Response surface methodology (RSM) based on central composite design was successfully applied to redesign MRS media for maximizing both biomass and bacteriocin production from Lactobacillus plantarum NH40. First, glucose and yeast extract were chosen as the best carbon and nitrogen sources based on classical optimization results of one factor at time which also revealed the possibility of eliminating peptone and meat extract from the original composition of medium without affecting the growth and bacteriocin production. Statistical experimental design based on a regression model generated using the Design expert 7 software showed that the optimum concentrations of glucose, yeast extract, tween80, NH4Cr, CH3COONa and K2PO4 were 40, 19.9, 1, 3.06, 7, 1.25 g/L respectively for maximum production of biomass (15.87 mg/mL) and bacteriocin (634.74 U/mL). In addition, from the analysis of variance, yeast extract with F-value 77.2 and glucose with 185.4 were the most effective factors on biomass and bacteriocin production. Formulation of empirical model explained that the interaction among factors showed that the determination coefficient R2 of biomass and bacteriocin production were 0.8777 and 0.8539 respectively. Furthermore, the accuracy of model of the optimized MRS medium suggested by design expert 7 for both biomass and bacteriocin was verified and results showed that concentrations of biomass and bacteriocin were 15 mg/mL and 640AU/mL respectively, which were approximately closed to predicted values.
Abstract
The current research aims to identify the negotiation behavior of administrative teachers, as well as to identify the significance of the differences in negotiation behavior according to the variables (gender, scientific title, length of service). After confirming the psychometric characteristics of (20) items, the researchers applied the scale to (400) male and female administrative teaching staff who were randomly selected from the University of Baghdad for the academic year 2021/2022. The results showed the following the research sample has a negotiating behavior. There are no statistically significant differences between gender, scientific title, and length of service in the means of negotiating beha
... Show MoreCefixime (CFX) was treated with sodium nitrite and hydrochloric acid for diazotization reaction followed by coupling with ?-Naphthol in alkaline medium to form, a yellow colored azo dye compound which exhibits maximum absorption (?max) at 412 nm where the concentration of (CFX) was determined spectrophotometrically. The optimum reaction conditions and other analytical parameters were evaluated. Beer’s law was obeyed in the concentration range of (1-20) ?g.mL-1 with a molar absorptivity of 34870.5 L.mol-1.cm-1. The limit of detection was found to be 0.1090 ?g.mL-1 and the Sandell's sensitivity value was 0.0130 ?g.cm-2. The proposed method could be successfully applied to
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With the advancement of technology ,the study of cross-cultural communication via on line has become an important and researchable topic in linguistic theory and its applications.The aims of this study are two- fold (a) exploring the influence of cultural diversity on on-line interaction between American native speakers (NSs) and Iraqi non-native speakers (NNSs) of English which, together with other factors might potentially lead to what Thomas(1983) calls "pragmatic failure" (PF), a main cause of communication breakdowns and (b) specifying which type of PF occurs more frequently between the two groups along with the reasons behind such failures. To achie
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Determining the aerodynamic characteristics of iced airfoil is an important step in aircraft design. The goal of this work is to study experimentally and numerically an iced airfoil to assess the aerodynamic penalties associated with presence of ice on the airfoil surface. Three iced shapes were tested on NACA 0012 straight wing at zero and non-zero angles of attack, at Reynolds No. equal to (3.36*105). The 2-D steady state continuity and momentum equations have been solved utilizing finite volume method to analyze the turbulent flow over a clean and iced airfoil. The results show that the ice shapes affected the aerodynamic characteristics due to the change in airfoil shape. The experimental results show that the horn iced airfoil
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Abstract
The fiber Bragg grating (FBG) technology has been rapidly applied in the sensing technology field. In this work, uniform FBG was used as pressure sensor based on measuring related Bragg wavelength shift. The pressure was applied directly by air compressor to the sensor and the pressure was ranged from 1 to 6 bar.
This sensor also was affected by the external temperature so as a result it could be used as a temperature sensor. This sensor could be used to monitor the pressure of dams. It has been shown from the result that the sensor is very sensitive to the pressure and the sensitivity was (67 pm\bar) and is very sensitive to temperature and the sensitivity was (10p
... Show MoreAbstract The percent study aimed to determination the association between infant feeding practices and Insulin-Dependent Diabetes Mellitus (IDDM). The study was conducted at (he National Center of Diabetes in Baghdad City the Capital of Iraq throughout the period of January 2001 to January 2002. The sample was comprised of (200) mother of Insulin-Dependent Diabetes Mellitus (IDDM) of children under age of 12 years old. Data was collected through the use of a questionnaire that constructed by researcher and which were developed for the purpose of the present study. Reliability of the instruments was dete
In this paper, the productions of gallium oxide (Ga2O3) nanoparticles were achieved via using the Nd: YAG laser deposition method with a fundamental wavelength (1064 nm). These nanoparticles were characterized by using different methods such as X-ray diffractometer (XRD), atomic force microscopy (AFM) and Ultraviolet–visible (UV–vis) spectroscopy. To examine the effects of laser energy on the properties of nanoparticles, the experimental results and theoretical considerations were prepared by the effective method of pulse laser deposition. The synthesis of Ga2O3NPs) was achieved with different ranges of energies (500 to 900 mJ). Average crystallite sizes of the synthesized nanopar
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In this study, Cr−Mo−N thin films with different Mo contents were synthesised via closed field unbalanced magnetron sputtering ion plating. The effects of Mo content on the microstructure, chemical bonding state, and optical properties of the prepared films were investigated by X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy, and ultraviolet-visible spectrophotometry. XRD results determined the face centered cubic (fcc) structure of pure CrN film. The incorporation of molybdenum (Mo) in the CrN matrix was confirmed by both XRD and XPS analyses. The CrMoN coatings demonstrate various polycrystalline phases including CrN, γ-Mo2N, Cr with oxides layers of MoO3, CrO3
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