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Sample records for acidulants

  1. Agronomic Effectiveness of Partially Acidulated Phosphate Rock

    HENIAN-ZU; SUNQI-WEI

    1994-01-01

    Laboratorial incubation and field experiments were conducted on soils ranging in texture from sandy loam to clay and in pH from 3.6 to 9.0 to determine the agronomic effectiveness of single superphosphate (SSP).fused magnesium phosphate(FMP) and partially acidulated phosphate rock(PAPR) on 8 field crops.The results showed that the pattern of available P released from SSP was fixing-releasing-fixing-steady state,while that of PAPR was shortly fixing-slowly releasing-fixing steady state.And the PAPR,SSP and FMP were equally effective as judged by yield Puptake by phants and extractable P in soils after crop harvesting,The PAPR used as basal fertilizer was more effective than that as top dressing,and its residual effect was also obvious.

  2. Corrosion behavior of zirconia in acidulated phosphate fluoride

    Anie Thomas; Sathyanarayanan Sridhar; Shant Aghyarian; Pilanda Watkins-curry; Chan, Julia Y.; Alessandro Pozzi; Danieli C. Rodrigues

    2016-01-01

    ABSTRACT Objective The corrosion behavior of zirconia in acidulated phosphate fluoride (APF) representing acidic environments and fluoride treatments was studied. Material and Methods Zirconia rods were immersed in 1.23% and 0.123% APF solutions and maintained at 37°C for determined periods of time. Surfaces of all specimens were imaged using digital microscopy and scanning electron microscopy (SEM). Sample mass and dimensions were measured for mass loss determination. Samples were charac...

  3. Corrosion behavior of zirconia in acidulated phosphate fluoride

    Thomas, Anie; Sridhar, Sathyanarayanan; Aghyarian, Shant; Watkins-Curry, Pilanda; Chan, Julia Y.; Pozzi, Alessandro; Danieli C. Rodrigues

    2016-01-01

    ABSTRACT Objective The corrosion behavior of zirconia in acidulated phosphate fluoride (APF) representing acidic environments and fluoride treatments was studied. Material and Methods Zirconia rods were immersed in 1.23% and 0.123% APF solutions and maintained at 37°C for determined periods of time. Surfaces of all specimens were imaged using digital microscopy and scanning electron microscopy (SEM). Sample mass and dimensions were measured for mass loss determination. Samples were characteri...

  4. ANTICARIOGENIC POTENCIAL OF ACIDULATE SOLUTIONS WITH LOW FLUORIDE CONCENTRATION

    Alberto Carlos Botazzo Delbem; Gilberto Carlos Tiano; Karina Mirela Ribeiro Pinto Alves; Robson Frederico Cunha

    2006-01-01

    OBJETIVES: The aim of this study was to verify the anticariogenic effect of acidulate solutions with low NaF concentration, using pH-cycling model and bovine enamel. MATERIAL AND METHODS: Enamel blocks were submitted to the surface microhardness (SMH) test and randomly divided in 12 experimental and one placebo groups. The blocks were submitted to pH cycling for 7 days, with daily applications once/day of 0.05% NaF and 0.1% NaF and twice/day of 0.02% NaF solutions. Four different pH: 4.0, 5.0...

  5. Corrosion behavior of zirconia in acidulated phosphate fluoride.

    Thomas, Anie; Sridhar, Sathyanarayanan; Aghyarian, Shant; Watkins-Curry, Pilanda; Chan, Julia Y; Pozzi, Alessandro; Rodrigues, Danieli C

    2016-02-01

    Objective The corrosion behavior of zirconia in acidulated phosphate fluoride (APF) representing acidic environments and fluoride treatments was studied. Material and Methods Zirconia rods were immersed in 1.23% and 0.123% APF solutions and maintained at 37°C for determined periods of time. Surfaces of all specimens were imaged using digital microscopy and scanning electron microscopy (SEM). Sample mass and dimensions were measured for mass loss determination. Samples were characterized by powder X-ray diffraction (XRD) to detect changes in crystallinity. A biosensor based on electrochemical impedance spectroscopy (EIS) was used to detect ion dissolution of material into the immersion media. Results Digital microscopy revealed diminishing luster of the materials and SEM showed increased superficial corrosion of zirconia submerged in 1.23% APF. Although no structural change was found, the absorption of salts (sodium phosphate) onto the surface of the materials bathed in 0.123% APF was significant. EIS indicated a greater change of impedance for the immersion solutions with increasing bathing time. Conclusion Immersion of zirconia in APF solutions showed deterioration limited to the surface, not extending to the bulk of the material. Inferences on zirconia performance in acidic oral environment can be elucidated from the study. PMID:27008257

  6. Corrosion behavior of zirconia in acidulated phosphate fluoride

    Thomas, Anie; Sridhar, Sathyanarayanan; Aghyarian, Shant; Watkins-curry, Pilanda; Chan, Julia Y.; Pozzi, Alessandro; Rodrigues, Danieli C.

    2016-01-01

    ABSTRACT Objective The corrosion behavior of zirconia in acidulated phosphate fluoride (APF) representing acidic environments and fluoride treatments was studied. Material and Methods Zirconia rods were immersed in 1.23% and 0.123% APF solutions and maintained at 37°C for determined periods of time. Surfaces of all specimens were imaged using digital microscopy and scanning electron microscopy (SEM). Sample mass and dimensions were measured for mass loss determination. Samples were characterized by powder X-ray diffraction (XRD) to detect changes in crystallinity. A biosensor based on electrochemical impedance spectroscopy (EIS) was used to detect ion dissolution of material into the immersion media. Results Digital microscopy revealed diminishing luster of the materials and SEM showed increased superficial corrosion of zirconia submerged in 1.23% APF. Although no structural change was found, the absorption of salts (sodium phosphate) onto the surface of the materials bathed in 0.123% APF was significant. EIS indicated a greater change of impedance for the immersion solutions with increasing bathing time. Conclusion Immersion of zirconia in APF solutions showed deterioration limited to the surface, not extending to the bulk of the material. Inferences on zirconia performance in acidic oral environment can be elucidated from the study. PMID:27008257

  7. Corrosion behavior of zirconia in acidulated phosphate fluoride

    Anie Thomas

    2016-02-01

    Full Text Available ABSTRACT Objective The corrosion behavior of zirconia in acidulated phosphate fluoride (APF representing acidic environments and fluoride treatments was studied. Material and Methods Zirconia rods were immersed in 1.23% and 0.123% APF solutions and maintained at 37°C for determined periods of time. Surfaces of all specimens were imaged using digital microscopy and scanning electron microscopy (SEM. Sample mass and dimensions were measured for mass loss determination. Samples were characterized by powder X-ray diffraction (XRD to detect changes in crystallinity. A biosensor based on electrochemical impedance spectroscopy (EIS was used to detect ion dissolution of material into the immersion media. Results Digital microscopy revealed diminishing luster of the materials and SEM showed increased superficial corrosion of zirconia submerged in 1.23% APF. Although no structural change was found, the absorption of salts (sodium phosphate onto the surface of the materials bathed in 0.123% APF was significant. EIS indicated a greater change of impedance for the immersion solutions with increasing bathing time. Conclusion Immersion of zirconia in APF solutions showed deterioration limited to the surface, not extending to the bulk of the material. Inferences on zirconia performance in acidic oral environment can be elucidated from the study.

  8. Effect of Acidulated Phosphate Fluoride (APF) on the Mcroleakage of Composite Flow and Fssure Sealant Restorations

    Arash Poorsattar Bejeh Mir; Zahra Bani Ameri; Vahid Soltankarimi; Hengame Saffarcherati; Mitra Tabari

    2012-01-01

    Background and Aims: A large number of investigations have revealed that physical and chemical alterations and weight loss could occur in composite materials exposed to acidic phosphate fluoride (APF) gel. The purpose of this study was to assess the microleakage of a fissure sealant and a flow composite exposed to acidulated phosphate fluoride (APF) gel. Materials and Methods: In this in vitro study, 60 intact human extracted premolar teeth were used. After preparing the occlusal groove, the ...

  9. Field evaluation of partially acidulated phosphate rocks in a Ferralsol from Cuba

    Phosphorus (P) is needed in large areas of developing countries to improve soil fertility for crop production. The use of phosphate rock (PR) is an alternative to costly soluble P fertilizers, but it is ineffective usually in non-acid soils unless it is modified i.e. partially acidulated (PAPR). A laboratory incubation study using the isotopic exchange kinetic method of 32P and field experiments were undertaken on a neutral Ferralsol of Cuba to evaluate the effectiveness of PAPRs as fertilizers for common bean (Phaseolus vulgaris, L.). Sulfuric-acid based PAPR using 40%, 50% and 60% of the acid required to produce single superphosphate were studied. In the laboratory experiment Trinidad de Guedes PAPR was effective in providing P to the soil, through increases in isotopically exchangeable P and the percentage of P derived from fertilizer (% Pdff). In the three field experiments carried out to compare the P sources, yields of common bean were increased by PAPR, though the response was less than with triple superphosphate (TSP). The relative agronomic effectiveness (RAE) of PAPR was greater than that of unacidulated PR. Taking into account the RAE values and the current cost of the P sources, the choice of Trinidad de Guedes PAPR instead of TSP could be economic, although the RAE value for PAPR was lower than that of TSP. This result indicates that PAPR could be used in the soil understudy to obtain the best economic return. DM yield, P uptake and grain yield of common bean were significantly increased by applying P as 50% PAPR. Low cost improvement of the agronomic value of PR can be achieved by partial acidulation, so this modification of the phosphate rock show promise for utilization of PR reserves indigenous to developing countries. (author)

  10. Field evaluation of partially acidulated phosphate rocks in a Ferralsol from Cuba

    Rodriguez, R.; Herrera, J. [Ciego de Avila University, Ciego de Avila (Cuba)]. E-mail: herrera@uctr.unica.cu

    2002-05-15

    Phosphorus (P) is needed in large areas of developing countries to improve soil fertility for crop production. The use of phosphate rock (PR) is an alternative to costly soluble P fertilizers, but it is ineffective usually in non-acid soils unless it is modified i.e. partially acidulated (PAPR). A laboratory incubation study using the isotopic exchange kinetic method of {sup 32}P and field experiments were undertaken on a neutral Ferralsol of Cuba to evaluate the effectiveness of PAPRs as fertilizers for common bean (Phaseolus vulgaris, L.). Sulfuric-acid based PAPR using 40%, 50% and 60% of the acid required to produce single superphosphate were studied. In the laboratory experiment Trinidad de Guedes PAPR was effective in providing P to the soil, through increases in isotopically exchangeable P and the percentage of P derived from fertilizer (% Pdff). In the three field experiments carried out to compare the P sources, yields of common bean were increased by PAPR, though the response was less than with triple superphosphate (TSP). The relative agronomic effectiveness (RAE) of PAPR was greater than that of unacidulated PR. Taking into account the RAE values and the current cost of the P sources, the choice of Trinidad de Guedes PAPR instead of TSP could be economic, although the RAE value for PAPR was lower than that of TSP. This result indicates that PAPR could be used in the soil understudy to obtain the best economic return. DM yield, P uptake and grain yield of common bean were significantly increased by applying P as 50% PAPR. Low cost improvement of the agronomic value of PR can be achieved by partial acidulation, so this modification of the phosphate rock show promise for utilization of PR reserves indigenous to developing countries. (author)

  11. Effect of casein phosphopeptide-amorphous calcium phosphate and acidulated phosphate fluoride gel on erosive enamel wear

    Maryam HajeNorouz Ali Tehrani; Maryam Ghafournia; Pouran Samimi; Omid Savabi; Iman Parisay; Navid Askari; Seyed-Hossein Abtahi

    2011-01-01

    Background: Some studies have shown that casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and acidulated phosphate fluoride (APF) gel can protect teeth against erosion. The aim of this study was to assess whether CPP-ACP and fluoride could reduce enamel wear rates under erosive conditions simulating abrasion and acidic diet regimen. Materials and Methods: Enamel specimens consisted of 3 experimental groups (receiving CPP-ACP, APF or both) and a control group. Specimens were sub...

  12. Effect of casein phosphopeptide-amorphous calcium phosphate and acidulated phosphate fluoride gel on erosive enamel wear

    Tehrani, Maryam HajeNorouz Ali; Ghafournia, Maryam; Samimi, Pouran; Savabi, Omid; Parisay, Iman; Askari, Navid; Abtahi, Seyed-Hossein

    2011-01-01

    Background: Some studies have shown that casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and acidulated phosphate fluoride (APF) gel can protect teeth against erosion. The aim of this study was to assess whether CPP-ACP and fluoride could reduce enamel wear rates under erosive conditions simulating abrasion and acidic diet regimen. Materials and Methods: Enamel specimens consisted of 3 experimental groups (receiving CPP-ACP, APF or both) and a control group. Specimens were subject...

  13. Surface micromorphological changes of glass ionomer following application of 1.23% acidulated phosphate fluoride: A scanning electron microscope study

    Ektah Khosla; Sobha Kuriakose; Chintu Suderasen

    2014-01-01

    Objectives: The purpose of this study was to evaluate the surface micromorphological changes of conventional glass ionomer cement (GIC) (Fuji II, GC Corporation, Tokyo, Japan) and high strength, high viscosity GIC (Fuji IX GP, GC Corporation) subjected to 1.23% acidulated phosphate fluoride (APF) gel for 4 min. It also evaluated the surface micromorphological changes that occurred in these materials when they were coated with a layer of glass ionomer varnish prior to the application of 1.23% ...

  14. Acidulants for japanese quails housed at high stocking rates at finishing phase

    Ana Paula de Oliveira Saccomani

    2013-12-01

    Full Text Available The quail for being an alternative species will be able to supply a new market niche due to its fast growth, high laying rate, low feed intake, in addition to the increase of the acceptance of its products by the consumer. A growing interest in raising the stocking rates in the cages as an alternative to increase the performance of the stock is noticed; although studies demonstrate that high densities can result into unfavorable environment to the birds’ welfare with alterations in the performance of the flocks and as a stressing factor being able to alter the production and profitability of the flock. At high stocking rates, the birds become predisposed to aggressiveness reactions, presenting cannibalism behavior, besides the combination of factors such as pH, temperature, ventilation and humidity deficiency which create environmental conditions favorable for certain benign bacteria which utilize uric acid of the manure through their enzymatic complexes and produce ammonia, causing stress to birds and which can cause damages to performance with significant economic losses to the producer.  The experiment with 112-day duration was conducted with the objective of evaluating the inclusion of acidulants in the Japanese quails’ drinking water and verifying the effect on the stocking rate in cages. A completely randomized design with four treatments (2 stocking rates of quails x 2 additions of and 5 replications of 24 and 36 birds per cage, corresponding to the stocking rates of 141.67 and 94.44 cm2/bird, respectively, receiving or not acidulant in the water (acetic, lactic and phosphoric acid was utilized. Performance was evaluated through egg weight (EWg, egg yield (%Laying., egg mass (EMg/bird/day, feed intake (FIg/bird/day, feed conversion (FCkg/dz and FCkg/kg and mortality (%Mort. No significant statistical differences about the performance (P>0.05 were found. There was a significant effect (P<0.05 of the density for daily feed intake with

  15. Evaluation of residual effect of partially acidulated phosphate rock on crop production

    Many countries in Sub -Saharan Africa are rich in phosphate rock (PR) -the primary raw material for the production of phosphate fertilizers. Because of the low local demand and the global surplus of P fertilisers, these deposits have not been developed. Technical, economic and conducive policy regimes are needed in order to initiate tapping of these resources and providing them at low cost.Direct application of of ground PR would be one way of providing the PR at low cost, but this mode of application has proved not to be effective with Zambian PR. In current field trials, simply processed partially acidulated PR (PAPR) was utilised. The main objective of this study was to evaluate the agronomic effectiveness of PAPR produced from simply processed phospate rock products in soils of varying soil chemical properties for direct and residual application on field crops. The results of the three year study have demonstrated that PAPR was a good source of P in providing P to plants and improving crop yields.Where soils were acidic and acutely P deficient, PAPR was a better source of P compared to highly soluble fertilizers.The results have also shown that in the third year as in the second year , there was a greater residual effect of PAPR to increase crop yields. A one time application of P was effective for up to three years. (author)

  16. Water intake and digestive metabolism of broilers fed all-vegetable diets containing acidulated soybean soapstock

    SL Vieira

    2006-09-01

    Full Text Available A study was conducted to compare live performance and digestive metabolism of broiler chickens fed all-vegetable diets (All-Veg compared to a regular diet including animal by-products. Three feeds were formulated and provided to broilers according to the feeding program: pre-starter from 1 to 10 days, starter from 11 to 21 days, and grower from 21 to 35 days. All feeds had corn and soybean meal as major ingredients; however, two of them were all-vegetable diets having either Degummed Soybean Oil (DSO or Acidulated Soybean Soapstock (ASS as fat sources. The third diet included poultry by-product and poultry fat. A total number of 360 day-old broiler chicks were allocated to 1m² battery cages, 10 chicks in each, and 12 replicates per treatment. Live performance was similar between groups of birds receiving the different diets with the exception of weight gain, which was increased for birds fed the All-Veg diet with ASS. Birds fed All-Veg diets had increased water intake and produced more excreta with a concurrent reduced feed metabolizability at both ages, regardless of fat source. Metabolizable Energy was not different for the three diets.

  17. The effect of acidulated phosphate fluoride application on dental enamel surfaces hardness

    Edhie Arief P

    2007-09-01

    Full Text Available Enamel demineralization by acid is the first step of caries process. It has recently been shown that acidulated phosphate fluoride (APF can maintain the hardness of enamel surface. The aim of this study was examine the effect of APF application in the hardest of enamel surface. Fifty extracted teeth were cut at their crown, 40 teeth were taken randomly then divided into 4 groups, group 1 as the control, group 2 was treated with APF for 1 minute, group 3 for 4 minutes and group 4 for 7 minutes, then all the samples were washed with demineralized water. To see the effect of APF, all of the samples were soaked in lactic acid demineralization solution with pH 4,5 for 72 hours., the hardness of the surfaces of those samples before and after the treatment was measured by Micro Vickers Hardness Tester. The data were analyzed using One-Way ANOVA and LSD tests. In conclusion, 1.23% APF gel can reduce higher enamel demineralization.

  18. Effect of Acidulated Phosphate Fluoride (APF on the Mcroleakage of Composite Flow and Fssure Sealant Restorations

    Arash Poorsattar Bejeh Mir

    2012-09-01

    Full Text Available Background and Aims: A large number of investigations have revealed that physical and chemical alterations and weight loss could occur in composite materials exposed to acidic phosphate fluoride (APF gel. The purpose of this study was to assess the microleakage of a fissure sealant and a flow composite exposed to acidulated phosphate fluoride (APF gel. Materials and Methods: In this in vitro study, 60 intact human extracted premolar teeth were used. After preparing the occlusal groove, the teeth were divided into two groups (n=30. Teeth were filled with either Helioseal fissure sealant (Vivadent, Germany or Tetric flow composite (Vivadent, Germany. After that, each group was divided into two subgroups (n=15: 1.23% APF gel (Sultan, U.S.A was applied in the case subgroups, while control subgroups were preserved in normal saline solution. All of teeth were covered with 2 layers of nail varnish except for the filling zone and 1mm around the border of filling. After submerging in 0.5% fushin solution, specimens were sectioned bucco-lingually. Then dye penetration through the filling and fissure sealant was assessed by means of a stereo-microscope. The depth of dye penetration was scored. The data were analyzed using One-way ANOVA and Levene test. Results: The mean values of dye penetration were 1.26±1.09, 1.4±1.05, 1.2±1.37, and 1.4±1.35 for fissure sealant+gel, composite+gel, composite+normal saline, and normal saline groups, respectively. No significant difference was found in inter-groups (P=0.96. Conclusion: Considering the result of the present research, APF gel had no significant effect on the microleakage of Tetric flow composite filling and Helioseal fissure sealant and thus, it can be applied for routine usage.

  19. Surface degradation of glass ceramics after exposure to acidulated phosphate fluoride

    Vanessa Z.S. Ccahuana

    2010-04-01

    Full Text Available OBJECTIVE: This study evaluated the surface degradation effect of acidulated phosphate fluoride (APF gel exposure on the glassy matrix ceramics as a function of time. MATERIAL AND METHODS: Disc-shaped ceramic specimens (N = 120, 10/per ceramic material were prepared in stainless steel molds (inner diameter: 5 mm, height: 2 mm using 6 dental ceramics: 3 indicated for ceramic-fused-to-metal (Vita Omega 900, Carmen and Vita Titankeramik, 2 for all-ceramic (Vitadur Alpha and Finesse® Low Fusing and 1 for both types of restorations (IPS d.SIGN. The specimens were wet ground finished, ultrasonically cleaned and auto-glazed. All specimens were subjected to calculation of percentage of mass loss, surface roughness analysis and topographical description by scanning electron microscopy (SEM before (0 min and after exposure to 1.23 % APF gel for 4 min and 60 min representing short- and long-term etching effect, respectively. The data were analyzed using two-way ANOVA with repeated measures and Tukey's test (a=0.05. RESULTS: Significant effect of the type of the ceramics (p=0.0000, p=0.0031 and exposure time (p=0.0000 was observed in both surface roughness and percentage of mass loss values, respectively. The interaction factor between both parameters was also significant for both parameters (p=0.0904, p=0.0258. Both 4 min (0.44±0.1 - 0.81±0.2 mm and 60 min (0.66±0.1 - 1.04±0.3 mm APF gel exposure created significantly more surface roughness for all groups when compared to the control groups (0.33±0.2 - 0.68±0.2 mm (p0.05 but at 60 min exposure, IPS d.SIGN showed the highest percentage of mass loss (0.1151±0.11. The mean surface roughness for Vita Titankeramik (0.84±0.2 mm and Finesse® Low Fusing (0.74.±0.2 mm was significantly higher than those of the other ceramics (0.59±0.1 mm - 0.49±0.1 mm and Vita Titankeramik (p<0.05 regardless of the exposure time. A positive correlation was found between surface roughness and percentage of mass loss for

  20. Optimisation of the acidulation process of soapstock from the neutralisation of rice bran oil

    Barrera-Arellano, Daniela

    2004-06-01

    Full Text Available Soapstock from the neutralisation of rice bran oil was characterised through the most important parameters with direct influence on the acidulation process. A central composite rotational experimental design of two levels was used. The responses of the trials were γ -oryzanol concentration in the acid oil and process time necessary for total hydrolysis of the soaps present. The optimal process conditions were determined using the response surface methodology. Adjustments were made to second order mathematical models and validity was verified by analysis of variance using the STATISTICA program. The process variables studied were: molar ratio - sulphuric acid/soaps (0.55-0.95 and process temperature (70- 100 °C . The results indicated that the process temperature does not significantly interfere in the concentration of γ -oryzanol of the acid oil, but it does affect process time. In the different concentrations of sulphuric acid added, represented by the molar ratio of sulphuric acid/soaps, the concentration of γ -oryzanol varied between 3.13 and 3.74 %. Through the superposition of the areas of the response surface contour curves the optimal process parameters were determined: process temperature of 95 °C and molar ratio of sulphuric acid/soaps of 0.74, resulting in a γ -oryzanol concentration of 3.64 % and a process time of 90 minutes.La borra de neutralización de aceite de salvado de arroz se caracterizó por los parámetros más importantes con influencia directa sobre el proceso de acidulación. Se utilizó un diseño estadístico experimental compuesto rotacional central con dos niveles. Los resultados de los ensayos fueron la concentración de γ -orizanol en el aceite ácido y el tiempo de proceso necesario para la hidrólisis total de los jabones presentes. Se determinaron las condiciones óptimas del proceso utilizando la metodología de superficie de respuesta. Los ajustes se hicieron a modelos matemáticos de

  1. Interaction of ionising radiation and acidulants on the growth of the microflora of a vacuum-packaged chilled meat product

    Microbiological effects of gamma irradiation dose of 2 kGy, with and without reduction of pH to 5.3-5.2, have been investigated with a vacuum-packaged, minced meat product prepared from pork and beef with spices and cereal fillings. Either glucono-delta-lactone or ascorbic acid were used as acidulants. Experimental batches were stored at 0-2 degrees C for 4 weeks. Effect of temperature abuse condition was also studied by transferring packages for one week to 10 degrees C after 2-week holding at 0-2 degrees C. The irradiation caused two decimal reduction of the aerobic viable cell count determined after incubation at room temperature and four decimal reduction in the Enterobacteriaceae count. Lactic acid bacteria appeared to be more radiation resistant and became the dominant component of the microflora during storage. Combination of pH-reduction and irradiation prevented growth of Enterobacteriaceae even at 10 degrees C incubation. (author)

  2. Efficacy of silver diamine fluoride as an antibacterial as well as antiplaque agent compared to fluoride varnish and acidulated phosphate fluoride gel: An in vivo study

    Shalin Shah; Vijay Bhaskar; Karthik Venkataraghavan; Prashant Choudhary; M Ganesh; Krishna Trivedi

    2013-01-01

    Background: Silver diamine fluoride (SDF) is already proven as an antibacterial agent in vitro. Present study was formulated to compare the efficacy of SDF as an antibacterial as well as antiplaque agent in vivo with fluoride varnish and acidulated phosphate fluoride (APF) gel. Study Design: Total 123 children (male = 82, female = 41) were included in the study for a period of 18 months. Children were divided into three different groups-Group 1: SDF; Group 2: fluoride varnish; and Group 3...

  3. Effect of water and citrate solubility on agronomic effectiveness of acidulated phosphates in three consecutive corn crops

    L. I. Prochnow

    2002-09-01

    Full Text Available In the process of phosphate rock acidulation, several impure P compounds may be formed along with the desirable Ca and NH4 phosphates. Such compounds normally reduce the content of water-soluble P and thus the agronomic effectiveness of commercial fertilizers. In order to study this problem, a greenhouse experiment consisting of three consecutive corn crops was conducted in samples of a Red-Yellow Latosol (Typical Hapludox in a completely randomized design (6 x 2 x 2, with four replicates. Six commercial fertilizers were added to 2 kg of soil at a rate of 70 mg kg-1 P, based on the content of soluble P in neutral ammonium citrate plus water (NAC + H2O of the fertilizers. Fertilizer application occurred either in the original form or leached to remove the water-soluble fraction, either by mixing the fertilizer with the whole soil in the pots or with only 1 % of its volume. The corn plants were harvested 40 days after emergence to determine the shoot dry matter and accumulated P. For the first crop and localized application, the elimination of water-soluble P from the original fertilizers resulted in less bioavailable P for the plants. For the second and third crops, the effects of P source, leaching and application methods were not as evident as for the first, suggesting that the tested P sources may have similar efficiencies when considering successive cropping. The conclusion was drawn that the water-insoluble but NAC-soluble fractions of commercial P fertilizers are not necessarily inert because they can provide P in the long run.

  4. Production of Italian Dry Salami: Effect of Starter Culture and Chemical Acidulation on Staphylococcal Growth in Salami Under Commercial Manufacturing Conditions

    Metaxopoulos, J.; Genigeorgis, C.; Fanelli, M. J.; Franti, C.; Cosma, E.

    1981-01-01

    The effect of starter culture and chemical acidulation on the growth and enterotoxigenesis of Staphylococcus aureus strain S-6 in Italian dry salami under commercial manufacturing conditions was studied. The experimental design included two levels of S. aureus (104 and 105/g), three levels of starter culture (0, 105, and 106/g), three levels of initial pH (pH0) (6.1, 5.5, and 4.8), two manufacturing plants, and three replications. S. aureus growth in the salami was affected significantly (P <...

  5. Comparision of Shear Bond Strength of Stainless Steel and Ceramic Brackets at 24 Hours after Etching Enamel with Different Proportions of Acidulated Phosphate Fluoride

    Abinaya; Karthikeyan; Sarvanan; Vikram, Raj

    2014-01-01

    Aims and Objectives: To evaluate and compare the shear bond strength of stainless steel brackets and ceramic brackets at 24h after etching the enamel with acidulated phosphate fluoride gel (1.23% APF) at different proportions (40%,30%,20%) incorporated in conventional etchant (37% phosphoric acid). Materials and Methods: Eighty premolars (maxillary and mandibular first and second premolars) extracted for orthodontic purpose has been selected for the study and samples were divided into 4 groups containing 10 teeth each. Comprised of teeth etched Group 1 with 40% of APF gel etchant is Group 2 teeth etched with 30% of APF gel in Group 3 teeth etched with 20% of APF gel etchant and Group 4 teeth were etched with conventional etchant (37% phosphoric acid). Results: The experimental group of Acidulated Phosphate Fluoride (APF) at different proportion (40%, 30%, 20%) incorporated with etchant application for 40s on the enamel surface at 24h indicated that group 4 showed the higher bond strength of all other remaining groups and the groups 1, 2 and 3 showed satisfactory bond strength. The statistical evaluation also revealed that the bond strength of control group (37% phosphoric acid) was greater than those of experimental groups. Conclusion: The present study results shows that the ceramic brackets have higher bond strength than stainless steel brackets (material wise). PMID:25302260

  6. Atomic force microscopic comparison of remineralization with casein-phosphopeptide amorphous calcium phosphate paste, acidulated phosphate fluoride gel and iron supplement in primary and permanent teeth: An in-vitro study

    Nikita Agrawal; N D Shashikiran; Shilpy Singla; Ravi, K.S.; Vinaya Kumar Kulkarni

    2014-01-01

    Context: Demineralization of tooth by erosion is caused by frequent contact between the tooth surface and acids present in soft drinks. Aim: The present study objective was to evaluate the remineralization potential of casein-phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste, 1.23% acidulated phosphate fluoride (APF) gel and iron supplement on dental erosion by soft drinks in human primary and permanent enamel using atomic force microscopy (AFM). Materials and Methods: Specimens were...

  7. Degradation in performance of orthodontic wires caused by hydrogen absorption during short-term immersion in 2.0% acidulated phosphate fluoride solution.

    Kaneko, Kazuyuki; Yokoyama, Ken'ichi; Moriyama, Keiji; Asaoka, Kenzo; Sakai, Jun'ichi

    2004-08-01

    The purpose of this study was to investigate the degradation in performance of four major alloys of orthodontic wires, namely nickel-titanium, beta titanium, stainless steel, and cobalt-chromium-nickel, caused by hydrogen absorption during short-term immersion in an acid fluoride solutions. The hydrogen-related degradation of orthodontic wires after immersion in 2.0% acidulated phosphate fluoride solution at 37 degrees C for 60 minutes was evaluated by a tensile test, scanning electron microscope observation, and hydrogen thermal desorption analysis. Upon immersion, the tensile strengths of the nickel-titanium and beta titanium wires decreased. Particularly, the nickel-titanium wire fractured before yielding, and the fracture mode changed from ductile to brittle. The amounts of absorbed hydrogen in the nickel-titanium and beta titanium wires were 200 and 100 mass ppm, respectively. On the other hand, the tensile strengths of the stainless steel and cobalt-chromium-nickel wires were only slightly affected by immersion. The results of this study suggest that degradation in performance of orthodontic wires of titanium alloys occurs because of hydrogen absorption even after a short-term immersion in fluoride solutions. PMID:15387026

  8. Efficacy of silver diamine fluoride as an antibacterial as well as antiplaque agent compared to fluoride varnish and acidulated phosphate fluoride gel: An in vivo study

    Shalin Shah

    2013-01-01

    Full Text Available Background: Silver diamine fluoride (SDF is already proven as an antibacterial agent in vitro. Present study was formulated to compare the efficacy of SDF as an antibacterial as well as antiplaque agent in vivo with fluoride varnish and acidulated phosphate fluoride (APF gel. Study Design: Total 123 children (male = 82, female = 41 were included in the study for a period of 18 months. Children were divided into three different groups-Group 1: SDF; Group 2: fluoride varnish; and Group 3: APF gel. All subjects were evaluated via plaque score at 6 th , 12 th , and 18 th months as well as Streptococcus mutans counts in saliva at 72 h, 6 th , 12 th , and 18 th months of follow-up. Results: Significant reduction was found in plaque score as well as S. mutans counts irrespective of group division. On intergroup comparison, no statistically significant difference was found in plaque score, but significant reduction in S. mutans counts was found in Group 1 as compared with Groups 2 and 3, while no significant difference was found between Groups 2 and 3. Conclusion: In vivo application of SDF on enamel significantly decreases S. mutans counts as compared to fluoride varnish and APF gel.

  9. Utilização da Energia de Dietas para Frangos de Corte Formuladas com Óleo Ácido de Soja Energy Utilization of Broiler Feeds Formulated with Acidulated Soybean Soapstock

    SL Vieira

    2002-05-01

    Full Text Available O produto comercialmente chamado "óleo ácido de soja", resulta da acidificação da borra residual do processo de refino do óleo de soja. Este tem sido muito utilizado na indústria de rações animais, ainda que com vários questinamentos a cerca de sua eficiência, tais como a adulteração com outros ácidos graxos de baixo valor nutricional, nível de peroxidação, presença de impurezas, e valores energéticos não confiáveis. Neste estudo, foi avaliado o desempenho de frangos de corte consumindo dietas contendo óleo de soja ou óleo ácido de soja nos níveis de 4 e 8% ou a mistura das duas fontes em partes iguais de 2 e 4% cada. Essas dietas foram fornecidas para frangos de corte alojados em baterias climatizadas a partir dos 7 dias de idade. As aves que receberam misturas equivalentes de óleo ácido de soja e óleo de soja apresentaram menor peso corporal no final do experimento (aos 42 dias quando comparadas com aquelas que consumiram apenas óleo ou óleo ácido de soja, independentemente do nível adicionado. O nível de inclusão de óleo de soja ou óleo ácido de soja não influenciou o peso final das aves. Foi verificado maior consumo de ração pelos animais que receberam dietas de menor nível de inclusão, o que contribuiu para piorar a conversão alimentar dos mesmos. O óleo ácido de soja demonstrou ser uma fonte energética alternativa de alto potencial econômico para uso em dietas comerciais para frangos de corte, apresentando valor energético de 8.114 kcal EMAn/kg de MS, valor 5% inferior ao determinado para o óleo de soja degomado.Acidulated soapstock, a by-product from the vegetable oil industry has been widely used in poultry nutrition. It is produced by the acid treatment of the residue left after refining vegetable oils. Several concerns exist on the use of this product, such as: adulteration, peroxidation, impurity, and uncertain energetic value. The current experiment focused on the use of the acidulated

  10. Energy utilization of by-products from the soybean oil industry by broiler chickens: acidulated soapstock, lecithin, glycerol and their mixture

    JEM Peña

    2014-12-01

    Full Text Available Acidulated soy soapstock (ASS and lecithin (LEC are by-products from processing soy oil (SO for human consumption, whereas glycerol (GLY can be obtained through the transesterification of vegetable oils during the production of biodiesel. These are valuable by-products for poultry feeds that have been underutilized in many parts of the world. One study was conducted to estimate the AMEn of ASS, LEC, GLY as well as of their mixture (MIX: 85% ASS, 5% LEC and 10% GLY. Two hundred and sixty Cobb 500 female broilers of 20 days of age were housed in steel wire battery cages in a controlled temperature room for broilers. A completely randomized (energy sources x fat inclusion level factorial design was applied, with 4 replicates of three birds per treatment. Birds were fed a corn-soybean meal control diet without supplemental fat or with the addition of 2, 4, or 6 % of the four energy sources. Total excreta collection was performed from 26 to 28 days. The AMEn values of by-products were calculated using regression analysis as well as by the difference method. The average AMEn values calculated by regression analysis were: 9,232, 7,502, 5,447 and 8,404, whereas results with the difference method were: 7,951, 6,579, 3,979 and 8,101 kcal/kg for, in both cases for ASS, LEC, GLY and MIX, respectively. It is concluded that these energy sources can be for broilers and that there are significant differences between the methods used to estimate AMEn of fats.

  11. Atomic force microscopic comparison of remineralization with casein-phosphopeptide amorphous calcium phosphate paste, acidulated phosphate fluoride gel and iron supplement in primary and permanent teeth: An in-vitro study

    Nikita Agrawal

    2014-01-01

    Full Text Available Context: Demineralization of tooth by erosion is caused by frequent contact between the tooth surface and acids present in soft drinks. Aim: The present study objective was to evaluate the remineralization potential of casein-phosphopeptide-amorphous calcium phosphate (CPP-ACP paste, 1.23% acidulated phosphate fluoride (APF gel and iron supplement on dental erosion by soft drinks in human primary and permanent enamel using atomic force microscopy (AFM. Materials and Methods: Specimens were made from extracted 15 primary and 15 permanent teeth which were randomly divided into three treatment groups: CPP-ACP paste, APF gel and iron supplement. AFM was used for baseline readings followed by demineralization and remineralization cycle. Results and Statistics: Almost all group of samples showed remineralization that is a reduction in surface roughness which was higher with CPP-ACP paste. Statistical analysis was performed using by one-way ANOVA and Mann-Whitney U-test with P < 0.05. Conclusions: It can be concluded that the application of CPP-ACP paste is effective on preventing dental erosion from soft drinks.

  12. Surface micromorphological changes of glass ionomer following application of 1.23% acidulated phosphate fluoride: A scanning electron microscope study

    Ektah Khosla

    2014-01-01

    Conclusion: APF gel caused erosive wear of the GICs esp. Fuji II. Hence, it is advisable to avoid the use of APF containing preparations for regular home use especially in children having glass ionomer restoration. If APF gel is indicated or preferred for professional application, it is recommended to apply glass ionomer varnish on the restored teeth prior to the APF gel application.

  13. Effect of casein phosphopeptide-amorphous calcium phosphate and acidulated phosphate fluoride gel on erosive enamel wear

    Maryam HajeNorouz Ali Tehrani

    2011-01-01

    Conclusions: We concluded that although either CPP-ACP or APF can protect enamel against wear, their combination provides significant enamel wear reduction. These findings would lead to new strategies for the clinical management of tooth wear.

  14. Phosphogypsum amendments and irrigation with acidulated water affect tomato nutrition in reclaimed marsh soils from SW Spain

    Jose M. Quintero

    2014-07-01

    Full Text Available Phosphogypsum (PG is a by-product of the P fertilizer industry usually valorised as amendment for acidic and sodic soils. This work was aimed to study the effects of PG on nutrient uptake by industrial tomato plants in an originally sodic soil. A completely randomized experiment was performed involving two factors: (i acidification with nitric acid (mimics cleaning techniques in drip irrigation, and (ii PG rate (equivalents to 0, 20, 60, and 200 Mg ha–1. The highest PG rate resulted in an increased dry matter yield, which can be ascribed at least in part to an increased water use efficiency. PG decreased K, Mg and P concentrations in shoots, and P and Cu concentrations in fruits. At the highest rate, PG increased B concentration in shoots and total B content in the aerial parts of plants when acid was applied. The highest PG rate also increased Ca concentration in fruits, which can be considered positive in view of reducing the incidence of blossom end rot. The total content of Ni and Mo in aerial parts increased with PG, probably related to a decreased adsorption of these nutrients in soils. Acid application increased the concentration of all micronutrients in shoots and the concentration of Fe, Cu and B in fruits. In conclusion, PG promoted positive effects on B, Ni, Mo, and Ca nutrition, and some negative nutritional effects through antagonisms or affecting nutrient cycling in the soils, which however did not result in decreasing yields, even at a large dose which mimics the cumulative application during 20-30 years. Acid treatments resulted in improved micronutrient nutrition of tomato plants.

  15. Effect of acidulated phosphate fluoride – gel and foam – on enamel caries-like lesion of primary teeth: an in vitro study

    Karin Faust Souza; Carla Miranda; Izabel Cristina Santos Almeida

    2013-01-01

    The purpose of this study was to evaluate in vitro the effect of APF, gel and foam, for 1 to 4 minutes, on artificial enamel caries-like lesion of primary teeth submitted to the pH cycling. The specimens with medium values of initial superficial enamel micro-hardness between 272 and 331KHN were selected for the formation of the artificial caries lesion. Later, they were randomly divided into 6 groups (n=15): no pH cycling control, cycled control, gel 1min, gel 4min, foam 1min and foam 4min.Th...

  16. Effect of acidulated phosphate fluoride – gel and foam – on enamel caries-like lesion of primary teeth: an in vitro study

    Karin Faust Souza

    2013-12-01

    Full Text Available The purpose of this study was to evaluate in vitro the effect of APF, gel and foam, for 1 to 4 minutes, on artificial enamel caries-like lesion of primary teeth submitted to the pH cycling. The specimens with medium values of initial superficial enamel micro-hardness between 272 and 331KHN were selected for the formation of the artificial caries lesion. Later, they were randomly divided into 6 groups (n=15: no pH cycling control, cycled control, gel 1min, gel 4min, foam 1min and foam 4min.The no pH cycling control group was maintained in an humid environment, while the application of APF and the pH cycling were accomplished. After, the specimens were sectioned at the center for the enamel cross-sectional micro-hardness test. The values of micro-hardness of the depths from 20 to 180mm were converted into percentile of mineral volume (%Vol and the area of mineral recovery (∆ZR was calculated.  In spite of there is no statistically significant differences, it was observed through the analysis of the ∆ZR a difference in the values for the groups gel 1min and foam 4min (p>0.05. The evaluation of %Vol indicated a significant difference only at 60mm depth (p=0.005. This study concluded that a single application of APF gel or foam, for 1 or 4 minutes, do not remineralize artificial enamel caries-like lesion of primary teeth

  17. 钙基调理剂对酸化农田土壤的调控效果研究①%Regulatory Effect of Calcium-based Conditioner on the Acidulated Soil of Farmland

    侯宪文; 张梁; 邹雨坤; 李光义

    2015-01-01

    农田土壤酸化已成为制约农业发展的全球性问题,在强降雨淋溶地区尤为严重。本研究利用硝酸磷肥生产过程中所产生的中间产物制造的低pH值土壤调理剂来改良酸化土壤。结果表明:该调理剂按用量1 g/kg (折合亩施150 kg)即可显著地提高土壤pH值,且其在不同pH值土壤上的施用效果有所差异;施用后短期内存在返酸现象;该调理剂与约一半用量的生石灰的调控效果相当;调理剂对土壤有效磷含量的影响因土壤性质不同而异;施用调理剂对土壤有效钾的影响不显著。%Farmland soil acidification has become a global problem which has been restricted the development of agriculture. And it is particularly serious in heavy rainfall and eluvial area. This experiment uses a kind of low pH value soil conditioner which is made by intermediate product from producing the nitrophosphate fertilizer. The results show that the soil conditioner can improve soil pH value significantly with the dosage of 1 g/kg (that is the dosage 150 kg/mu), but the effects of application were different when the soil pH value were different. The soil became sour again after applying the soil conditioner within a period. Regulatory effect of the soil conditioner was the same when we halve the amount of quick lime. The effect of soil conditioner on available phosphorus content differed with soil property. The soil conditioner did not impact on content of available potassium significantly.

  18. Regulatory Effect of Calcium-based Conditioner on the Acidulated Soil of Farmland%钙基调理剂对酸化农田土壤的调控效果研究①

    侯宪文; 张梁; 邹雨坤; 李光义

    2015-01-01

    农田土壤酸化已成为制约农业发展的全球性问题,在强降雨淋溶地区尤为严重。本研究利用硝酸磷肥生产过程中所产生的中间产物制造的低pH值土壤调理剂来改良酸化土壤。结果表明:该调理剂按用量1 g/kg (折合亩施150 kg)即可显著地提高土壤pH值,且其在不同pH值土壤上的施用效果有所差异;施用后短期内存在返酸现象;该调理剂与约一半用量的生石灰的调控效果相当;调理剂对土壤有效磷含量的影响因土壤性质不同而异;施用调理剂对土壤有效钾的影响不显著。%Farmland soil acidification has become a global problem which has been restricted the development of agriculture. And it is particularly serious in heavy rainfall and eluvial area. This experiment uses a kind of low pH value soil conditioner which is made by intermediate product from producing the nitrophosphate fertilizer. The results show that the soil conditioner can improve soil pH value significantly with the dosage of 1 g/kg (that is the dosage 150 kg/mu), but the effects of application were different when the soil pH value were different. The soil became sour again after applying the soil conditioner within a period. Regulatory effect of the soil conditioner was the same when we halve the amount of quick lime. The effect of soil conditioner on available phosphorus content differed with soil property. The soil conditioner did not impact on content of available potassium significantly.

  19. The chemistry and physiology of sour taste – A review

    Sour taste is the key element in the flavor profile of food acidulants. Understanding the chemistry and physiology of sour taste is critical for efficient control of flavor in the formulation of acid and acidified foods. After a brief introduction to the main applications of food acidulants, several...

  20. Influência da aplicação tópica de flúor fosfato acidulado sobre a rugosidade superficial do esmalte humano e de diferentes materiais restauradores =: Influence of topical acidulated phosphate fluoride on surface roughness of human enamel and different restorative materials

    Botta, Ana Carolina

    2010-01-01

    Objetivo: Este estudo avaliou a influência da aplicação tópica de flúor fosfato acidulado sobre a rugosidade do esmalte e de diferentes materiais restauradores. Metodologia: Amostras de cimento de ionômero de vidro modificado por resina (Vitremer - V), resina composta microhíbrida com flúor (Tetric Ceram - T) e resina nanopartículada sem flúor em sua composição (Z350 - Z) foram confeccionadas. Metade das amostras recebeu aplicação tópica de flúor fosfato acidulado a 1,23% (FFA) (grupos VF, TF...

  1. 21 CFR 172.810 - Dioctyl sodium sulfo-suc-cinate.

    2010-04-01

    ... agent in the following fumaric acid-acidulated foods: Dry gelatin dessert, dry beverage base, and fruit... dessert and dry beverage base shall bear adequate directions for use, and the additive shall be used in such an amount that the finished gelatin dessert will contain not in excess of 15 parts per million...

  2. Effects of the low-intensity laser therapy on the prevention of dental caries induced in rats

    The purpose of this study was to investigate the effects of low intensity laser therapy, associated or not to an acidulated phosphate fluoride, on the prevention of dental caries induced in rats. It was used 40 wistar rats, female, weaned with 18 days, fed with a cariogenic diet during 48 days and inoculated orally with Streptococcus mutans by three consecutive days starting from the second day of the diet. On the fifth day of experiment the animals were divided into five groups: Gc (control) the animas were no submitted to any treatment; GL (laser) irradiation with low power laser (GaAlAs, λ=660 nm, P=30 mW, Δt=5 sec, 5 J/cm2); GF (fluoride) topical application of acidulated phosphate fluoride (APF 1,23%) for four minutes; GLF (laser + fluoride) irradiation with low power laser followed by topical application of acidulated phosphate fluoride; GFL (fluoride + laser) topical application of acidulated phosphate fluoride followed by low power laser. The animals were sacrificed after 48 days; the molars were extracted and prepared to determine the dental caries lesions area by optical microscopy, enamel microhardness and analysis of the calcium and phosphorus ratio (Ca/P) by energy dispersive spectroscopy. The results were statistically analyzed by ANOVA (pLF was smaller than that for GF and GFL groups but no statistical difference was observed. There was no significant statistical difference between the microhardness of the GC and GL groups and among GFL, GLF and GF groups. Regarding to the calcium and phosphorus ratio, it was not observed significant statistical differences among the groups. These findings suggest that low-intensity laser radiation associated with acidulated phosphate fluoride reduces the caries area and could be an alternative in the prevention of the dental caries. (author)

  3. Enhancement of the agronomic effectiveness of phosphate rock in a ferralsol from Cuba

    The Ferralsols from Ciego de Avila, Cuba, have a pH near neutrality and very low exchangeable acidity, thus, they are not suitable for direct application of phosphate rock. In laboratory and greenhouse experiments, different P fertilizers were tested in order to assess their agronomic effectiveness through the use of nuclear and conventional methods. The phosphate rocks (PRs) came from different deposits (Higuanojo, La Pimienta and Trinidad de Guedes from Cuba; Riecito, Baja California and North Carolina from other countries). Partial acidulation (PA) of some of these rocks was also evaluated. Trinidad de Guedes PAPRs were found to be highly effective compared to their natural PR when evaluated through dry matter production, P uptake and isotopic parameters. Further field experiments are needed to validate the greenhouse results to enhance the agronomic effectiveness of the local Trinidad de Guedes PR through partial acidulation. (author)

  4. 黑液成分分析及溶出木素的测定%Componential Analysis of Black Liquor and Determining of Dissohtion Lignin

    张春敬; 刘玉

    2012-01-01

    The composition of black liquor was analyzed, then dissolved lignin was separated by fractionation with acidulation precipitation, and the UV lignin was quantified by UV analysis. The result showed that UV lignin is more than 90% of the total lignin in the black liquor. In other words, using acidulation precipitation can separate lignin from the black liquor is completely feasible.%对黑液的成分进行分析。利用改进酸析法分级分离析出黑液中的木素,并用紫外法对酸析后黑液中的木素进行定量分析。实验结果表明,酸析木素占黑液中总木素的比例可达90%以上,证明应用此法分离黑液中的木素是可行的。

  5. Stochastic dominance analysis of on-farm-trial data: The riskiness of alternative phosphate sources in Burkina Faso

    Hien, Victor; Kabore, Daniel; Youl, Sansan; Lowenberg-DeBoer, J.

    1997-01-01

    Stochastic dominance was used to determine the risk characteristics of phosphate fertilization of millet, sorghum and maize with commercial NPK fertilizer, rock phosphate and partially acidulated rock phosphate in Burkina Faso. On-farm-trial data from 1989, 1990 and 1991 in three rainfall zones was used. The analysis shows that among the four treatments tested, commercial NPK fertilizer has the most desirable risk characteristics. It is acceptable to risk averse decision makers for all three ...

  6. Nd:YAG laser in caries prevention: a clinical study; Avaliacao clinica da eficiencia do laser de Nd:YAG associado ao fluor fosfato acidulado na prevencao de caries de sulcos e fissuras de criancas e adolescentes

    Boari, Heloisa Gomes Dimiranda

    2000-07-01

    The caries prevention by using laser irradiation has been investigated during the last 30 years. The Nd: YAG laser associated with acidulated phosphate fluoride has been shown as a very promising technique for enamel caries prevention. The aim of this work was to clinically evaluate the efficiency of Nd: YAG laser associated with acidulated phosphate fluoride in pit and fissure caries prevention of children and adolescents. In this work it was determined the dye that enhance the effect of Nd: YAG laser in enamel. It was selected 242 pre-molar and molar teeth from 33 children and adolescents, aged from 7 to 15 years old. The selected teeth were free from caries or decalcification marks (active white marks) to the clinical and radiographic exams. The teeth were divided into two groups: the first group was laser irradiated and their homologous remained as a control. The right side teeth were dye-assisted Nd:YAG laser irradiated. The dye solution was a moisture of dust coal and equal parts of water and alcohol. The irradiation conditions were 60 mJ/10 Hz, optical fiber in contact mode, with diameter of 300 {mu}m, resulting in an energy density of 84,9 J/cm{sup 2}. The oclusal surface of the teeth was completely irradiated, specially on the slopes and in the deepest part of the pits and fissures. This procedure was repeated three times. In the sequence it was applied the acidulated phosphate fluoride for 4 minutes. On the left side teeth - control group- only acidulated phosphate fluoride was applied for the same time. The final examination considered the presence of caries and active white marks after a period of one year. There were statistical significant differences (p < 0.01) between the lased + fluoride group and the non irradiated group. The present study concluded that the technique used in this work can be an alternative clinical method for caries prevention. (author)

  7. Geodynamic and metabolic cycles in the Hadean

    RUSSELL, M. J.; Arndt, N. T.

    2005-01-01

    High-degree melting of hot dry Hadean mantle at ocean ridges and plumes resulted in a crust about 30km thick, overlain in places by extensive and thick mafic volcanic plateaus. Continental crust, by contrast, was relatively thin and mostly submarine. At constructive and destructive plate boundaries, and above the many mantle plumes, acidic hydrothermal springs at ~400°C contributed Fe and other transition elements as well as P and H2 to the deep ocean made acidulous by diss...

  8. Nd:YAG laser in caries prevention: a clinical study

    The caries prevention by using laser irradiation has been investigated during the last 30 years. The Nd: YAG laser associated with acidulated phosphate fluoride has been shown as a very promising technique for enamel caries prevention. The aim of this work was to clinically evaluate the efficiency of Nd: YAG laser associated with acidulated phosphate fluoride in pit and fissure caries prevention of children and adolescents. In this work it was determined the dye that enhance the effect of Nd: YAG laser in enamel. It was selected 242 pre-molar and molar teeth from 33 children and adolescents, aged from 7 to 15 years old. The selected teeth were free from caries or decalcification marks (active white marks) to the clinical and radiographic exams. The teeth were divided into two groups: the first group was laser irradiated and their homologous remained as a control. The right side teeth were dye-assisted Nd:YAG laser irradiated. The dye solution was a moisture of dust coal and equal parts of water and alcohol. The irradiation conditions were 60 mJ/10 Hz, optical fiber in contact mode, with diameter of 300 μm, resulting in an energy density of 84,9 J/cm2. The oclusal surface of the teeth was completely irradiated, specially on the slopes and in the deepest part of the pits and fissures. This procedure was repeated three times. In the sequence it was applied the acidulated phosphate fluoride for 4 minutes. On the left side teeth - control group- only acidulated phosphate fluoride was applied for the same time. The final examination considered the presence of caries and active white marks after a period of one year. There were statistical significant differences (p < 0.01) between the lased + fluoride group and the non irradiated group. The present study concluded that the technique used in this work can be an alternative clinical method for caries prevention. (author)

  9. Comparative efficacy of two treatment modalities for dentinal hypersensitivity: A clinical trial

    Aparna S; Setty Swati; Thakur Srinath

    2010-01-01

    Background: Dentin hypersensitivity is a recurrent condition causing discomfort and sometimes pain to the patient, which also deters him from maintaining adequate oral hygiene. Home care and office measures are used for treatment of this malady. Aim: To evaluate and compare the efficacy of 2 treatment modalities for dentinal hypersensitivity, iontophoresis with acidulated phosphate gel (APF) gel, and dentin-bonding agent application. Materials and Methods: This split mouth randomized clinic...

  10. Effects of the low-intensity laser therapy on the prevention of dental caries induced in rats; Efeitos da radiacao laser em baixa intensidade na prevencao de carie dental induzida em ratos

    Mueller, Karin Praia

    2004-07-01

    The purpose of this study was to investigate the effects of low intensity laser therapy, associated or not to an acidulated phosphate fluoride, on the prevention of dental caries induced in rats. It was used 40 wistar rats, female, weaned with 18 days, fed with a cariogenic diet during 48 days and inoculated orally with Streptococcus mutans by three consecutive days starting from the second day of the diet. On the fifth day of experiment the animals were divided into five groups: G{sub c} (control) the animas were no submitted to any treatment; G{sub L} (laser) irradiation with low power laser (GaAlAs, {lambda}=660 nm, P=30 mW, {delta}t=5 sec, 5 J/cm{sup 2}); G{sub F} (fluoride) topical application of acidulated phosphate fluoride (APF 1,23%) for four minutes; G{sub LF} (laser + fluoride) irradiation with low power laser followed by topical application of acidulated phosphate fluoride; G{sub FL} (fluoride + laser) topical application of acidulated phosphate fluoride followed by low power laser. The animals were sacrificed after 48 days; the molars were extracted and prepared to determine the dental caries lesions area by optical microscopy, enamel microhardness and analysis of the calcium and phosphorus ratio (Ca/P) by energy dispersive spectroscopy. The results were statistically analyzed by ANOVA (pacidulated phosphate fluoride reduces the caries area and could be an alternative in the prevention of the dental caries. (author)

  11. Alkali-soluble fluoride deposition on enamel after professional application of topical fluoride in vitro Formação de flúor fracamente ligado ao esmalte após a aplicação tópica profissional de flúor in vitro

    Mitsue Fujimaki Hayacibara; Adriana Franco Paes Leme; Ynara Bosco de Oliveira Lima; Nilza Cristina Lopez Afonso Valor Gonçalves; Celso Silva Queiroz; Maria José Gomes; Fábio Carlos Kozlowski

    2004-01-01

    Since the efficacy of topical fluoride products is related to the fluoride (F) availability and its reactivity with enamel, this study was conducted. The F concentration of the following materials was verified: I- acidulated phosphate fluoride (APF) gel (1.23% F), II- APF foam (1.23% F) and III- Varnish (2.26% F). Forty blocks of bovine enamel were divided into 4 groups and treated according to the materials described, being one of them used as control. Loosely bound fluoride (''CaF2'') was d...

  12. Bottom-up assembly of hydrophobic nanocrystals and graphene nanosheets into mesoporous nanocomposites.

    Huang, Jijiang; Liu, Wenxian; Wang, Li; Sun, Xiaoming; Huo, Fengwei; Liu, Junfeng

    2014-04-22

    A general strategy for constructing graphene-based nanocomposites is achieved by emulsion-based bottom-up self-assembly of hydrophobic nanocrystals (NCs) to positively charged colloidal spheres, followed by the electrostatic assembly of NC colloidal spheres with negatively charged graphene oxide in an acidulous aqueous solution. With a simple heat treatment, 3D mesoporous NC spheres/graphene composites are obtained. TiO2/graphene composites typically exhibit a better rate capability and cycle performance than do the corresponding isolated TiO2 spheres. PMID:24684553

  13. Extraction process

    A process is described for extracting at least two desired constituents from a mineral, using a liquid reagent which produces the constituents, or compounds thereof, in separable form and independently extracting those constituents, or compounds. The process is especially valuable for the extraction of phosphoric acid and metal values from acidulated phosphate rock, the slurry being contacted with selective extractants for phosphoric acid and metal (e.g. uranium) values. In an example, uranium values are oxidized to uranyl form and extracted using an ion exchange resin. (U.K.)

  14. In vitro comparison of the cariostatic effect between topical application of fluoride gels and fluoride toothpaste Comparação in vitro do efeito cariostático entre a aplicação tópica de flúor e dentifrício fluoretado

    Alberto Carlos Botazzo Delbem; Fernanda Lourenção Brighenti; Ana Elisa de Mello Vieira; Jaime Aparecido Cury

    2004-01-01

    The aim of this study was to compare the effect of topical fluoride products [acidulated phosphate fluoride (APF) or neutral gel (NF) x fluoride toothpaste (MFP)], in respect to fluoride uptake and anticariogenic action. One hundred and twenty five blocks of human teeth, sorted in 5 groups according to the treatment, were submitted to pH cycling for ten days. The parameters analyzed were: fluoride uptake before and after pH cycling and surface (SMH) and cross-sectional (CSMH) microhardness of...

  15. Effects of dietary oregano essential oil and vitamin E on the lipid oxidation stability of cooked chicken breast meat.

    Avila-Ramos, F; Pro-Martínez, A; Sosa-Montes, E; Cuca-García, J M; Becerril-Pérez, C M; Figueroa-Velasco, J L; Narciso-Gaytán, C

    2012-02-01

    The antioxidant effect of oregano essential oil and vitamin E was evaluated in cooked chicken breast meat. In total, 480 broilers were randomly assigned to 6 treatments and 4 replications. Broilers were raised with a corn-soybean meal diet including either crude soybean oil or acidulated soybean oil soapstock, each supplemented with vitamin E at 10 or 100 mg or oregano essential oil at 100 mg/kg of feed. At 42 d, broilers were slaughtered and their breast meat was prepared into strips (1.5 × 10 cm) or patties (150 g). Fatty acid composition of the muscle was determined. For lipid oxidation stability, both meat strips and patties were cooked to an internal temperature of 74°C and malonaldehyde contents were assessed during 0, 3, 6, and 9 d of storage at 4°C. Each storage day had 4 replications per treatment. The meat lipid oxidative stability was estimated by content of malonaldehyde values. Results showed that feed consumption, weight gain, and feed conversion were not affected by the dietary oils or antioxidants, except for the mortality in acidulated soybean oil soapstock with the 10-mg vitamin E treatment. The fatty acid composition of the meat was similar between the 2 diets given the same antioxidant supplement. The oxidation stability of meat lipids in both types of meats showed a significant (P oils, antioxidants, and storage time. In the crude soybean oil oil diet, the malonaldehyde value in the 10-mg vitamin E treatment was the highest, followed by oregano essential oil, and then the 100-mg vitamin E treatment at 9 d of storage, whereas the value of oregano essential oil in the acidulated soybean oil soapstock diet was the highest, followed by the 10-mg vitamin E, and then the 100-mg vitamin E treatment during the 9 d of storage. In conclusion, the dietary oils and antioxidants used can be included in broiler diets without negative effects on their productivity. The antioxidant effect of vitamin E was higher with a higher supplementation level

  16. Geodynamic and metabolic cycles in the Hadean

    Russell, M.J.; Arndt, N. T.

    2005-01-01

    High-degree melting of hot dry Hadean mantle at ocean ridges and plumes resulted in a crust about 30km thick, overlain in places by extensive and thick mafic volcanic plateaus. Continental crust, by contrast, was relatively thin and mostly submarine. At constructive and destructive plate boundaries, and above the many mantle plumes, acidic hydrothermal springs at ~400°C contributed Fe and other transition elements as well as P and H2 to the deep ocean made acidulous by dissolved CO2 and m...

  17. Pollution and atmospheric pollution abatement in case of accident in water purification installation at deuterated water plant

    The technology of heavy water production uses huge water volumes. After the recovery of H2S, the exhaustion water is treated by acidulation, stripping and alkalinization to neutralize the noxious effect of H2S. In the paper we demonstrate that by shutting down the power, even for a short period of time, do to the big water volume, the H2S from the acid water could be very dangerous. In order to avoid the accidental pollution with H2S when the power is shut down we proposed a gravitational device. (authors)

  18. Improving grain yield and nitrogen fixation of common bean grown in an acrisol from Cuba

    Field experiments were carried out to evaluate the effect of selected management practices such as the use of phosphate rock (PR), partially acidulated phosphate rocks (PAPRs) and soil liming, on improving grain yields and biological nitrogen fixation (BNF) of common bean (Phaseolus vulgaris) grown in an strongly acid Acrisol from Cuba. In Experiment 1 the agronomic effectiveness of the indigenous Trinidad de Guedes PR and FPA 50, a PAPR from Trinidad de Guedes PR with H2SO4 at 50% acidulation level were evaluated as P sources for the common bean genotypes, BAT 477, DOR 364, DOR 390 and Censa. In Experiment 2 the response of the CC 25-9N common bean genotype to the increasing application rates (40, 80 and 120 kg P2O5 ha-1) of two P sources, i.e. triple super phosphate and C 40, was determined at two liming levels. C40 was a PAPR from the indigenous Trinidad de Guedes PR with H2SO4 at 40% acidulation level. In Experiment 3 the effect of soil liming on grain yield and BNF of BAT 58, BAT 304, BAT 477, DOR 364, DOR 390, Judia Roja Camagueyana (JRC) and Censa common bean genotypes was studied. The most effective P sources to increase grain yields of the studied bean genotypes were the water-soluble superphosphate in experiments 1 and 2. Both partially acidulated PR products, FPA 50 and C 40, showed intermediate agronomic effectiveness and they increased grain yields over the PR and control (without P) treatments. Soil liming increased grain yields and BNF of the common bean genotypes tested. Based on an economic analysis of profit and value/cost ratios, single superphosphate was the P source that gave the highest economic profit for all common bena genotypes while FPA 50 was efficient for DOR 390 and Censa. Lime application increased the economic profit of all bean genotypes. Genotype BAT 304 showed adaptability to soil acidity and gave the highest profit in limed soil. (author)

  19. Age determination of ground-waters by means of carbon 14

    At present the age determination of ground-waters aged between 1,500 and approximately 40,000 years is only possible by measuring their 14C content. A precise age assignment can be established in slightly mineralised waters, whereas it becomes vague in mineralised waters, particularly in acidulous springs. In general, additional information and data are required about the 13C, D, 18O, 3H, 85Kr and the 39Ar contents, about the ph value, temperature and the principal ions. (DG)

  20. Effect of fertilizer type on cadmium and fluorine concentrations in clover herbage

    This study investigated whether changing phosphatic fertilizer type affects the accumulation of cadmium (Cd) and fluorine (F) in pasture herbage. North Carolina phosphate rock and partially acidulated fertilizers derived from this rock generally have higher Cd and F concentrations compared to single superphosphate currently manufactured in Australia. Clover herbage from sites of the National Reactive Phosphate Rock (RPR) trial was collected and analysed for concentrations of Cd (11 sites) and F (4 sites). A comparison was made between pastures fertilized with 4 rates of single superphosphate, North Carolina phosphate rock, and partially acidulated phosphate rock having Cd concentrations of 283, 481, and 420 mg Cd/kg P respectively, and 170, 271, and 274 g F/kg P respectively. One site used Hemrawein (Egypt) phosphate rock (HRP) having a Cd and F concentration of 78 mg Cd/kg P and 256 g F/kg P respectively. To help identify differences in herbage Cd concentrations between sites, unfertilised soils from each site were analyzed for total and extractable Cd contents. At one site Cd concentrations in bulk herbage (clover, grasses and weeds) were related to infestation of the pasture by capeweed (Arctotheca calendula L. Levyns). There were no significant differences between F in herbage from plots fertilized with single superphosphate, partially acidulated phosphate rock or North Carolina phosphate rock, or between sites. Concentrations of F in herbage were low, generally less than 10 mg F /kg. However, there were large differences in Cd concentrations in herbage between sites, while differences between fertilizer treatments were small in comparison. The site differences were only weakly related to total or extractable (0.01 mol/L CaCl2) Cd concentrations in soil. Significant differences in Cd concentrations in clover due to fertilizer type were found at 5 sites. North Carolina phosphate rock treatments had significantly higher Cd concentrations in clover compared to

  1. The use of nuclear and related techniques for evaluating the agronomic effectiveness of phosphate fertilizers, in particular rock phosphate, in Venezuela: I. phosphorus uptake, utilization and agronomic effectiveness

    Field experiments were conducted to evaluate the efficiency of natural and modified rock phosphate using conventional and isotopic techniques in an acid soil from El Pao, Cojedes state, Venezuela, using maize and sorghum with the application of different phosphate fertilizers to measure dry matter production, P accumulated in plant, efficiency parameters using isotopic techniques or yield. Finally, commercial plots were established with the application of soluble P fertilizers and rock phosphate products to validate the results obtained in the field experiments. The results showed highly significant differences between partially acidulated rock phosphate, natural rock phosphate, and the check plot in dry matter production, and P accumulation in plant and grain yield. When the efficiency parameters were evaluated in microplots with 32P-TSP at 60 days of plant growth, it confirmed results obtained in semi commercial plots where the P in the plant derived from the fertilizer was 46% with partially acidulated rock phosphate (PAR) and 14% with natural Riecito rock phosphate (RR). Utilization coefficients of P by the plants were 34.2 and 8.8% for both treatments, respectively. The Substitution relation parameter showed that just 0.8 kg of P of PAR or 3.1 kg P of RR was required to produce the same yield as 1 kg P of TSP. These results were further validated in 5 ha commercial plots using corn and sorghum. (author)

  2. A study in vitro on radiation effects by Er:YAG laser combined with the fluorine therapy in the acid resistance of the dental enamel submitted to orthodontical brackets; Um estudo in vitro sobre os efeitos da irradiacao pelo laser de Er:YAG combinado com a terapia com fluor na resistencia acida do esmalte de dentes submetidos a aparelho ortodontico fixo

    Yoshiyasu, Roseli Y.A

    2001-07-01

    Several researches have been demonstrating an increase in the resistance acid of the enamel surface when irradiated by some lasers types as Nd:YAG, C0{sub 2}, Er:YAG, and others, mainly when combined with the fluoride therapy after the irradiation of the laser. This study in vitro used the laser of Er:YAG which density of energy of 8.1 J/cm{sup 2} on the enamel about of orthodontical brackets of teeth extracted pre-molars. These teeth were then submitted to a rich way in S. mutans for twenty one days. The cases were analyzed: (1) enamel surface without any treatment, (2) enamel surface without any irradiation laser, but with therapy with acidulated phosphate fluoride, (3) enamel surface irradiated with laser of Er:YAG and (4) enamel surface irradiated by laser of Er:YAG and with application of acidulated phosphate fluoride. The results were analyzed through optical microscopy and scanning electron microscopy. The morphologic changes observed to the scanning electron microscopy suggest increase in the acid resistance of the enamel surface. However, to the optical microscopy, it was still possible to visualize undesirable white stains in the surface of the enamel. (author)

  3. A study in vitro on radiation effects by Er:YAG laser combined with the fluorine therapy in the acid resistance of the dental enamel submitted to orthodontical brackets

    Several researches have been demonstrating an increase in the resistance acid of the enamel surface when irradiated by some lasers types as Nd:YAG, C02, Er:YAG, and others, mainly when combined with the fluoride therapy after the irradiation of the laser. This study in vitro used the laser of Er:YAG which density of energy of 8.1 J/cm2 on the enamel about of orthodontical brackets of teeth extracted pre-molars. These teeth were then submitted to a rich way in S. mutans for twenty one days. The cases were analyzed: (1) enamel surface without any treatment, (2) enamel surface without any irradiation laser, but with therapy with acidulated phosphate fluoride, (3) enamel surface irradiated with laser of Er:YAG and (4) enamel surface irradiated by laser of Er:YAG and with application of acidulated phosphate fluoride. The results were analyzed through optical microscopy and scanning electron microscopy. The morphologic changes observed to the scanning electron microscopy suggest increase in the acid resistance of the enamel surface. However, to the optical microscopy, it was still possible to visualize undesirable white stains in the surface of the enamel. (author)

  4. Evaluation of available phosphorus and cadmium associated with phosphate rock for direct application

    Three greenhouse experiments were conducted to evaluate available P and Cd associated with the use of phosphate rock (PR) for direct application. These experiments were: (1) 'Estimation of Phosphorus Availability to Maize and Cowpea From Phosphate Rock as Enhanced by Water-Soluble Phosphorus'; (2) 'Modified Iron Oxide-Impregnated Paper Strip (Pi) Test for Soils Treated With Phosphate Fertilizers'; and (3) 'Effect of Acidulation of High Cadmium Containing Phosphate Rocks on Cadmium Uptake by Upland Rice'. In the first experiment, a medium-reactive Central Florida phosphate rock (PR) was used. The effectiveness of P sources in terms of increasing dry-matter yield and P uptake followed the order of TSP≥(PR+TSP)>PR for maize and TSP=(TSP+PR)>PR for cowpea. P uptake from PR in the presence of TSP was higher than P uptake from PR applied alone. With respect to P uptake from PR applied alone, the corresponding relative increase in P uptake from PR due to TSP influence was 165% for maize and 72% for cowpea. In the second experiment, a highly reactive North Carolina PR was used. Both Bray I and the Pi test (with CaCl2) underestimated available P from PR with respect to TSP. Available P estimated by the Pi test with KCl was more closely related to P uptake with both PR and TSP. More P was extracted from PR by the Pi test with KCl than with CaCl2, whereas no effect was observed for TSP. In the third experiment, a low-reactive Togo PR and a highly reactive North Carolina PR were used. Both PRs were fully acidulated to SSP and Togo PR was also partially acidulated with H2SO4 at 50% level to PAPR. Cd uptake by rice grain followed the order of NC-SSP > NC-PR and Togo-SSP > Togo PAPR > Togo PR. The results also showed that most of the Cd uptake was retained in rice root and straw. Total uptake of Cd, Ca, and P by the rice plant was higher from NC-PR than from Togo-PR. Cd concentration in rice grain showed no significant difference between NC-PR and Togo-PR, whereas Cd

  5. Uranium recovery from wet process phosphoric acid

    In the field of metallurgy, specifically processes for recovering uranium from wet process phosphoric acid solution derived from the acidulation of uraniferous phosphate ores, problems of imbalance of ion exchange agents, contamination of recycled phosphoric acid with process organics and oxidizing agents, and loss and contamination of uranium product, are solved by removing organics from the raffinate after ion exchange conversion of uranium to uranous form and recovery thereof by ion exchange, and returning organics to the circuit to balance mono and disubstituted ester ion exchange agents; then oxidatively stripping uranium from the agent using hydrogen peroxide; then after ion exchange recovery of uranyl and scrubbing, stripping with sodium carbonate and acidifying the strip solution and using some of it for the scrubbing; regenerating the sodium loaded agent and recycling it to the uranous recovery step. Economic recovery of uranium as a by-product of phosphate fertilizer production is effected. (author)

  6. Medna bijela (Vitis vinifera L. - Ampelographic properties

    Ivan Pezo

    2006-12-01

    Full Text Available Medna bijela is an autochthonous cultivar of the third Adriatic vine-growing subregion. Its synonyms in use are: Buboj, Bumba, Medna, Rizavac, Zložder etc. No detailed ampelographic study has been made to date; based on our research this cultivar is classified in the ecological-geographical group of Convarietas Pontica, Negr. Subconvarietas Balcanica, Provarietas Mesocarpa, Nem., Subprovarietas Dalmatica Nem. It is a medium lush wine cultivar with some 16-17 % of sugar and 6.0-7.0 g/l of total acidity, with a yield of 2.5-3.5 kg of grapes per grapevine and a load of 16 buds per grapevine. The wines are light, acidulous, with a specific fine aroma of honey, which is implied in the very name of the cultivar. It is recommended that the research should be continued, particularly on clonal selection.

  7. Physiological characterization of the high malic acid-producing Aspergillus oryzae strain 2103a-68

    Knuf, Christoph; Nookaew, Intawat; Remmers, Ilse;

    2014-01-01

    Malic acid is a C4 dicarboxylic acid that is currently mainly used in the food and beverages industry as an acidulant. Because of the versatility of the group of C4 dicarboxylic acids, the chemical industry has a growing interest in this chemical compound. As malic acid will be considered as a bulk...... chemical, microbial production requires organisms that sustain high rates, yields, and titers. Aspergillus oryzae is mainly known as an industrial enzyme producer, but it was also shown that it has a very competitive natural production capacity for malic acid. Recently, an engineered A. oryzae strain, 2103......a-68, was presented which overexpressed pyruvate carboxylase, malate dehydrogenase, and a malic acid transporter. In this work, we report a detailed characterization of this strain including detailed rates and yields under malic acid production conditions. Furthermore, transcript levels of the genes...

  8. Phosphate fertilisers and management for sustainable crop production in tropical acid soils

    Extensive research has been conducted over the past 25 years on the management of plant nutrients, especially N and P, for crop production on acidic infertile tropical soils. Under certain conditions, the use of indigenous phosphate rock (PR) and modified PR products, such as partially acidulated PR or compacted mixtures of PR with superphosphates, are attractive alternatives, both agronomically and economically, to the use of conventional water-soluble P fertilisers for increasing crop productivity on Oxisols and Ultisols. A combination of the effects of proper P and N management including biological N2 fixation, judicious use of lime, and the use of acid-soil tolerant and/or P-efficient cultivars in cropping systems that enhance nutrient cycling and use efficiency, can provide an effective technology to sustainably increase crop productivity and production in tropical agro-ecosystems dominated by these acid soils. (author)

  9. Characterization of caries progression on dentin after irradiation with Nd:YAG laser by FTIR spectroscopy and fluorescence imaging

    Ana, P. A.; Brito, A. M. M.; Zezell, D. M.; Lins, E. C. C. C.

    2015-06-01

    Considering the use of high intensity lasers for preventing dental caries, this blind in vitro study evaluated the compositional and fluorescence effects promoted by Nd:YAG laser (λ=1064 nm) when applied for prevention of progression of dentin caries, in association or not with topical application of acidulated phosphate fluoride (APF). Sixty bovine root dentin slabs were prepared and demineralized by 32h in order to create early caries lesions. After, the slabs were distributed into six experimental groups: G1- untreated and not submitted to a pH-cycling model; G2- untreated and submitted to a pH-cycling model; G3- acidulated phosphate fluoride application (APF); G4- Nd:YAG irradiation (84.9 J/cm2, 60 mJ/pulse); G5- treated with Nd:YAG+APF; G6- treated with APF+Nd:YAG. After treatments, the samples of groups G2 to G6 were submitted to a 4-day pH-cycling model in order to simulate the progression of early caries lesions. All samples were characterized by the micro-attenuated total reflection technique of Fourier transformed infrared spectroscopy (μATR-FTIR), using a diamond crystal, and by a fluorescence imaging system (FIS), in which it was used an illuminating system at λ= 405±30 nm. Demineralization promoted reduction in carbonate and phosphate contents, exposing the organic matter; as well, it was observed a significant reduction of fluorescence intensity. Nd:YAG laser promoted additional chemical changes, and increased the fluorescence intensity even with the development of caries lesions. It was concluded that the compositional changes promoted by Nd:YAG, when associated to APF, are responsible for the reduction of demineralization progression observed on root dentin.

  10. HPLC-UV Analysis Coupled with Chemometry to Identify Phenolic Biomarkers from Medicinal Plants, used as Ingredients in Two Food Supplement Formulas

    Raluca Maria Pop

    2013-11-01

    Full Text Available . High performance liquid chromatography (HPLC with UV detection is nowadays the reference method to identify and quantify the biomarkers of quality and authenticity of plants and food supplements. Seven medicinal plants were collected from wild flora: Taraxacum officinalis (1, Cynara scolimus (2, Silybum marianum (3, Hypericum perforatum (4,  Chelidonium majus (5, Lycopodium clavatum (6 and  Hippophae rhamnoides (7  leaves and fruits.  Two products (A and B were obtained by mixing individual plant powders. Therefore product A was obtained by mixing dandelion, artichoke and milk thistle, 1:1:1 while product B by mixing St John’s wort, Celandine and Wolf’s claw, 1:1:1. The methanolic extracts of individual plants as well as three different extracts of products A and B (using acidulated water, neutral water and acidulated methanol were analyzed using HPLC-UV for their phenolics’ fingerprint and composition. The qualitative (untargeted analysis and quantitative (targeted analysis results were further compared using Principal Component Analysis (PCA in order to identify their specific biomarkers. Thus, quantitative evaluation of individual phenolics in case of individual plants and products A and B extracts, showed specific and significant differences of composition. Both products A and B contained elagic acid as major compound. For product A, good biomarkers were trans-cinnamic, chlorogenic, caffeic and p-coumaric acids, as well silymarin and silibine originating from milk thistle. For product B, good biomarkers were quercetin and kaempherol, gallic and protocatecuic acids, this product being rich in flavonoids. In conclusion, HPLC-UV coupled with PCA analysis proved to be a rapid and useful way to identify the main biomarkers of plants’ authentication, as well of final products’ quality and safety.

  11. Improvement of the quality of wood derived biofuel-oils; Puuperaeisten biopolttooeljyjen laadun parantaminen. Raakasuovan terminen nestefaasikaesittely hiilivety-polttoaineiksi

    Oasmaa, A.; McKeough, P.; Kuoppala, E.; Kylloenen, H.; Levander, J.; Tapola, E.; Haekkinen, R.

    1995-12-31

    Liquid-phase thermochemical processing of tall oil soap has been experimentally investigated. The organic matter of tall oil soap, which is a by-product of kraft pulping, originates mainly from wood extractives. Conventional processing of tall oil soap involves acidulation to yield crude tall oil and subsequent distillation of the oil at centralized refineries. Because tall oil originating from birch wood is far less valuable than that from pine, there is an economic incentive in the Nordic countries to develop alternative conversion processes for the tall oil soap produced at pulp mills where birch is widely used as feedstock. Both catalytic hydrotreatment and liquid-phase thermal treatment of a mixed pine/birch soap have been investigated in the laboratory. Liquid and gaseous hydrocarbons were the principal products formed in both types of treatment. Although the liquid product formed under hydrotreatment conditions contained a higher proportion of aliphatic compounds, it was clear that the thermal treatment process would be, economically, the more favorable option. In the thermal process, a predominantly hydrocarbon oil product was obtained at 450 deg C using a residence time of at least 60 min. About 50 % of the energy content of the tall oil soap was recovered as oil product, about 30 % as gases, and about 20 % as organic material contained in an aqueous slurry phase. When the oil product was carefully separated from the aqueous slurry phase, only trace amounts of impurities, such as water, sodium and organic acid salts were present in the product. A techno-economic evaluation of the process concept has been performed. The economics of the thermal treatment process appear to be favorable in comparison with those of the conventional acidulation process

  12. Liming effect on the agronomic effectiveness of phosphate sources varying in solubility applied to upland rice and soybean grown on an acid ultisol

    A greenhouse study was conducted over a 3-year period to investigate the effect of liming on the relative agronomic effectiveness (RAE) of P sources varying in solubility in three cropping sequences. The P sources were (1) a highly reactive Sechura phosphate rock (PR) from Peru, (2) a partially acidulated medium-reactive Huila PR from Colombia at 50% acidulation with H2SO4 (PAPR), and (3) a commercial-grade triple superphosphate (TSP). An acid Ultisol that was unlimed (pH 4.8) and limed to pH 5.6 and 6.6 was used in the three experiments. The first two experiments were carried out over the same period involving upland rice-upland rice-upland rice and soybean-upland rice-soybean cropping sequences. The three P sources were evaluated in terms of RAE based on dry matter yield and changes of soil pH, available P, and exchangeable Ca and Al in these two experiments. The third experiment was conducted over a two-year period to evaluate the effect of freshly applied P sources (1st year) and their residual effect on on biological nitrogen (N) fixation (BNF) by soybean using 15N isotopic dilution technique. Soybean residue was then compared with urea as an N source for the following upland rice. The results show that the use of Sechura PR will not only provide available P nutrient, but also reduce potential Al toxicity for upland rice and soybean contributing to sustainable crop production and BNF in the legume crop, especially for its residual P effect, in this acid Ultisol. The use of possibly more cost-effective Huila PAPR can be also an alternative P source to TSP for this soil due to its good agronomic performance. However, the effect of liming on the soil properties should also be carefully determined and monitored since liming can significantly reduce the agronomic effectiveness of PR. This is due to an increase in soil pH and exchangeable Ca that reduces PR dissolution and soil available P. In the third experiment, P was more limiting than N in influencing upland

  13. Uranium recovery from phosphate fertilizer in the form of a high purity compound

    Uranium recovery from phosphate fertilizer industry is based on a one cycle extraction-stripping process. The process was experimented on both sulfuric and nitric acid attack of phosphate rock when uranium is dissolved in phosphoric acid (WPA) or phosphonitric (PN) solution respectively. The WPA and PN solution must be clarified. In the first alternative by ageing and settling and in the second by settling in the presence of flocculant. The organic components must be removed on active carbon for WPA only since in the case of nitric attack calcined phosphates are used. In both alternatives uranium is extracted from aqueous acidic solutions in the same time with the rare earths (REE), by di(2-ethylhexyl) phosphate (DEPA) as basic extractants, eventually in the presence of octylphosphine oxide (TOPO) as synergic agent. The stripping process is carried out in two stages: in the first stage REE are stripped and precipitated by HF or NH4F + H2S04 and in the second stage uranium as U(VI) is stripped by the same reagents but in the presence of Fe(II) as reductant for U(VI) to U(IV) inextractible species. Tetravalent uranium is also precipitated as green cake either UF4xH20 or (NH4)7U6F31 as dependent on reagents HF or NH4F + H2S04. Uranium stripping is possible for PN solution only if HNO3 partially extracted is previously washed out by a urea solution. The green cake washed and filtered is dissolved in nitric acid in presence of Al(OH)3 as complexant for F. The filtered nitric solution is adjusted to 3-5 mol/L HNO3 and extracted by 20% TBP when uranium is transferred to the organic phase which after scrubbing is stripped in the classic way with acidulated (HN03) demineralized water. Uranium is precipitated as diuranate of high purity. Rare earths left in the aqueous raffinate are extracted by pure TBP from 8-10 mol/L HNO3 medium. The stripping process takes place with acidulated water. Rare earths are precipitated as hydroxides. (author)

  14. Iron-sulfide-bearing chimneys as potential catalytic energy traps at life's emergence.

    Mielke, Randall E; Robinson, Kirtland J; White, Lauren M; McGlynn, Shawn E; McEachern, Kavan; Bhartia, Rohit; Kanik, Isik; Russell, Michael J

    2011-12-01

    The concept that life emerged where alkaline hydrogen-bearing submarine hot springs exhaled into the most ancient acidulous ocean was used as a working hypothesis to investigate the nature of precipitate membranes. Alkaline solutions at 25-70°C and pH between 8 and 12, bearing HS(-)±silicate, were injected slowly into visi-jars containing ferrous chloride to partially simulate the early ocean on this or any other wet and icy, geologically active rocky world. Dependent on pH and sulfide content, fine tubular chimneys and geodal bubbles were generated with semipermeable walls 4-100 μm thick that comprised radial platelets of nanometric mackinawite [FeS]±ferrous hydroxide [∼Fe(OH)(2)], accompanied by silica and, at the higher temperature, greigite [Fe(3)S(4)]. Within the chimney walls, these platelets define a myriad of micropores. The interior walls of the chimneys host iron sulfide framboids, while, in cases where the alkaline solution has a pH>11 or relatively low sulfide content, their exteriors exhibit radial flanges with a spacing of ∼4 μm that comprise microdendrites of ferrous hydroxide. We speculate that this pattern results from outward and inward radial flow through the chimney walls. The outer Fe(OH)(2) flanges perhaps precipitate where the highly alkaline flow meets the ambient ferrous iron-bearing fluid, while the intervening troughs signal where the acidulous iron-bearing solutions could gain access to the sulfidic and alkaline interior of the chimneys, thereby leading to the precipitation of the framboids. Addition of soluble pentameric peptides enhances membrane durability and accentuates the crenulations on the chimney exteriors. These dynamic patterns may have implications for acid-base catalysis and the natural proton motive force acting through the matrix of the porous inorganic membrane. Thus, within such membranes, steep redox and pH gradients would bear across the nanometric platelets and separate the two counter-flowing solutions

  15. Biological treatment of the liquid effluents of a paper industry

    The objective of this paper is to determine the effect of the microorganisms Candida utilis and Candida tropicalis in the reduction of the chemical oxygen demand (COD) of the liquid effluents of a producing factory of paper kraft type, by means of fermentations made to pH of 5 and a 30 centigrade degrees during 6 days. The biological processing is preceded by a physicochemical process of directed acidulation to reduce pH of the effluent (liquor black) from its initial value, of approximately 13, to 5, in order to it is adapted for the growth of yeast. In this process, which forms precipitated, that is necessary to eliminate by centrifugation and filtration to facilitate the growth of the microorganisms, with is obtained one first removal of the COD of the order of 70 %. With the biological processing obtains for both yeasts a percentage of removal of 45 -50% of the COD surplus. The total removal of the COD, that is to say, obtained with the pre-cure and the fermentation it is of the order of 84% for the yeast. Additionally the possibility studied of implementing some complementary procedures to the biological processing, with a view to obtaining greater growth of yeast in the black liquor and thus obtaining additional reductions in the OCD of the same one

  16. Micro energy-dispersive x-ray fluorescence spectrometry study of dentin coating with nanobiomaterials

    Soares, Luís. Eduardo Silva; Nahorny, Sídnei; Marciano, Fernanda Roberta; Zanin, Hudson; Lobo, Anderson de Oliveira

    2015-06-01

    New biomaterials such as multi-walled carbon nanotubes oxide/graphene oxide (MWCNTO/GO), nanohydroxyapatite (nHAp) and combination of them together or not to acidulated phosphate fluoride gel (F) have been tested as protective coating before root dentin erosion. Fourteen bovine teeth were cleaned, polished, divided into two parts (n=28) and assigned to seven groups: (Control) - without previous surface treatment; F treatment; nHAp; MWCNTO/GO; F+nHAp; F+MWCNTO/GO and F+MWCNTO/GO/nHAp composites. Each sample had two sites of pre-treatments: acid etched area and an area without treatment. After the biomaterials application, the samples were submitted to six cycles (demineralization: orange juice, 10 min; remineralization: artificial saliva, 1 h). Micro energy-dispersive X-ray fluorescence spectrometry (μ-EDXRF) mapping area analyses were performed after erosive cycling on both sites (n=84). μ-EDXRF mappings showed that artificial saliva and MWCNTO/GO/nHAp/F composite treatments produced lower dentin demineralization than in the other groups. Exposed dentin tubules allowed better interaction of nanobiomaterials than in smear layer covered dentin. Association of fluoride with other biomaterials had a positive influence on acid etched dentin. MWCNTO/GO/nHAp/F composite treatment resulted in levels of demineralization similar to the control group.

  17. Use of residual soapstock from the refining of edible vegetable oils to make biodiesel; Aprovechamiento de las oleinas residuales procedentes del proceso de refinado de los aceites vegetales comestibles, para la fabricaciond e biodiesel

    Marin, P.; Barriga Mateos, F.; Alvarez Mateos, P. [Universidad de Sevilla (Spain)

    2003-07-01

    A procedure to obtain Biodiesel from Oiliness is studied. Biodiesel is a suitable product to replace diesel oil currently used to power the Diesel engines. It consists of a mixture of methyl esters of the fatty acids presents as triglycerides in vegetables oils (oil, sunflower, soya, rape oils). As a result of the refining of these oils for their use as food, a waste product is formed, the oleins (acidulated soapstock). The oiliness consist of a mixture of triglycerides and free fatty acids, the latter amounting to 50% or more of the mixture and are subject to a fluctuating market, therefore it exist at times a problem for their disposal. In our research work we have tried to obtain biodiesel from oiliness. The process resulting from our experimental work is as follows. 1. Scarification of the free fatty acids with methanol, by acid catalysis, centrifuging the reaction product and removal of the acid-methanol phase. Drying of the latter. At this stage we have a product containing about 70% of methyl esters. 2. Transesterification of the triglycerides present in the sterified product with methanol by alkaline catalysis, washing the reaction product with a water methanol solution. Centrifuging and removal of the water-methanol phase. At this stage a biodiesel products is obtained containing about 90% of methyl esters. 3. Fractional vacuum distillation of the 90% biodiesel gives a final product with a methyl esters content higher than 98%. (Author)

  18. Salivary retention after application of fluoride gel using toothbrush or tray: a crossover trial.

    Ribeiro, Cecilia Claudia Costa; Lula, Estevam Carlos de Oliveira; Azevedo, Izabelle Maria Cabral de; Maia, Mariana de Figueiredo Lopes E; Lopes, Fernanda Ferreira

    2012-01-01

    Currently, there are no studies in the literature evaluating salivary fluoride retention after small amounts of fluoride gel are applied to children's teeth. Therefore, the objective of the present study was to compare salivary retention after gel application using a toothbrush or by traditional application with trays. In this crossover study, children with active caries (n = 10) were randomized into one of the following treatment groups: a) application of fluoride gel using a tray (control), or b) application of fluoride gel with a toothbrush (treatment). After a 7-day washout period, the treatments were inverted. Unstimulated saliva samples were collected at baseline and 0.5, 5, 15, 30, 60 and 120 minutes after acidulated phosphate fluoride (APF) gel application in order to analyze fluoride retention in saliva. The area under the curve (AUC) was also calculated. There were no differences in fluoride retention after application of small amounts of APF with a toothbrush compared to traditional gel application using trays at all time points studied, and no differences in AUC were observed (Student t-test, p > 0.05). These results suggest that application of fluoride gel in children using a toothbrush can be utilized as an option rather than traditional trays, since the same salivary retention of fluoride is obtained using a lower dose. PMID:23184162

  19. In situ imaging of microorganisms in geologic material.

    Tobin, K J; Onstott, T C; DeFlaun, M F; Colwell, F S; Fredrickson, J

    1999-09-01

    In order to fully delineate the interactions of microorganisms with geological substrates, unequivocal identification of intact microbial cells within geologic samples is required without the disruption of either the rock texture or the relationship of the microorganisms to the mineral fabric. To achieve this objective we developed a protocol that enables the visualization of intact microbial cells in petrographic thin sections, avoids detaching the cells from their host mineral surfaces and avoids microbial contamination during the lapidary process. Propidium iodide and POPO-3, nucleic acid stains that specifically target double-stranded DNA and RNA were utilized for in situ visualization of cells in surface and subsurface basalts from northeastern Idaho. Additionally, examination of samples incubated with acetic acid-UL-14C via phosphor imagining facilitated the in situ visualization of 14C labeled biomass. Biomass observed was low (<10(7) cells/g). These observations indicate that the microbial distribution in these rocks exhibits a high degree of spatial heterogeneity at the sub-centimeter scale. PMID:10480264

  20. The effects of artificial saliva and topical fluoride treatments on the degradation of the elastic properties of orthodontic chains.

    von Fraunhofer, J A; Coffelt, M T; Orbell, G M

    1992-01-01

    The effect of artificial saliva and topical fluoride treatments on the force relaxation and change in force delivery by three brands of elastomeric chains over a 4 week period was studied. The effect of storage in air and in the different test media on the distraction to achieve forces of 150g and 300g was determined for the chains. The effect of the test media on load relaxation of the chains was also examined. Elastomeric chains exhibit good elastic behavior when distracted to an initial force of less than 300g. When forces exceeded 300g, permanent deformation occurred and the force delivery was less predictable. Exposure to artificial saliva and topical fluoride affected the elastic properties of the elastomeric chains and increased the distraction required to deliver both the 150g and 300g force. The increase in distraction for a force of 150g, however, was relatively small and probably insignificant in the clinical setting. The distraction required to produce 300g was significantly larger and appeared to be clinically significant. Pre-stretching the elastomeric chains by 100% of their initial length was not found to be advantageous in terms of the load relaxation behavior. There was less load relaxation found in chains that were immersed in distilled water and Acidulated Phosphate Fluoride than in chains exposed only to air. PMID:1456474

  1. Removal of fission and corrosion products from alkaline solutions of boric acid by the ion exchange method

    Results are given for ion exchange on organic resines method application in experiments on removal of some fission products and corrosion products from solutions containing boric acid. As it is known, presence of boric acid in solution makes it difficult radioactive wastes processing, concentration and solidification. The main task of the investigation was to develop methods for boric acid regeneration from the coolant of primary coolant circuits of nuclear power plant. Special attention was pade to investigations on cesium sorption from the boric acid solutions, containing potassium ions. It was shown that by means of acidulation of solutions, increase of efficiency of radioactive wastescontaining boric acin by mens of ion exchange is gained. But this method is practical only in the case when solution is not returned into the primary coolant circuit after purification. Expediency of preliminary removal of cesium from solution by means of selective nonorganic ionites is shown. Attention is called to the danger of boric acid for natural waters and danger of liquid wastes containing boric acid even after removal of radionuclides from them. (I.T.)

  2. Potency of Agroindustrial Wastewaters to Increase the Dissolution of Phosphate Rock Fertilizers

    Ainin Niswati

    2014-06-01

    Full Text Available The used of agroindustrial wastewaters are not maximum yet in Lampung Province, althought it can be used as an acid solvent because of its acidic properties. This study was aimed to explore the most potential agroindustrial wastewaters in dissolving phosphate rock through acidulation in the laboratory scale. The experiment was arranged in a factorial. The first factor was origined of phosphate rock (Sukabumi, west Java and Selagailingga, central Lampung and the second factor was solvent types (agroindustrial wastewaters which were pineapple, tapioca, tofu industry, and palm oil as well as conventional acid solvents which were HCl, H2SO4, and CH3COOH. The incubation processes were 0, 1, 2, and 3 months. The results showed that agroindustrial wastewaters that have the highest potency to solubize phosphate rock was industrial tofu wastewaters and followed by industrial wastewaters of tapioca, palm oil, and pineapple. Both the conventional acid and agroindustrial wastewaters solvent had a big potency to solubilize phosphate rock, however, its highest soluble P-value did not match with the ISO criteria for phosphate fertilizers Quality I (SNI because it did not reach the solubility of 80% of its total P2O5, but it has been qualified as a fertilizer both the quality phosphate A, B, and C (SNI.

  3. Quantification of Carbonyl Compounds Generated from Ozone-Based Food Colorants Decomposition Using On-Fiber Derivatization-SPME-GC-MS

    Wenda Zhu

    2014-12-01

    Full Text Available Fruit leathers (FLs production produces some not-to-specification material, which contains valuable ingredients like fruit pulp, sugars and acidulates. Recovery of FL for product recycling requires decolorization. In earlier research, we proved the efficiency of an ozone-based decolorization process; however, it produces carbonyls as major byproducts, which could be of concern. A headspace solid-phase microextraction with on-fiber derivatization followed by gas chromatography-mass spectrometry was developed for 10 carbonyls analysis in ozonated FL solution/suspension. Effects of dopant concentration, derivatization temperature and time were studied. The adapted method was used to analyze ozonated FL solution/suspension samples. Dopant concentration and derivatization temperature were optimized to 17 mg/mL and 60 °C, respectively. Competitive extraction was studied, and 5 s extraction time was used to avoid non-linear derivatization of 2-furfural. The detection limits (LODs for target carbonyls ranged from 0.016 and 0.030 µg/L. A much lower LOD (0.016 ppb for 2-furfural was achieved compared with 6 and 35 ppb in previous studies. Analysis results confirmed the robustness of the adapted method for quantification of carbonyls in recycled process water treated with ozone-based decolorization. Ethanal, hexanal, 2-furfural, and benzaldehyde were identified as byproducts of known toxicity but all found below levels for concern.

  4. Calcium hydroxide mixed with camphoric p-monochlorophenol or chlorhexidine in delayed tooth replantation.

    Trevisan, Carolina Lunardelli; Panzarini, Sônia Regina; Brandini, Daniela Atili; Poi, Wilson Roberto; Luvizuto, Eloá Rodrigues; Dos Santos, Cláudia Letícia Vendrame; Saito, Célia Tomiko Hamada Matida

    2011-11-01

    This study evaluated the repair process after delayed replantation of rat teeth, using calcium hydroxide (Ca(OH)2) mixed with camphorated p-monochlorophenol (CMCP), chlorhexidine 2% (CHX), or saline as temporary root canal dressing to prevent and/or control inflammatory radicular resorption. Thirty Wistar rats (Rattus norvegicus albinos) had their right upper incisor extracted, which was bench-dried for 60 minutes. The dental papilla, the enamel organ, the dental pulp, and the periodontal ligament were removed. The teeth were immersed in 2% acidulated-phosphate sodium fluoride solution for 10 minutes. The root canals were dried with absorbent paper cones and divided into 3 groups of 10 animals according to root canal dressing used: group 1: Ca(OH)2 + saline, group 2: Ca(OH)2 + CMCP, and group 3: Ca(OH)2 + CHX 2%. Before replanting, the teeth sockets were irrigated with saline. Histological analysis revealed the presence of inflammatory resorption, replacement resorption, and ankylosis in all 3 groups. Statistical analysis showed a significant difference between group 3 and the other groups. The use of Ca(OH)2 mixed with CMCP or CHX did not show an advantage over the use of Ca(OH)2 mixed with saline in preventing and/or controlling inflammatory resorption in delayed replantation of rat teeth. PMID:22067873

  5. The management of nutrients and water in the west African semi-arid tropics

    At present, the farming systems in the west African semi-arid tropics are unsustainable, low in productivity, and destructive to the environment. A striking feature of the soils is their inherently low fertility, with negative plant-nutrient balance in many cropping systems. Research in N-use efficiency (NUE) indicated that calcium ammonium nitrate (CAN) significantly outperformed urea on millet. Fertilizer losses, greater for urea (53%) than for CAN (25%) were believed to be due to ammonia volatilization. Continuous cropping resulted in lower yields compared to a cereal grown after cowpea or groundnut, and NUE was improved with crop rotation. Phosphorus deficiency is a major constraint. Phosphate rock (PR), indigenous to the region, e.g. at Tahoua in Niger and Tilemsi in Mali, is suitable for direct application. Partial acidulation of low-solubility PR improves agronomic effectiveness. Long-term soil-fertility management trials indicate that although application of mineral fertilizers increase yields, they alone cannot sustain productivity. When mineral fertilizers are combined with other technologies, such as the return of crop residues and manure, productive and sustainable production systems are possible. Water-use efficiency increased dramatically with the addition of plant nutrients. Technologies for land surface management and water harvesting, and appropriate cropping systems with careful varietal selection all contribute to the optimization of soil-water use. Future research should focus on water and nutrient interactions and on understanding why presently available improved technologies are not adopted by farmers even when using a participatory approach. (author)

  6. Development and validation of a liquid chromatography method for anthocyanins in strawberry (Fragaria spp.) and complementary studies on stability, kinetics and antioxidant power.

    Canuto, Gisele A B; Oliveira, Daniel R; da Conceição, Lucas S M; Farah, João P S; Tavares, Marina F M

    2016-02-01

    A RPLC-DAD method for the analysis of eight anthocyanins was developed, validated and applied to strawberry extracts. The chromatographic method was conducted under gradient elution in acidulated water-methanol mobile phase and octadecyl-silica columns. An ultrasound extraction procedure was optimized by a 3(2) factorial design (%HCl in methanol, temperature, and time) and response surface methodology. Method validation was performed according to the following parameters: linearity (R(2)>0.99, p-value725), LOD (3-7 μmol L(-1)) and LOQ (9-22 μmol L(-1)), selectivity/specificity (baseline separation of all analytes and peak purity), instrumental precision (temperature and flow rate) and stability (high temperatures and storage; 1st order kinetics). The antioxidant power of anthocyanins was measured on-line (ABTS(+) reaction; Trolox as reference). Ten strawberry extracts were quantified (average values: 24.2 μg/g for cyanidin-3-glucoside and 49.1 μg/g for pelargonidin-3-glucoside). PMID:26304385

  7. Inhibition of hydrogen embrittlement of Ni-Ti superelastic alloy in acid fluoride solution by hydrogen peroxide addition.

    Yokoyama, Ken'ichi; Yazaki, Yushin; Sakai, Jun'ichi

    2011-09-01

    Inhibition of the hydrogen embrittlement of Ni-Ti superelastic alloy in an acidulated phosphate fluoride (APF) solution has been attempted by adding various amounts of H(2)O(2). In a 0.2% APF solution, hydrogen absorption is markedly inhibited by adding H(2)O(2), although corrosion is slightly enhanced by increasing the amount of added H(2)O(2). By adding a small amount of H(2)O(2) (0.001 M), in the early stage of immersion, hydrogen embrittlement is inhibited and corrosion is only slightly enhanced. Upon adding H(2)O(2), it appears that the dominant cathodic reactions change from hydrogen evolution to H(2)O(2) reduction reactions, or the surface conditions of the alloy are changed by H(2)O(2) with a high oxidation capability, thereby inhibiting hydrogen absorption. The present study clearly indicates that infinitesimal addition of H(2)O(2) into acid fluoride solutions is effective for the inhibition of the hydrogen embrittlement of the alloy. PMID:21630433

  8. Hydrogen embrittlement of work-hardened Ni-Ti alloy in fluoride solutions.

    Yokoyama, Ken'ichi; Kaneko, Kazuyuki; Ogawa, Toshio; Moriyama, Keiji; Asaoka, Kenzo; Sakai, Jun'ichi

    2005-01-01

    Hydrogen embrittlement of work-hardened Ni-Ti alloy has been examined in acidulated phosphate fluoride (APF) solutions. Upon immersion in a 2.0% APF solution with a pH of 5.0, tensile strength decreased markedly with immersion time. Moreover, the fracture mode changed from ductile to brittle due to brittle layer formation at the peripheral part of the cross section of the specimen. The amount of absorbed hydrogen increased linearly with immersion time, and it reached above 5000 mass ppm after 24 h. The hydrogen desorption temperature of the immersed specimens shifted from 450 degrees C to a lower temperature with immersion time. As the amount of absorbed hydrogen was larger than 500 mass ppm, the degradation of mechanical properties was recognized. Although the tensile properties and fracture mode scarcely change in a 0.2% APF solution, the slight reduction in hardness and hydrogen absorption of several hundreds mass ppm were observed. The results of the present study imply that work-hardened Ni-Ti alloy is less sensitive to hydrogen embrittlement compared with Ni-Ti superelastic alloy. PMID:15193885

  9. Bioavailability of Micronutrients from Plant Foods: An Update.

    Platel, Kalpana; Srinivasan, Krishnapura

    2016-07-26

    Deficiencies of iron, zinc, iodine and vitamin A are widespread in the developing countries, poor bioavailability of these micronutrients from plant-based foods being the major reason for their wide prevalence. Diets predominantly vegetarian are composed of components that enhance as well as inhibit mineral bioavailability, the latter being predominant. However, prudent cooking practices and use of ideal combinations of food components can significantly improve micronutrient bioavailability. Household processing such as heat treatment, sprouting, fermentation and malting have been evidenced to enhance the bioavailability of iron and β-carotene from plant foods. Food acidulants amchur and lime are also shown to enhance the bioavailability of not only iron and zinc, but also of β-carotene. Recently indentified newer enhancers of micronutrient bioaccessibility include sulphur compound-rich Allium spices-onion and garlic, which also possess antioxidant properties, β-carotene-rich vegetables-carrot and amaranth, and pungent spices-pepper (both red and black) as well as ginger. Information on the beneficial effect of these dietary compounds on micronutrient bioaccessibility is novel. These food components evidenced to improve the bioavailability of micronutrients are common ingredients of Indian culinary, and probably of other tropical countries. Fruits such as mango and papaya, when consumed in combination with milk, provide significantly higher amounts of bioavailable β-carotene. Awareness of the beneficial influence of these common dietary ingredients on the bioavailability of micronutrients would help in devising dietary strategies to improve the bioavailability of these vital nutrients. PMID:25748063

  10. Effects of the low-intensity red laser radiation on the fluoride uptake in enamel. A clinical trial

    Fluoride has been the most important preventive method on development of the caries. This in vivo study evaluated the effects of low-intensity red laser radiation on the fluoride uptake in enamel. Ten healthy participants were recruited for this study. The two maxillary central incisors of each volunteer to be biopsied were used and divided into 4 groups: group GC (control, which was untreated; group GF (fluoride), which received topical acidulated phosphate fluoride (APF) 1,23% treatment for 4 minutes; group GLF (laser + fluoride), which was irradiated with a low-intensity diode laser (λ= 660 nm and dose= 6 J/cm2) with APF application after irradiation and group GFL (fluoride + laser), which received APF before irradiation using the same parameters as GLF. The determination of fluoride was performed using a fluoride ion electrode after an acid-etch enamel biopsy. The results show a significant increase of the fluoride uptake in enamel for groups GF, GLF and GFL when compared to control group. Although a percentage increase of 57% was observed for GLF with respect to GF, there were no statistical differences among treated groups. These findings suggest that low-intensity laser radiation used before APF could be employed in the clinical practice to prevent dental caries. (author)

  11. Hydrolytic stability of heavy metal compounds in fly ash of a heat power plant

    Ash and slag from solid fuels are utilized widely in building materials and road surfaces, and in agriculture for soil acidulation. For all these uses it is important to know the amount and form of heavy metal compounds contained in ash and their likely behavior when ash and slag wastes are utilized. Studying the behavior of heavy metals in ash residues at contact with water media is important also because, for most trace elements, the authors lack experimental data that would enable us to predict their behavior after prolonged storage and industrial utilization. The present paper describes a study of lixiviation (at various pH in static conditions) of heavy metals form fly ash obtained by burning Azeisk coal. Homogenized ash selected from electric filter sections 1-4 was used, which has the following composition (%): SiO2 59.8; Al2O3; Fe23O3 7.1; CaO 4.1; MgO 1.3; other 2.8. In a neutral medium, Ni, Cu, Zn, Pb, and Mn lixiviation was slight, amounting to 0.01-0.4%. During coal combustion, these elements apparently form compounds that are slightly soluble in water, although it is also possible that ash retains high adsorptivity for heavy metals. As a result, in these conditions the reverse process of sorption of heavy metals from the solution by fly ash is also possible, which would reduce the heavy metal concentration in the solution

  12. Electrochemical performance of single crystal belt-like NH4V3O8 as cathode material for lithium-ion batteries

    NH4V3O8 with belt-like morphology has been synthesized via a hydrothermal process, using acetic acid as acidulant. The resulting phase-pure NH4V3O8 microcrystals have smooth surfaces and are typically 25–45 μm long, 2–15 μm wide, and 0.6–1.2 μm thick. Electrochemical studies by means of cyclic voltammetry and galvanostatic cycling show that the pristine material is a suitable host for reversible Li+ de-/intercalation. Analysis of the peak currents from cyclic voltammetry by means of the Randles-Sevcik equation suggests that the Li+ de-/intercalation is diffusion-controlled with D ∼ 5·10−15 cm2 s−1. The maximum discharge capacity, at 20 mA g−1, amounts to 299 mA h g−1. At 90 mA g−1, it is still 201 mA hg−1 with a capacity retention of 90% in the 100th cycle, indicating the belt-like NH4V3O8 being a promising candidate for application as cathode material in secondary lithium-ion batteries

  13. WATER HARDNESS AS AN IMPORTANT PARAMETER OF PH

    Žigmund Tóth

    2013-02-01

    Full Text Available Quality of final product is to great extent influenced by intermediate products that are formed during beer production. In addition quality of pH is one of the most important properties that forms suitable medium for activity of enzymes complexes that have crucial influence on character of produced wort. Moreover enzymes influence the yield of production process and quality of final product as well. Quality of boiling water and especially its hardness have crucial task in terms of keeping optimal qualitative parameters. Water hardness is given by amount of salts, mainly calcium and magnesium salts. It is expressed as absolute hardness which is given by sum of temporary (carbonate and permanent (noncarbonate hardness. In our work we solved the effect of total water hardness on final pH of various intermediate products. We used different water samples and we prepared variants of total hardness by stirring of unpurified water with distilled water thus we achieved various values of hardness. For comparison we prepared several brews with regard to combinations of unpurified water and distilled water. Higher pH of boiling water was caused due to higher water alkalinity that negatively affected enzyme complex present in used malt. Presence of hydrogenphosphates in used malt had high buffering ability and pH lowering ability. Such unfavorable result could be adjust by use of various additions of acidulates that would have in great extent influence on beer final price therefore boiling water adjustment seems to be the most acceptable approach.

  14. Effects of the low-intensity red laser radiation on the fluoride uptake in enamel. A clinical trial; Avaliacao dos efeitos da radiacao laser de emissao vermelha em baixa intensidade na incorporacao de fluor no esmalte. Estudo clinico

    Nakasone, Regina Keiko

    2004-07-01

    Fluoride has been the most important preventive method on development of the caries. This in vivo study evaluated the effects of low-intensity red laser radiation on the fluoride uptake in enamel. Ten healthy participants were recruited for this study. The two maxillary central incisors of each volunteer to be biopsied were used and divided into 4 groups: group G{sub C} (control, which was untreated; group G{sub F} (fluoride), which received topical acidulated phosphate fluoride (APF) 1,23% treatment for 4 minutes; group G{sub LF} (laser + fluoride), which was irradiated with a low-intensity diode laser ({lambda}= 660 nm and dose= 6 J/cm{sup 2}) with APF application after irradiation and group G{sub FL} (fluoride + laser), which received APF before irradiation using the same parameters as G{sub LF}. The determination of fluoride was performed using a fluoride ion electrode after an acid-etch enamel biopsy. The results show a significant increase of the fluoride uptake in enamel for groups G{sub F}, G{sub LF} and G{sub FL} when compared to control group. Although a percentage increase of 57% was observed for G{sub LF} with respect to G{sub F}, there were no statistical differences among treated groups. These findings suggest that low-intensity laser radiation used before APF could be employed in the clinical practice to prevent dental caries. (author)

  15. OBTENÇÃO DE BEBIDA A PARTIR DE SUCO DE CAJU (Anacardium occidentale, L. E EXTRATO DE GUARANÁ (Paullinia cupana sorbilis Mart. Ducke OBTENTION OF DRINK FROM CASHEW APPLE JUICE (Anacardium occidentale, L. AND GUARANA EXTRACT (Paullinia cupana sorbilis Mart. Ducke

    LILIANA COSTA SOARES

    2001-08-01

    Full Text Available A partir do extrato de semente de guaraná com 0,96% de cafeína, foram testadas várias formulações para obtenção de uma bebida, utilizando-se de suco de caju clarificado e concentrado, caramelo, aromatizantes artificiais de caju e guaraná e acidulante, tendo também como variável os diversos graus de doçura (ºBrix. As melhores formulações foram selecionadas de acordo com os resultados da avaliação sensorial, onde se utilizou o teste de ordenação. A formulação selecionada foi processada e envasada em embalagens de vidro. Para determinar a aceitabilidade, o produto final foi submetido a análises físico-químicas e sensoriais.From Guaraná seeds extract with 0,96% caffein content several formulations were evaluated in order to obtain a beverage using clarified cashew juice concentrate, caramel and guaraná artificial flavors and acidulant, using several sweetness grade a variable. The best formulations were selected according to sensorial evaluation results, using the ordenation test. The selected product (14 ºBrix formulation was manufactured and filled in glass bottles. In order to determine the acceptability the final product was submited to physical chemical and sensorial analysis.

  16. Bioconversion of Cheese Waste (Whey)

    The US dairy industry produces 67 billion pounds of cheese whey annually. A waste by-product of cheese production, whey consists of water, milk sugar (lactose), casein (protein), and salts amounting to about 7% total solids. Ultrafiltration is used to concentrate cheese whey into a protein-rich foodstuff; however, it too produces a waste stream, known as ''whey permeate,'' (rejected water, lactose, and salts from the membrane). Whey permeate contains about 4.5% lactose and requires treatment to reduce the high BOD (biological oxygen demand) before disposal. Ab Initio, a small business with strong chemistry and dairy processing background, desired help in developing methods for bioconversion of whey permeate lactose into lactic acid. Lactic acid is an organic acid primarily used as an acidulant in the food industry. More recently it has been used to produce polylactic acid, a biodegradable polymer and as a new method to treat meat carcasses to combat E. coli bacteria. Conversion of whey permeate to lactic acid is environmentally sound because it produces a valued product from an otherwise waste stream. FM and T has expertise in bioconversion processes and analytical techniques necessary to characterize biomass functions. The necessary engineering and analytical services for pilot biomass monitoring, process development, and purification of crude lactic acid were available at this facility

  17. Anticaries Potential of Low Fluoride Dentifrices Found in The Brazilian Market.

    Ortiz, Adriana de Cássia; Tenuta, Livia Maria Andaló; Tabchoury, Cínthia Pereira Machado; Cury, Jaime Aparecido

    2016-01-01

    Low-fluoride (F) dentifrices (water (1:3, w/v). The pH of the slurries was checked, and only the acidulated one had low pH. After the pH cycling, SH was again determined and the percentage of surface hardness loss was calculated as indicator of demineralization. Loosely- and firmly-bound F concentrations in enamel were also determined. The 1,100 μg F/g dentifrice was more effective than the low-F ones to reduce enamel demineralization and was the only one that differed from the non-F (p<0.05). All F dentifrices formed higher concentration of loosely-bound F on enamel than the non-F (p<0.05), but the 1,100 μg F/g was the only one that differed from the non-F in the ability to form firmly-bound F. The findings suggest that the low-F dentifrices available in the Brazilian market, irrespective of their formulation, do not have anticaries potential. PMID:27224563

  18. RESEARCH ON THE TRENDS IN MILK PRODUCTION AND CONSUMPTION IN ROMANIA

    Agatha POPESCU

    2015-04-01

    Full Text Available The purpose of the paper was to analyze the main trends in the milk and dairy products market in Romania in the period 2007-2012 and to set up the forecast for the 2013-2015 horizon, based on the empirical data provided by the National Institute of Statistics and Eurostat and using the fixed basis index, average change method, and comparison method. Milk production for consumption reached 210 thou tons in 2012 registering a descending trend. Despite that milk production decreased in the period 2007-2012, the production diversification applied by dairies supported the growth of dairy products output as follows: by 13.54 % for milk, by 3.45 % for sour cream, and by 13 % for butter. The forecast for the year 2015 provides that the production of dairy products will account for: 223,936.6 tons milk for consumption, 48,709.4 tons sour cream, 166,674.2 tons acidulated milk, 9,937.6 tons butter and 66,584.4 tons cheese. The development of milk processing imposes the improvement of production technologies, products quality, efficiency and competitiveness. Due to the unbalanced demand/offer ratio, after the elimination of milk quota, the Romanian milk and dairy products market will be invaded by foreign products.

  19. The importance of monitoring the identity and quality standards in fruit pulp industry

    Edna Marinho de Oliveira Moura

    2016-03-01

    Full Text Available Due to the significant increase in consumption of fruits and their derivatives, it is necessary to invest in operations aimed at their use, minimizing the pre and post-harvest losses, due to its high perishability. The fruit processing pulp is a widely used technique because much of the population seeking convenience and a healthier diet, in addition to increase the product shelf life and can provide it to distant regions and periods off season. This study evaluated physicochemical and microbiological characteristics, in three consecutive months, 17 flavors of fruit pulp of a manufacturing company in order to use the final product control as a means to identify control gaps present in the acquisition of raw materials as well as during processing steps and packaging. It was noticed that about 60% of all pulps were unfit for human consumption, with the highest percentage in the physicochemical analysis (45%, followed by microbiological (30%. In the microbiological characteristics, the large amount of molds and yeasts suggest failure through cleaning and sanitizing fruits and in the processing area. For the physicochemical analysis, pH and total soluble solids content were the most alarming, verifying the possibility of water adittion (illegal and acidulant excess, which causes the pulp loses its fruit identity. The most problematic fruits were pineapple, prune, cajá, cashew, graviola, guava and passion fruit. The control of the final product proved essential to the company's quality assurance.

  20. Metabolic engineering of a laboratory-evolved Thermobifida fusca muC strain for malic acid production on cellulose and minimal treated lignocellulosic biomass.

    Deng, Yu; Mao, Yin; Zhang, Xiaojuan

    2016-01-01

    Malic acid is mainly used as an acidulant and taste enhancer in the beverage and food industry. Previously, a mutant strain Thermobifida fusca muC, obtained by adaptive evolution was found to accumulate malic acid on cellulose with low yield. In this study, the malic acid synthesis pathway in T. fusca muC was confirmed to be from phosphoenolpyruvate to oxaloacetate, followed by reduction of oxaloacetate to malate. To increase the yield of malic acid by the muC strain significantly, the carbon flux from pyruvate was redirected to oxaloacetate by expressing an exogenous pyruvate carboxylase (PCx) gene from Corynebacterium glutamicum ATCC 13032 in the chromosome of T. fusca muC-16. The yield of malic acid in the engineered strain muC-16 was increased by 47.9% compared to the parent strain muC. The muC-16 strain was then grown on ∼100 g/L cellulose and the highest titer of malic acid was 62.76 g/L by batch fermentation. T. fusca muC-16 strain converted milled corn stover to malic acid with the highest titer of 21.47 g/L with minimal treatment. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:14-20, 2016. PMID:26439318

  1. Applications and functions of food-grade phosphates.

    Lampila, Lucina E

    2013-10-01

    Food-grade phosphates are used in the production of foods to function as buffers, sequestrants, acidulants, bases, flavors, cryoprotectants, gel accelerants, dispersants, nutrients, precipitants, and as free-flow (anticaking) or ion-exchange agents. The actions of phosphates affect the chemical leavening of cakes, cookies, pancakes, muffins, and doughnuts; the even melt of processed cheese; the structure of a frankfurter; the bind and hydration of delicatessen meats; the fluidity of evaporated milk; the distinctive flavor of cola beverages; the free flow of spice blends; the mineral content of isotonic beverages; and the light color of par-fried potato strips. In the United States, food-grade phosphates are generally recognized as safe, but use levels have been defined for some foods by the Code of Federal Regulations, specifically Titles 9 and 21 for foods regulated by the U.S. Department of Agriculture (USDA) and the U.S. Food and Drug Administration (FDA), respectively. Standards for food purity are defined nationally and internationally in sources such as the Food Chemicals Codex and the Joint Food and Agriculture Organization and World Health Organization (FAO/WHO) Expert Committee on Food Additives. PMID:24033359

  2. Efficacy of various topical agents to prevent enamel demineralization

    Priska Lestari Hendrawan

    2011-09-01

    Full Text Available Background: Enamel demineralization is a common and undesirable side effect of fixed appliance orthodontic treatment. Many sudies showed that the prevalence varied between 2–96%. There are many ways to prevent demineralization and increased remineralization such as oral hygiene instruction and by topical application such as acidulated phosphate fluor (APF casein phospo peptide-amorphous calcium phosphate (CPP-ACP, casein phospo peptide-amorphous calcium phosphate plus (CPP-ACPF. Purpose: The purpose of this in-vitro study was to evaluate the efficacy of various topical agents to prevent enamel demineralization. Methods: Fourty extracted human premolars were allocated to 1 of 4 groups: 1.23% APF gel; 10% CPP-ACP paste; 10% CPP-ACPF paste; and untreated control. All samples were subjected to pH cycling treatment for 12 days through a daily procedure of demineralization solution with pH 4 for 6 hours and remineralization solution with pH 7 for 18 hours. Microhardness testing were done before and after pH cycling and the delta hardness values were determined. Results: APF, CPP-ACP and CPP-ACPF application significantly prevent lowering of enamel microhardness value compared with untreated control group. Kruskal-Wallis, ANOVA, Mann-Whitney U, Tukey and Bonferroni Post-Hoc multiple comparison test showed significant difference between mean delta microhardness value of CPP-ACPF and CPP-ACP group with APF group, but there is no significant difference between mean delta microhardness value of CPP-ACPF and CPP-ACP group. Conclusion: APF, CPP-ACP and CPP-ACPF prevent enamel demineralization. CPP-ACP and CPP-ACPF prevent demineralization more than APF.Latar belakang: Demineralisasi email merupakan efek samping negatif yang sering dijumpai pada perawatan ortodontik cekat. Beberapa penelitian menyatakan bahwa prevalensinya bervariasi 2–96 persen. Ada beberapa cara untuk mencegah demineralisasi dan meningkatkan remineralisasi, misalnya dengan instruksi

  3. The Australian national reactive phosphate rock project - Aims, experimental approach, and site characteristics

    Field-based cutting trials were established across Australia in a range of environments to evaluate the agronomic effectiveness of 5 phosphate rocks, and 1 partially acidulated phosphate rock, relative to either single super-phosphate or triple superphosphate. The phosphate rocks differed in reactivity, as determined by the degree of carbonate substitution for phosphate in the apatite structure and solubility of phosphorus present in the fertilizers in 2% formic acid, 2% citric acid and neutral ammonium citrate. Sechura (Bayovar) and North Carolina phosphate rocks were highly reactive (>70% solubility in 2% formic acid), whilst Khouribja (Moroccan) and Hamrawein (Egypt) phosphate rock were moderately reactive. Duchess phosphate rock from Queensland was relatively unreactive (2, from 4.0 to 5.1, and Colwell extractable phosphorus ranged from 3 to 47 μg/g prior to fertilizer application. Two core experiments were established at each site. The first measured the effects of phosphate rock reactivity on agronomic effectiveness, while the second core experiment measured the effects of the degree of water solubility of the phosphorus source on agronomic effectiveness. The National Reactive Phosphate Rock Project trials provided the opportunity to confirm the suitability of accepted procedures to model fertilizer response and to develop new approaches for comparing different fertilizer responses. The Project also provided the framework for subsidiary studies such as the effect of fertilizer source on soil phosphorus extractability; cadmium and fluorine concentrations in herbage; evaluation of soil phosphorus tests; and the influence of particle size on phosphate rock effectiveness. The National Reactive Phosphate Rock Project presents a valuable model for a large, Australia-wide, collaborative team approach to an important agricultural issue. The use of standard and consistent experimental methodologies at every site ensured that maximum benefit was obtained from data

  4. Nanostructural effect of acid-etching and fluoride application on human primary and permanent tooth enamels

    Cheong, Youjin [Department of Biomedical Engineering and Healthcare Industry Research Institute, College of Medicine, Kyung Hee University, Seoul (Korea, Republic of); Choi, Samjin [Department of Biomedical Engineering and Healthcare Industry Research Institute, College of Medicine, Kyung Hee University, Seoul (Korea, Republic of); Department of Orthodontics, College of Dental Medicine, Kyung Hee University, Seoul (Korea, Republic of); Kim, So Jung [Department of Pediatric Dentistry, College of Dental Medicine, Kyung Hee University, Seoul (Korea, Republic of); Park, Hun-Kuk, E-mail: sigmoidus@khu.ac.kr [Department of Biomedical Engineering and Healthcare Industry Research Institute, College of Medicine, Kyung Hee University, Seoul (Korea, Republic of); Program of Medical Engineering, Kyung Hee University, Seoul (Korea, Republic of)

    2012-07-01

    This study examined the nanostructural effects of fluoride application and the acid-etching time with respect to the time elapsed after fluoride application on the primary and permanent tooth enamel layers using atomic force microscopy (AFM) and scanning electron microscopy (SEM). 192 non-carious teeth were assigned to sixteen experimental groups (n = 12) including primary (1 to 8) and permanent (9 to 16) teeth, based on the timing of acid-etching with 37% phosphoric acid after an acidulated phosphate fluoride (APF) pre-treatment. The APF pre-treatment led to a decrease in surface roughness in both the primary and permanent teeth. After the APF treatment, the roughness in both primary and permanent teeth increased with the time elapsed. An acid-etching time of 40 s led to increased nanostructural changes in the enamel surfaces compared to the conventional acid-etching time of 20 s. This acid-etching process led to a higher roughness changes in the primary teeth than in the permanent teeth. To obtain proper enamel adhesion of a sealant after APF pre-treatment, it is important to apply acid-etching two weeks after pre-treatment. In addition, the acid-etching time should be prolonged to apply etching more quickly than two weeks, regardless of the primary and permanent teeth. Highlights: Black-Right-Pointing-Pointer APF pre-treatment led to decreased surface roughness in the enamel. Black-Right-Pointing-Pointer After APF treatment, the more roughness increased with increasing time elapsed. Black-Right-Pointing-Pointer Acid-etching should be performed two weeks after fluoride application.

  5. Sulphursoil - Delano Development Corporation

    None

    1985-06-01

    A sizable amount of technical information has been accumulated on the effects of agricultural applications of the natural mineral product called Sul-Fe. This technical information supports the field observations of farmers, landscapers and gardeners who have used the product. Sul-Fe is often evaluated in terms of its sulphur content alone. When compared to elemental sulphur (100% sulphur), the 18 to 21% sulphur content of Sul-Fe seems relatively low. However, as the following technical data indicates, when judged on actual effects, Sul-Fe's complex mixture of minerals has several advantages over elemental sulphur. When judged on the basis of soil acidulation, Sul-Fe has more immediate effects than elemental sulphur. The rapid acidifying effect is due to Sul-Fe's content of crystalline sulphuric acid. Sul-Fe also has long-term effects on soil pH due to its content of sulphur and sulfides and the time required to oxidize these materials. Elemental sulphur contains sulphur in only one chemical form which must be microbially oxidized before it becomes reactive in the soil solution, a reaction that takes quite some time in some soils. Sul-Fe is thus better than elemental sulphur in terms of immediate effects and comparable in terms of long term effects. Applied blends of Sul-Fe supplemented with elemental sulphur may provide for a maximization of both short and long term effects. An additional benefit derived from the use of Sul-Fe is the addition to the soil of a variety of trace nutrients including iron, calcium, zinc, copper, manganese, magnesium, and molybdenum.

  6. Development of a phosphating process for corrosion protection in NdFeB magnets

    NdFeB magnets are important materials, which produce better energy efficiency in electrical devices, but they are rather vulnerable to corrosion. In this study, a phosphating treatment for protection against corrosion of NdFeB magnets has been investigated. Phosphating is generally used as a pretreatment in the application of protective coatings. This treatment increases the corrosion assistance in defective areas of the coating as well as improves the adhesion between coating and substrate. A commercial NdFeB magnet produced by powder metallurgy has been used and the effect of the following parameters on phosphating was studied: time of phosphating; pH of phosphating solution; anodic polarization and molybdate addition to the phosphating solution. The results showed a significant increase in the corrosion resistance of magnets phosphated in a solution concentrated between 10-20 g/L NaH2PO4, pH in the range of 3 to 4.6, acidulated preferably with H3PO4 at room temperature (20±1) deg C. Conversion coatings formed at solutions of pH 3.8 showed better corrosion resistance. Phosphating times longer than 4 hours increased the magnet corrosion resistance 10 to 20 times. This resistance improves with higher immersion times. Anodic polarization of the magnet in the range 200-400 mVSCE accelerated phosphating. Results indicated that molybdate interacts preferentially with Nd rich phase of the magnet. In addition to the newly developed technology in this work for NdFeB corrosion protection, two methodologies have been introduced to facilitate electrochemical analyses: selection of samples of similar electrochemical behavior, based on the current density after 200s of constant anodic polarization; and evaluation of the corrosion protection provided by conversion coatings by monitoring of gas evolution during corrosion in acid solution. (author)

  7. Uranium recovery from wet process phosphoric acid

    Improvement in the process for recovering uranium from wetprocess phosphoric acid solution derived from the acidulation of uraniferous phosphate ores by the use of two ion exchange liquidliquid solvent extraction circuits in which in the first circuit (A) the uranium is reduced to the uranous form; (B) the uranous uranium is recovered by liquid-liquid solvent extraction using a mixture of mono- and di-(Alkyl-phenyl) esters of orthophosphoric acid as the ion exchange agent; and (C) the uranium oxidatively stripped from the agent with phosphoric acid containing an oxidizing agent to convert uranous to uranyl ions, and in the second circuit (D) recovering the uranyl uranium from the strip solution by liquid-liquid solvent extraction using di(2ethylhexyl)phosphoric acid in the presence of trioctylphosphine oxide as a synergist; (E) scrubbing the uranium loaded agent with water; (F) stripping the loaded agent with ammonium carbonate, and (G) calcining the formed ammonium uranyl carbonate to uranium oxide, the improvement comprising: (1) removing the organics from the raffinate of step (B) before recycling the raffinate to the wet-process plant, and returning the recovered organics to the circuit to substantially maintain the required balance between the mono and disubstituted esters; (2) using hydogren peroxide as the oxidizing agent in step (C); (3) using an alkali metal carbonate as the stripping agent in step (F) following by acidification of the strip solution with sulfuric acid; (4) using some of the acidified strip solution as the scrubbing agent in step (E) to remove phosphorus and other impurities; and (5) regenerating the alkali metal loaded agent from step (F) before recycling it to the second circuit

  8. Microleakage and shear bond strength of orthodontc brackets bonded to hypomineralized enamel following different surface preparations

    Shahabi, Mostafa; Mohamadipour, Hamideh; Moosavi, Horieh

    2014-01-01

    Objectives: This study investigated the effects of several conditioning methods on shear bond strength (SBS) and microleakage of orthodontic brackets bonded to demineralized enamel. Study Design: One hundred premolars were selected and immersed in a cariogenic solution for 12 weeks. The teeth were randomly assigned into 5 groups. In groups 1 and 2, the teeth underwent acid etching for 30 and 120 seconds, respectively. In group 3, a combination of laser and acid etching was employed. A self-etch primer (SEP) was applied in group 4 and in group 5, the teeth were exposed to acidulated phosphate fluoride (APF) for 4 minutes before etching. After bracket bonding, the teeth were immersed in methylen blue for 12 hours and then were mounted in acrylic resin. SBS was determined with an Instron Universal Testing Machine and the amount of microleakage under the brackets was assessed under a stereomicroscope. Results: The lowest SBS was related to the SEP group and the highest one was observed in the specimens prepared by APF+acid etching. There was a significant difference in SBS (p=0.009), but not in microleakage (p=0.971) of the study groups. The SBS of the specimens treated with SEP was significantly Lower than the other groups, which were not significantly different from each other. The SEP group displayed a higher frequency of bond failure at the enamel-adhesive interface. Conclusions: Enamel preparation with SEP provided the lowest SBS among the groups. All groups showed some degree of microleakage. There was no significant correlation between SBS and microleakage. Key words:Bond strength, microleakage, bonding, self-etch primer, Er:YAG laser. PMID:24790708

  9. Effect of Topical Fluoride on Surface of Cast Titanium and Nickel-Chromium: An In Vitro Study

    Gayatri Sheena Suvarna

    2015-11-01

    Full Text Available Objectives: The aim of this in-vitro study was to evaluate the effect of topical fluoride on surface of cast titanium and nickel-chromium.Materials and Methods: Thirty-nine rectangular specimens of titanium (grade 2 and 39 rectangular specimens of nickel-chromium were cast in equal dimensions and divided into three groups of 13 samples each. Group one specimens of titanium and nickel-chromium were placed in 2% neutral sodium fluoride (NaF solution for 16 minutes. Group two specimens of titanium and nickel-chromium were immersed in 1.23% acidulated phosphate fluoride (APF gel for eight minutes. Group three specimens of titanium and nickel-chromium were immersed in distilled water for 16 minutes. The surface roughness of the specimens was evaluated and the data were analyzed using two-way ANOVA and post-hoc comparison test with the level of significance set at 5% (P< 0.05. The surface of the specimens was further analyzed using a scanning electron microscope (SEM and energy dispersive spectrometer (EDS.Results: Group two titanium specimens showed a statistically significant increase in surface roughness (P<0.05; but no statistically significant increase was noted in the surface roughness of nickel-chromium specimens in groups one, two and three (P>0.05. Qualitative SEM and EDS analyses further revealed the surface corrosion of titanium (group two and localized mild corrosive pitting of nickel-chromium specimens (group two.Conclusion: Topical fluoride with acidic pH affects the surface roughness of titanium and to a certain extent, nickel-chromium. Neutral NaF solutions cause no significant change in corrosion resistance of titanium or nickel-chromium.

  10. Nanostructural effect of acid-etching and fluoride application on human primary and permanent tooth enamels

    This study examined the nanostructural effects of fluoride application and the acid-etching time with respect to the time elapsed after fluoride application on the primary and permanent tooth enamel layers using atomic force microscopy (AFM) and scanning electron microscopy (SEM). 192 non-carious teeth were assigned to sixteen experimental groups (n = 12) including primary (1 to 8) and permanent (9 to 16) teeth, based on the timing of acid-etching with 37% phosphoric acid after an acidulated phosphate fluoride (APF) pre-treatment. The APF pre-treatment led to a decrease in surface roughness in both the primary and permanent teeth. After the APF treatment, the roughness in both primary and permanent teeth increased with the time elapsed. An acid-etching time of 40 s led to increased nanostructural changes in the enamel surfaces compared to the conventional acid-etching time of 20 s. This acid-etching process led to a higher roughness changes in the primary teeth than in the permanent teeth. To obtain proper enamel adhesion of a sealant after APF pre-treatment, it is important to apply acid-etching two weeks after pre-treatment. In addition, the acid-etching time should be prolonged to apply etching more quickly than two weeks, regardless of the primary and permanent teeth. Highlights: ► APF pre-treatment led to decreased surface roughness in the enamel. ► After APF treatment, the more roughness increased with increasing time elapsed. ► Acid-etching should be performed two weeks after fluoride application.

  11. Trace elements in rock phosphates and P containing mineral and organo-mineral fertilizers sold in Germany.

    Kratz, Sylvia; Schick, Judith; Schnug, Ewald

    2016-01-15

    68 rock phosphates and 162 P containing (organo-)mineral fertilizers sold in Germany were evaluated with regard to trace element contents. While Al, As, B, Be, Cd, Cr, Mo, Ni, Pb, Sb, Se, Tl, U, and Zn were higher in sedimentary than in igneous rock phosphates, the opposite was true for Co, Cu, Sn, Mn, Ti, Fe, and Sr. Comparing element concentrations to the currently valid legal limit values defined by the German Fertilizer Ordinance, it was found that some PK and many straight P fertilizers (superphosphate, triple superphosphate, partly acidulated rock phosphates) exceeded the limit of 50 mg Cd/kg P2O5. Mean values for As, Ni, Pb, and Tl remained below legal limits in almost all cases. While no legal limit has been defined for U in Germany yet, the limit of 50 mg U/kg P2O5 for P containing fertilizers proposed by the German Commission for the Protection of Soils was clearly exceeded by mean values for all fertilizer types analyzed. A large share of the samples evaluated in this work contained essential trace elements at high concentrations, with many of them not being declared as such. Furthermore, trace elements supplied with these fertilizers at a fertilization rate leveling P uptake would exceed trace element uptake by crops. This may become most relevant for B and Fe, since many crops are sensitive to an oversupply of B, and Fe loads exceeding plant uptake may immobilize P supplies for the crops by forming Fe phosphate salts. The sample set included two products made from thermochemically treated sewage sludge ash. The products displayed very high concentrations of Fe and Mn and exceeded the legal limit for Ni, emphasizing the necessity to continue research on heavy metal removal from recycled raw materials and the development of environmentally friendly and agriculturally efficient fertilizer products. PMID:26328946

  12. Upgrading of raw tall oil soap into fuel oils and lubricants; Raakasuovan jalostus poltto- ja voiteluoeljyksi

    Oasmaa, A.; Arpiainen, V.; McKeough, P.; Tapola, E.; Haekkinen, R.; Kuoppala, E.; Koskela, K. [VTT Energy, Jyvaeskylae (Finland). Energy Production Technologies

    1997-12-01

    Thermochemical processing of tall oil soap originating from various mixtures of birch and pine has been experimentally investigated. The organic matter of tall oil soap, which is a by- product of Kraft pulping, originates mainly from wood extractives. Conventional processing of tall oil soap involves acidulation with sulphuric acid to yield crude tall oil and subsequent distillation of the oil at centralised refineries. Because tall oil originating from birch wood is far less valuable than that from pine, there is an economic incentive in the Nordic countries to develop alternative conversion processes for the tall oil soap produced at pulp mills where birch is widely used as feedstock. Furthermore, thermochemical processing of tall oil soap does not introduce sulphur into the chemical recovery cycle. This would be a significant advantage in future mills employing closure of water circuits and/or sulphur-free pulping. In small-scale experiments tall oil soaps from wood mixtures with high birch content have been processed using both liquid-phase thermal treatment and pyrolysis. The liquid-phase thermal treatment at 450 deg C under a nitrogen atmosphere yielded a good-quality oil product at high yield (about 50 % of the energy content of the tall oil soap). In the atmospheric pyrolysis of birch tall oil soap a separation of inorganic and organic constituents was obtained. The energy value of the product gases was high. Both processes are promising, but the pyrolysis alternative has the greater economic potential, providing that the promising preliminary experimental results have given a true picture of the performance of the full-scale pyrolysis process. (orig.)

  13. FT-Raman spectroscopic analysis of Nd:YAG and Er,Cr:YSGG laser irradiated enamel for preventive purposes

    This study evaluated the effect of combining laser irradiation with fluoride on an enamel microstructure and demineralization by FT-Raman spectroscopy (FTRS). Eighty human enamel slabs were divided into eight groups: (G1) untreated; (G2) acidulated phosphate fluoride application (APF—1.23% F− for 4 min); (G3) Nd:YAG irradiation (84.9 J cm−2, 60 mJ/pulse); (G4) Nd:YAG + APF; (G5) APF + Nd:YAG; (G6) Er,Cr:YSGG irradiation (2.8 J cm−2, 12.5 mJ/pulse); (G7) Er,Cr:YSGG + APF; and (G8) APF + Er,Cr:YSGG. After treatment, the samples were submitted to a ten-day pH-cycling model. Chemical changes were determined on the slabs before and after treatment, and also after pH-cycling, by FTRS in the range 400−4000 cm−1. The inorganic bands at 440, 590, 870, 960, 1100 cm−1, and the organic bands at 1270, 1450, 1670, 2945 cm−1 were considered. Demineralization promoted reduction in organic contents; Nd:YAG laser irradiation promoted loss of carbonate and organic content, while Er,Cr:YSGG did not produce significant changes in the relative band intensities of organic and inorganic contents of the enamel. In lased samples, no effects caused by pH-cycling on enamel were observed. In conclusion, laser treatment and its association with fluoride can somehow interfere with the demineralization dynamics, reducing its effects over the enamel. (paper)

  14. Thermal reduction and U-recovery from uraniferous phosphorite concentrate of phosphatic sandstone deposit of G. Qatrani, western desert, Egypt

    The produced uraniferous phosphorite concentrate from cationic floatation of phosphatic sandstone of G. Qatrani contain 32.01% P2O5, 0.39% eU and 5.65% SiO2. Thermal reduction technique using a high calorific hydrocarbon (Mazout) is used to recover U and P2O5. At elevated temperature ranging from 500 to 8000C, reducing gases mainly, Co are evolved due to mazout cracking; beside a carbon film is precipitated around the treated phosphate grains. These conditions have proved quite beneficial in reducing U+6 into U+4, as well as creating a sufficiently low redox potential below 350 mV in the subsequent leach solution. The effect of different relevant factors are studied and optimized as 700 C, 30 minutes and 20% (wt/wt) ratio for reducing temperature, duration time and amount of reductant added respectively. Hydrochloric acid of 8 N appears to offer the best potential for acidulation of the reduced phosphates at room temperature (250C) and 30 minutes retention time of agitation leaching. The results showed that, more than 98% of P2O5 reports in solution as phosphoric acid and about 97% of uranium is retained in an insoluble form (U+4). Applying oxidizing roast of the leached reduced materials at 8000C in the presence of 2% NaCl, would result in both removing the carbon content and oxidizing the contained U+4 to U+6. By subsequent leaching with dilute acidic solution (2N HCl) more than 98% of the contained U+6 is readily soluble

  15. Effects of 960 nm diode laser irradiation on dental enamel in vitro: temperature and morphological analysis and evaluation of enamel demineralization; Estudo in vitro dos efeitos promovidos pelo laser de diodo em 960 nm no esmalte dental humano: analise de temperatura, analise morfologica e avaliacao da resistencia a desmineralizacao

    Kato, Ilka Tiemy

    2004-07-01

    The aim of this study is to determine the effects of diode laser irradiation on enamel demineralization. To achieve this goal appropriate photon absorbing substances for the laser radiation, safe laser parameters and adequate temperature measuring apparatus had to be determined. Next, the effects of diode laser and acidulated phosphate fluoride on enamel demineralization by calcium content analysis were evaluated with inductively coupled plasma atomic emission spectrometry (ICP-AES). In the first part of the study, five dyes consisting of vegetable coal diluted in five different liquids were analyzed and vegetable coal diluted in physiological solution was chosen for use as absorber. Methodologies to measure pulp chamber temperature were evaluated and modeling clay was chosen as fixture for the enamel samples held at body temperature. In the second part of the study, different energy density parameters (1.8 J/cm{sup 2}, 3.7 J/cm{sup 2}, 5.6 J/cm{sup 2}, 7.4 J/cm{sup 2} and 9.3 J/cm{sup 2}) exposure times (10, 15, 20, 25 e 30 seconds) and time intervals between dye application and laser irradiation (5, 30, 60, 90 e 120 seconds) were evaluated with respect to temperature changes in the pulp chamber. The enamel morphology was analyzed by scanning electron microscopy. Acid resistance was measured using seventy five enamel specimens, divided in five groups (control, fluoride, laser, laser + fluoride and fluoride + laser). The amount of calcium lost during demineralization in lactic acid was measured by ICP-AES. The results obtained in this experiment permit the conclusion that diode laser irradiation did not increase acid resistance. When associated with fluoride, the acid resistance did not differ from the results obtained with fluoride alone. (author)

  16. Effects of 960 nm diode laser irradiation on dental enamel in vitro: temperature and morphological analysis and evaluation of enamel demineralization

    The aim of this study is to determine the effects of diode laser irradiation on enamel demineralization. To achieve this goal appropriate photon absorbing substances for the laser radiation, safe laser parameters and adequate temperature measuring apparatus had to be determined. Next, the effects of diode laser and acidulated phosphate fluoride on enamel demineralization by calcium content analysis were evaluated with inductively coupled plasma atomic emission spectrometry (ICP-AES). In the first part of the study, five dyes consisting of vegetable coal diluted in five different liquids were analyzed and vegetable coal diluted in physiological solution was chosen for use as absorber. Methodologies to measure pulp chamber temperature were evaluated and modeling clay was chosen as fixture for the enamel samples held at body temperature. In the second part of the study, different energy density parameters (1.8 J/cm2, 3.7 J/cm2, 5.6 J/cm2, 7.4 J/cm2 and 9.3 J/cm2) exposure times (10, 15, 20, 25 e 30 seconds) and time intervals between dye application and laser irradiation (5, 30, 60, 90 e 120 seconds) were evaluated with respect to temperature changes in the pulp chamber. The enamel morphology was analyzed by scanning electron microscopy. Acid resistance was measured using seventy five enamel specimens, divided in five groups (control, fluoride, laser, laser + fluoride and fluoride + laser). The amount of calcium lost during demineralization in lactic acid was measured by ICP-AES. The results obtained in this experiment permit the conclusion that diode laser irradiation did not increase acid resistance. When associated with fluoride, the acid resistance did not differ from the results obtained with fluoride alone. (author)

  17. Production of Succinic Acid for Lignocellulosic Hydrolysates

    Davison, B.H.; Nghiem, J.

    2002-06-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) is to add and test new metabolic activities to existing microbial catalysts for the production of succinic acid from renewables. In particular, they seek to add to the existing organism the ability to utilize xylose efficiently and simultaneously with glucose in mixtures of sugars or to add succinic acid production to another strain and to test the value of this new capability for production of succinic acid from industrial lignocellulosic hydrolyasates. The Contractors and Participant are hereinafter jointly referred to as the 'Parties'. Research to date in succinic acid fermentation, separation and genetic engineering has resulted in a potentially economical process based on the use of an Escherichia coli strain AFP111 with suitable characteristics for the production of succinic acid from glucose. Economic analysis has shown that higher value commodity chemicals can be economically produced from succinic acid based on repliminary laboratory findings and predicted catalytic parameters. The initial target markets include succinic acid itself, succinate salts, esters and other derivatives for use as deicers, solvents and acidulants. The other commodity products from the succinic acid platform include 1,4-butanediol, {gamma}-butyrolactone, 2-pyrrolidinone and N-methyl pyrrolidinone. Current economic analyses indicate that this platform is competitive with existing petrochemical routes, especially for the succinic acid and derivatives. The report presents the planned CRADA objectives followed by the results. The results section has a combined biocatalysis and fermentation section and a commercialization section. This is a nonproprietary report; additional proprietary information may be made available subject to acceptance of the appropriate proprietary information agreements.

  18. Effects of topical fluoride prophylactic agents on the mechanical properties of orthodontic nickel-titanium closed coil springs and stainless steel closed coil springs

    Carpenter, Brittany Gelene

    The purpose of this study was to investigate the effects of topical fluoride prophylactic agents on the mechanical unloading properties of nickel-titanium (NiTi) and stainless steel (SS) closed coil springs. Spring were stored at 37°C under static load in phosphate buffered saline (PBS) and treated with either neutral sodium fluoride (NaF) or acidulated phosphate fluoride (APF) five days per week for two minutes. Mechanical testing was done in a dH2O bath at 37°C at 0-, 1-, 4-, 8-, and 12 weeks. Unloading forces for NiTi and SS springs were measured at 9-, 6-, and 3 mm and 2-, 1.5-, and 1 mm, respectively. Scanning electron microscopy was used to evaluate surface topography of selected springs after 12 weeks. Based on a 1-Factor ANOVA and Dunnett's post hoc, 3M NiTi springs showed a significant decrease (p springs showed a significant decrease in unloading force at each extension after 12 weeks following exposure to NaF. However, with SS springs, there was no significant effect of either fluoride treatment on the SS springs at any extension or time point. SS also springs showed no significant surface topography changes, irrespective of storage conditions, which correlates with the lack of fluoride effects on SS mechanical property effects. In contrast, while there were NiTi surface topography changes (pitting and mottling) following PBS+APF exposure, those changes could not be directly linked to the observed changes in mechanical properties. Results suggest topical fluoride used with NiTi springs could potentially lead to prolonged treatment time due to decreased unloading properties. However, topical fluoride used with SS springs should not affect treatment duration.

  19. CO2 laser irradiation enhances CaF2 formation and inhibits lesion progression on demineralized dental enamel-in vitro study.

    Zancopé, Bruna R; Rodrigues, Lívia P; Parisotto, Thais M; Steiner-Oliveira, Carolina; Rodrigues, Lidiany K A; Nobre-Dos-Santos, Marinês

    2016-04-01

    This study evaluated if Carbon dioxide (CO2) (λ 10.6 μm) laser irradiation combined with acidulated phosphate fluoride gel application (APF gel) enhances "CaF2" uptake by demineralized enamel specimens (DES) and inhibits enamel lesion progression. Thus, two studies were conducted and DES were subjected to APF gel combined or not with CO2 laser irradiation (11.3 or 20.0 J/cm(2), 0.4 or 0.7 W) performed before, during, or after APF gel application. In study 1, 165 DES were allocated to 11 groups. Fluoride as "CaF2 like material" formed on enamel was determined in 100 DES (n = 10/group), and the surface morphologies of 50 specimens were evaluated by scanning electron microscopy (SEM) before and after "CaF2" extraction. In study 2, 165 DES (11 groups, n = 15), subjected to the same treatments as in study 1, were further subjected to a pH-cycling model to simulate a high cariogenic challenge. The progression of demineralization in DES was evaluated by cross-sectional microhardness and polarized light microscopy analyses. Laser at 11.3 J/cm(2) applied during APF gel application increased "CaF2" uptake on enamel surface. Laser irradiation and APF gel alone arrested the lesion progression compared with the control (p fusion, and cracks were observed. CO2 laser irradiation, combined with a single APF application enhanced "CaF2" uptake on enamel surface and a synergistic effect was found. However, regarding the inhibition of caries lesion progression, no synergistic effect could be demonstrated. In conclusion, the results have shown that irradiation with specific laser parameters significantly enhanced CaF2 uptake by demineralized enamel and inhibited lesion progression. PMID:26873502

  20. Effects of minimal processing on the respiration rate and quality of rambutan cv. ‘Rong-Rien’

    Buncha Ooraikul

    2008-04-01

    Full Text Available Respiration rate at 4oC and minimal processing of rambutan cv. ‘Rong-Rien’ were investigated. Rambutan was harvested from Amphur Ban Na San, Surat Thani Province, at the stage when its skin was turning into a combination of red, green and yellow. After harvesting, the fruits were size-graded to 27-30 fruits/kg, hydrocooled to 14oC, packed with ice in Styrofoam boxes and transported to the laboratory at Prince of Songkla University within 6 h. The respiration rate of fresh rambutan fruits was monitored. For minimal processing, the fruits were soaked in warm solution (55oC of 100 ppm sodium hypochlorite for one min and immediately cooled in cold water until their internal temperature reached 14oC. The minimal process included peeling, with and without coring. The peeled and peeled and cored rambutan samples were immersed in a solution of 0.5% citric acid + 0.5% CaCl2 at 4oC for 2 min. The average respiration rates (within 6 h at 4oC of whole fruit, peeled, and peeled and cored rambutan samples were measured and found to be 122, 134 and 143 mg CO2/kg/h, respectively. These findings indicated that a preparation style as peeled rambutan without coring, nylon/LLDPE bag, storage temperature of 4.0±1oC, were suitably applied for processed rambutans. To obtain a longer extended shelf life (>12 days of minimally processed peeled rambutans, further study on food additives, including acidulants and preservative used and gas composition in modified atmosphere packaging (MAP is needed.

  1. Comparison of Antibacterial Effect of Fluoride and Chlorhexidine on Two Cariogenic Bacteria: An in Vitro Study

    Poureslami HR

    2014-09-01

    Full Text Available Statement of problem: Dental plaque is the main source for dental caries and there is no proper vaccine that can affect dental plaques. Objectives: Daily use of an efficient anti-plaque product can be very beneficial in plaque control and, thus, prevention of caries. This study aims to evaluate the antibacterial effects of four products of Chlorhexidine and Fluoride on two types of cariogenic bacteria. Materials and Methods: In this in vitro study, the antibacterial effect of Chlorhexidine and Fluoride (gel and solution against Streptococci Sanguis and Sobrinus was evaluated. Chlorhexidine gluconate 1% gel (Corosodyl, France, Chlorhexidine gluconate 2% solution (Consepsis, Ultradent, US, Sodium fluoride 0.2% solution (Oral-B, US and Acidulated Phosphate Fluoride 1.23% gel ( Denti-Care, Canada were used. The disc diffusion method was used for testing bacterial sensitivity. The data were analyzed using paired t-test and Chi-square test. Results: In comparison with the negative control, each of the four gels and solutions showed antibacterial effects but the effects were not statistically significant for fluoride solution (P=0.217. For S. Sobrinus, the mean diameter of inhibition zone around the discs coated with fluoride gel (F g, fluoride solution (F s, Chlorhexidine gel (CHX g and Chlorhexidine solution (CHX s were 19, 9, 21.5 and 27.5mm, respectively. For S. Sanguis, the mean diameter of inhibition zone around the discs coated with F g, F s, CHX g and CHX s were 17, 11, 17 and 25mm, respectively. CHX s had the most effect on both bacteria and F s had the least. CHX g and F g were less effective than CHX s, respectively. Conclusion: The results demonstrated that 2% CHX s and 1.23% F g can be effective on inhibition of the growth of some of cariogenic bacteria. Therefore, these agents can be used in the prevention of Early Childhood Caries.

  2. EKSTRAKSI PEWARNA ALAMI DARI BUAH ARBEN (Rubus idaeus Linn. [Extraction of Natural Colorant from Red Raspberry (rubus idaeus linn. And its application in food sistem

    Tensiska1

    2007-06-01

    Full Text Available Red raspberry fruit has not been optimally utilized even though it contains anthocyanin pigment. The pigment can be used as a natural colorant which also function as antioxidant. The aim of this study was to determine the appropriate solvent for anthocyanin extraction from red raspberry fruit and its possibility for food colorant. The research was started with preliminary research to determine appropriate acidulants (citric, acetic and tartaric acid with levels of 0,1 ;0,25;0,5 ;0,75 and 1 %. The main research was divided into three stages, which were: (1 to determine the appropriate solvent of extraction (aquadest, ethanol and etil acetate; (2 the best extract was determined its color stability in pH of 1,2,3,4,5,6,7,8,9 and (3 to examine the pigment solubility into some food system (aqua96%dest, 25% of acetic acid, 96% of ethanol and coconut oil. The best extract also was examined its solubility in carbonated drink (pH of 3.69, pasteurized milk (pH of 6.49 and yogurt (pH of 2.6. the results showed that the extraction using aquadest with 0.75% of tartaric acid resulted in the highest total anthocyanin and showed the best color intensity. This extract was stable at pH of 2-5 and its solubility was best in aquaeous system with low pHs, thus it can be applied for aqueous product with low pHs.

  3. Evaluating agronomic effectiveness of phosphate rocks using nuclear and related techniques: Results from an FAO/IAEA co-ordinated research project

    An FAO/IAEA Co-ordinated Research Project, 'The use of nuclear and related techniques for evaluating the agronomic effectiveness of phosphatic fertilisers, in particular rock phosphates', was in operation during the period 1993-98. The research network comprised twenty-three scientists, of whom seventeen were in developing countries, with six in industrialized nations. Conventional and 32P-isotope techniques were utilized to assess the bioavailability of P in soils amended with phosphate rock (PR) and water-soluble fertilisers, and to evaluate the agronomic effectiveness of PR products. No single chemical extraction method was found to be suitable for all soils and fertilisers. The Pi strip method showed promising results, but more testing is needed with tropical acid soils. The 32P-phosphate-exchange kinetics method allowed a complete characterization of P dynamics, and provided basic information for estimating the kinetic pools of soil P. The agronomic effectiveness (AE) of PRs depends on their solubility (reactivity), which is related to the degree of carbonate substitution for phosphate in the apatite structure. Rock phosphates of low reactivity were unsuitable for direct application to annual crops. Research in Venezuela, China, Cuba, Brazil, and Thailand demonstrated that AE can be increased by partial acidulation, or by mixing with organic materials or a water-soluble source. The AE can be enhanced also through inoculation with mycorrhizal fungi and rhizobacteria. The AE, which depends on species, is particularly high in crops such as canola and lupin that exude organic acids from the roots. Agronomic effectiveness of PR is higher on soils with low pH, low available P, low exchangeable Ca, high cation exchange capacity and high organic-matter content. The 32P-techniques are powerful tools for studying the factors that affect AE. Information from field trials was used to create a database for validating a model for providing recommendations for PR application

  4. Repairability of Compomers with Different Methods of Surface Conditioning

    P.Samimi

    2005-06-01

    Full Text Available Statement of Problem: Considering the cost and amount of time and also the quantity of tooth loss in the process of cavity preparation, repair of the restoration instead of itsreplacement would be much more efficient.Purpose: The aim of this study was to determine the effect of different methods of surface conditioning on the shear bond strength of repaired compomers.Materials and Methods: Sixty blocks of compomer were prepared in acrylic molds and then they were randomly divided into five groups of 12. Group I (control groupreceived no treatment. The remaining samples were immersed in 37 ºC distilled water for one week, then the surfaces were roughened with a coarse diamond bur. Samples ineach group were prepared by different surface treatment and conditioning: In group II specimens were conditioned with 35% phosphoric acid for 20s. Specimens in group III were etched with 10% polyacrylic acid for 20s. In group IV 1.23% acidulated phosphatefluoride was applied for 30s, and compomer surfaces were sandblasted with 50μm Al2O3 powder in group V. After the initial preparations, all groups were treated with silane and resin before bonding of the second mix of compomer. Shear forces were applied with a universal testing machine at a cross-head speed of 5mm/min. The data were analyzed using one-way ANOVA and Duncan's multiple range tests.Results: The mean shear bond strengths and standard deviations (in parentheses for groups I to V were 31.56(10.86, 20.02(5.49, 17.74(7.34, 19.31(4.31 and 27.7(6.33MPa, respectively. The mean bond strengths for Groups I and V were significantly higher than that of the other groups (P<0.05.Conclusion: The results showed that among the surface treatments used in this study,sandblasting with alumina could be the best surface preparation method for repairing compomer restorations.

  5. Geodynamic and metabolic cycles in the Hadean

    N. T. Arndt

    2004-09-01

    Full Text Available High-degree melting of hot dry Hadean mantle at ocean ridges and plumes resulted in a crust about 30km thick, overlain in places by extensive and thick mafic volcanic plateaus. Continental crust, by contrast, was relatively thin and mostly submarine. At constructive and destructive plate boundaries, and above the many mantle plumes, acidic hydrothermal springs at ~400°C contributed Fe and other transition elements as well as P and H2 to the deep ocean made acidulous by dissolved CO2 and minor HCl derived from volcanoes. Away from ocean ridges, submarine hydrothermal fluids were cool (≤100°C, alkaline (pH ~10, highly reduced and also H2-rich. Reaction of solvents in this fluid with those in ocean water was catalyzed in a hydrothermal mound, a natural self-restoring flow reactor and fractionation column made up of carbonates and freshly precipitated Fe-Ni sulfide and greenrust pores and bubbles, developed above the alkaline spring. Acetate and the amino acetate glycine were the main products, much of which was eluted to the ocean. Other organic byproducts were retained, concentrated and reacted within the compartments. These compartments comprising the natural hydrothermal reactor consisted partly of greigite (Fe5NiS8. It was from reactions between organic modules confined within these inorganic compartments that the first prokaryotic organism evolved. These acetogenic precursors to the Bacteria diversified and migrated down the mound and into the ocean floor to inaugurate the "deep biosphere". Once there the Bacteria, and the recently differentiated Archaea, were protected from cataclysmic heating events caused by large bolide impacts. Geodynamic forces led to the eventual obduction of the deep biosphere into the photic zone where, initially protected by a thin veneer of sediment, the use of solar energy was mastered and photosynthesis emerged. The further evolution to oxygenic photosynthesis was effected as catalytic [CaMn4+] bearing

  6. Interaction of ionizing radiation with other physical and chemical factors in improving the safety and storage stability of foods

    Experiments on the preservation of a vacuum packed, ready to fry, chilled meat product (tenderloin rolls), using the combination of a 2 kGy radiation dose with a reduction in pH and/or a reduction in water activity, and on the fate of Listeria monocytogenes in this product were carried out. Irradiation caused a 1-2 decimal reduction in the aerobic viable cell counts, and a 4 decimal reduction in the Enterobacteriaceae counts. Lactic acid bacteria appeared to be more resistant, and were the dominant component of the microflora during chilled storage. Combination treatments prevented growth of Enterobacteriaceae, even at 10 deg. C refrigeration. The microbial stability of the chilled product at 2 deg. C was extended for at least 5 weeks by the triple combination of a dose of 2 kGy, pH reduction to approximately 5.6 and water activity reduction to about 0.960. The combined preserved product proved to be acceptable, both sensorially and from the point of view of the thiobarbituric acid values. The ascorbic acid (as the acidulant) and Na lactate (as the humectant) additives considerably reduced the radiolytic loss of thiamine. The Listeria inoculum survived well in the chilled, non-irradiated product, but diminished by 2 log cycles as a result of irradiation; it tended to decrease even further during post-irradiation storage. In model studies, the radiation survivors of L. monocytogenes showed significantly increased salt and pH sensitivities and an increased minimum temperature for growth in tryptic phosphate broth media, but were less sensitized when recovering in brain heat infusion broth media. A reduction in pH resulted in an increase in not only the apparent lag phase of growth of this test organism but also in the lag phase ratios between the irradiated and non-irradiated populations. The predictive mathematical equations that describe the combined effect of hydrogen ion and salt concentrations on the growth parameters at 30 deg. C were constructed for

  7. A Descriptive in vitro Electron Microscopic Study of Acidic Fluoride-Treated Enamel: Potential Anti-Erosion Effects.

    Hjortsjö, Carl; Young, Alix; Kiesow, Andreas; Cismak, Andreas; Berthold, Lutz; Petzold, Matthias

    2015-01-01

    This study aimed to investigate the surface zones of acidic fluoride-treated enamel. Human teeth were each divided into three or four enamel specimens that were treated for 10 min with solutions of 0.2 and 0.4% HF (pH 3.09 and 2.94), 1.74% SnF2 (pH 2.9), 0.68% TiF4 (pH 1.6) and 0.84% NaF (pH 4.5). Untreated specimens functioned as negative controls. The microstructure and elemental composition of the surface zones were studied by scanning electron microscopy/energy-dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM) and nanospot-EDX following cross-sectional preparation using focused ion beam technology. TEM/EDX analyses of NaF-treated specimens showed a 500-nm-thick closed surface film containing 20-40 at% (atomic percent) F. HF-treated specimens had a distinct surface film 200-600 nm thick (dense, not globular) containing 45-47 at% F. TiF4-treated specimens had a surface film of 200-300 nm in thickness containing 8-11 at% Ti but no detectable fluoride. SnF2-treated specimens had a modified surface enamel layer varying in thickness from 200 to 800 nm with an inhomogeneous distribution of Sn. Local spots were detected with as high as 8 at% Sn (30 wt%, weight percent). The results suggest that the reaction mechanisms of SnF2 and TiF4 solutions with dental enamel differ from those occurring after enamel exposure to acidulated NaF and HF solutions. While the HF and NaF treatments resulted in the formation of CaF2-like material as shown by EDX, no significant surface fluoridation was found for SnF2 and TiF4 solutions within the TEM/EDX detection limits. These results suggest that the erosion-protective mechanisms of these latter compounds probably relate more to the formation of hardly soluble and acid-resistant reaction surface films and less to surface fluoride incorporation. PMID:26536617

  8. Fertilizer management for sustainable crop production in acid savannah soils of Latin America and Africa

    As development of more agricultural lands is limited in highly populated Asia, the greatest potential for expanding crop production to feed an increasing world population lies in the tropical savannah regions dominated by acid, infertile soils (Oxisols and Ultisols) of Latin America and Africa. The major soil-related chemical constraints of acid savannah soils are deficiency of most of the plant nutrients plus aluminium (Al) toxicity and high phosphorus (P) fixation. Phosphorus is probably the single most widespread limiting nutrient on plant growth in Oxisols and Ultisols. Use of conventional water-soluble P fertilizers such as TSP or SSP at high P rates can be agronomically effective but may be economically prohibitive to resource-poor farmers. Under certain conditions, use of indigenous phosphate rocks (PR) and modified PR products such as partially acidulated PR (PAPR) or compaction of PR with TSP/SSP are potentially attractive alternatives to the use of water-soluble P fertilizers, both agronomically and economically, in increasing crop production on acid Oxisols and Ultisols. Additionally, reactive PR sources may provide Ca nutrient and reduce Al saturation that in turn may reduce Al toxicity to plants. Some PR sources may also contain micronutrients such as Zn, Mo. A combination of the effects of proper P and nitrogen (N) management including biological N fixation, judicious use of lime, and the development of acid soil tolerant and/or P-efficient cultivars in a sustainable cropping system can provide an effective technology to increase crop yield in these acid savannah soils. Nuclear techniques including 15N and 32P isotopes as tracers are powerful tools to study: (1) efficiency of N and P from mineral and organic sources, (2) transformations of N and P in soil, (3) biological N fixation, and (4) recycling of N and P in the soil-plant system. It was shown that Sechura PR (Peru) was 78% as effective as TSP in biological N fixation by soybean in an Ultisol

  9. Phosphorus availability from phosphate rock and sewage sludge as influenced by the addition of water soluble phosphate fertilizer

    Phosphorus (P) inputs are required for sustainable agricultural production in most acid soils of the tropics and subtropics. Phosphate rocks (PR) and organic materials have been suggested as alternative P sources in these soils. Quantitative information on the P availability from sewage sludge (SL) is scanty. Methods to improve the effectiveness of PR such as partial acidulation and compaction with water-soluble P sources have been recommended. The objective of this greenhouse study was to evaluate the relative agronomic effectiveness (RAE) of Florida PR and sewage sludges (irradiated and non-irradiated) applied alone and in mixture with a water-soluble source (triple superphosphate, TSP) at two rates (50 and 150 mg P kg-1 soil). The 32P isotope dilution technique was utilised to determine the proportion of P in the plant taken up from the P fertilizer treatments. Wheat was grown on an acid loamy sand Dystric Eutrocrepts and harvested 6 weeks after planting. Results on total P uptake and the RAE of the P fertilizer sources tested indicated that the addition of 50 mg P kg-1 soil as TSP was adequate in supplying P to the 6-week-old wheat plants as compared to PR and sewage sludge. Intermediate values were obtained for the mixtures. Similar responses were observed for the high P rate. For a given P rate, phosphorus uptake from PR and SL in presence of TSP was higher than P uptake from these sources alone, indicating an enhancement effect of TSP on the effectiveness of these non-readily available sources. With respect to P uptake from PR applied alone, the relative increases in P uptake from PR due to TSP influence were 52 and 67% for the low and high P rates, respectively. The relative increases in P uptake from SL due to TSP when compared to P uptake from SL alone were 102 and 59% for the low and high P rates of application. Application of a water-soluble P fertilizer together with a non-readily available P source shows an enhancement on the P uptake from the non

  10. Disponibilidade de cádmio e chumbo para milho em solo adubado com fertilizantes fosfatados Cadmium and lead availability to corn in soil amended with phosphorus fertilizers

    Eriberto Vagner de Souza Freitas

    2009-12-01

    and Pb concentrations were found in Gafsa rock phosphate. For the acidulated phosphates, simple superphosphate was the richest in Cd and Pb, while the Pb concentration was highest in Yoorin thermophosphate. Gafsa application induced the highest Pb concentration in corn shoots in the first crop cycle. This fertilizer was also responsible for the highest Cd concentration in plants in the second crop. Citric acid was the most efficient extractant for predicting the available soil Cd contents, whereas DTPA estimated Pb availability best.

  11. Phosphorus availability from phosphate rock and sewage sludge as influenced by the addition of water soluble phosphate fertilizer

    Zapata, F. [Soil and Water Management and Crop Nutrition Section, International Atomic Energy Agency, Vienna (Austria)]. E-mail: F.Zapata@iaea.org; Zaharah, A.R. [Department of Land Management, Universiti Putra Malaysia, Serdang, Selangor (Malaysia)

    2002-05-15

    Phosphorus (P) inputs are required for sustainable agricultural production in most acid soils of the tropics and subtropics. Phosphate rocks (PR) and organic materials have been suggested as alternative P sources in these soils. Quantitative information on the P availability from sewage sludge (SL) is scanty. Methods to improve the effectiveness of PR such as partial acidulation and compaction with water-soluble P sources have been recommended. The objective of this greenhouse study was to evaluate the relative agronomic effectiveness (RAE) of Florida PR and sewage sludges (irradiated and non-irradiated) applied alone and in mixture with a water-soluble source (triple superphosphate, TSP) at two rates (50 and 150 mg P kg{sup -1} soil). The {sup 32}P isotope dilution technique was utilised to determine the proportion of P in the plant taken up from the P fertilizer treatments. Wheat was grown on an acid loamy sand Dystric Eutrocrepts and harvested 6 weeks after planting. Results on total P uptake and the RAE of the P fertilizer sources tested indicated that the addition of 50 mg P kg{sup -1} soil as TSP was adequate in supplying P to the 6-week-old wheat plants as compared to PR and sewage sludge. Intermediate values were obtained for the mixtures. Similar responses were observed for the high P rate. For a given P rate, phosphorus uptake from PR and SL in presence of TSP was higher than P uptake from these sources alone, indicating an enhancement effect of TSP on the effectiveness of these non-readily available sources. With respect to P uptake from PR applied alone, the relative increases in P uptake from PR due to TSP influence were 52 and 67% for the low and high P rates, respectively. The relative increases in P uptake from SL due to TSP when compared to P uptake from SL alone were 102 and 59% for the low and high P rates of application. Application of a water-soluble P fertilizer together with a non-readily available P source shows an enhancement on the P

  12. The radiological impact of the Belgian phosphate industry

    The Belgian phosphate industry processes huge amounts of phosphate ore (1.5 to 2 Mton/year) for a wide range of applications, the most important being the production of phosphoric acid, fertilizers and cattle food. Marine phosphate ores show high specific activities of the natural uranium decay series (usually indicated by Ra-226) (e.g. 1200 to 1500 Bq/kg for Moroccan ore). Ores of magmatic origin generally contain less of the uranium and more of the thorium decay series (up to 500 Bq/kg). These radionuclides turn up in by-products, residues or product streams depending on the processing method and the acid used for the acidulation of the phosphate rock. Sulfuric acid is the most widely used, but also hydrochloric acid and nitric acid are applied in Belgium. For Flanders, the northern part of Belgium, we already have a clear idea of the production processes and waste streams. The five Flemish phosphate plants, from 1920 to 2000, handled 54 million ton of phosphate ore containing 65 TBq of radium-226 and 2.7 TBq of thorium- 232. The total surface area of the phosphogypsum and calcium fluoride sludge deposits amounts to almost 300 ha. There is also environmental contamination along two small rivers receiving the waste waters of the hydrochloric production process: the Winterbeek (> 200 ha) and the Grote Laak (12 ha). The data on the impact of the phosphate industry in the Walloon provinces in Belgium is less complete. A large plant produced in 2004 0.8 Mton of phosphogypsum, valorizing about 70 % of the gypsum in building materials (plaster, cement), in fertilizers, and in other products such as paper. The remainder was stored on a local disposal site. The radiological impact of the Belgian phosphate industry on the local population will be discussed. At present most contaminated areas are still recognizable as waste deposits and inaccessible to the population. However as gypsum deposits and other contaminated areas quickly blend in with the landscape, it is

  13. In vitro study of morphological and chemical modification threshold of bovine dental enamel irradiated by the holmium laser; Estudo in vitro das alteracoes morfologicas e quimicas do esmalte dental bovino irradiado pelo laser de holmio

    Eduardo, Patricia Lerro de Paula

    2001-07-01

    The aim of this study is to investigate the Ho:YLF laser effects on the dental enamel surface with regards to its morphology, thermal variations during its irradiation in the pulp chamber and its increased resistance to demineralization through quantitative analysis of calcium and phosphorous atoms reactive concentrations in samples. Twenty samples of bovine enamel were used and divided in four groups: control - acidulated phosphate fluoride (APF) application followed by demineralization treatment with lactic acid; irradiation with Ho:YLF laser (100 J/cm{sup 2}) followed by APF topic application and demineralization treatment with lactic acid; irradiation with Ho:YLF laser (350 J/cm{sup 2}) followed by APF topic application and demineralization treatment with lactic acid: and irradiation with Ho:YLF laser ( 450 J/cm{sup 2}) followed by APF topic application and demineralization treatment with lactic acid. Ali samples were quantified according to their calcium and phosphorous atoms relative concentrations before and after the treatments above. X-Ray fluorescence spectrochemical analysis and scanning electron microscopy were carried out. It was observed an increase on the calcium and phosphorous atoms concentration ratio and therefore the enamel demineralization reduction as a result of the lactic acid treatment in the samples irradiated with the holmium laser followed by the APF application. In order to evaluate the feasibility of this study for clinical purposes, morphological changes caused by the holmium laser irradiation were analyzed. Such modifications were characterized by melted and re-solidified regions of the enamel with consequent changes on its permeability and solubility. Temperature changes of ten human pre-molars teeth irradiated with 350 J/cm{sup 2} and 450 J/cm{sup 2} were also monitored in the pulp chamber in real time. Temperature increases over 4,20 C did not occur. The results obtained from this study along with the results from previous

  14. In vitro study of morphological and chemical modification threshold of bovine dental enamel irradiated by the holmium laser

    The aim of this study is to investigate the Ho:YLF laser effects on the dental enamel surface with regards to its morphology, thermal variations during its irradiation in the pulp chamber and its increased resistance to demineralization through quantitative analysis of calcium and phosphorous atoms reactive concentrations in samples. Twenty samples of bovine enamel were used and divided in four groups: control - acidulated phosphate fluoride (APF) application followed by demineralization treatment with lactic acid; irradiation with Ho:YLF laser (100 J/cm2) followed by APF topic application and demineralization treatment with lactic acid; irradiation with Ho:YLF laser (350 J/cm2) followed by APF topic application and demineralization treatment with lactic acid: and irradiation with Ho:YLF laser ( 450 J/cm2) followed by APF topic application and demineralization treatment with lactic acid. Ali samples were quantified according to their calcium and phosphorous atoms relative concentrations before and after the treatments above. X-Ray fluorescence spectrochemical analysis and scanning electron microscopy were carried out. It was observed an increase on the calcium and phosphorous atoms concentration ratio and therefore the enamel demineralization reduction as a result of the lactic acid treatment in the samples irradiated with the holmium laser followed by the APF application. In order to evaluate the feasibility of this study for clinical purposes, morphological changes caused by the holmium laser irradiation were analyzed. Such modifications were characterized by melted and re-solidified regions of the enamel with consequent changes on its permeability and solubility. Temperature changes of ten human pre-molars teeth irradiated with 350 J/cm2 and 450 J/cm2 were also monitored in the pulp chamber in real time. Temperature increases over 4,20 C did not occur. The results obtained from this study along with the results from previous researches developed at 'Center for

  15. Alkali-soluble fluoride deposition on enamel after professional application of topical fluoride in vitro Formação de flúor fracamente ligado ao esmalte após a aplicação tópica profissional de flúor in vitro

    Mitsue Fujimaki Hayacibara

    2004-03-01

    Full Text Available Since the efficacy of topical fluoride products is related to the fluoride (F availability and its reactivity with enamel, this study was conducted. The F concentration of the following materials was verified: I- acidulated phosphate fluoride (APF gel (1.23% F, II- APF foam (1.23% F and III- Varnish (2.26% F. Forty blocks of bovine enamel were divided into 4 groups and treated according to the materials described, being one of them used as control. Loosely bound fluoride (''CaF2'' was determined on enamel after extraction with 1.0M KOH and analyzed by ion-selective electrode. Total F concentration found in gel was 12,642, in foam 12,755 and in varnish 23,183 mg F/g. All products formed statistically higher amounts of ''CaF2'' on enamel compared to the control group (p 0.05. Thus, ''CaF2'' formation was not proportional to the total F content in the products, suggesting that the pH and the vehicle used are more important.Considerando que a eficácia dos produtos para aplicação tópica profissional de flúor (géis, espumas e vernizes está relacionada com a reatividade do flúor (F com o esmalte e sendo esta dependente da disponibilidade do F em cada produto, este estudo foi conduzido. A concentração de F nos seguintes produtos foi estudada: I - Flúor Fosfato Acidulado (FFA gel (1,23% F, II - FFA espuma (1,23% F e III- Verniz fluoretado (2,26% F. Foram confeccionados 40 blocos de esmalte bovino, tratados de acordo com os grupos descritos, sendo um deles utilizado como controle. O F fracamente ligado (''CaF2'' ao esmalte foi determinado após a extração com 1.0 M KOH e analisado em eletrodo específico. A concentração de F encontrada no gel foi de 12.642, na espuma 12.755 e no verniz 23.183 mg F/g. Todos os produtos formaram uma quantidade significantemente maior de ''CaF2'' na superfície do esmalte, comparado ao grupo controle (p 0,05. Assim, a formação de ''CaF2'' na superfície do esmalte não foi proporcional ao conteúdo de F nos

  16. Characterization of chemicals mediating ovipositional host-plant finding byAmyelois transitella females.

    Phelan, P L; Roelofs, C J; Youngman, R R; Baker, T C

    1991-03-01

    Ovipositional host-finding in the navel orangeworm,Amyelois transitella (Walker), is brought about by an in-flight response to host odors. Wind-tunnel studies of the response of gravid females to almonds showed that this response is mediated primarily by long-chain fatty acids, particularly oleic acid and linoleic acid. Evidence for the behavioral activity of fatty acids is based on the fact that: (1) behavioral activity of almond oil was concentrated in a single liquid chromatographic fraction whose composition was predominantly long-chain fatty acids, (2) behavioral activity was lost when either almond oil or the active fraction of that oil was treated with diazomethane, (3) full activity was elicited by a selective extraction of free fatty acids from crude almond oil, and (4) upwind response by females was elicited by a blend of synthetic oleic and linoleic acids, albeit at a level less than that elicited by almond oil. Five fatty acids identified from the almond oil were: myristic acid (1%), palmitic acid (16%), stearic acid (3%), oleic acid (58%), and linoleic (22%). Attraction to various combinations of synthetic acids was observed only when oleic acid was present, and oleic acid elicited upwind flights to the source when presented alone; however, short-range responses were enhanced by the addition of linoleic acid, which elicited no long-range orientation by itself. Despite significant levels of attraction to synthetic blends, the percentage of females flying to the source was lower than that flying to acidulated almond oil, the best natural attractant tested. Thus, although longrange response may be mediated primarily by a blend of oleic and linoleic acids, additional and as yet unidentified components must also play an important role. Long-range chemically modulated host finding in this and other generalist plant feeders is discussed with respect to current models of the evolution of host finding, and it is argued that suggestions that long-range host

  17. Avaliação da higroscopicidade de fertilizantes e corretivos Higroscopicity evaluation of fertilizers and agricultural liming materials

    J.C. Alcarde

    1992-01-01

    Full Text Available Visando determinar a quantidade de água absorvida em função da umidade do ambiente e do tempo de exposição por alguns fertilizantes simples, misturas de fertilizantes e corretivos, foram colocadas em três ambientes de umidade relativa constante de 70,4%, 80,5% e 88,8% . As amostras foram pesadas após 0, 3, 6, 24, 48 e 72 horas determinando a porcentagem de água absorvida. A absorção de água pelos produtos aumentou com o aumento da umidade relativa do ar e do tempo de exposição. Todos os materiais absorveram alguma umidade no menor tempo e na menor umidade relativa estudados, isto é, 3 horas de 70,4%, porém essa absorção foi insignificante nos casos do sulfato de amônio, fosfato diamônico, fosfato natural parcialmente acidulado, cloreto de potássio, sulfato de potássio, calcário calcinado. Os fertilizantes nitrogenados, uréia e nitrocálcio, foram os que apresentaram maior higroscopicidade dentre os materiais estudados. Foi possível verificar também que a presença de 5% de calcário calcinado ou de vermiculita nas misturas de grânulos diminuiu sensivelmente sua higroscopicidade.The percentual of water absorbed by fertilizer materials, bulk blend fertilizer mixtures and agricultural liming materials was determined as a function of the environment relative humidity and time of exposition. Samples of these were exposed to three relative humidity environments: 70,4%, 80,5% and 77,8%, during 3, 6, 12, 24, 48, 72 hours, after drying at 50°C for 24 hours. The water absorbed by all products increased with air relative humidity and exposition time. All the materials absorbed some humidity for the lowest exposition time and lowest relative humidity (3 hours and 70,4% but was insignificant in the case of ammonium sulphate, diammonium phosphate, natural phosphate parcially acidulated, potassium chloride, potassium sulphate, limestone and hidrated lime. The urea and calcium nitrate presented major higroscopicity among the materials

  18. The alkaline solution to the emergence of life: energy, entropy and early evolution.

    Russell, Michael J

    2007-01-01

    The Earth agglomerates and heats. Convection cells within the planetary interior expedite the cooling process. Volcanoes evolve steam, carbon dioxide, sulfur dioxide and pyrophosphate. An acidulous Hadean ocean condenses from the carbon dioxide atmosphere. Dusts and stratospheric sulfurous smogs absorb a proportion of the Sun's rays. The cooled ocean leaks into the stressed crust and also convects. High temperature acid springs, coupled to magmatic plumes and spreading centers, emit iron, manganese, zinc, cobalt and nickel ions to the ocean. Away from the spreading centers cooler alkaline spring waters emanate from the ocean floor. These bear hydrogen, formate, ammonia, hydrosulfide and minor methane thiol. The thermal potential begins to be dissipated but the chemical potential is dammed. The exhaling alkaline solutions are frustrated in their further attempt to mix thoroughly with their oceanic source by the spontaneous precipitation of biomorphic barriers of colloidal iron compounds and other minerals. It is here we surmise that organic molecules are synthesized, filtered, concentrated and adsorbed, while acetate and methane--separate products of the precursor to the reductive acetyl-coenzyme-A pathway-are exhaled as waste. Reactions in mineral compartments produce acetate, amino acids, and the components of nucleosides. Short peptides, condensed from the simple amino acids, sequester 'ready-made' iron sulfide clusters to form protoferredoxins, and also bind phosphates. Nucleotides are assembled from amino acids, simple phosphates carbon dioxide and ribose phosphate upon nanocrystalline mineral surfaces. The side chains of particular amino acids register to fitting nucleotide triplet clefts. Keyed in, the amino acids are polymerized, through acid-base catalysis, to alpha chains. Peptides, the tenuous outer-most filaments of the nanocrysts, continually peel away from bound RNA. The polymers are concentrated at cooler regions of the mineral compartments through

  19. Double vacuum assisted resin infusion molding and property of carbon nanotube-glass fiber/epoxy resin laminates%碳纳米管-玻璃纤维/环氧层板双真空灌注工艺及性能

    赵艳文; 顾轶卓; 李敏; 张佐光

    2011-01-01

    The carbon nanotube (CNT)-glass fiber/epoxy resin laminates were prepared by traditional vacuum assisted resin infusion molding (VARIM) and double vacuum assisted resin infusion molding (DVARIM),respectively. The defects of the laminates processed with the two methods were examined, and the mechanical properties including flexural property and interlaminar shear strength (ILSS) were measured. The distribution and the enhancement mechanism of CNT in the laminates with DVARIM were studied by the measurement of the resin properties and the observation of the fiber/resin interracial bonding. It shows that, compared with traditional VARIM, the defects in the fiber bundles decrease because the spaces within fibers increase and the resin infiltration improves in DVARIM. The mechanical properties of the laminates are enhanced by adding 0.05% mass fraction of acidulated CNT, especially for the laminates processed by DVARIM. In addition, the infusion process influences the distribution of CNT in the laminates, and further changes the effects of CNT on the interface bonding of fiber/resin,which is dependent on the compactness of the fabric.%针对碳纳米管(CNT)-玻璃纤维/环氧树脂体系,采用传统的真空灌注工艺(VARIM)和双真空灌注工艺(DVARIM)制备复合材料层板,分析了不同工艺方法下层板缺陷状况,测试了层板的弯曲性能和层间剪切性能,并结合树脂性能和纤维/树脂界面粘结状况观察,探讨了DVARIM对CNT分布的影响及碳管的增强机制.结果表明:与传统的VARIM相比,DVARIM能增加纤维的间距,提高树脂对纤维的浸润能力,减小纤维束内的孔隙缺陷;添加质量分数为0.05%的酸化CNT后层板性能提高,而且采用DVARIM性能提高更明显;不同灌注工艺对CNT的分布产生影响,从而改变了CNT对纤维/树脂界面粘接的影响,同时这种影响与织物结构的紧密程度有关.

  20. Geodynamic and metabolic cycles in the Hadean

    M. J. Russell

    2005-01-01

    Full Text Available High-degree melting of hot dry Hadean mantle at ocean ridges and plumes resulted in a crust about 30km thick, overlain in places by extensive and thick mafic volcanic plateaus. Continental crust, by contrast, was relatively thin and mostly submarine. At constructive and destructive plate boundaries, and above the many mantle plumes, acidic hydrothermal springs at ~400°C contributed Fe and other transition elements as well as P and H2 to the deep ocean made acidulous by dissolved CO2 and minor HCl derived from volcanoes. Away from ocean ridges, submarine hydrothermal fluids were cool (≤100°C, alkaline (pH ~10, highly reduced and also H2-rich. Reaction of solvents in this fluid with those in ocean water was catalyzed in a hydrothermal mound, a natural self-restoring flow reactor and fractionation column developed above the alkaline spring. The mound consisted of brucite, Mg-rich clays, ephemeral carbonates, Fe-Ni sulfide and green rust. Acetate and glycine were the main products, some of which were eluted to the ocean. The rest, along with other organic byproducts were retained and concentrated within Fe-Ni sulfide compartments. These compartments, comprising the natural hydrothermal reactor, consisted partly of greigite (Fe5NiS8. It was from reactions between organic modules confined within these inorganic compartments that the first prokaryotic organism evolved. These acetogenic precursors to the bacteria diversified and migrated down the mound and into the ocean floor to inaugurate the 'deep biosphere'. Once there they were protected from cataclysmic heating events caused by large meteoritic impacts. Geodynamic forces led to the eventual obduction of the deep biosphere into the photic zone where, initially protected by a thin veneer of sediment, the use of solar energy was mastered and photosynthesis emerged. The further evolution to oxygenic photosynthesis was effected as catalytic [Mn,Ca]-bearing molecules that otherwise would have been

  1. Why and How Life is Driven into Being at Ancient Submarine Alkaline Springs

    Russell, Michael

    2016-07-01

    The disequilibria between volcanic CO2 plus NO dissolved in acidulous oceans, as against the H2 plus CH4 exhaling through hot alkaline springs on the ocean floors of young wet rocky worlds, cannot be relaxed, much less put to useful biological work, through mere geochemical reactions. Instead their dissipation must be coupled to the production of essential thermodynamically 'up-hill' products. A metabolic pathway, involving disequilibria converting nano-engines, is the only way to achieve such tasks as fixing the otherwise intractable CO2. Indeed, hydrogenating CO2 is life's contribution to entropy generation in the Universe. Long-lived alkaline springs could have supplied the low entropy nourishment in the form of H2 as electrons and CH4 as a carbon source, while the CO2, nitrate, photolytic Fe3+ and Mn4+ in the earliest ocean could have accepted the waste electrons, i.e., the 'breathing' [1]. But what of life's first boundaries? These could be generated spontaneously at the vent, where natural precipitates of iron oxyhydroxides and sulfides would have acted as precipitate membranes, separating the reduced alkaline hydrothermal fluid from the acidulous carbonic ocean, thus imposing steep redox and protonic (ambient pmf) gradients with the potential to drive otherwise endergonic reactions such as the reduction of CO2 to formate or CO, and the oxidation of CH4 to methyl and formyl entities. In turn, the CO and the methyl group reacted to form acetate. Acetate was then hydrogenated and carbonated to pyruvate. However, these endergonic reactions could not progress by catalysis or mass action chemistry as often assumed. They would have required natural processors acting as nanoengines to couple the endergonic driven processes to appropriate exergonic driving reactions. This is what the nano-engines do in life. These mechanochemical 'engines' are protein complexes that are each precisely tuned to the specific driving and driven disequilibria pairs being converted. They

  2. Novel technology of resource recovery from reed black liquor%芦苇浆造纸黑液资源化处理新工艺

    杨卫春; 尤翔宇; 王云燕; 赵静; 柴立元; 舒余德

    2012-01-01

    A novel process was proposed to treat reed black liquor: desilication-acidification-three-dimensional electrolysis-causticization-reuse in pulp making. The precipitation method was used to remove silicon by adding Ca(OH)2. The residual concentration of silicon decreases from 6.68 g/L to 0.12 g/L and the removal rate of silicon is maintained at 98.2%. Lignin was recovered by acidulation-precipitation after the addition of sulfuric acid. The residual concentration of CODCr can be reduced from 220.648 g/L to 54.179 g/L and its removal rate is maintained at 75.45%. 8.5 g lignin was recovered from 100 mL black liquor. Based on the analysis of FTIR, EDX and SEM, it is found that the structure of lignin consists mainly of syringyl monomers and hydroxyl groups, and the lignin particles are not fibrous but granular. The reed pulp black liquor pretreated by acidification method was treated by electrolysis with a three-dimensional electrode reactor. The removal rate of TOC is maintained at 35.57% and the residual concentration of CODCr can be reduced to 36.761 g/L. Then, causticization was adopted to recovery residual alkali from the black liquor, which can be reused in the paper mill. After causticization, the concentration of effective alkali is 8.30 g/L and the causticization rate of the solution is about 78.60%, the residual concentration of CODcr in the black liquor is further reduced to 33.085 g/L and the removal rate of TOC is 9.99%.%针对芦苇浆造纸产生的浓缩黑液的特点,提出了黑液脱硅—酸析回收木质素—三维电极电解—苛化回收NaOH-出水返回生产的工艺流程.采用Ca(OH)2沉淀法去除黑液中的SiO2,黑液中硅含量由6.68 g/L降至0.12g/L,脱硅率为98.20%;黑液脱硅后加入H2SO4去除COD并回收木质素,CODCr由220.648 g/L降至54.179 g/L左右,脱除率达到75.45%,每100mL黑液可回收8.5 g木质素.FTIR、SEM和EDX的分析结果表明:酸析木质素结构以紫丁香基和对羟基的单体结构为

  3. Avaliação qualitativa do efeito de agentes de limpeza na camada de lama dentinária: estudo ultra-estrutural em microscopia eletrônica de varredura Smear layer removal: a qualitative scanning electron microscopy study

    Maria Auxiliadora Junho de ARAÚJO

    1998-04-01

    surface was then removed with a water-cooled high speed carbide bur # 56 in order to obtain the smear layer. Different solutions were applied on the dentin surface for 30 seconds, which was then rinsed and dried. The specimens were mounted on metallic holder stubs, prepared, and examined under the scanning electron microscope (DSM 95-Zeiss. Removal of the smear layer by the tested solutions was qualitatively observed, and the solutions, rated according to their performance in increasing order of extent of removal, as follows: 1. air/water spray; 2. 2% NaF; 3. sodium hypochloride/anodic detergent; 4. 3% H2O2; 5. sandblasting with 50 mm aluminum oxide; 6. 1.27% acidulated fluoride; 7. 25% polyacrylic acid; 8. 10% phosphoric acid. The best solutions for the removal of the smear layer were the acid ones.

  4. In vitro study of demineralization resistance and fluoride retention in dental enamel irradiated with Er,Cr: YSGG laser

    This study aimed to establish irradiation conditions of Er,Cr:YSGG laser (λ of 2.79 μm) which could propitiate changes on human dental enamel and increase its resistance to demineralization, when associated or not with topical application of acidulated phosphate fluoride (APF). Fluences of 2,8 J/cm2, 5,6 J/cm2 e 8,5 J/cm2 were selected; they were associated or not with previous application of a photo absorber (coal paste) and then APF was applied or not after laser irradiation. In a first step, the morphological findings, the surface temperatures, and the pupal temperatures were evaluated during laser irradiation. After that, the treated samples were submitted to a a ten-day pH-cycling model. After producing the incipient white-spots lesions, the following aspects were evaluated: the mineral loss, the loosely bound fluoride and the firmly bound fluoride. All the demineralizing and remineralizing pH-cycling solutions were evaluated with respect to their calcium (Ca), inorganic phosphorous (Pi) and fluoride (F-) concentrations. The data had their normality and homogeneity distribution statistically evaluated, and it was chosen an appropriated statistical test for each performed analysis according to the obtained results, considering 5% significant level. The fluences selected for this study created ablated surfaces; the fluences of 5.6 J/cm2 and 8.5 J/cm2 promoted increments in surface temperature above 110 deg C. The intrapupal temperature changes revealed that laser irradiation did not increase the pulpal temperatures above the critical threshold for induction of pulpitis. The coal paste did not promote any changes on surface morphology or in the intrapulpal temperature changes; however, this paste increased the surface temperatures during laser irradiation. Only laser irradiation at 8.5 J/cm2 was able to decrease the mineral loss when compared to the no-treatment group; although the association of coal paste + laser at 2.8 J/cm2 + APF application presented the

  5. Evaluating the effectiveness of phosphate fertilizers in some Venezuelan soils

    greenhouse experiment, the crop response was related to the P fixing properties of the soil, the initial availability and the solubility of the P source used. The P in plant derived from the fertilizer and the Utilization Coefficient decreased significantly as the P fixing capacity of the soils increases indicating a lower availability of P for the the index plant (Agrostis sp.). The P in plant derived from the P fertilizers calculated by using the specific activity of each treatment and the one of the check plot showed that triple superphosphate had the highest values with acidulated Riecito rock phosphate (40%) having intermediate values, and Riecito rock phosphate having the lowest value. The use of 32P techniques as a powerful method to study soil P dynamics and P uptake from different P sources and the effectiveness of phosphate rocks (natural and modified) produced in Venezuela with respect to the water-soluble P source (imported), are some of the practical implications of this study. (author)

  6. Evaluating the effectiveness of phosphate fertilizers in some Venezuelan soils

    Casanova, E. [Instituto de Edafologia, Facultad de Agronomia, Universidad Central de Venezuela, Maracay, Aragua (Venezuela)]. E-mail: casanova@pdvsa.com; Salas, A.M. [Instituto de Edafologia, Facultad de Agronomia, Universidad Central de Venezuela, Maracay, Aragua (Venezuela); Toro, M. [Instituto de Zoologia Tropical, Facultad de Ciencias, Universidad Central de Venezuela, Caraca (Venezuela)

    2002-05-15

    . In the greenhouse experiment, the crop response was related to the P fixing properties of the soil, the initial availability and the solubility of the P source used. The P in plant derived from the fertilizer and the Utilization Coefficient decreased significantly as the P fixing capacity of the soils increases indicating a lower availability of P for the the index plant (Agrostis sp.). The P in plant derived from the P fertilizers calculated by using the specific activity of each treatment and the one of the check plot showed that triple superphosphate had the highest values with acidulated Riecito rock phosphate (40%) having intermediate values, and Riecito rock phosphate having the lowest value. The use of {sup 32}P techniques as a powerful method to study soil P dynamics and P uptake from different P sources and the effectiveness of phosphate rocks (natural and modified) produced in Venezuela with respect to the water-soluble P source (imported), are some of the practical implications of this study. (author)

  7. In vitro study of demineralization resistance and fluoride retention in dental enamel irradiated with Er,Cr: YSGG laser; Estudo in vitro da resistencia a desmineralizacao e da retencao de fluor em esmalte dental irradiado com laser de Er, Cr: YSGG

    Ana, Patricia Aparecida da. E-mail: patriciadaana@yahoo.com.br

    2007-07-01

    This study aimed to establish irradiation conditions of Er,Cr:YSGG laser ({lambda} of 2.79 {mu}m) which could propitiate changes on human dental enamel and increase its resistance to demineralization, when associated or not with topical application of acidulated phosphate fluoride (APF). Fluences of 2,8 J/cm{sup 2}, 5,6 J/cm{sup 2} e 8,5 J/cm{sup 2} were selected; they were associated or not with previous application of a photo absorber (coal paste) and then APF was applied or not after laser irradiation. In a first step, the morphological findings, the surface temperatures, and the pupal temperatures were evaluated during laser irradiation. After that, the treated samples were submitted to a a ten-day pH-cycling model. After producing the incipient white-spots lesions, the following aspects were evaluated: the mineral loss, the loosely bound fluoride and the firmly bound fluoride. All the demineralizing and remineralizing pH-cycling solutions were evaluated with respect to their calcium (Ca), inorganic phosphorous (Pi) and fluoride (F{sup -}) concentrations. The data had their normality and homogeneity distribution statistically evaluated, and it was chosen an appropriated statistical test for each performed analysis according to the obtained results, considering 5% significant level. The fluences selected for this study created ablated surfaces; the fluences of 5.6 J/cm{sup 2} and 8.5 J/cm{sup 2} promoted increments in surface temperature above 110 deg C. The intrapupal temperature changes revealed that laser irradiation did not increase the pulpal temperatures above the critical threshold for induction of pulpitis. The coal paste did not promote any changes on surface morphology or in the intrapulpal temperature changes; however, this paste increased the surface temperatures during laser irradiation. Only laser irradiation at 8.5 J/cm{sup 2} was able to decrease the mineral loss when compared to the no-treatment group; although the association of coal paste

  8. In vitro comparison of the cariostatic effect between topical application of fluoride gels and fluoride toothpaste Comparação in vitro do efeito cariostático entre a aplicação tópica de flúor e dentifrício fluoretado

    Alberto Carlos Botazzo Delbem

    2004-06-01

    Full Text Available The aim of this study was to compare the effect of topical fluoride products [acidulated phosphate fluoride (APF or neutral gel (NF x fluoride toothpaste (MFP], in respect to fluoride uptake and anticariogenic action. One hundred and twenty five blocks of human teeth, sorted in 5 groups according to the treatment, were submitted to pH cycling for ten days. The parameters analyzed were: fluoride uptake before and after pH cycling and surface (SMH and cross-sectional (CSMH microhardness of the enamel blocks. The results of fluoride concentration in enamel after the pH cycling showed an enhancement of fluoride uptake for all groups compared to sound control. No significant differences between APF and MFP were observed for surface microhardness, percentage change of surface microhardness and mineral loss. The volume percent mineral obtained from cross-sectional microhardness demonstrated that APF has a different lesion progression rate regarding subsurface carious lesion. The results suggest that professionally applied fluoride gel or frequent fluoride application in low concentration is a positive preventive measure for the control of dental caries.O objetivo do presente estudo foi comparar in vitro o efeito da aplicação tópica de flúor na forma de gel acidulado (FFA ou neutro (FFN com um dentifrício fluoretado (MFP, na incorporação e ação anticariogênica do flúor. Foram utilizados 125 blocos obtidos de esmalte humano, divididos em 5 grupos de acordo com o tratamento e submetidos à ciclagem de pH durante dez dias. Analisou-se o flúor incorporado antes e depois da ciclagem de pH; a microdureza superficial (SMH e a microdureza interna do esmalte (CSMH. Os resultados da concentração de flúor no esmalte após a ciclagem indicou uma maior quantidade de flúor incorporado para todos os grupos comparados ao grupo controle sadio. A microdureza superficial entre APF e MFP, assim como a porcentagem de alteração da microdureza superficial e

  9. Optimización del proceso de esterificación química del destilado de desodorización del aceite de soja previamente saponificado y acidulado

    Barrera-Arellano, Daniel

    2002-06-01

    Full Text Available In this research work, it was optimized the reaction conditions for the chemistry esterification of unsaponifiable matter in soybean oil deodorizer distillate. The process involves (i alkaline hydrolysis of saponifiable matter; (ii acidulation of soaps and (iii acid catalyzed esterification of resulting total fatty acid. To determine the best process conditions to get the higher conversion rates of total fatty acids to ethylic esters, preserving the tocopherols, it was used, to analyze the results, the response surface methodology in a 2nd order factorial planning. In the step (i saponification of soybean oil deodorizer distillate saponifiable matter using NaOH:total fatty acids molar ratio = 2:1, temperature = 80º C and reaction time of 40 min. In the step (ii the resulting soaps were rapidly and stoichiometrically converted in free fatty acids with sulfuric acid (23 %, using an acid molar excess of 50 %, at 80º C, for 40 min and under atmospheric pressure. In the step (iii the optima conditions for the esterification reaction of soybean oil deodorizer distillate were: ethanol:total fatty acids molar ratio from 6.4 to 11.2:1, SO2H4 concentration from 0.9 to 1.5 % and reaction time from 1.3 to 2.6 h, with ethyl esters conversion rates up to 98 %. The mathematical model obtained is predictive and statistically significant (pEn esta investigación fueron optimizadas las condiciones de reacción de esterificación de la materia saponificable del destilado de desodorización del aceite de soja. El proceso engloba (i hidrólisis alcalina da materia saponificable; (ii acidulación de los jabones y (iii esterificación catalizada por ácido de los ácidos grasos totales resultantes. Las condiciones óptimas del proceso, para obtener el mayor rendimiento en ésteres etílicos y perdidas mínimas de tocoferoles, fueron determinadas usando la metodología de superficie de respuesta de un diseño factorial completo de 2a orden. Etapa (i saponificaci

  10. Growth-Inhibiting and morphostructural effects of constituents identified in Asarum heterotropoides root on human intestinal bacteria

    2013-01-01

    Background The growth-inhibiting and morphostructural effects of seven constituents identified in Asarum heterotropoides root on 14 intestinal bacteria were compared with those of the fluoroquinolone antibiotic ciprofloxacin. Method A microtiter plate-based bioassay in sterile 96-well plates was used to evaluate the minimal inhibitory concentrations (MICs) of the test materials against the organisms. Results δ-3-Carene (5) exhibited the most potent growth inhibition of Gram-positive bacteria (Clostridium difficile ATCC 9689, Clostridium paraputrificum ATCC 25780, Clostridium perfringens ATCC 13124, and Staphylococcus aureus ATCC 12600) and Gram-negative bacteria (Escherichia coli ATCC 11775 and Bacteroides fragilis ATCC 25285) (minimal inhibitory concentrations (MIC), 0.18–0.70 mg/mL) except for Salmonella enterica serovar Typhimurium ATCC 13311 (MIC, 2.94 mg/mL). The MIC of methyleugenol (2), 1,8-cineole (3), α-asarone (4), (−)-asarinin (6), and pellitorine (7) was between 1.47 and 2.94 mg/mL against all test bacteria (except for compound 2 against C. difficile (0.70 mg/mL); compounds 1 (23.50 mg/mL) and 4 (5.80 mg/mL) against C. paraputricum; compounds 2 (5.80 mg/mL), 4 (12.0 mg/mL), and 7 (0.70 mg/mL) against C. perfringens); compound 1 against E. coli (7.20 mg/mL) and S. enterica serovar Typhimurium (12.0 mg/mL). Overall, all of the constituents were less potent at inhibiting microbial growth than ciprofloxacin (MIC, 0.063–0.25 mg/ mL). The lactic acid-producing bacteria (four bifidobacteria and two lactobacilli) and one acidulating bacterium Clostridium butyricum ATCC 25779 were less sensitive and more susceptible than the five harmful bacteria and two nonpathogenic bacteria (B. fragilis and E. coli) to the constituents and to ciprofloxacin, respectively. Beneficial Gram-positive bacteria and harmful and nonpathogenic Gram-negative bacteria were observed to have different degrees of antimicrobial susceptibility to the constituents, although

  11. Comparison of greenhouse and 32P isotopic laboratory methods for evaluating the agronomic effectiveness of natural and modified rock phosphates in some acid soils of Ghana

    fixation index of the soils were variable. Application of water-soluble P as TSP increased both the CP and E1 values of all the soils above the critical levels. Togo PR was least effective among the fertilizers tested for all soil soils, except in Boi soil. Acidulation of Togo PR (Togo PAPR-50%) was an effective means to increase its agronomic effectiveness. Direct application of natural Togo PR would be only feasible in the Boi soil series as reflected by its high Pdff% value in soil solution. Incubation with the P fertilizers caused an increase in the soil pH and a decline in the effectiveness of the applied P fertilizers, irrespective of the soil and the fertilizer utilized. Based upon the results of the greenhouse pot experiment, the relative crop response index (RCRI) in terms of increasing dry matter yield and P uptake followed the order of TSP > PAPR = Mali PR >Togo PR = Control. Both the laboratory index, Pdff% in soil solution derived from the isotopic method and the RCRI values obtained from the pot experiment produced similar results in ranking the P fertilizers tested according to their agronomic effectiveness. The isotopic kinetic method may be considered as an alternative to both greenhouse and field methods in the evaluation of agronomic effectiveness of P fertilizers in tropical acid soils when it offers comparative advantages in assessing the soil P status and its changes. But trained staff and adequate laboratory facilities are needed to perform this technique. Also the method can be used as a reference for comparison purposes as in this case. Further research is needed to assess the overall agronomic effectiveness (immediate and residual effects) of PR sources in predominant cropping systems of this region of Ghana. (author)

  12. Aprovechamiento de las oleinas residuales procedentes del proceso de refinado de los aceites vegetales comestibles, para la fabricación de biodiesel

    Álvarez Mateos, P.

    2003-06-01

    Full Text Available A procedure to obtain Biodiesel from “Oleinas” is studied. Biodiesel is a suitable product to replace diesel oil currently used to power the Diesel engines. It consists of a mixture of methyl esters of the fatty acids presents as triglycerides in vegetables oils (olive, sunflower, soya, rape oils. As a result of the refining of these oils for their use as food, a waste product is formed, the “oleinas” (acidulated soapstock. The oleinas consist of a mixture of triglycerides and free fatty acids, the latter amounting to 50% or more of the mixture and are subject to a fluctuating market, therefore it exist at times a problem for their disposal. In our research work we have tried to obtain biodiesel from oleinas. The process resulting from our experimental work is as follows: 1. Sterification of the free fatty acids with methanol, by acid catalysis, centrifuging the reaction product and removal of the acid-methanol phase. Drying of the latter. At this stage we have a product containing about 70% of methyl esters. 2. Transesterification of the triglycerides present in the sterified product with methanol by alkaline catalysis, washing the reaction product with a water methanol solution. Centrifuging and removal of the water-methanol phase. At this stage a biodiesel product is obtained containing about 90% of methyl esters. 3. Fractional vacuum distillation of the 90% biodiesel gives a final product with a methyl esters content higher than 98%.Se estudia un procedimiento para la obtención de Biodiesel a partir de las “Oleínas”. Biodiesel es un producto capaz de sustituir al combustible Diesel ordinario que se obtiene del petróleo y que consiste en una mezcla de ésteres metílicos de ácidos grasos. Las oleínas son unos residuos que resultan del proceso de refinado de aceites vegetales para su uso alimentario y se componen de una mezcla de triglicéridos y ácidos grasos libres, con un contenido de estos últimos

  13. Radiological impact of applying phosphogypsum to tilled land cropped to annual ryegrass

    The production of phosphoric acid by acidulation of rock phosphate with sulfuric acid produces phosphogypsum (PG) as a byproduct. Phosphogypsum is primarily CaSO4.2H2O and is a potential source of S and Ca for crops. Because of the presence of small amounts of 226Ra, the U.S. Environmental Protection Agency (EPA) has imposed severe restrictions on the use of PG. The objective of the study was to evaluate the radiological impact of applying phosphogypsum to tilled land. The experimental land spanned over two soils (Myakka-sandy, siliceous, hyperthermic Aeric Haplaquods and Pomona-sandy, siliceous, hyperthermic Ultic Haplaquods) tilled and cropped to annual ryegrass (Lolium multiflorum Lam.) for 3 crop-years. The PG with 792 226Ra, 836 210Pb, and 744 210Po Bq kg-1 was applied all at once at the start of the study at 2 and 4 Mg ha-1, with no PG as control, and harrowed into the top 15-cm layer of the soil. This layer initially contained 15.9, 28.1, and 14.1 Bq kg-1 of 226Ra, 210Pb, and 210Po, respectively. The 4 Mg PG ha-1 would have increased the initial soil 226Ra and 210Po by 9% each and 210Pb by 5%, assuming a soil bulk density of 1500 kg m-3. The results, averaged over crop-year and over the 3-crop-year period, showed no measurable increases in 226Ra, 210Pb, or 210Po in soil down to 90 cm sampled in layers of 15 cm, in groundwater sampled at 90 to 120 cm depth, in regrowth and mature forages, and in gamma radiation and airborne 222Rn both measured 1 m above the plots. However, 222Rn flux measured at the soil surface increased by 0.74 x 10-4 Bq m-2 s-1 per Mg PG ha-1. Thus, yearly application of 0.675 Mg ha-1 (upper level of annual application rates for gypsum as S or Ca source for crops) over a 100-year period of PG used in the study could increase 222Rn flux from the experimental land from 8.14 X 10-4 to 58.09 x 10-4 Bq m-2 s-1 at the end of said period, assuming no loss of 226Ra, the source of 222Rn in soil and PG. This 100-year-end value, however, would still

  14. Comparison of greenhouse and {sup 32}P isotopic laboratory methods for evaluating the agronomic effectiveness of natural and modified rock phosphates in some acid soils of Ghana

    Owusu-Bennoah, E. [Department of Soil Science, University of Ghana, Legon, Accra (Ghana); Zapata, F. [International Atomic Energy Agency, Vienna (Austria)]. E-mail: F.Zapata@iaea.org; Fardeau, J.C. [Departement Environnement et Agronomie, INRA, Versailles (France)

    2002-05-15

    exchangeable P (E{sub 1}min < 5 mg P kg{sup -1}). The capacity factor and the fixation index of the soils were variable. Application of water-soluble P as TSP increased both the C{sub P} and E{sub 1} values of all the soils above the critical levels. Togo PR was least effective among the fertilizers tested for all soil soils, except in Boi soil. Acidulation of Togo PR (Togo PAPR-50%) was an effective means to increase its agronomic effectiveness. Direct application of natural Togo PR would be only feasible in the Boi soil series as reflected by its high Pdff% value in soil solution. Incubation with the P fertilizers caused an increase in the soil pH and a decline in the effectiveness of the applied P fertilizers, irrespective of the soil and the fertilizer utilized. Based upon the results of the greenhouse pot experiment, the relative crop response index (RCRI) in terms of increasing dry matter yield and P uptake followed the order of TSP > PAPR = Mali PR >Togo PR = Control. Both the laboratory index, Pdff% in soil solution derived from the isotopic method and the RCRI values obtained from the pot experiment produced similar results in ranking the P fertilizers tested according to their agronomic effectiveness. The isotopic kinetic method may be considered as an alternative to both greenhouse and field methods in the evaluation of agronomic effectiveness of P fertilizers in tropical acid soils when it offers comparative advantages in assessing the soil P status and its changes. But trained staff and adequate laboratory facilities are needed to perform this technique. Also the method can be used as a reference for comparison purposes as in this case. Further research is needed to assess the overall agronomic effectiveness (immediate and residual effects) of PR sources in predominant cropping systems of this region of Ghana. (author)

  15. Delayed tooth replantation after root surface treatment with sodium hypochlorite and sodium fluoride: histomorphometric analysis in rats Reimplante dentário tardio após o tratamento da superfície radicular com hipoclorito de sódio e fluoreto de sódio: análise histomorfométrica em ratos

    André Dotto Sottovia

    2006-04-01

    Full Text Available In cases of delayed tooth replantation, non-vital periodontal ligament remnants have been removed with sodium hypochlorite in an attempt to control root resorption. Nevertheless, reports of its irritating potential in contact with the alveolar connective tissue have been described. Therefore, this study evaluated the healing process on delayed replantation of rat teeth, after periodontal ligament removal by different treatment modalities. Twenty-four rats, assigned to 3 groups (n=8, had their upper right incisor extracted and left on the workbench for desiccation during 60 min. Afterwards, the teeth in group I were immersed in saline for 2 min. In group II, root surfaces were scrubbed with gauze soaked in saline for 2 min; and in group III, scrubbing was done with gauze soaked in 1% sodium hypochlorite solution. Thereafter, root surfaces were etched with 37% phosphoric acid and immersed in 2% acidulate-phosphate sodium fluoride solution, at pH 5.5. Root canals were filled with a calcium hydroxide-based paste and the teeth were replanted. The animals were sacrificed 60 days postoperatively and the pieces containing the replanted teeth were processed and paraffin- embedded. Semi-serial transversally sections were obtained from the middle third of the root and stained with hematoxylin and eosin for histomorphometric analysis. Data were analyzed statistically using Kruskal-Wallis and Dunn's tests. The results showed that root structure and cementum extension were more affected by resorption in group III (pEm reimplante dentário tardio, o ligamento periodontal desvitalizado tem sido removido empregando-se o hipoclorito de sódio, buscando o controle da reabsorção radicular. Relatos de efeito irritante no tecido conjuntivo alveolar após o seu uso, têm sido descritos. Isso justificou a realização deste trabalho buscando minimizar esse inconveniente. Para isso 24 ratos, divididos em 3 grupos de 8 animais, tiveram o incisivo superior direito extra