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41.
Correlation of phenolic acid content of maize to resistance toSitophilus zeamais,the maize weevil,in CIMMYT'S collections 总被引:2,自引:0,他引:2
D. Classen J. T. Arnason J. A. Serratos J. D. H. Lambert C. Nozzolillo B. J. R. Philogéne 《Journal of chemical ecology》1990,16(2):301-315
The (E)-ferulic acid content of the grain of nine populations of land races of maize derived from CIMMYT's collections was found to be negatively correlated to susceptibility characteristics towards the maize weevilSitophilus zeamais. Correlation coefficients for six susceptibility parameters and (E)-ferulic acid content were significant and ranged from –0.58 to –0.79. A multiple regression analysis by the SAS forward procedure using the primary seed characteristics associated with susceptibility indicated that the ferulic acid content was the only significant factor in explaining variation in at least two susceptibility parameters: the Dobie index and adult preference. In 15 CIMMYT pools, correlations between four susceptibility parameters and (E)-ferulic acid content were also significant (–0.76 to –0.81). The results suggest that phenolic acid content is a leading indicator of grain resistance or susceptibility to insects and may represent a newly identified mechanism of resistance. 相似文献
42.
Two samples of naturally occurring pyrite were treated with acetyl acetone, silanes, humic acids, lignin-NaOH mixture, and oxalic acid. The corrosion rate of pyrite was observed to decrease significantly due to the surface treatment by the chemicals used in this study. Surface characterization methods indicate that phenyl triacetoxy silane forms a passive coating a few Angstroms thick on the pyrite, thus preventing its dissolution in 1M H2SO4. 相似文献
43.
将稀土固体超强酸与微波辐射技术相结合研究蔗糖酯的合成,考察了微波辐射功率、反应时间、催化剂、乳化剂对反应的影响。结果表明,当辐射功率为390W、反应时问为20min时,稀土固体超强酸Gd^3+(Y^3+)-SO4^2-/ZrO2对合成蔗糖酯的催化活性优于常规催化剂无水碳酸钾。并且微波辐射使反应时间从传统减压加热4~8h缩短到常压反应20min。 相似文献
44.
Insect cuticle as a natural biocomposite includes many favored microstructures which have been refined over centuries and endow the cuticle eminent mechanical properties. This paper first studies the microstructures of chafer cuticle through SEM observations. Several peculiar fiber configurations and fiber-ply arrangements such as branched fiber, acanth-fiber and helicoid plies are observed. These microstructures are useful for man-made fiber-reinforced composites to improve their mechanical properties. Then, a special configuration of the branched fiber found in chafer cuticle is in details analyzed through a mechanical model and experimental verification. The pullout force of fibers as an index is firstly studied through parameter study. The factors, which can improve the pullout forces, are identified. Finally, the maximal pullout force of the branched fiber is experimentally tested and compared with that of plain straight fiber. It is proved that the maximal pullout force of branched fibers is obviously greater than that of the plain straight fibers. 相似文献
45.
以癸酸(CA)、肉豆蔻酸(MA)、硬脂酸(SA)三元低共熔物为相变材料,有机改性蒙脱土(OMMT)为层状封装材料,采用熔融浸渗法制备 CA-MA-SA/OMMT 复合相变材料,相变材料和层状材料的最佳质量比 m(CA-MA-SA)∶m(OMMT)=7∶3。采用 X 射线衍射(XRD)、红外光谱(FT-IR)和差示扫描量热分析(DSC)对复合相变材料的结构、性能进行表征。结果表明:三元脂肪酸低共熔物被有效封装在改性后的蒙脱土层间,复合相变材料的相变温度为20.14℃,相变潜热为89.14 J·g-1。相变动力学分析结果,复合相变材料的相变反应级数为1.18,活化能为14.22 kJ·mol-1。活化能说明低共熔物与蒙脱土之间是嵌合关系,不是化学吸附。 相似文献
46.
GC/MS分析纸浆及沉积树脂中脂肪酸组成 总被引:3,自引:0,他引:3
本文用色谱-质谱联用分析了纸浆及其沉积物的树脂中的脂肪酸成分。结果表明:纸浆中脂肪酸成分主要是油酸、9,11-十八碳二烯酸和软脂酸。沉积树脂的脂肪配成分基本上与之相同。纸浆中甘油三酸酯的脂肪酸的主要成分是油酸和软脂酸。纸浆中的甘油三酸酯是导致制浆造纸过程中产生树脂障碍的主要有害成分之一。 相似文献
47.
Ning-Wei Lai Zhi-Chao Zheng Dan Hua Jiang Zhang Huan-Huan Chen Xin Ye Zeng-Rong Huang Jiuxin Guo Lin-Tong Yang Li-Song Chen 《International journal of molecular sciences》2022,23(10)
Low pH-induced alterations in gene expression profiles and organic acids (OA) and free amino acid (FAA) abundances were investigated in sweet orange [Citrus sinensis (L.) Osbeck cv. Xuegan] leaves. We identified 503 downregulated and 349 upregulated genes in low pH-treated leaves. Further analysis indicated that low pH impaired light reaction and carbon fixation in photosynthetic organisms, thereby lowering photosynthesis in leaves. Low pH reduced carbon and carbohydrate metabolisms, OA biosynthesis and ATP production in leaves. Low pH downregulated the biosynthesis of nitrogen compounds, proteins, and FAAs in leaves, which might be conducive to maintaining energy homeostasis during ATP deprivation. Low pH-treated leaves displayed some adaptive responses to phosphate starvation, including phosphate recycling, lipid remodeling, and phosphate transport, thus enhancing leaf acid-tolerance. Low pH upregulated the expression of some reactive oxygen species (ROS) and aldehyde detoxifying enzyme (peroxidase and superoxidase) genes and the concentrations of some antioxidants (L-tryptophan, L-proline, nicotinic acid, pantothenic acid, and pyroglutamic acid), but it impaired the pentose phosphate pathway and VE and secondary metabolite biosynthesis and downregulated the expression of some ROS and aldehyde detoxifying enzyme (ascorbate peroxidase, aldo-keto reductase, and 2-alkenal reductase) genes and the concentrations of some antioxidants (pyridoxine and γ-aminobutyric acid), thus disturbing the balance between production and detoxification of ROS and aldehydes and causing oxidative damage to leaves. 相似文献
48.
精炼吊瓜籽油的脂肪酸分析 总被引:1,自引:0,他引:1
对压榨吊瓜籽毛油进行了精炼,计算出得率为54%。采用GC分析、比较了吊瓜籽精油、橄榄油和菜籽油的脂肪酸组分,表明吊瓜籽油中油酸、亚油酸含量为8.48%、33.6%,亚油酸含量高于橄榄油(8.48%)和菜籽油(13.03%).经过GC-MS确证,吊瓜籽含有丰富的角鲨烯(22.7%),是营养保健物质的新型来源. 相似文献
49.
Matteo Sibilano Valentina Tullio Gaspare Adorno Isabella Savini Valeria Gasperi Maria Valeria Catani 《International journal of molecular sciences》2022,23(10)
Among the surrounding cells influencing tumor biology, platelets are recognized as novel players as they release microvesicles (MVs) that, once delivered to cancer cells, modulate signaling pathways related to cell growth and dissemination. We have previously shown that physiological delivery of platelet MVs enriched in miR-126 exerted anti-tumor effects in different breast cancer (BC) cell lines. Here, we seek further insight by identifying AKT2 kinase as a novel miR-126-3p direct target, as assessed by bioinformatic analysis and validated by luciferase assay. Both ectopic expression and platelet MV-mediated delivery of miR-126-3p downregulated AKT2 expression, thus suppressing proliferating and invading properties, in either triple negative (BT549 cells) or less aggressive Luminal A (MCF-7 cells) BC subtypes. Accordingly, as shown by bioinformatic analysis, both high miR-126 and low AKT2 levels were associated with favorable long-term prognosis in BC patients. Our results, together with the literature data, indicate that miR-126-3p exerts suppressor activity by specifically targeting components of the PIK3/AKT signaling cascade. Therefore, management of platelet-derived MV production and selective delivery of miR-126-3p to tumor cells may represent a useful tool in multimodal therapeutic approaches in BC patients. 相似文献
50.
Xi Li Fabin Qiu Kui Guo Bo Zou Jianmin Gu Jing Wang Baokun Xu 《Materials Chemistry and Physics》1997,50(3):1105-232
Nanocrystalline Ba1−xSrxTiO3 (x=0, 0.2, 0.4, 0.6, 0.8 and 1.0) precursors were synthesized using the stearic acid gel method. After the precursors had been calcined at 600–950°C for 0.5–1 h, nanocrystalline powders with the cubic perovskite structure were obtained and these were made into thick films. The powder samples were characterized by differential thermal analysis, X-ray diffraction and transmission electron microscopy, and the thick film samples were characterized by scanning electron microscopy and X-ray diffraction. The humidity-sensitive properties of the nanocrystalline Ba1−xSrxTiO3 thick films were investigated. The results show that these nanocrystalline thick films possess higher humidity sensitivity and lower resistance than those of conventional materials. 相似文献