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321.
Summary . We consider analysis of clustered data with mixed bivariate responses, i.e., where each member of the cluster has a binary and a continuous outcome. We propose a new bivariate random effects model that induces associations among the binary outcomes within a cluster, among the continuous outcomes within a cluster, between a binary outcome and a continuous outcome from different subjects within a cluster, as well as the direct association between the binary and continuous outcomes within the same subject. For the ease of interpretations of the regression effects, the marginal model of the binary response probability integrated over the random effects preserves the logistic form and the marginal expectation of the continuous response preserves the linear form. We implement maximum likelihood estimation of our model parameters using standard software such as PROC NLMIXED of SAS . Our simulation study demonstrates the robustness of our method with respect to the misspecification of the regression model as well as the random effects model. We illustrate our methodology by analyzing a developmental toxicity study of ethylene glycol in mice. 相似文献
322.
Sixteen new and one known metabolites 4-20 were obtained by incubation of tibolone (1) and hydroxytibolones (2 and 3) with various fungi. Their structures were elucidated by means of a homo and heteronuclear 2D NMR and by HREI-MS techniques. The relative stereochemistry was deduced by 2D NOESY experiment. Metabolites of tibolone (1) exhibited significant inhibitory activities against α-glucosidase and tyrosinase enzymes. Hydroxylations at C-6, C-10, C-11, C-15 positions and α,β-unsaturation at C-1/C-2, C-4/C-5 showed potent inhibitory activities against these enzymes. 相似文献
323.
通过构建pVB4215植物双元表达载体,采用农杆菌介导法转化烟草,研究VviDREB1在植物体中的异源表达特性.结果显示,实验获得了25个Hyg抗性株系,经过PCR、RT-PCR和GUS组织化学染色检测及Hyg基因的PCR复检等多点验证,证实表达载体边界内序列完整地整合到2个烟草株系的基因组中.转基因烟草株系在4℃低温处理20 h后,恢复生长5 h,叶片光系统PSⅡ抗寒性分析结果表明,转基因植株的叶片快速叶绿素荧光曲线OJIP各点数值高于对照植株,VviDREB1基因能够显著提高烟草的荧光产量,最大光化学效率Fv/Fm和以吸收光能为基础的性能指数PIABS较对照高,说明VviDREB1对保护植物组织细胞内光合系统PSⅡ有明显的作用,转VviDREB1基因烟草对低温有一定的忍耐能力. 相似文献
324.
325.
A minimal linear gene cassette (35S-phytase gene-nos) with T-DNA borders was acquired by PCR and directly introduced into
soybean through the pollen tube pathway. A total of 13% of T1 plants were positive for phyA by specific PCR. Southern blot analyses showed that phyA insertions were harbored stably in T2 progeny. Phytase expression level increased 2.5-fold over a 6-week period; its highest activity was 150 U/mg protein, compared
to 56 U/mg protein in untransformed controls. Activity of phytase increased to 125 FTU/kg in T3 transgenic seeds as compared to 64 FTU/kg in wild-type plants. 相似文献
326.
Joo Mi Jeon Nam Young Ahn Bo Hwa Son Cha Young Kim Chang-deok Han Gun-Do Kim Sang Wan Gal Sung-Ho Lee 《Plant Cell, Tissue and Organ Culture》2007,88(2):225-232
PEG-mediated transformation was used for gene delivery and evaluation of various parameters affecting the transient expression of a gene for ß-glucuronidase (gus) in mesophyll protoplasts of Capsicum annuum. Transient expression was found to be dependent on PEG concentration and exposure time of plasmid DNA to protoplasts as well as the amount of plasmid DNA. Maximum GUS activity was obtained when protoplasts were applied to 40% concentration and molecular weight was 6,000 of PEG solution with 30 min of exposure time. Protoplasts of pepper were transformed with a vector, pCAMBIA::Ac, which contained a pCAMBIA1302 T-DNA vector carrying a maize transposable element, Ac (activator), a selection marker HPT (hygromycin phosphotransferase), and a GFP-coding region driven by the 35S promoter in the presence of PEG. Approximately 30% of the protoplasts expressed GFP. Visibly transformed colonies were obtained from protoplasts after 2 months of culture and GFP was expressed. Southern hybridization confirmed the presence of Ac in the pepper genome. 相似文献
327.
Tileye Feyissa Li-Hua Zhu Legesse Negash Margareta Welander 《Plant Cell, Tissue and Organ Culture》2007,88(3):277-288
The effects of growth regulators, wounding and antibiotics on regeneration of Hagenia abyssinica were investigated and the rolB gene was introduced into this species by Agrobacterium-mediated transformation. Regeneration was affected by type of growth regulators, wounding and antibiotics. Up to 100% regeneration
could be obtained. Three transformed clones (T1, T2.1, T2.2), confirmed by PCR and Southern blot, were obtained only by excluding
kanamycin from the selection medium 6 weeks after culture, followed by selection during shoot multiplication. RT-PCR revealed
strong expression of rolB gene in shoots and roots of all the transgenic clones, but from leaf samples, it was detected only in T1. Rooting frequency
was 77% (T1), 50% (T2.1), 57% (T2.2) and 0% for control shoots on growth regulator-free rooting medium. 相似文献
328.
Yamagishi K Kimura T Oita S Sugiura T Hirai H 《Applied microbiology and biotechnology》2007,76(5):1079-1091
Phanerochaete sordida YK-624 is a hyper lignin-degrading basidiomycete possessing greater ligninolytic selectivity than either P. chrysosporium or Trametes versicolor. To construct a gene transformation system for P. sordida YK-624, uracil auxotrophic mutants were generated using a combination of ultraviolet (UV) radiation and 5-fluoroorotate resistance
as a selection scheme. An uracil auxotrophic strain (UV-64) was transformed into a uracil prototroph using the marker plasmid
pPsURA5 containing the orotate phosphoribosyltransferase gene from P. sordida YK-624. This system generated approximately 50 stable transformants using 2 × 107 protoplasts. Southern blot analysis demonstrated that the transformed pPsURA5 was ectopically integrated into the chromosomal DNA of all transformants. The enhanced green fluorescent protein (EGFP) gene
was also introduced into UV-64. The transformed EGFP was expressed in the co-transformants driven by P. sordida glyceraldehyde-3-phosphate dehydrogenase gene promoter and terminator regions. 相似文献
329.
Sehye Kim 《Inorganica chimica acta》2007,360(6):1870-1874
A new organic-inorganic hybrid solid with 3-D framework, [Mn(DMF)3]2[Re6Se8(CN)6] (1), has been synthesized and transformed to [H][Mn(salen)]3[Re6Se8(CN)6] (2) by a ligand exchange. Hexarhenium chalcocyanide clusters are closest packed in cubic symmetry for 1 and rhombohedral symmetry for 2. The manganese complexes in the interstitial sites are three-coordinated to the rhenium cluster in 1 and two-coordinated in 2. 相似文献
330.
Numerous brain regions encode variables using spatial distribution of activity in neuronal maps. Their specific geometry is usually explained by sensory considerations only. We provide here, for the first time, a theory involving the motor function of the superior colliculus to explain the geometry of its maps. We use six hypotheses in accordance with neurobiology to show that linear and logarithmic mappings are the only ones compatible with the generation of saccadic motor command. This mathematical proof gives a global coherence to the neurobiological studies on which it is based. Moreover, a new solution to the problem of saccades involving both colliculi is proposed. Comparative simulations show that it is more precise than the classical one. 相似文献