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Brassinosteroids (BRs) are steroidal phytohormones that regulate various physiological processes, such as root development and stress tolerance. In the present study, we showed that brassinolide (BL) affects potato root in vitro growth in a dose-dependent manner. Low BL concentrations (0.1 and 0.01 μg/L) promoted root elongation and lateral root development, whereas high BL concentrations (1–100 μg/L) inhibited root elongation. There was a significant (P<0.05) positive correlation between root activity and BL concentrations within a range from 0.01 to 100 μg/L, with the peak activity of 8.238 mg TTC·g−1 FW·h−1 at a BL concentration of 100 μg/L. Furthermore, plants treated with 50 μg/L BL showed enhanced salt stress tolerance through in vitro growth. Under this scenario, BL treatment enhanced the proline content and antioxidant enzymes’ (superoxide dismutase, peroxidase, and catalase) activity and reduced malondialdehyde content in potato shoots. Application of BL maintain K+ and Na+ homeostasis by improving tissue K+/Na+ ratio. Therefore, we suggested that the effects of BL on root development from stem fragments explants as well as on primary root development are dose-dependent and that BL application alleviates salt stress on potato by improving root activity, root/shoot ratio, and antioxidative capacity in shoots and maintaining K+/Na+ homeostasis in potato shoots and roots. [ABSTRACT FROM AUTHOR]

A novel method for the synthesis of the 17-deoxyroflamycoin roflamycoin analog was developed based on a series of alkylation reactions. The synthetic process was characterized by the alkylation of a nitrile anion with bromide to produce an intermediate product. The C6 iodide for the secondary alkylation reaction was synthesized via the deprotection and iodination of the intermediate product. The dinitrile from the second alkylation reaction is also a protected polyol that undergoes phosphonopropionate ester synthesis to produce the desired 17-deoxyroflamycoin.

A series of substituted isoquinolinones were synthesized and their binding affinities and functional activities towards human melatonin MT1 and MT2 receptors were evaluated. Structure-activity relationship analysis revealed that substituted isoquinolinones bearing a 3-methoxybenzyloxyl group at C5, C6 or C7 position respectively (C5>C6>C7 in terms of their potency) conferred effective binding and selectivity toward the MT2 receptor, with 15b as the most potent compound. Most of the tested compounds were MT2-selective agonists as revealed in receptor-mediated cAMP inhibition, intracellular Ca2+ mobilization and phosphorylation of extracellular signal-regulated protein kinases. Intriguingly, compounds 7e and 7f bearing a 4-methoxybenzyloxyl group or 4-methylbenzyloxyl at C6 behaved as weak MT2-selective antagonists. These results suggest that substituted isoquinolinones represent a novel family of MT2-selective melatonin ligands. The position of the substituted benzyloxyl group, and the substituents on the benzyl ring appeared to dictate the functional characteristics of these compounds. [ABSTRACT FROM AUTHOR]

Oleanolic acid (3β-hydroxy-olea-12-en-28-oic acid) is a natural pentacyclic triterpenoic acid found in many fruits, herbs and medicinal plants. In the past decade, increasing evidence has suggested that oleanolic acid exhibits inhibitory activities against different types of cancer including skin cancer and colon cancer, but not leukemia. We report here that a derivative of oleanolic acid, olean-12-eno[2,3-c] [1], [2], [5]oxadiazol-28-oic acid (designated OEOA) effectively blocks the proliferation of human leukemia cells. OEOA significantly reduces cell proliferation without inducing cell death in three types of leukemia cell lines, including K562, HEL and Jurket. Moreover, exposure of K562 cells to OEOA results in G1 cell cycle arrest, with a concomitant induction of cyclin-dependent kinase inhibitor p27 and downregulation of cyclins and Cdks that are essential for cell cycle progression. Interestingly, OEOA also enhances erythroid differentiation in K562 cells through suppressing the expression of Bcr-Abl and phosphorylation of Erk1/2. These findings identify a novel chemical entity for further development as therapeutics against leukemia. [ABSTRACT FROM AUTHOR]

In clinical study, calculation for sample size is often done using the frequentist framework. However, several methods of calculation using the Bayesian framework have been proposed. In this paper, we propose a method for the determination of sample sizes using the index where X1 and X2 denote the binomial random variables for trials n1 and n2 and parameters π1 and π2, respectively. In this paper, we propose a new method of calculation, by which we determine in advance the estimated difference between the posterior proportions and the value to be derived at the end of the test to obtain the necessary sample size. We provide the lists of necessary sample sizes with various assumptions and the calculation program using Mathematica. [ABSTRACT FROM AUTHOR]

Nonparametric tests are commonly used tests for two sample comparison in clinical studies. However, the estimation of treatment effects associated with the tests may not be obvious, especially under the covariate adjustment. In this article, we evaluated the effect of covariate adjustment on estimating treatment effects based on the Wilcoxon Rank Sum test, the van Elteren test, aligned rank test, and Jaeckel, Hettmansperger-McKean test through Monte Carlo simulations via mean square error and coverage probability. Based on the simulation, commonly used ANCOVA-based approach do not have good estimation of treatment effect when the covariate imbalance is severe. Aligned rank test seems perform well across most scenarios. [ABSTRACT FROM AUTHOR]

Meta-analysis is a statistical methodology that combines the outcomes of several independent studies. Either a fixed-effects or a random-effectsmodel is used to combine the results of the independent studies. The choice depends on whether the outcomes can be considered homogeneous or not. Several methods have been developed to test the homogeneity of effect sizes. Although many of them have been compared already, they have not been studied in more realistic practical settings where individuals all have their own risk of an event and a complete overview is lacking. In this article, we investigate the performance of 10 statistical methods to test homogeneity of a binary exposure on a binary clinical outcome, using an extensive simulation study and a real life meta-analysis. We evaluated the Type I error and the statistical power. The fixed-effects regression model for treatment and study interactionwas found to be a slightly liberal test, while the Q-statistic and the Bliss statistic can be considered conservative tests. The random-effects regression model, the Peto statistic and the I2 perform rather poorly compared to the other methods. All chisquare tests that are based on the calculation of a specific odds ratio and the fixed-effects logistic regression analysis perform best. Among these chi-square tests, we recommend the Breslow-Day test, but only for convenience purposes, since it is available in most statistical software packages and the other tests are not. [ABSTRACT FROM AUTHOR]

This paper considers the estimation of parameters based on a progressively type-I interval-censored data from a mixed generalized exponential distribution. The maximum likelihood estimation is used but an analytic form cannot be obtained. The EM algorithm is applied to obtain the maximum likelihood estimates. The performance of the estimates is judged by a simulating study and a real data is presented to illustrate the method of estimation developed here. [ABSTRACT FROM AUTHOR]