Effect of maltodextrin on the freezing point and thermal conductivity of uvaia pulp (Eugenia piriformis Cambess)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of calcium pre-rinse and fluoride dentifrice on remineralisation of artificially demineralised enamel and on the composition of the dental biofilm formed in situ

Objective: This in situ blind crossover study investigated the effect of calcium (Ca) rinse prior to the use fluoride (F) dentifrice on remineralisation of artificially demineralised enamel and on the composition of biofilm. Design: During four phases of 14 days, 10 volunteers wore appliances containing two artificially demineralised bovine enamel blocks. Three times a day, they rinsed with 10 mL, of Ca (150 mM) or placebo rinse (1 min). A slurry (1:3, w/v) of F (1030 ppm) or placebo dentifrice was dripped onto the blocks. During I min, the volunteers brushed their teeth with the respective dentifrice. The appliance was replaced into the mouth and the volunteers rinsed with water. The biofilm formed on the blocks was analysed for F and Ca. Enamel alterations were evaluated by the percentage of surface microhardness change (%SMHC), cross-sectional microhardness (% mineral volume) and alkali-soluble F analysis. Data were analysed by ANOVA (p < 0.05). Results: the use of the Ca pre-rinse before the F dentifrice produced a six- and four-fold increase in biofilm F and Ca concentrations, respectively. For enamel, the remineralisation was significantly improved by the Ca pre-rinse when compared to the other treatments. There was a significantly higher concentration of alkali-soluble F in enamel when the F dentifrice was used, but the Ca pre-rinse did not have any significant additive effect. Conclusions: According to our protocol, the Ca pre-rinse significantly increased biofilm F concentration and, regardless the use of F dentifrice, significantly enhanced the remineralisation of artificially demineralised enamel. (c) 2007 Elsevier Ltd. All rights reserved.

Effect of the type of environmental stress on the emergence of sunflower (Helianthus annus L.), soybean (Glycine max (L.) Merril) and maize (Zea mays L.) seeds with different levels of vigor

Sowing is a critical time in the cycle of a crop and the seeds are frequently exposed to adverse conditions that may compromise the establishment of seedlings in the field. on this basis, the objective of the present study was to determine the effect of types of environmental stress on the emergence of sunflower, maize and soybean seeds with different levels of vigor. High vigor seeds were artificially aged in order to obtain medium and low vigor seeds and then they were sown in clay soil in plastic boxes and submitted to the following types of environmental stress during the germination process : 1) high temperature (35degreesC), 2) low temperature (15 or 18degreesC), 3) water excess (Psi > -0.0001 MPa), 4) water deficiency (Psi approximately equal to -1.1; -1.2 and -0.6 MPa for sunflower, maize and soybean, respectively), 5) sowing at a depth of 7 cm and 6) pathogenic infection of sunflower seeds with Alternaria helianthi, of maize seeds with Fusarium moniliforme and of soybean seeds with Colletotrichum dematium, var. truncata. The results were compared to those obtained with controls sown under optimal condition. It was concluded that: 1) the effect of seed vigor on emergence depends on the type of enviromental stress to which the seeds are exposed, 2) the stress to which the the seeds demonstrated highest sensitivity varied with species and 3) high temperature stress was the one that most impaired the emergence of the three species.

Effect of long-term treatment with insulin and/or acarbose on glomerular basement membrane thickening in alloxan-diabetic rats

Acarbose is a competitive inhibitor of the intestinal alpha-glycosidases, that can delay absorption of intestinal carbohydrates causing their malabsorption. In the present paper we studied the effects of insulin, acarbose and their association on glomerular basement membrane thickening in alloxan-diabetic rats. Twenty-five male and female Wistar rats, approximately 3 months old at the beginning of the experiment, were assigned randomly to each of five experimental groups: normal control rats, alloxan-diabetic control rats, alloxan-diabetic rats treated with acarbose, alloxan-diabetic rats treated with insulin, and alloxan-diabetic rats treated with insulin plus acarbose. Alloxan was administered in a single iv dose of 42 mg/kg body weight. Insulin was given subcutaneously at doses of 18 to 30 IU/kg corrected daily on the basis of glycosuria and ketonuria. Acarbose was given mixed with rat chow in a dose of 50 mg/100 g chow. Body weight, water and food intake and diuresis, as well as blood and urine glucose were determined after 1, 3, 6, 9, and 12 months of treatment. Glomerular basement membrane (GBM) thickening was determined by electron microscopy at the same times. Clear clinical and laboratory signs of severe diabetes, with blood glucose levels above 200 mg/dl and urine glucose above 3000 mg/dl, were observed in all alloxan-diabetic control rats, in all periods of follow-up, whereas administration of insulin or acarbose reduced the blood glucose levels of treated groups. The most satisfactory control of blood and urine glucose was observed in animals treated with both insulin and acarbose. However, diarrhea was observed in diabetic rats treated with acarbose associated or not with insulin. GBM thickening was correlated with age in all groups. Beginning at six months after diabetes induction, the GBM of untreated diabetic rats was significantly thicker (mean +/- SEM, 4.446 +/- 0.45 mm) than that of normal rats (2.977 +/- 0.63 mm). Both insulin and acarbose prevented GBM thickening and their combination induced thickening similar to the age-dependent thickening observed for normal rats of the same age. We conclude that acarbose when combined with insulin may be a good option in the control of diabetes and its renal complications.

Effect of thermocycling on bond strength and elasticity of 4 long-term soft denture liners

Statement of problem. Two problems found in prostheses with soft liners are bond failure to the acrylic resin base and loss of elasticity due to material aging.Purpose. This in vitro study evaluated the effect of thermocycling on the bond strength and elasticity of 4 long-term soft denture liners to acrylic resin bases.Material and methods. Four soft lining materials (Molloplast-B, Flexor, Permasoft, and Pro Tech) and 2 acrylic resins (Classico, and Lucitone 199) were processed for testing according to manufacturers' instructions. Twenty rectangular specimens (10 X 10-mm(2) cross-sectional area) and twenty cylinder specimens (12.7-mm diameter X 19.0-mm height) for each liner/resin combination were used for the tensile and deformation tests, respectively. Specimen shape and liner thickness were standardized. Samples were divided into a test group that was thermocycled 3000 times and a control group that was stored for 24 hours in water at 37degreesC. Mean bond strength, expressed in megapascals (Wa), was determined in the tensile test with the use of a universal testing machine at a crosshead speed of 5 mm/min. Elasticity, expressed as percent of permanent deformation, was calculated with an instrument for measuring permanent deformation described in ADA/ANSI specification 18. Data from both tests were examined with 1-way analysis of variance and a Tukey test, with calculation of a Scheffe interval at a 95% confidence level.Results. In the tensile test under control conditions, Molloplast-B (1.51 +/- 0.28 MPa [mean SD]) and Pro Tech (1.44 +/- 0.27 MPa) liners had higher bond strength values than the others (P < .05). With regard to the permanent deformation test, the lowest values were observed for Molloplast-B (0.48% +/- 0.19%) and Flexor (0.44% +/- 0.14%) (P < .05). Under thermocycling conditions, the highest bond strength occurred with Molloplast-B (1.37 +/- 0.24 MPa) (P < .05) With regard to the deformation test, Flexor (0.46% +/- 0.13%) and Molloplast-B (0.44% +/- 0.17%) liners had lower deformation values than the others (P < .05).Conclusion. The results of this in vitro study indicated that bond strength and permanent deformity values of the 4 soft denture liners tested varied according to their chemical composition. These tests are not completely valid for application to dental restorations because the forces they encounter are more closely related to shear and tear. However, the above protocol serves as a good method of investigation to evaluate differences between thermocycled and control groups.

Structural organization of cetyltrimethylammonium sulfate in aqueous solution: the effect of Na2SO4

We used dynamic light scattering (DLS), a steady-state fluorescence, time resolved fluorescence quenching (TRFQ), tensiometry, conductimetry, and isothermal titration calorimetry (ITC) to investigate the self-assembly of the cationic surfactant cetyltrimethylammonium sulfate (CTAS) in aqueous solution, which has SO42- as divalent counterion. We obtained the critical micelled concentration (cmc), aggregation number (N-agg), area per monomer (a(0)), hydrodynamic radius (R-H), and degree of counterion dissociation (alpha) of CTAS micelles in the absence and presence of up to 1 M Na2SO4 and at temperatures of 25 and 40 degrees C. Between 0.01 and 0.3 M salt the hydrodynamic radius of CTAS micelle R-H approximate to 16 angstrom is roughly independent on Na2SO4 concentration; below and above this concentration range R-H increases steeply with the salt concentration, indicating micelle structure transition, from spherical to rod-like structures. R-H increases only slightly as temperature increases from 25 to 40 degrees C, and the cmc decreases initially very steeply with Na2SO4 concentration up to about 10 mM, and thereafter it is constant. The area per surfactant at the water/air interface, a(0), initially increases steeply with Na2SO4 concentration, and then decrases above ca. 10 mM. Conductimetry gives alpha = 0.18 for the degree of counterion dissociation, and N-agg obtained by fluorescence methods increases with surfactant concentration but it is roughly independent of up to 80 mM salt. The ITC data yield cmc of 0.22 mM in water, and the calculated enthalpy change of micelle formation, Delta H-mic = 3.8 kJ mol(-1), Gibbs free energy of micellization of surfactant molecules, Delta G(mic) = -38.0 kJ mol(-1) and entropy T Delta S-mic = 41.7 kJ mol(-1) indicate that the formation of CTAS micelles is entropy-driven. (c) 2006 Elsevier B.V. All rights reserved.

Effect of tillage on fractal indices describing soil surface microrelief of a Brazilian Alfisol

Soil surface roughness is known to influence water infiltration, runoff and erosion. Soil surface roughness changes with management and weather and its mathematical description still remains an important issue. The main objective of this study was to investigate the effect of tillage on the two fractal indices, fractal dimension, D, and crossover length, 1, currently used in characterizing soil surface microrelief. The statistical index random roughness, RR, was also assessed. Field experiments were done on an Alfisol located at Rio Grande do Sul State (Brazil). Two tillage treatments (conventional versus direct drilling) were tested. The soil surface microrelief was assessed by point elevation measurements in 16 plots for each treatment. The sampling scheme was a square grid with 20 x 20 mm between point spacing and the plot size was 280 x 280 mm, so that each data set consisted of 225 individual elevation points. All indices were calculated after trend removal, both by slope correction, i.e., oriented microrelief, and by slope plus tillage marks correction, i.e., random microrelief. The implemented algorithm for estimating D and 1 consisted in evaluating the roughness around the local root mean square deviation (RMS) of the point elevation values. Irrespective of tillage treatment and detrending procedure, fractal behavior extended only over a bounded range of scales, from 40 to 100 mm, due to the experimental setup. In these conditions, assessing fractal indices was not always straightforward. The statistical index RR and the fractal index I were significantly different between tillage treatments for oriented and random surface conditions. D values of random soil surfaces were not affected by tillage treatment, whereas D values of oriented microrelief were significantly lower in the direct drilled plots. Removal of tillage marks trend resulted in a significant increase in D values. Within each tillage treatment, 1 and D were significantly correlated. (c) 2006 Elsevier B.V. All rights reserved.

METABOLIC EFFECT OF PANCREATICODUODENAL TRANSPLANTATION IN DIABETIC RATS

Outbred Wistar rats were randomly assigned to three experimental groups: GI, 10 nondiabetic control rats; GII, 10 alloxan-diabetic control rats; GIII, 25 alloxan-diabetic rats that received pancreaticoduodenal transplantation (PDT) from normal donor Wistar rats and were immunosuppressed with cyclosporin A. For 7 prior and 4, 7, 14, 21, and 30 days posttransplantation (during which the animals were housed in metabolic cages for periods of 24 hours) body weight, water and food intake, urine output, blood and urinary glucose, plasma insulin, and glucagon were recorded. These parameters were also concurrently recorded for diabetic and nondiabetic control rats. Animals were sacrificed after 30 days and histological and immunohistochemical studies of the pancreas were performed. Pancreatic transplants consistently and significantly improved the metabolic abnormalities of the diabetic rat (P < 0.01) by restoring body weight gain, and by immediate relief of hyperglycemia, glucosuria, polyuria, polydipsia, and also the low levels of plasma insulin. The plasma glucagon, elevated in diabetic control rats, did not change after transplant.

The effect of polymerization cycles on porosity of microwave-processed denture base resin

Statement of problem. Although most of the physical properties of denture base resin polymerized by microwave energy have been shown to be similar to resins polymerized by the conventional heat polymerization method, the presence of porosity is a problem.Purpose. This study evaluated the effect of different microwave polymerization cycles on the porosity of a denture base resin designed for microwave polymerization.Material and methods. Thirty-two rectangular resin specimens (65 X 40 X 5 mm) were divided into 3 experimental groups (A, B, and C; Onda-Cryl, microwave-polymerized resin) and I control group (T; Classico, heat-polymerized resin), according to the following polymerization cycles: (A) 500 W for 3 minutes, (B) 90 W for 13 minutes + 500 W for 90 seconds, (C) 320 W for 3 minutes + 0 W for 4 minutes + 720 W for 3 minutes, and (T) 74degreesC for 9 hours. Porosity was calculated by measurement of the specimen volume before and after its immersion in water. Data were analyzed using 1-way analysis of variance (alpha = .05).Results. The mean values and SDs of the percent mean porosity were: A = 1.05% +/- 0.28%, B = 0.91% +/- 0.15%, C = 0.88% +/- 0.23%, T = 0.93% +/- 0.23%. No significant differences were found in mean porosity among the groups evaluated.Conclusion. Within the limitations of this study, a denture base resin specifically designed for microwave Polymerization tested was not affected by different polymerization cycles. Porosity was similar to the conventional heat-polymerized denture base resin tested.

Biocompatibility of denture base acrylic resins evaluated M culture of L929 cells. Effect of polymerisation cycle and postpoymerisation treatments

Objective: the purpose of this study was to evaluate the effect of two post-polymerisation treatments and different cycles of polymerisation on the cytotoxicity of two denture base resins.Materials and methods: the resins tested were Lucitone 550 and QC 20. Discs of resins were fabricated following the manufacturer's instructions. Lucitone 550 was processed by long cycle or short cycle. The resin QC 20 was processed by reverse cycle or normal cycle. The specimens were divided into groups: (i) post-polymerised in microwave for 3 min at 500 W; (ii) post-polymerised in water-bath at 55 degrees C for 60 min and (iii) without post-polymerisation. Eluates were prepared by placing three discs into a sterile glass vial with 9 ml of Eagle's medium and incubated at 37 degrees C for 24 hours. L929 cells were seeded into 96 3 well culture plates and DNA synthesis was assessed by H-thymidine incorporation assay.Results: the results were submitted to two-way ANOVA and Tukey HSD test. QC 20 specimens polymerised by the normal cycle and submitted to microwave post-polymerisation were graded as moderately cytotoxic. Similar results were observed for Lucitone 550 processed by long cycle without post-polymerisation. The other experimental groups were graded as not cytotoxic. After water-bath post-polymerisation, specimens of Lucitone 550 processed by long cycle produced significantly lower inhibition of DNA synthesis than the other groups.Conclusion: the long cycle increased the cytotoxicity of Lucitone 550 and water-bath post-polymerisation reduced the cytotoxicity of Lucitone 550 processed by long cycle.

Effect of 3,4,4 '-trichlorocarbanilide on growth of lactic acid bacteria contaminants in alcoholic fermentation

3,4,4'-trichlorocarbanilide (TCC) was rested as a new method of bacterial growth control for S. cerevisiae alcoholic fermentations of diluted high test molasses (HTM). Minimal inhibitory concentration (MIC) was tested to determine the necessary concentration of TCC to control bacterial growth. The fed-batch alcoholic fermentation process was used with cell recycle similar to industrial conditions and Lactobacillus fermentum CCT 1407 was mixed in the first inoculum to grow with the yeast. Yeast extract was added into the must to stimulate bacterial growth. The best results of TCC's MIC to bacterial growth of Lactobacillus fermentum and Leuconostoc mesenteroides (< 0.125-1.0 mu g/ml) and Saccharomyces cerevisiae (16 mu g/ml) occurred when it was combined with sodium dodecylsulphate (SDS) in a 1: 4 TCC/SDS ratio (wt/wt) in distilled water solution. 1.8 g/l TCC entrapped in calcium alginate added to the must with yeast extract inhibited the growth of Lactobacillus fermentum CCT 1407 maintaining a controlled acidity, higher yeast viability and up to 20.8% of improvement in the average of alcoholic efficiency. Addition of 0.075 g/l TCC entrapped in calcium alginate and 1.67 mg/l SDS in the wort with yeast extract (0-5.0 g/l), inhibited and controlled the extensive bacterial contamination for 19 cycles of fermentation. (C) 1998 Published by Elsevier B.V. Ltd.

Effect of indomethacin on hyperthermia induced by heat stress in broiler chickens

An investigation was carried out to verify whether the heat stress hyperthermia response of broilers is prostaglandin-dependent. Male broiler chickens of the Hubbard-Petterson strain, aged 35-49 days, were used. Chickens were injected with indomethacin (1 mg/kg intraperitoneally) 15 min before or 2 h after heat exposure (at 35 degrees C for 4 h), and rectal temperature was measured before injection and up to 4 h thereafter. Birds were separated into two groups with and without access to water during heat stress. The increase in rectal temperature was lower (P<0.05) in birds with access to drinking water during heat exposure. All birds injected with indomethacin exhibited an increase in rectal temperature, irrespective of whether indomethacin was administered before or in the course of the rise in temperature. The results revealed that the increase in rectal temperature during heat exposure is not prostaglandin-dependent, and that the use of cyclooxigenase inhibitors is not recommended to attenuate heat stress hyperthermia in broiler chickens.

Impact of an environmentally realistic intake of water contaminants and superoxide formation on tissues of rats

Water contaminants have a high potential risk for the health of populations and for this reason their toxic effects urgently should be established. The present study was carried out to determine whether an environmentally realistic intake of water contaminants can induce tissue lesions, and to clarify the contribution of superoxide radical (O-2(.-)) formation to this effect. Male Wistar rats were given drinking water from the Tiett River (group A) and from the Capivara River (group B). The increased creatinine, glucose, alanine transaminase and amylase levels in serum reflected the toxic effects of river-water contaminants to renal, pancreatic and hepatic tissues of rats. As changes in lipoperoxide were observed in rats after river-water intake while superoxide dismutase activities decreased in these animals, it is assumed that the superoxide anion elicits lipoperoxide formation and induces tissue damage. There is evidence that oxygen tension reflects water pollution, since river-water with a-low oxygen tension induced more elevated toxicity in rat tissues. (C) 1999 Elsevier B.V. Ltd. All rights reserved.

EFFECT OF ELECTROLYTIC AND CHEMICAL LESION BY IBOTENIC ACID OF THE AMYGDALA ON SALT INTAKE

Sodium chloride intake was studied in male Holtzman rats weighing 250-300 g submitted to electrolytic and chemical lesion of the cell bodies, not fibers of the amygdaloid complex. Sodium chloride (1.5%) intake increased in animals with electrolytic lesion of the corticomedial nucleus of the amygdala. Sodium chloride (1.5%) intake increased after ibotenic acid injection into the corticomedial nucleus of the amygdala to a larger extent (26.6 +/- 9.2 to 147.6 +/- 34.6 ml/5 days). The results indicate that sodium intake response can be induced by lesions, which involved only cell bodies. The fibers of passage of the corticomedial nucleus of the amygdala produce a water intake less consistent than that induced by ibotenic acid, which is more acute. The results show that cell bodies of this region of the amygdala are involved in the control of sodium chloride intake.