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71.
Alteration in expression of miRNAs can cause various malignant changes and the metastatic process. Our aim was to identify the miRNAs involved in cervical squamous cell carcinoma (SqCC) and metastasis, and to test their utility as indicators of metastasis and survival. Using microarray technology, we performed miRNA expression profiling on primary cervical SqCC tissue (n = 6) compared with normal control (NC) tissue and compared SqCC that had (SqC-M; n = 3) and had not (SqC-NM; n = 3) metastasized. Four miRNAs were selected for validation by qRT-PCR on 29 SqC-NM and 27 SqC-M samples, and nine metastatic lesions (ML-SqC), from a total of 56 patients. Correlation of miRNA expression and clinicopathological parameters was analyzed to evaluate the clinical impact of candidate miRNAs. We found 40 miRNAs differentially altered in cervical SqCC tissue: 21 miRNAs were upregulated and 19 were downregulated (≥2-fold, p < 0.05). Eight were differentially altered in SqC-M compared with SqC-NM samples: four were upregulated (miR-494, miR-92a-3p, miR-205-5p, and miR-221-3p), and four were downregulated (miR-574-3p, miR-4769-3p, miR-1281, and miR-1825) (≥1.5-fold, p < 0.05). MiR-22-3p might be a metastamiR, which was gradually further downregulated in SqC-NM > SqC-M > ML-SqC. Downregulation of miR-30e-5p significantly correlated with high stage, lymph node metastasis, and low survival rate, suggesting an independent poor prognostic factor.  相似文献   
72.
Efficient gas recovery and separation in a hydrate-based system was investigated for a model gaseous mixture of R22 and nitrogen. The formed hydrate settled in the recovery vessel; excess water was recycled and the hydrate was subsequently decomposed by releasing pressure from the vessel. The gas uptake rate of R22 gas from the vapor phase and the gas recovery rate from the hydrate were determined from hydrate formation and decomposition, respectively. The gas recovery rate of R22 gas gradually increased with time. On the contrary, the nitrogen gas recovery rate was a maximum in the initial stage of hydrate decomposition. A high separation factor (S.F.) was achieved by first separating the N2-rich gas generated during initial hydrate decomposition. An efficient hydrate-based gas separation and recovery process is proposed.  相似文献   
73.
In this article we propose a new correction for the penalty term of the Akaike’s information criterion (AIC), when it is used in the context of order selection for an autoregressive fit of the spectral density of a stationary time series. The classical AIC penalty term may be viewed as an approximation of an appropriate target quantity. Simulations show that the quality of this approximation strongly depends on the type of autoregressive estimator used, as well as on the discrepancy used. Therefore here we consider the least squares autoregressive estimator and the Whittle discrepancy only. In this context we propose a closed formula correction of the AIC penalty term. We also develop asymptotic theory which justifies this proposal: an asymptotically valid second‐order expansion of a stochastic approximation of the target quantity. This expansion assumes a non‐parametric framework: it does not assume gaussianity of the process and only requires its spectral density to be smooth enough. Simulations show that, as compared to previously introduced corrections, this new correction performs similarly to finite sample information criterion, while they both outperform AIC corrected and AIC.  相似文献   
74.
目的 在大肠杆菌中表达、纯化重组靶向毒素hIL6(T22)-PE38,并检测其细胞毒性。方法以PHis-hIL6(T22)-PE38质粒为模板,PCR扩增hIL6(T22)-PE38基因,插入表达载体pET-28a(+)的NcoⅠ和XhoⅠ多克隆位点,构建重组表达质粒,分别转化至大肠杆菌BL21(DE3)、Rosettablue(DE3)和BL21(DE3)pLysS中,IPTG诱导表达,并对表达条件进行优化。表达产物经亲和层析纯化后,检测其细胞毒性。结果重组表达质粒pET-28a-hIL6(T22)-PE38经双酶切和测序证明构建正确。表达的重组毒素相对分子质量约56 000,在大肠杆菌Rosettablue(DE3)中表达量最高。最适诱导表达条件为:1 mmol/L IPTG 28℃诱导4 h。重组毒素能选择性地杀伤人骨髓瘤细胞U266和鼠骨髓瘤细胞SP2/0,体外对U266和SP2/0细胞的IC50分别为0.5~1.0和1.0~1.5μg/ml。结论重组靶向毒素hIL6(T22)-PE38在大肠杆菌中成功获得可溶性表达,纯化的蛋白可明显选择性杀伤U266和SP2/0细胞。  相似文献   
75.
李晋  朱开宪  谢顶衫 《广东化工》2011,38(5):149-150
R-(-)-N,N-二乙基-2(α-萘氧基)丙酰胺是高效旋光性除草剂。它以α-萘酚、氯丙酸和二乙胺为原材料合成,分别用成盐拆分法、定向合成法和优先结晶法制得。通过比较,优先结晶法折分工艺先进,适合于工业化生产。经HPLC检测,光学纯度≥98%。经药效试验表明,R-(-)-N,N-二乙基-2(α-萘氧基)丙酰胺的药效是S-(+)-N,N-二乙基-2(α-萘氧基)丙酰胺的8倍,是(±)-N,N-二乙基-2(α-萘氧基)丙酰胺的1.7~2倍。  相似文献   
76.
徐会青  刘全杰  贾立明 《当代化工》2011,(9):881-884,892
采用动态水热晶化法,通过加入结构导向剂,在较短的时间内成功合成出结晶度良好的ZSM-22分子筛。结果表明,结构导向剂能够明显影响分子筛的合成过程,尤其是能够大幅度缩短晶化时间,与常规方法相比,晶化时间由36 h缩短到20 h。采用XRD、SEM、TG-DTA技术,对合成的ZSM-22分子筛表征,并考察了一些参数对合成过程的影响。  相似文献   
77.
ZSM-22是一种高硅铝比分子筛,由于特殊的孔道结构,在异构化和烷基化反应中表现出较好的选择性和催化性能,近年来备受关注。综述了ZSM-22分子筛的结构特征、合成研究进展及各种合成因素的影响。  相似文献   
78.
5种杀虫剂对玉米螟的药效评价   总被引:4,自引:0,他引:4  
张强  罗万春  李慧冬 《农药》2001,40(9):26-26,29
在田间用5种常用杀虫剂对玉米螟作了药效试验,试验采用“撒毒沙”和“灌心叶”两种施药方法,旨在寻求更加方便、适用、有效的防治玉米螟的药剂和方法。试验表明供试5种药剂对玉米螟均有优良的防治效果,且“撒毒沙”施药防效好于“灌心叶”施药。  相似文献   
79.
This article considers the problem of order selection of the vector autoregressive moving‐average (VARMA) models under the assumption that the errors are uncorrelated but not necessarily independent. These models are called weak VARMA by opposition to the standard VARMA models, also called strong VARMA models, in which the error terms are supposed to be i.i.d. We relax the standard independence assumption to extend the range of application of the VARMA models, allowing us to treat linear representations of general nonlinear processes. We propose a modified version of the Akaike information criterion for identifying the orders of weak VARMA models.  相似文献   
80.
This article proposes methods for testing the null hypothesis that a number of so‐called long run canonical correlations (LRCCs) are zero. Two test statistics are proposed and their limiting distributions are derived under the null hypothesis. The finite sample properties of the tests are illustrated via a number of simulation studies that reveal the asymptotic theory provides a good guidance to behaviour in moderate or large sized samples. It is shown that the statistics provide a natural way for testing the asymptotic independence of two standardized sums. The usefulness of the tests is illustrated via the following examples: inference about cointegrating vector in a particular cointegration model; inference about break points in a cointegration model; moment estimation; parameter estimation in Generalized Method of Moments estimation.  相似文献   
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