24,599 research outputs found

    The effects of prolonged oral administration of the disinfectant calcium hypochlorite in Nigerian commercial cockerels

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    This study was designed to investigate the effects of prolonged oral administration of calcium hypochlorite in the drinking water of commercial cockerels. It was carried out in order to ascertain probable toxicity associated with prolonged exposure to calcium hypochlorite. Thirty-two healthy birds were used; they were grouped into four groups of eight. Group 1, which served as the control, received 10 mL/kg body weight of physiological saline. Groups 2, 3 and 4 received 0.0375 g, 0.375 g and 0.75 g of calcium hypochlorite per 10 litres of drinking water for six weeks respectively. Six weeks after the administration of calcium hypochlorite, blood was collected from the jugular vein to assess liver function, lipid profiles and for markers of oxidative stress. The results revealed a significant (p < 0.05) increase in alanine aminotransferase activity in a dose-dependent manner when compared with the control. Also, there was a significant (p < 0.05) increase in aspartate aminotransferase and alkaline phosphatase activity. Similarly, there was a significant (p < 0.05) increase in total cholesterol, triglycerides, high-density lipoprotein and low-density lipoprotein levels compared with the control. There was a significant increase in malondialdehyde and hydrogen peroxide generation with a concomitant significant (p < 0.05) decrease in serum glutathione level in a dose-dependent manner when compared with the control. In this study, calcium hypochloriteinduced hepatic damage via oxidative stress and decrease in antioxidant defense system was found. Therefore, prolonged exposure of chickens to calcium hypochlorite is potentially harmful

    Pengaruh Penambahan Zat Aditif (Calcium Hypochlorite) terhadap Coolant Properties (Viscosity) Minyak Sawit

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    Cutting fluid (coolant) are required in the machining processes. Most of cutting fluid are from mineral oil, and they are as unrenewable resource, therefore look for alternative resources ofmineral oil, which derived from vegetables oil. Palm oil have potency based of cutting fluid, however of coolant properties increased additive. This research want investigate effect ofadditive on phiysical properties of coolant. The method on mixture combining palm oil and additive (calcium hypochlorite) are conducted take of three proportion (95:5), (90:10), (85:15), the results from mixture the tested physical properties of viscosity at 40oC and 100oC of temperature. The results acknowledge the addition of (calcium hypochlorite) with palm oileffects on phiysical properties of coolant, the greater the percentage of calcium hypochlorite viscosity increased

    Agua y Suero Fisiológico para Prevenir la Formación de Paracloroanilina

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    Indexación: Web of Science; Scielo.ABSTRACT: This study determined if p-chloroaniline (PCA) can be minimized by using distilled water and physiological saline solution following sodium hypochlorite but before chlorhexidine. Hypochlorite 5%, 0.5%, 0.05%, 0.005% and 0.0005% dissolved in 0.9% NaCl and in distilled water were mixed with 2% chlorhexidine for the formation of PCA. The PCA was determined using UV-VISIBLE spectrometry, with spectral curve was determined the wavelength of maximum absorption of PCA. Formed PCA absorbance was measured between 0.025%, 0.02%, 0.015%, 0.01%, 0.005% and 0.0025% hypochlorite and 2% chlorhexidine. 2% chlorhexidine and hypochlorite with physiological saline form a white precipitate which prevents the measurement of PCA. Colored PCA is formed with 0.05%, 0.005% hypochlorite aqueous dilutions and 2% chlorhexidine. The lwavelength of maximum absorption obtained was 470 nm and absorbance of PCA showed a linear decrease. 0.005% NaClO produces the least amount of PCA. The best solvent to prevent the formation of PCA during the interaction of sodium hypochlorite with chlorhexidine is distilled water.Este estudio determinó si la p-cloroanilina (PCA) puede ser minimizada mediante el uso de agua destilada y solución salina fisiológica seguido de la aplicación de hipoclorito de sodio, previo a la aplicación de clorhexidina. Hipoclorito al 5%, 0,5%, 0,05%, 0,005% y 0,0005% fue disuelto en 0,9% de NaCl y en agua destilada se mezcló con 2% de clorhexidina para la formación de PCA. El PCA se determinó mediante espectrometría UV-Visible, y con curva espectral se determinó la longitud de onda máxima del PCA. La absorbancia del PCA formado se midió con 0,025%, 0,02%, 0,015%, 0,01%, 0,005% y 0,0025% de hipoclorito y 2% de clorhexidina. La combinación de 2% de clorhexidina e hipoclorito en solución salina fisiológica forman un precipitado blanco que impide la medición del PCA. El PCA coloreado es formado con 0,05%, 0,005% diluciones acuosas de hipoclorito y 2% de clorhexidina. La longitud de onda máxima obtenida fue de 470 nm y la absorbancia del PCA mostró una disminución lineal. NaClO al 0,005% produce menor cantidad de PCA. El mejor disolvente para evitar la formación de PCA durante la interacción de hipoclorito de sodio con clorhexidina es agua destilada.http://ref.scielo.org/2kpw6

    Low Shrinkage Bleaching of Unbleached Neutral Sulphite Semichemical Pulp

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    The main objective of this research project was the investigation of the most feasible method for the bleaching of a soft-cooked unbleached neutral sulphite semichemical aspen pulp cooked to a 70 percent yield. Furthermore, treatment of unbleached, laboratory bleached and commercially bleached neutral sulphite semichemical pulp with a new chemical, sodium borohydride, was also carried out. The results of our experimental work showed that, the best bleaching procedure was when 15 percent chlorine as hypochlorite was used in the first stage, followed by a hydrochloric acid soaking stage with a final treatment of 2.6 percent hydrogen peroxide. With the above procedure brightness values over 80 percent were obtained with the yields in the 90 percent range based on the weight of the pulp. Sodium borohydride treatment of the three pulps showed that, with regards to ultra-violet light and heat stability the chemical, sodium borohydride, had no effect on the unbleached and the bleached lignin-containing pulps. Treatment of the commercially bleached, lignin-free, pulp however showed that the chemical had a marked effect in improving the heat and light stability of the pulp. It was noted that with all three types of pulp the chemical sodium borohydride did procedure a bleaching effect

    Bleaching of High Yield Mutual Sulphite Semichemical Pulp

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    The objective of this research project was to investigate the effect of various bleaching agents and procedures on brightness, degree of yellowness and retention of the original high yield of the unbleached neutral sulphite semichemical pulp. In order to avoid excessive losses in bleaching of the high yield pulp, it was decided to limit the selection of bleaching chemicals to hypochlorites, peroxides and hydrosulphites. Furthermore, caustic extraction was to be employed only under relatively mild conditions as to temperature and concentration. Based on the experimental conditions and results described in this report and on the use of an unbleached pulp with relatively low brightness of 32 percent, the following conclusions were drawn: Bleaching of neutral sulphite semichemical pulp by means of one stage calcium hypochlorite treatment brought about only limited brightness development with concurrent relatively high yellowness. Two stage bleaching with calcium hypochlorite was found to be more effective than one stage bleaching for a given amount of chemical. Best results were obtained when about 25 percent of the total hypochlorite were used in the first stage and the remaining 75 percent in the second stage. Caustic extraction between two stages of hypochlorite bleaching improved brightness and reduced the yellow cast of the bleached pulp. With this procedure, best results were obtained by using 50 to 75 percent of the total hypochlorite in the first stage. Pulp bleached with hypochlorite followed by acidification and hydrogen peroxide treatment produced encouraging results as to brightness and decrease yellow cast. Zinc hydrosulphite, although it did not improve brightness was effective in reducing the yellow cast of the bleached pulp. All experiments caused only modest shrinkage of the pulp used

    New technologies to improve root canal disinfection

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    Effective irrigant delivery and agitation are prerequisites to promote root canal disinfection and debris removal and improve successful endodontic treatment. This paper presents an overview of the currently available technologies to improve the cleaning of the endodontic space and their debridement efficacy. A PubMed electronic search was conducted with appropriate key words to identify the relevant literature on this topic. After retrieving the full-text articles, all the articles were reviewed and the most appropriate were included in this review. Several different systems of mechanical activation of irrigants to improve endodontic disinfection were analysed: manual agitation with gutta-percha cones, endodontic instruments or special brushes, vibrating systems activated by low-speed hand-pieces or by sonic or subsonic energy, use of ultrasonic or laser energy to mechanically activate the irrigants and apical negative pressure irrigation systems. Furthermore, this review aims to describe systems designed to improve the intracanal bacterial decontamination by a specific chemical action, such as ozone, direct laser action or light-activated disinfection. The ultrasonic activation of root canal irrigants and of sodium hypochlorite in particular still remains the gold standard to which all other systems of mechanical agitation analyzed in this article were compared. From this overview, it is evident that the use of different irrigation systems can provide several advantages in the clinical endodontic outcome and that integration of new technologies, coupled with enhanced techniques and materials, may help everyday clinical practice

    Effect of Additives on Mineral Trioxide Aggregate Setting Reaction Product Formation

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    Introduction Mineral trioxide aggregate (MTA) sets via hydration of calcium silicates to yield calcium silicate hydrates and calcium hydroxide (Ca[OH]2). However, a drawback of MTA is its long setting time. Therefore, many additives have been suggested to reduce the setting time. The effect those additives have on setting reaction product formation has been ignored. The objective was to examine the effect additives have on MTA\u27s setting time and setting reaction using differential scanning calorimetry (DSC). Methods MTA powder was prepared with distilled water (control), phosphate buffered saline, 5% calcium chloride (CaCl2), 3% sodium hypochlorite (NaOCl), or lidocaine in a 3:1 mixture and placed in crucibles for DSC evaluation. The setting exothermic reactions were evaluated at 37°C for 8 hours to determine the setting time. Separate samples were stored and evaluated using dynamic DSC scans (37°C→640°C at10°C/min) at 1 day, 1 week, 1 month, and 3 months (n = 9/group/time). Dynamic DSC quantifies the reaction product formed from the amount of heat required to decompose it. Thermographic peaks were integrated to determine enthalpy, which was analyzed with analysis of variance/Tukey test (α = 0.05). Results Isothermal DSC identified 2 main exothermal peaks occurring at 44 ± 12 and 343 ± 57 minutes for the control. Only the CaCl2 additive was an accelerant, which was observed by a greater exothermic peak at 101 ± 11 minutes, indicating a decreased setting time. The dynamic DSC scans produced an endothermic peak around 450°C–550°C attributed to Ca(OH)2 decomposition. The use of a few additives (NaOCl and lidocaine) resulted in significantly less Ca(OH)2 product formation. Conclusions DSC was used to discriminate calcium hydroxide formation in MTA mixed with various additives and showed NaOCl and lidocaine are detrimental to MTA reaction product formation, whereas CaCl2 accelerated the reaction

    Micromethods for determination of ammonia, urea, total nitrogen, uric acid, creatinine (and creatine), and allantoin

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    The success with which Krebs and Henseleit (1) employed Warburg’s method of surviving tissue slices in the problem of the formation of urea in the liver encouraged its use for a direct attack on other problems of nitrogen metabolism in animals

    Higher diversity of Rhizobium leguminosarum biovar viciae populations in arable soils than in grass soils

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    The bacterial genetic diversity after long-term arable cultivation was compared with that under permanent grassland using replicated paired contrasts, Pea-nodulating Rhizobium leguminosarum populations were sampled from pairs of arable and grass sites at four locations in Yorkshire, United Kingdom, isolates were characterized using both chromosomal (16S-23S ribosomal DNA internal transcribed spacer PCR-restriction fragment length polymorphism) and plasmid (group-specific repC PCR amplification) markers. The diversities of chromosomal types, repC profiles, and combined genotypes were calculated using richness in types (adjusted to equal sample sizes by rarefaction), Shannon-Wiener index, and Simpson's index. The relative differences in diversity within each pair of sites were similar for all three diversity measures, Chromosomal types, repC profiles, and combined genotypes were each more diverse in arable soils than in grass soils at two of the four locations. The other comparisons showed no significant differences. We conclude that rhizobial diversity can be affected by differences between these two management regimens. Multiple regression analyses indicated that lower diversity was associated with high potential nitrogen and phosphate levels or with acidity
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