962 resultados para aflatoxin M1
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利用在束核谱学实验技术,建立了169Re基于9/2-[514]组态的强耦合转动带.该带在已知的奇ARe核中具有最大的低自旋旋称劈列.对于奇ARe中的9/2-[514]转动带,研究了它们的能量旋称劈列和M1跃迁矩阵元相对旋称劈列与核形状偏离轴对称的关系,揭示了非常缺中子的奇ARe核具有相当的负三轴形变.
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利用在束γ谱实验技术 ,通过 12 8Te(10 B ,3n) 13 5La反应研究了 13 5La的高自旋态 .基于γ γ符合关系、γ射线的相对强度和各向异性度的测量结果 ,建立了 13 5La的能级纲图 .在ω≈ 0 .4 0MeV附近 ,观测到基于πh11 2 质子轨道上的负宇称带的带交叉 .比较N =78同中子素链能级结构的系统性 ,认为该带交叉是由一对h11 2 准质子发生转动顺排造成的 .在高自旋态处 ,观测到具有很强M1跃迁、Signature劈裂很小的ΔI =1负宇称带 ,根据系统性认为该带是建立在πh11 2 (νh11 2 ) 2 组态上的γ≈ - 6 0°的扁椭球形变带 .
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利用在束γ谱学方法 ,通过反应1 4 4 Sm( 2 8Si,1p3n) 1 69Re研究了1 69Re的激发态能级结构 .实验进行了X γ符合、γ γ符合、DCO系数和带内B(M1 ) B(E2 )比率测量 .基于这些测量 ,建立了组态为π9 2 - [51 4 ]的强耦合带和组态为π1 2 -[54 1 ]的退耦合带 .通过比较1 69Re的转动带与邻近奇质子核已知转动带的结构和B(M1 ) B(E2 )比率 ,指定了1 69Re转动带的组态 .实验观测到π9 2 - [51 4 ]和π1 2 - [54 1 ]转动带的中子AB带交叉的转动频率分别为 0 .2 3和 0 .2 7MeV .着重讨论了1 69Re转动带的中子AB带交叉频率、转动角动量顺排和旋称劈列等 ,并讨论了奇ARe核转动带结构的系统性
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利用15 4 Sm( 31P ,5nγ) 180 Ir反应产生并研究了双奇核180 Ir的高自旋态 .实验中进行了180 Ir核的在束γ测量 ,包括γ射线的激发函数测量、X γ和γ γ符合测量 ,首次建立了双奇核180 Ir由 5个转动带构成的能级纲图 .依据从实验数据中提取出的带内B(M1 ) /B(E2 )值与理论计算值的比较 ,以及相邻双奇核的带结构特征 ,给出了转动带的准粒子组态 .在推转壳模型的理论框架中 ,定性地讨论了转动带结构特征的组态依赖性
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利用1 4 9Sm( 31 P ,4nγ)反应 ,通过γ射线的激发函数测量、X γ和γ γ符合测量研究了双奇核1 76Ir的高自旋态 .首次建立了双奇核1 76Ir由 4个转动带构成的能级纲图 .依据从实验数据中提取出的带内B(M1 ) B(E2 )值与理论计算值的比较 ,以及相邻双奇核的带结构特征 ,给出了转动带的准粒子组态 .基于本实验建立起的带间跃迁和在I=1 8处观测到的旋称交叉 ,指出1 76Ir核基于πh9 2 νi1 3 2 和πi1 3 2 νi1 3 2 组态的两个转动带在低自旋时出现旋称反转现象 .
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用二维可积系统的半经典量子化方案和二维无关联振子系统的量子能级与周期轨道之间的对应关系 ,讨论了一组量子能级之间具有长程关联的内在机制 ,在二维无关联振子系统中 ,发现了具有相同拓扑M(M1 ,M2 )的周期轨道相对应的量子能级之间存在着长程关联 ,并以二维 4次无关联振子系统为例做了具体说明 .
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通过控制单核能大小 ,将 1 6 O离子注入小麦种子胚乳 ,结果引起 M1 代幼苗可溶性蛋白质的较大变化。可溶性蛋白质电泳凝胶胶片的扫描曲线显示 :1 )在高剂量的处理中 ,有的峰消失 ;有的峰高于对照 ,中、高剂量值呈升高趋势 ;有的峰低于对照 ,中、高剂量值呈下降趋势。 2 )按分子量的大小将可溶性蛋白质分成 5个区段 ,并计算不同区段蛋白质组分的相对含量。结果表明 ,同对照相比 ,第 2区段的相对含量降低 (分子量较大区段 ) ,而第 5区段的相对含量升高 (分子量最小区段 )。 3 )同时也表明 ,低剂量效应表现异常。本文也讨论了诱变胚乳对胚作用的可能机理
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利用中能重离子束辐照生物靶材料时产生的中子、γ射线和次级碎片等次级辐射对春麦种子进行辐照 ,然后通过田间试验和实验室的分析测定 ,得到了 M1代植株的变化 . (1 )在生物学性状中 ,穗粒数、小穗数、千粒重、穗粒重、小穗密度和有效分蘖数变异率较大 ;(2 )除 SOD活性外 ,POD活性、CAT活性、MDA含量和蛋白质含量的变异率也较大 ;(3 )休眠种子和萌发种子辐照M1代在生物学性状的变化上存在很大的差异 ;(4)两个春麦材料的辐射敏感性差异明显 .由此表明 ,兰州重离子加速器辐照终端在进行生物学实验时产生的次级辐射是可能利用的诱变源
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50MeV u碳离子辐照春麦 86 336和 1 46 1 5的休眠和萌发种子。通过M1代生物学性状和苗期POD、SOD和CAT酶活性、蛋白质含量以及MDA含量等研究表明 :1 )同对照相比 ,许多生物学性状的变化表现出萌发种子大于休眠种子 ;除蛋白质含量外 ,SOD酶活性、POD酶活性、CAT酶活性和MDA含量等在休眠种子和萌发种子间差异显著 ;2 )两个春麦材料的表现 ,在有些性状的变化上也有所区别。
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<正>质量数80区的过渡性核表现了集体性和单粒子性的能级结构。对质子数Z为37~40、中子数N=45的原子核,如81Kr,87Mo核,在中低自旋时显示了单粒子特性,而在高自旋态时表现出较多的集体性。 近些年来,在过渡区在束γ谱学,如83Rb、83Y等核研究中,观察到了一串建立在较高K态的增强的△I=1的M1跃迁。它被认为是一种新的激发模式,叫做磁转动带。我们对85Zr的研究目的,一是将其能级推到更高自旋,另一个是寻找该核的磁转动带。
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通过控制单核能大小 ,将 1 2 C离子注入小麦种子胚乳 ,结果引起 M1 代植株的较大变化。这些变化包括 :生物学性状的变异 ;根尖细胞染色体畸变率和微核率的显著提高 ;POD酶活性显著提高和 CAT酶活性、MDA含量和蛋白质含量的较大程度的下降等。本文也讨论了诱变胚乳对胚作用的可能机理
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The effect of C-12(6+) heavy ions bombardment on mutagenesis in Salvia splendens Ker-Gawl. was studied. Dose-response studies indicated that there was a peak of malformation frequency of S. splendens at 200 Gy. Abnormal leaf mutants of the bileaf, trileaf and tetraleaf conglutination were selected. Meanwhile, a bicolor flower chimera with dark red and fresh red flower was isolated in M1 generation of S. splendens. Random amplified polymorphic DNA (RAPD) analysis demonstrated that DNA variations existed among the wild-type, fresh and dark red flower shoots of the chimera. The dark red flower shoots of the chimera were conserved and cultivated at a large-scale through micropropagation. MS supplemented with 2.0 mg/L BA and 0.3 mg/L NAA was the optimal medium in which the maximum proliferation ratio (5.2-fold) and rooting rate (88%) were achieved after 6 weeks. Our findings provide an important method to improve the ornamental quality of S. splendens.
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High-spin states in Pt-187 were studied via the Yb-173(O-18, 4n) reaction. Rotational bands based on the vi(13/2), v7/2(-)[503], vi(13/2)(2)vj, v3/2(-)[512] and v1/2(-)[521] configurations were observed, and interpreted within the framework of the cranked shell model. The TRS calculations show that the vi(13/2) band has an appreciable negative gamma deformation, and the negative-parity bands tend to have a near prolate shape with small positive gamma values. Experimental values of B(M1)/B(E2) ratios have been extracted and compared with theoretical values from the semi-classical Donau and Frauendof approach, strongly suggesting a low frequency pi h(9/2) alignment in the v7/2(-)[503] band.
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A phenol-degrading. microorganism, Alcaligenes faecalis, was used to study the substrate interactions during cell growth on phenol and m-cresol dual substrates. Both phenol and m-cresol could be utilized by the bacteria as,the sole carbon and energy sources. When cells grew on the mixture of phenol and m-cresol, strong substrate interactions were observed. m-Cresol inhibited the degradation of phenol, on the other hand, phenol also inhibited the utilization of m-cresol, the overall cell growth rate was the co-action of phenol and m-cresol. In addition, the cell growth and substrate degradation kinetics of phenol, m-cresol as single and mixed substrates for A. faecalis in batch cultures were also investigated over a wide range of initial phenol concentrations (10-1400 mg L-1) and initial m-cresol concentrations (5-200 mg L-1). The single-substrate kinetics was described well using the Haldane-type kinetic models, with model constants of it mu(m1) = 0.15 h(-1), K-S1 = 2.22 mg L-1 and K-i1 = 245.37 mg L-1 for cell growth on phenol and mu(m2) = 0.0782 h(-1), K-S2 = 1.30 mg L-1 and K-i2 = 71.77 mgL(-1), K-i2' = 5480 (mg L-1)(2) for cell growth on m-cresol. Proposed cell growth kinetic model was used to characterize the substrates interactions in the dual substrates system, the obtained parameters representing interactions between phenol and m-cresol were, K = 1.8 x 10(-6), M = 5.5 x 10(-5), Q = 6.7 x 10(-4). The results received in the experiments demonstrated that these models adequately described the dynamic behaviors of phenol and m-cresol as single and mixed substrates by the strain of A. faecalis.
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High-spin states in Pt-187 have been studied experimentally using the Yb-173(O-18, 4n) reaction at beam energies of 78 and 85 MeV. The previously known bands based on the nu i(13/2),nu 7/2(-)[503], and nu i(13/2)(2)nu j configurations have been extended to high-spin states, and new rotational bands associated with the nu 3/2(-)[512] and nu 1/2(-)[521] Nilsson orbits have been identified. The total Routhian surface calculations indicate that the transitional nucleus Pt-187 is very soft with respect to beta and gamma deformations. The band properties, such as level spacings, band crossing frequencies, alignment gains, and signature splittings, have been compared with the systematics observed in neighboring nuclei and have been interpreted within the framework of the cranked shell model. The rotational bands show different band crossing frequencies, which can be explained by the alignment either of i(13/2) neutrons or of h(9/2) protons. Importantly, evidence is presented for a pi h(9/2) alignment at very low frequency in the nu 7/2(-)[503] band. The proton nature of the band crossing is strongly suggested by comparing the measured B(M1;I -> I-1)/B(E2;I -> I-2) ratios with the theoretical values from the semiclassical Donau and Frauendof approach.