ABSTRACT
Environmental pollution by 2,4-dicholorphenol [2,4-DCP], commonly found in industrial wastewater has been a concern for humans over the past 50 years. Garden Radish Peroxidase [GRP] can eliminate this poisonous pollutant. The aim of this study was to apply an experimental Response Surface Methodology [RSM] and Central Composite Design [CCD] to optimize GRP-based treatment in order to maximize the removal of 2,4-DCP from wastewater. The effects of four factors; pH, enzyme activity [U/mL], hydrogen peroxide [H[2]O[2]] concentration [mM], and substrate concentration [mg/L] and their interactions were investigated for 2,4-DCP removal using a second-order polynomial model. The suitability of the polynomial model was described using coefficient of determination [R[2] =90.7%] and the results were created by analysis of variance [ANOVA]. A 3D response surface was made from the mathematical models and then applied to determine the optimal condition. These analyses exhibited that using a quadratic model was fitting for this treatment. Furthermore, desirability function was employed for the specific values of controlled factors for optimization and maximum desirability. Based on the desirability function results, the response predicted a 99.83% removal rate of 2,4-DCP from wastewater with 0.959 desirability. Under these conditions, the experimental removal percentage value would be 99.2%
ABSTRACT
Broccoli inflorescences are rich in health promoting compounds such as vitamin C which may contribute to the high antioxidant capacity found in freshly- harvested broccoli. However, high looses of this essential compound has been reported after harvesting. Modified atmosphere packaging has been shown to be potentially useful in storability and quality retention of Broccoli florets; however, supplemental methods of extending shelf life are desirable because of the high fermentation product. In this way florets were treated post harvest with benzyl adenine at 50 ppm before packaging in polymeric bags [polyethylene and polypropylene] and storage at 1°C. Factors including ethylene production, chlorophyll, vitamin C, fermentation product, appearance, pH and titrable acidity were measured every three day intervals. During storage of cytokinin treated florets under MAP, all changes related with loss of quality were reduced and delayed with time. Additionally vitamin C remained almost unchanged. This improved retention was mainly due to decreased ethylene production. Cytokinin treatment significantly reduced fermentation product in packaged broccoli
ABSTRACT
Complete knowledge of the morphologic and microscopic anatomy of the dental root apex has been recognized. Internal root canal anatomy especially root apex is variable in human teeth for example lateral canal and ramification may exist. The objective of this study was to determine the internal anatomy of root apex. For this investigation, 50 mandibular first premolar and 50 mandibular second premolar were obtained. The age and sex of the patients and reasons for extraction were not recorded. For better recognition of apical foramen and lateral foramen of the teeth, they were placed in methylen blue for 2 hours and then teeth were studied under the stereomicroscope with x25 magnification lens [the calibration of lens was 0.1mm] and percentage of lateral canal, root deviator and apical foramen exit were detected. Then, to study the internal anatomy, the teeth were grinded and stained with hematoxylin. The mean, standard deviation and standard error for the diameter of constriction and distance from apical foramen were measured. Also, the internal anatomy of the root canal was studied by two observers. The results showed that apical constrictions were always smaller than apical foramen and a distance existed between apical constrictions, apical foramen and vertex. Apical foramen did not exist in center in 80 to 90% of cases. Lateral canals were observed in 28% of mandibular first premolar and in 34% of mandibular second premolar. Also, 90% of first premolar teeth and 88% of second premolar teeth had one canal and 10% of first premolar and 12% of second premolar had two canals. As the mean distance between apical constriction and apical vertex in mandibular first premolars was 0.65mm and in mandibular second premolars was 0.68mm, therefore during root canal treatment and working length determination, this distances should be decreased from tooth length