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991.
The nematicidal effect of Pseudomonas fluorescens, Paecilomyces lilacinus, Pichia guilliermondii and Calothrix parietina singly or in combination was tested against root-knot nematode, Meloidogyne incognita. Treatments with P. fluorescens and P. lilacinus caused mortality of M. incognita as 45% and 30% of juveniles after 48 h of exposures, respectively compared to water control in vitro. Under greenhouse conditions, all treatments reduced the disease severity and enhanced plant growth compared to untreated control. Application of P. fluorescens, P. lilacinus and P. guilliermondii Moh 10 was more effective compared to C. parietina. There was a negative interaction between C. parietina and either P. lilacinus or P. guilliermondii. Fresh and dry weight of shoots and roots of plants were significantly reduced as a result of infection with M. incognita, however application of biocontrol agents singly or in mix recovered this reduction. Moreover, they enhanced the growth parameters compared with the control. Our results proved that application of different biocontrol agents (P. fluorescens, P. lilacinus and P. guilliermondii) not only has a lethal effect on nematode, but also enhances the plant growth, supplying many nutritional elements and induction the systemic resistance in plants. Presence of C. parietina as a soil inhabitant cyanobacterium could antagonize biocontrol agents leading to the reduction of their practical efficiency in soil. 相似文献
992.
R. Nirmala Jin Won Jeong Hyun Ju Oh R. Navamathavan Mohamed El-Newehy Salem S. Al-Deyab Hak Yong Kim 《Fibers and Polymers》2011,12(8):1021-1024
We report on the preparation and electrical characterization of nylon-6 nanofibers via electrospinning technique. During electrospinning,
the polymer solution became highly ionized and emerging out of the micro-tip syringe by forming mesh-like ultrafine nanofibers
structure in between the main fibers. The resultant nylon-6 nanofibers were well-oriented with uniform structure. The diameter
of the ultrafine nanofibers (7 to 40 nm) is one order less than those of main fibers (100 to 200 nm). The current-voltage
(I-V) measurements revealed a linear curve with an occurrence of negative differential resistance (NDR) behavior. The existence
of NDR region in the nylon-6 nanofibers can be attributed to the tunneling current through the ultrafine structures. The fabrication
of nanofibers, in the form of ultrafine mesh-like form, is relatively fast and inexpensive, and it paves the way to build
up of new dimension for nano device applications. 相似文献
993.
Noor Hasyierah Mohd Salleh Mohamed Zulkali Mohamed Daud Dachyar Arbain Muhammad Syarhabil AhmadKu Syahidah Ku Ismail 《Industrial Crops and Products》2011,34(3):1635-1640
Response Surface Methodology (RSM) via Central Composite Design (CCD) was used to optimize the alkaline hydrolysis of paddy straw to improve ferulic acid extraction. The parameters involved, namely temperature (°C), concentration of NaOH (M) and duration of extraction (h) are screened by Full Factorial Studies (FFD). The result obtained from FFD was 0.518% (5.18 mg/g). The interactions between each parameters involved were studied using Central Composite Design (CCD). Upon optimization, the percentage of ferulic acid improved from 0.518% to 0.817% (8.17 mg/g). The optimum conditions obtained from this study are 125 °C, 3.90 M, 2.30 h for temperature, concentration of NaOH and extraction time, respectively. This result shows a significant improvement than the previous published work. Details of the experimental design, statistical analysis and interpretation are discussed below. 相似文献
994.
Soil erosion by water is a common environmental problem which can affect the sustainable development and the agriculture of
developing countries especially. Therefore, several countries, threatened by this phenomenon, adopt different measures to
preserve and protect their natural resources. The main purpose of this study was to identify vulnerable areas to establish
a soil erosion risk map in Tunisia. In order to do so, an approach based on a combination of the Revised Universal Soil Loss
Equation (RUSLE) as an erosion model, Geographic Information System (GIS) and Remote Sensing was applied. RUSLE, which is
a model to predict soil loss, is composed of five factors. Erosivity factor (R factor), erodibility factor (K factor), topography factor (LS factor), crop management factor (C factor), and supporting practices factor (P factor). Furthermore, in order to get the most accurate C factor for each land use, times series Moderate Resolution Imaging Spectroradiometer Enhanced Vegetation index (MODIS-EVI)
were used. MODIS-EVI time series was helpful for distinguishing vegetation dynamics with taking into account phenological
variation of the crops. The results indicated that Tunisia has a serious risk of soil erosion. Indeed, about 24.57% of our
study area had a soil loss rate more than 30 t/ha. In these areas, suitable and urgent measures and treatments should be required.
Finally, this approach which is based on remote sensing techniques, GIS and erosion model can be useful for planning appropriate
environmental decision-making policy in a global scale. 相似文献
995.
Ibtissem Hamrouni Sellami Emna Maamouri Thouraya Chahed Wissem Aidi Wannes Mohamed Elyes Kchouk Brahim Marzouk 《Industrial Crops and Products》2009,30(3):395-402
The variation in the content and composition of Origanum majorana L. essential oil has been studied. Plant material has been harvested at four phenological stages (early vegetative, late vegetative, budding and full-flowering). Essential oil yield varied from 0.04 to 0.09% reached during the full-flowering stage. Analysis of the essential oils by GC and GC/MS revealed the presence of 38 components represented mainly by oxygenated monoterpenes (64.01–71.4%), monoterpene hydrocarbons (21.73–29.92%) and sesquiterpene hydrocarbons (1.47–4.05%). The main components were terpinen-4-ol (29.13–32.57%), cis-sabinene hydrate (19.9–29.27%), trans-sabinene hydrate (3.5–11.61%), γ-terpinene (2.11–8.20%), bornyl acetate (1.52–2.94%) and linalool (1.05–1.39%). On the other hand, phenolic contents varied from 2.706 to 6.834 mg/g of dry weight obtained during the later vegetative stage. RP-HPLC analysis of the methanolic extract of O. majorana L. dried aerial parts showed the predominance of phenolic acids during the early vegetative stage whereas flavonoids predominate during the other stages of growth. The main phenolic acids identified were trans-2-hydroxycinnamic, rosmarinic, vanillic, chlorogenic, gallic and cinnamic whereas the main flavonoids were amentoflavone, apigenin, quercetin, luteolin, coumarin and rutin. Results obtained showed that later vegetative stage is characterized by the highest contents of bioactive compounds and therefore it could be considered as the best stage for harvesting marjoram plants. 相似文献
996.
The presence of pesticide residues in wheat produced and imported in South Africa was determined and their health risks assessed. Pesticides were detected in all local (median = 1, range: 1–3, n = 71) and imported (median = 1, range: 1–6, n = 13) samples. Multiple pesticides (>1 pesticide) were detected in about 30% local samples and 39% imported samples. Eight different pesticides were detected in total. The most frequently detected pesticides were mercaptothion (99%), permethrin (19%) and chlorpyrifos (17%). Nine (11%) samples exceeded the EU wheat MRL for permethrin (0.05 mg/kg) which included 7 (10%) local samples and 2 (15%) imported samples. The highest fenitrothion level (0.65 mg/kg) corresponds to an intake that was below but near the estimated short-term safety threshold. The results call for an investigation into the levels of pesticide residues in cereal-based food and for tighter regulation and regular monitoring by government and industry. 相似文献
997.
Background:MLKL, one of the main downstream components of the necroptosis or programmed necrosis has recently been demonstrated in advanced atherosclerotic lesions. However, its precise role in the atherosclerosis pathogenesis still requires more elucidation. Our study was set to delineate both the changes in peripheral MLKL gene expression and its influence on disease severity in atherosclerotic patients with and without type 2 DM. Methods:The study involved 50 patients (20 non-diabetics and 30 diabetics) undergoing coronary artery bypass graft and 20 apparently healthy controls. Taqman RT-PCR was used to quantify MLKL mRNA expression levels, while ELISA was employed to estimate serum insulin and hsCRP levels. Results:Compared with the control group, MLKL gene was up regulated significantly in CVD (p ≤ 0.001). Higher MLKL expression was demonstrated in diabetic CVD group than non-diabetic group (p < 0.05). Correlation studies reported positive associations between MLKL and markers of dyslipidemia, inflammation, and insulin resistance. Multiple regression analysis revealed that FBG levels, hsCRP levels, and total WBCs count were significant predictors for MLKL levels. ROC showed a significant diagnostic value of MLKL for CVD. Moreover, regression analysis demonstrated that MLKL and hsCRP were independent predicting factors for the severity of CVD. Conclusion:MLKL is linked to hallmarks of atherosclerosis and could explain increased cardiovascular risk in diabetic patients. Thus, it can be a potential drug target for treatment of atherosclerotic patients. Key Words: Atherosclerosis, Diabetes mellitus, Inflammation, Insulin resistance, Necroptosis 相似文献
998.
Preparation of boron-selective adsorbent was carried out by radiation induced grafting of glycidyl methacrylate (GMA) onto polyethylene-coated polypropylene (PE-PP) nonwoven fabric in emulsion or solvent medium followed by immobilization of N-methyl-D-glucamine (NMDG). Adsorbent precursors with 180 % degree of grafting (DG) were obtained by applying reaction parameters comprising 20 kGy dose, 5 % monomer concentration and 1 h reaction time in emulsion compared to 30 kGy, 10 % and 3 h in solvent medium. A glucamine density of 2.2 mmol/g could be imparted to the obtained adsorbents. The emulsion-mediated grafting was found more efficient and economical for preparation of boron chelating adsorbents. 相似文献
999.
Four new cembranoids, lobophylins A-D (1-4), and one novel secocembrane, lobophylin E (5) were isolated from a soft coral Lobophytum sp. The structures of new metabolites were elucidated on the basis of extensive spectroscopic methods. Among these metabolites, 1-4 are rarely found cembranoids possessing a tetrahydrofuran moiety with a 3,14-ether linkage. In addition, 5 is the first secocembrane possessing two tetrahydrofuran moieties with 3,14- and 4,7-ether linkages. 相似文献
1000.
The genetic diversity and population structure of two Tunisian Thymus species (Thymus algeriensis and Thymus capitatus), from 46 natural populations growing in six bioclimates, were analysed by starch gel electrophoresis using eight isozymes. The genetic diversity within populations varied at species level. Variation in T. algeriensis was higher than that observed for T. capitatus, and exclusive alleles were detected for the two studied species. A high differentiation among populations, for each species, estimated by Wright's F-statistics was revealed. In each species, a high level of inbreeding within populations induced by Wahlund effect was observed. A relatively high level of differentiation associated with a restricted gene flow among species was revealed. The PCA and UPGMA analysis, performed on all populations, showed two distinct groups with respect of specific differentiation level. The high genetic divergence between the two species corroborates their taxonomic status, as previously reported using morphological traits. The strategy for the management and conservation of populations should be made for each taxa according to its level of diversity and bioclimate. 相似文献