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Research subject: Hydrodesulfurization is one of the effective methods to remove sulfur compounds from oil fractions and improve fuel quality. One of the major challenges in this process is to find the proper catalyst support that performs best. In the meantime, modified supports with zeolite have allocated a lot of attention due to their strong acidic sites, specific surface area and high hydrothermal and chemical stability; But the acidity and volume of zeolite mesopores need to be corrected.
Research approach: In this study, first, hierarchical Y zeolite was prepared using post-synthesis (Dealumination) and using ammonium form of zeolite and NH₄F solution (0.75 M) at 90˚C for 3h under reflux conditions. Physicochemical properties of zeolite were investigated by BET, FESEM, FTIR, AAS and XRD analyzes. Modified zeolites were used in the support synthesis of the HDS process catalyst. The sulfidation and performance evaluation of the prepared catalysts were carried out in the fixed-bed microreactor were performed with diesel cutting feed from the Isomax unit of the target refinery.
Main results: The results show that the volume of mesopores, specific surface area and SiO₂/Al₂O₃ ratio in hierarchical zeolites has increased 0.073 cm³ g^-1, 783.36 m² g^-1 and 5.2, respectively (initial values are 0.032 cm³ g^-1, 567.18 m² g^-1 and 4.5). The results of zeolite analysis show the preservation of the structure and crystallinity during the zeolite modification process. The effect of zeolite modification, especially the Si/Al ratio variations, mesopores and specific surface area, was investigated on the activity of NiMo/Zeolite+Al₂O₃ catalysts. Increasing the acidity and improving the physicochemical properties of the modified zeolites has increased the catalyst performance in the process of diesel hydrodesulfurization (Conversion= 90%). Improving the activity of catalysts can be attributed to the positive effect of zeolites on the dispersion of the metallic site, surface area, acidity, optimal size of pores and volume of catalyst mesopores.

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The performance of different yield loss models from an exponential family was evaluated in safflower-redroot pigweed systems in two field experiments conducted during 2007 and 2008 growing seasons at the research field of Agricultural College of Shiraz University, Iran. The yield loss of safflower was recorded as relative yield loss in experimental plots laid out in split plot design with three replicates. Three different irrigation treatments were allocated to the main plots and consisted of full irrigation or 100% field capacity (FC), 75% FC, and 50% FC, while five weed densities (0, 3, 6, 9, and 12 weeds m-2) were assigned to the sub-plots The Logistic and Gompertz models and a user defined Power-Exponential model were fitted to the data to relate crop yield loss to the weed densities under different water stress conditions. The Power-Exponential model was chosen as the best fit to the data with statistically acceptable model diagnostics. Logistic and Gompertz models showed good fit to the observed data, but underestimated the yield loss under three levels of irrigation. Model performance in all cases was influenced by water stress as models generally showed greater constant and systematic biases under severe water stress (50% FC). Model parameters were used to explain the impact of water stress in crop/weed system. The exponential family models globally performed better over common empirical models such as Spitters, Kropff and Lotz and Cousens models.

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The effect of nitrogen (N) levels on N uptake by high weed densities at early growth stages of corn (Zea mays L., CV. Double Cross 370) was investigated for two years (2008-2009) at the Agricultural Research Station of Shiraz University. The experiment was arranged in a split-plot arrangement in the randomized complete blocks design with three replications. Two levels of weed control (weedy and weed free) and three levels of preplanting N (0, 50, and 90 kg ha-1) were employed as main and subplots, respectively. One month after crop sowing, total weed species were determined and shoot dry weights of both corn and weeds were measured. The highest weed biomass and N uptake by weeds were obtained from the application of 50 kg N ha-1. In the first year of the study, average N content of weed seedlings grown at any rates were not significantly different, whereas in the second year, N content of the weeds in the zero N plot was 31 and 39 % less than the weeds grown in 50 and 90 kg N ha-1 applied plots, respectively. Higher uptake of N by weeds, especially redroot pigweed (Amaranthus retroflexus) at the early corn growth stage is an important issue for crop-weed competition.

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A two-year field experiment was carried out in semi-arid region of southern Iran (Shiraz), during 2007-2008 and 2009-2010 growing seasons using various mixtures of an early- (cv Falat) and a middle-ripening (cv Shiraz) winter wheat cultivar to evaluate the beneficial effects of inducing temporal growth heterogeneity on reduction of intra-specific competition during post-anthesis moisture stress conditions. Treatments were composed of five combination ratios of the two cultivars (1:0; 2:1; 1:1; 1:2, 0:1), and two levels of post-anthesis moisture conditions i.e. equal to Field Capacity and 50% FC. The results showed that the equal ratio (1:1 mixed cropping of early and middle-ripening cultivars) was superior in grain yield components as well as post-anthesis water use efficiency (PWUE) among the mixture treatments. It appeared that mixed cropping of early- and middle-ripening cultivars had the potential for altering the intensified competition under deficient moisture conditions and may improve PWUE. Additional research for determining the best choices of cultivars, mixing ratios, sowing date, phenological differences, input requirements, and management practices for each regional environment are essential to achieve the maximum benefits.

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Salmonella spp. and Campylobacter can be transmitted through raw milk and cause foodborne illness. The aim of this study was to investigate the prevalence of Campylobacter and pathogenic species of Salmonella spp. species in raw cow's milk using molecular method in Mazandaran province. 100 samples of raw milk were randomly collected from traditional milk collection and retail centers in Mazandaran province in 2019. All samples were transferred as soon as possible to the microbiology laboratory of the Faculty of Veterinary Medicine, Amol University of Special Modern Technologies, in sterile containers and in suitable cold chain conditions. DNA was extracted from milk samples using a commercial kit and then the polymerase chain reaction was performed using appropriate primers to identify Campylobacter jejuni, Campylobacter coli and Salmonella. Out of 100 samples, 7 samples (7%) were infected with Campylobacter jejuni, no positive sample of Campylobacter coli was observed and 2 samples (2%) were infected with Salmonella. According to the results of the present study and the presence of the mentioned bacteria in milk, it is necessary to observe the hygienic principles in the dairy industry, processing and use of sufficient heat to eliminate the mentioned bacteria in raw milk and also use fast and accurate methods to identify These bacteria.
 

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A 2-year field experiment was conducted to evaluate the effect of N sources [Ammonium Nitrate (AN), Ammonium Sulfate (AS), Sulfur Coated Urea (SCU), and Urea (U)] and split application ((¹/₄,³/₄,0), (¹/₃,¹/₃,¹/₃), (¹/₂,¹/₂,0), and (¹/₃,²/₃,0)) on weed growth, safflower (Carthamus tinctorius L.) yield, and N Use Efficiency (NUE), using a split split-plot design with three replications, at the Experimental Research Station of Shiraz University, in 2015 and 2016. In weedy plots, applying AN-fertilizer in a split pattern of ¹/₂,¹/₂,0 (applying half of the N at sowing time and the rest at stem elongation) increased weed infestation. This treatment enhanced total weed N Uptake Efficiency (NUpE) up to 5% compared to U-fertilizer and similar split pattern. In weed free plots, the highest seed and oil yields (3303.52 and 753.09 kg ha^-1, respectively) were achieved by AN- and U-fertilizers in a split pattern of ¹/₂,¹/₂,0. Applying AN fertilizer and split patterns of ¹/₃,²/₃,0 (one third of N at sowing and two thirds at stem elongation) and ¹/₄,³/₄,0 (one quarter of N at sowing and three quarters at stem elongation) maximized safflower NUpE (0.78 kg kg^-1). Applying U fertilizer and split pattern of ¹/₂,¹/₂,0 increased safflower ability to compete vs. weeds up to 20% compared to AN-fertilizer. Overall, in order to improve safflower yield and NUE and control weed, applying U-fertilizer and split application of ¹/₃,²/₃,0 or ¹/₄,³/₄,0 can be suggested as a component of integrated weed management programs.
 

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The aim of this study was to evaluate the effect of aqueous extract of Shiitake mushroom on the survival of the probiotic bacterium Bifidobacterium bifidium and physicochemical properties in feta cheese during storage. In this study, the effect of Shiitake mushroom extract at the rates of 1, 1.5 and 2% on the survival of Bifidobacterium bifidum and the sensory features and physicochemical properties of Synbiotic feta cheese during 49 days of storage were investigated. Count of Bifidobacterium bifidum in probiotic cheese containing Shiitake mushroom extract on days 0 and 49, in groups containing 1, 1.5 and 2% of mushroom extract from Log CFU / g from 8.99 to 9.96 and from 8.95, respectively 22/10 and from 11/02 to 01/11 (P <0.05). The use of 2% mushroom extract in probiotic cheese improved the viability of Bifidobacterium bifidum at a rate of 1.99 Log CFU / g, while the use of 1.5% mushroom extract compared to 1% improved The survival of probiotic bacteria at Log CFU / g was 1.27 and 0.97.According to the results, acidity and pH increased and decreased during storage, respectively. Also, adding different concentrations of mushroom extract to probiotic cheese improved the texture, aroma, taste and increased the overall acceptance rank of the sample containing all three concentrations of mushroom extract compared to the control and probiotic cheese groups (P <0.05).In general, the addition of mushroom extract to probiotic cheese resulted in higher scores than the control groups.In general, the results of the study showed that the addition of Shiitake mushroom extract improved the viability of probiotic bacteria in cheese. Therefore, the combined use of shiitake mushroom extract as prebiotics and probiotics in cheese and other dairy products can be recommended as an effective and practical measure to improve consumer health and increase the nutritional value of products.
 

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The aim of this study is to investigate the effect of gelatin film containing Bifidobacterium bifidum and Lactobacillus rhamnosus bacteria on the survival of Staphylococcus aureus bacteria inoculated into rainbow trout meat as well as its physicochemical characteristics for 12 days during storage at refrigerator. Staphylococcus aureus was inoculated into fish samples with a concentration of 10⁶ log cfu/ml. Then the treatments (control group, rainbow trout samples packed with gelatin film, gelatin film containing each probiotic bacteria Bifidobacterium bifidum and Lactobacillus rhamnus with a concentration of 10⁹ log cfu/ml separately and gelatin film containing both probiotics) were prepared. Samples were packed in polythene bags and stored in refrigerator. Probiotic bacteria viability and Staphylococcus aureus bacteria count, pH, TVB-N, PV and TBARS were evaluated. According to the results, the survival of probiotic bacteria showed a decreasing trend during the study, and it was found that the survival of Bifidobacterium bifidum bacteria in gelatin film treatment and gelatin film treatment containing both probiotics on the last day respectively 6.81 log cfu/g and 5.37 log cfu/g and the viability of Lactobacillus rhamnosus bacteria was also reduced by 7.43 log cfu/g and 6.31 log cfu/g respectively in the mentioned treatments. Compared to the control group, probiotic films controlled the microbial growth of fish fillets well, while the gelatin film treatment containing both probiotics had the lowest rate. Chemical tests also had an increasing trend and their changes in all treated fish fillets were significantly lower than the untreated group (P<0.05). It was found that gelatin films containing probiotics, especially gelatin films containing Lactobacillus rhamnosus and Bifidobacterium bifidum, which had worked more successfully, had an effective antimicrobial effect against Staphylococcus aureus bacteria, and this coating can increase the shelf life of rainbow trout and this The category of products has a good effect.