30 research outputs found

    Evaluation of Candida colonization index, molecular identification, and antifungal susceptibility pattern of Candida species isolated from critically ill pediatric patients: A singlecenter study in Iran

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    Background and Purpose: Given the high mortality rate of invasive candidiasis inhospitalized pediatric patients, it is crucial to establish a predictive system to achieveearly diagnosis and treatment of patients who are likely to benefit from early antifungal treatment. This study aimed to assess the Candida colonization index, species distribution, and antifungal susceptibility pattern of Candida strains isolated frompediatric patients with high Candida colonization index (CI)Materials and Methods: This study was carried out at the Children’s Medical Center inTehran-Iran. In total, 661 samples were collected from 83 patients. The Candida CI wascalculated according to the descriptions of previous studies. The isolates were identified using polymerase chain reaction-based techniques. The Clinical and Laboratory Standard Institute protocol M60 was used to conduct the antifungal susceptibility test.Results: A colonization index greater than 0.5 was confirmed in 29 cases (58% ofpositive samples) with two children developing candidemia. Candida albicans (n=53,49.5%) was the most common Candida species in patients with CI > 0.5. Except foracute lymphoblastic leukemia, no risk factors were linked to a high index in colonizedchildren (P > 0.05). Twelve isolates (7.01%) were multi-azole resistant with high MICsagainst both isavuconazole and ravuconazole and seven strains (4.09%) wereechinocandins resistant.Conclusion: In pediatric intensive care units, patients are at risk of fungal infection,particularly candidemia. In this study, more than half of the children with positive yeastcultures had CI > 0.5, and 6.8% developed candidemia

    Antifungal activity of magnetically separable Fe3O4/ZnO/AgBr nanocomposites prepared by a facile microwave-assisted method

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    In the present work, magnetically separable Fe3O4/ZnO/AgBr nanocomposites with different weight ratios of Fe3O4 to ZnO/AgBr were prepared by a facile microwave-assisted method. The resultant samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive analysis of X-rays (EDX), and vibrating sample magnetometery (VSM). Antifungal activity of the as-prepared samples was evaluated against Fusarium graminearum and Fusarium oxysporum as two phytopathogenic fungi. Among the nanocomposites, the sample with 1:8 weight ratio of Fe3O4 to ZnO/AgBr was selected as the best nanocomposite. This nanocomposite inactivates Fusarium graminearum and Fusarium oxysporum at 120 and 60 min, respectively. Moreover, it was observed that the microwave irradiation time has considerable influence on the antifungal activity and the sample prepared by irradiation for 10 min showed the best activity. Moreover, the nanocomposite without any thermal treatment displayed the superior activity

    The Effect of Seed Priming and Accelerated Aging on Germination and Physiochemical Changes in Milk Thistle (Silybum marianum)

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    Effects of seed priming and aging on some physiological characteristics of Milk thistle was studied in a factoral experiment based on Complete Randomized Design (CRD). Tratments were included hydro priming (using distilled water), halo priming (0, 1.5, 3, 4.5 and 6% KNO3) and accelerated aging (0, 2, 4 and 6 days under 45°C and 95% humidity) in three replications. Determined parameters were germination charactristics including germination percentage, daily germination speed, mean time of germination, seed vigor index, hypocutile length and hypocutile dry weight. Activity of catalase, peroxidase and polyphenol oxidase were determined at 12 hours after imbibition and seedling stage. According to results of this experiment, germination percentage, seed vigor and seedling growth of seeds were increased under all priming treatments. Improving the catalase and peroxidase activity led to decrease the aging damages. Germination characteristics were improved under both priming treatments at the beginning of germination as well as seedling growth. Polyphenol oxidase activity was increased in the pre-treated seeds but decreased in seedling growth stage. Aging treatments led to reduce the germination percentage, daily germination speed, seed vigor and seedling growth while the germination time was increased. Accelerated aging caused to reduce the germination rate and seedling growth of milk thistle that is probably due to increasing the lipid peroxidation, free radical increment and decreasing the antioxidants activity. The greatest and lowest antioxidants activity, the germination percentage, germination speed and seed vigor were respectively observed under priming using 3% KNO3 concentration and control seeds

    The Effect of Seed Priming and Accelerated Aging on Germination and Physiochemical Changes in Milk Thistle (Silybum marianum)

    No full text
    Effects of seed priming and aging on some physiological characteristics of Milk thistle was studied in a factoral experiment based on Complete Randomized Design (CRD). Tratments were included hydro priming (using distilled water), halo priming (0, 1.5, 3, 4.5 and 6% KNO3) and accelerated aging (0, 2, 4 and 6 days under 45°C and 95% humidity) in three replications. Determined parameters were germination charactristics including germination percentage, daily germination speed, mean time of germination, seed vigor index, hypocutile length and hypocutile dry weight. Activity of catalase, peroxidase and polyphenol oxidase were determined at 12 hours after imbibition and seedling stage. According to results of this experiment, germination percentage, seed vigor and seedling growth of seeds were increased under all priming treatments. Improving the catalase and peroxidase activity led to decrease the aging damages. Germination characteristics were improved under both priming treatments at the beginning of germination as well as seedling growth. Polyphenol oxidase activity was increased in the pre-treated seeds but decreased in seedling growth stage. Aging treatments led to reduce the germination percentage, daily germination speed, seed vigor and seedling growth while the germination time was increased. Accelerated aging caused to reduce the germination rate and seedling growth of milk thistle that is probably due to increasing the lipid peroxidation, free radical increment and decreasing the antioxidants activity. The greatest and lowest antioxidants activity, the germination percentage, germination speed and seed vigor were respectively observed under priming using 3% KNO3 concentration and control seeds

    The Effect of Water Deficit and Nitrogen on the Antioxidant Enzymes’ Activity and Quantum Yield of Barley (<i>Hordeum vulgare</i> L.)</p>

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    The effects of water deficit and nitrogen fertilizer were studied on antioxidant enzymes activity and quantum yield of barley. An experiment carried out in greenhouse in factorial subject based on a completely randomized design with three replications. Irrigation schedules imposed at three levels of 85%, 60% and 35% field capacity (FC), and nitrogen were applied in quantities of 40, 80 and 120 kg N ha-1. We determined Catalase (CAT), Peroxidase (POX) Polyphenol oxidase (PPO) activities, proline, chlorophyll and carotenoid content, quantum yield and grain yield. The results showed that severe stress (35% FC) increased the activities of CAT, POX and PPO enzymes and proline content, whereas the carotenoids, chlorophyll a and chlorophyll b decreased. Water deficiency caused the reduction in the quantum yield and the grain yield by 34%. Application of 80 kg of N during stress treatments resulted in higher enzyme activity and proline content. High amount of nitrogen reduced carotenoids, chlorophyll a, chlorophyll b, and in contrast, enhanced quantum yield. Application of 120 kg N ha-1 increased the yield up to 37% under mild stress (35% FC). Correlation coefficient and path coefficient showed that, grain yield was affected directly by amount of carotenoids and quantum yield

    Feasibility of Using Computer Vision and Artificial Intelligence Techniques in Detection of Some Apple Pests and Diseases

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    There are many methods to detect plant pests and diseases, but they are primarily time-consuming and costly. Computer vision techniques can recognize the pest- and disease-damaged fruits and provide clues to identify and treat the diseases and pests in their early stages. This study aimed to identify common pests, including the apple capsid (Plesiocoris rugicollis)/AC, apple codling moth (Cydia pomonella)/ACM, Pear lace bug (Stephanitis pyri)/PLB, and one physiological disease-apple russeting/AR in two cultivars, Golden Delicious and Red Delicious, using the digital image processing and sparse coding method. The Sparse coding method is used to reduce the storage of the elements of images so that the matrix can be processed faster. There have been numerous studies on the identification of apple fruit diseases and pests. However, most of the previous studies focused only on diagnosing a pest or disease, not on computational volume reduction and rapid detection. This research focused on the comprehensive study on identifying pests and diseases of apple fruit using sparse coding. The sparse coding algorithm in this work was designed using Matlab software. The apple pest and disease detection were performed based on 11 characteristics: R, G, B, L, a, b, H, S, V, Sift, and Harris. The class detection accuracy using the sparse coding method was obtained for 10 classes with three views of apple for S. pyri of red apple as 81%, S. pyri of golden apple as 88%, golden apple russeting as 85%, S. pyri and russeting of red apple as 100%, S. pyri and russeting of golden apple as 80%, codling moth of red apple as 86%, codling moth of golden apple as 72%, S. pyri of red apple as 83%, S. pyri of golden apple as 90%, codling moth and S. pyri of red apple as 80%, and codling moth and S. pyri of golden apple as 67%. The total processing time for developing the dictionary was 220 s. Once the dictionary was developed, pest and disease detection took only 0.175 s. The results of this study can be useful in developing automatic devices for the early detection of common pests and diseases of apples. Although the study was focused on apple diseases, results for this work have huge potential for other crops
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