989 (followed up in 1991, 1993 and 1997). The subpopulation used in this study included 5783 subjects aged 20-45 years old from 3129 households. Dietary intakes were measured using a combination of the weighing method and three consecutive 24-h recalls. Detailed income and price data were collected, and predicted household per capita income was used in multivariate longitudinal random-effects models that described the consumption of several food groups and nutrients. Income elasticity was used to measure the changes for the effects of income over time on (a) the probability of consuming any food and (b) the quantity of food consumed. The structure of the Chinese diet is shifting away from high-carbohydrate foods toward high-fat, high-energy density foods. The variation in the income effects that we uncovered indicated that important changes in income effects took place between 1989 and 1997, with the changes varying considerably by socioeconomic status. These shifts in income effects indicate that increased income might have affected diets and body composition in a detrimental manner to health, with those in low-income groups having the largest increase in detrimental effects due to increased income. Extrapolating from our estimates, higher income levels in the future could lead to the reversal of the health improvements achieved in the last two decades, if diet-related noncommunicable diseases cannot be controlled.

Adult↗
PubMed2001

Characteristics of some wheat-based foods of the Italian diet in relation to their influence on postprandial glucose metabolism in patients with type 2 diabetes.

The present study was aimed at evaluating in patients with type 2 diabetes: (1) the glycaemic response to four starchy foods based on wheat, typical of the Italian diet; (2) the importance of some food characteristics in relation to their effects on postprandial glucose response. Seventeen patients with type 2 diabetes (eleven men and six women) participated in the study. All patients consumed, in random order and on alternate days, 50 g available carbohydrate provided by 90 g white bread and, according to a randomised procedure, an equivalent amount of carbohydrate provided by one (n 8) or two (n 9) of three other different test foods (g): pizza 85, potato dumplings 165, hard toasted bread 60. Foods had a similar nutrient composition. Plasma glucose response, measured for 180 min, was significantly lower after the potato dumplings than after white bread at 90 (P < 0.05), 120 (P < 0.01), and 150 (P < 0.05) min. No difference was observed in postprandial plasma insulin response after the various test foods. The percentage of starch hydrolysed after 5 h in vitro hydrolysis with alpha-amylase was about 30 % lower for potato dumplings than for the other foods. However, no differences in the resistant starch content, the rate of diffusion of simple sugars added to a dialysis tube containing the food, and the viscosity of digesta were observed among the test foods. Scanning electron microscopy of potato dumplings showed a compact structure compatible with impaired accessibility of starch to digestive enzymes. In conclusion, carbohydrate-rich foods typical of the Italian diet which are often consumed as an alternative to pasta dishes are not equivalent in terms of metabolic impact in diabetic patients. Due to their low blood glucose response, potato dumplings represent a valid alternative to other starchy foods in the diabetic diet. Food structure plays an important role in determining starch accessibility to digestion, thus influencing the postprandial blood glucose response.

Analysis of Variance↗
PubMed1975

The influence of food intake on the development of structural and functional adaptation following ileal resection in the rat.

The present study was undertaken to determine the influence of hyperphagia on the adaptive changes occurring in the rat jejunal mucosa as a result of intestinal resection. One group of resected rats was subjected to pair feeding with a sham-operated population, whilst another group was nourished ad libitum. The animals which ate ad libitum developed hypertrophy of the mucosa which was accompanied by increased glucose absorption in vivo without changes in enzyme levels. These alterations were much less pronounced in the pair-fed group of resected animals, a finding that indicates that the adaptive changes are at least partially influenced by increased luminal nutrition.

Adaptation, Physiological↗
PubMed1978

[Chromosomal structure or porcine lymphocytes effected by food additives].

Different concentrations of food additives were introduced in cultures of pig lymphocytes. No special chromosomal damage were induced by anticoccidians. On the contrary some antibiotics caused chromosomic anomalies. Chloramphenicol and furazolidone assayed in vitro and in vivo had also an antimitotic effect. The purpose of this work was to know the cytotoxic effect of some substances: a preliminary and cheap test could be a cytogenetic examination in vitro.

Animals↗