排序方式： 共有101条查询结果，搜索用时 15 毫秒
31.
Atta Akbari Omid Moini Jazani Mohammad Reza Saeb Kobra Pourabdollah Fariba Soltanolkottabi 《Fibers and Polymers》2014,15(6):1230-1235
A proper collector is designed and examined in electrospinning process to produce electrospun nanofibers with favored mechanical propertied. The quality of product was controlled by changing and optimizing the process variables, namely electrospinning time, gap distance, and collector rotating speed in a manner that well-aligned yarns were fabricated from polyacrylonitrile (PAN) dilute solutions. It was found that the tensile characteristics of fabricated yarns are greatly dependent on the process variables. Incorporation of multi-walled carbon nanotubes (MWCNTs) into the polymer solution revealed improvement to the yarn strength because of enhancement in alignment of the filaments. The state of fiber alignment and dispersion of MWCNTs were detected by means of scanning electron microscopy. It was illustrated that combination of nanofibers and microfibers gives PAN/MWCNTs composite nanofibers with high surface area and high porosity to satisfy sophisticated users. 相似文献
32.
Ebadi Arash Raja Omid Ebrahimian Hamed Yazdani Mohammad Reza Rezaverdinejad Vahid 《Paddy and Water Environment》2022,20(1):137-150
Paddy and Water Environment - One of the common irrigation systems in the paddy fields is field-to-field irrigation. The management of these irrigation systems is difficult and essential because of... 相似文献
33.
Direct measurement of soil moisture has been often expensive and time-consuming. The aim of this study was determining the best method to estimate the soil moisture using the pedotransfer functions in the soil par2 model. Soil samples selected from the database UNSODA in three textures include sandy loam, silty loam and clay. In clay soil, the Campbell model indicated better results at field capacity (FC) and wilting point (WP) with RMSE = (0.06, 0.09) and d = (0.65, 0.55) respectively. In silty loam soil, the Epic model had accurate estimation with MBE = 0.00 at FC and Campbell model had the acceptable result of WP with RMSE = 0.03 and d = 0.77. In sandy loam, Hutson and Campbell models had a better result to estimation the FC and WP than others. Also Hutson model had an acceptable result to estimation the TAW (Total Available Water) with RMSE = (0.03, 0.04, 0.04) and MBE = (0.02, 0.01, 0.01) for clay, sandy loam and silty loam, respectively. These models demonstrate the moisture points had the internal linkage with the soil textures. Results indicated that the PTFs models simulate the agreement results with the experimental observations. 相似文献
34.
Akbar?SharifianEmail author Saeed?Farahani Parvin?Pasalar Marjan?Gharavi Omid?Aminian 《Journal of circadian rhythms》2005,3(1):15
Background
Some medical disorders have higher prevalence in shift workers than others. This study was designed to evaluate the effect of night-shift-working on total plasma antioxidant capacity, with respect to the causative role of oxidative stress in induction of some of these disorders. 相似文献35.
Omid Askari-Khorasgani 《Journal of plant nutrition》2013,36(17):2176-2187
Genotype selection is an essential step in breeding programs determining nutrient content and composition and, thereby, the quality indices of grapevines and their products. The grapevine bioactive compounds, particularly flavonoids, are determinants of grape quality and possess strong health-promoting effects in grapevine and humans. Grapevine nutrient content and composition depends on genotype–environmental interaction in which genotype selection and stress conditions, particularly severity, time, and combination of stresses play significant roles in determining grape and wine quality. This review article aims to provide information required for appropriate genotype selection of grapevines for production of high-quality fruits. The influence of interacting factors, including genotype selection, grapevine metabolites, and environmental conditions, and their interrelationships on the quality of grapevines (flavor, aroma, pigmentation, color stability, and stress tolerance of red and white grapes) and their products (organoleptic properties and storage life of wine/must and juice) are discussed. 相似文献
36.
Omid R. Zandvakili Masoud Hashemi Fatemeh Etemadi Wesley R. Autio Sarah Weis 《Journal of plant nutrition》2013,36(14):1575-1593
AbstractFor plant growth and composition, the effects of fertilizers including blood meal (BLO), cottonseed meal (CSM), dehydrated cow manure (COW), and urea (UREA) factored with lettuce (Lactuca sativa L.) of different morphological phenotypes including iceberg, romaine, loose head, and loose leaf were studied in a greenhouse. Lettuce growth increased with increasing nitrogen (N) applications from 0 to 800?mg N/pot (kg), but the top application of BLO, CSM, or UREA suppressed yields. Lettuce grown with BLO, CSM, or UREA had higher concentrations of N than with COW. Nitrate-N concentration in leaves of all varieties exceeded some standards at high application of organic fertilizer or urea except for COW. In general, increasing N application resulted in higher concentration of NH4-N in lettuce with increases in applications of fertilizers. Organic fertilizers and urea were equally effective in supporting growth and affecting nutrient accumulation in lettuce if sufficient N was supplied. 相似文献
37.
Omid Massoudifar Farrokh Darvish Kodjouri Ghorban Noor Mohammadi Mohammad J. Mirhadi 《Archives of Agronomy and Soil Science》2013,59(7):925-934
In order to evaluate irrigation regimes and nitrogen fertilization on quality characteristics of wheat cultivars, a field experiment was carried out using split-plot factorial design based on randomized complete block design with three replications in Quchan, Iran (2010–2012). Main plots were assigned with four irrigation regimes; I1, 90 mm; I2, 130 mm; I3, 170 mm based on evaporation from a class A pan; and I4, water deficit stress during post-anthesis stage; sub-plots were assigned with four levels of nitrogen (N1, 0; N2, 70; N3, 140; and N4, 210 kg ha?1); and three wheat cultivars (V1, Mihan; V2, C-87-6; and V3, C-87-11) were used as factorial. The results showed that nitrogen fertilization increased some quality characteristics. Under water deficit (I4), gluten index, grain protein content, grain yield, and sedimentation volume decreased. Significant interactions between irrigation regimes and both nitrogen levels and cultivars were observed. 相似文献
38.
Maryam-Sadat Shobbar Omid Azhari Zahra-Sadat Shobbar Vahid Niknam Hossein Askari Mohammad Pessarakli 《Journal of plant nutrition》2013,36(7):1037-1052
Rice (Oryza sativa L.) is one of the most sensitive crops to drought, salt and cold stresses, particularly at post germination stage. The effects of these stresses on some physiological responses of two (a salt tolerant and a sensitive) rice cultivars ‘FL478’ and ‘IR29’ were investigated in this study. Two-day seedlings were transferred to MS media complemented with iso-osmotic concentrations of sodium chloride (NaCl; 0, 50, 100, and 150 mM) or mannitol (0, 100, 180, and 275 mM) at 25°C or four and 15°C for 10 days. Experiments were carried out based on completely randomized design, with at least three replicates. All three stresses decreased shoot growth, chlorophylls, carotenoids and root starch while increased shoot soluble sugars. The effect of exerted cold stress on growth, hydrogen peroxide (H2O2) and malonyldialdehyde levels, electrolyte leakage, chlorophylls and carotenoids contents was more than or comparable with drought, but greater than salinity. The results also indicated higher tolerance of ‘‘FL478’’ not only to salinity but also to drought compared to ‘‘IR29’’. Therefore, a mechanism for osmotic stress adjustment is probable in ‘‘FL478’’ in addition to low sodium (Na+) to potassium (K+) ratio in shoot tissues under salinity. 相似文献
39.
Mehdi Heydari Hassan Pourbabaei Omid Esmaelzade David Pothier Ali Salehi 《中国林学(英文版)》2013,15(4):286-301
The destruction of natural ecosystems is an important issue in many parts of the world. In the west of Iran, a vast area of the Zagros Mountain range is covered by typical vegetation including several rare plant species, of which many are currently considered endangered by anthropogenic activities. Despite the important role of soil seed banks to help conserve these degraded plant communities, the floristic studies in the Zagros forests have only focused on above- ground vegetation. In this study, the characteristics of soil seed banks and above-ground vegetation were examined at two forest sites： an undisturbed control （Un） and a disturbed （D） site. The objectives of this study were 1） to investigate the diversity of above-ground vegetation and soil seed banks in disturbed and undisturbed forests, 2） to examine the soil properties and the germination characteristics of the soil seed bank in disturbed and undisturbed oak forests and 3） to estimate the potential of soil seed banks in the restoration of disturbed sites. The results show that soil properties between Un and D sites were significantly different with higher values of pH, NH4-N, N~o,, CEC, OC, clay and canopy percentage in the Un site than in the D site. The Simpson diversity, Margalef richness and evenness indices differed significantly between sites, either for the soil seed banks or the above-ground vegetation. After a period of 26 weeks, the germination speed and the mean daily number of germinants were significantly different between Un and D sites. Without other conservation measures, soil seed banks alone cannot result in a full recovery after severe disturbances in the oak forests of Zagros. 相似文献
40.
Azizi S Tajbakhsh E Fathi F Oryan A Momtaz H Goodarzi M 《Tropical animal health and production》2012,44(1):113-118
Maedi-visna (MV) is an important slow viral disease of sheep leading to a progressive lymphoproliferative disease. It affects
multiple organs primarily the lungs, where it causes interstitial pneumonia (maedi). In this study, the lungs of 1,000 sheep
carcasses were grossly inspected and those suspected to have maedi were studied at histopathological and molecular levels.
A polymerase chain reaction (PCR) technique that amplified a 291-base pair DNA in the long terminal repeat (LTR) sequence
of MV provirus was conducted on all the 50 suspected lungs together with 10 normal appearing lungs as controls. Amplicons
of the expected size were detected in 11 (n = 11/50) suspected sheep, and one of the 10 control sheep. Histopathologic study of the pulmonary lesions of all 11 (n = 11/11) positive sheep showed MV lesions, including hyperplasia of the perivascular and peribronchiolar lymphoid cells,
interstitial lymphoplasmacytic infiltration and smooth muscle hyperplasia and the histopathologic findings were correlated
with PCR results. In contrast, the tissue sections of control animals were almost normal at histopathological level; however,
PCR technique demonstrated that one of them was affected by maedi. This study showed that the LTR-PCR had high specificity
and sensitivity in diagnosis of this viral infection. This study is the first to evaluate the prevalence of MV virus infection
in sheep in Iran. 相似文献