Unlike other widely known Aloe species used for treatment of rheumatoid arthritis, this species suffers from a lack of sufficient studies on its biological and chemical characters. This is what drove us to perform this work to evaluate the in vivo anti-arthritic potential of its leaf ethanolic extract. The in vivo anti-arthritic activity of the leaf ethanolic extract at 100 and 200 mg/kg/day b.wt. was evaluated alone and in combination with methotrexate (MTX) using complete Freund’s adjuvant. Serum levels of rheumatoid factor, anti-cyclic citrullinated peptide (anti-CCP), cytokines pro-inflammatory marker, inflammatory mediator serum levels, and oxidative stress mediators were analyzed, in addition to liver function. Orientin, isoorientin, β-sitosterol, its palmitate and its glucoside were isolated. The combined therapy of MTX and the leaf ethanolic extract (especially at 200 mg/kg b.wt.) group showed better activity compared to MTX alone. Moreover, the combined therapy provided additional benefits in lowering the liver toxicity by comparison to MTX alone. We concluded that a synergetic combination of the leaf ethanolic extract and MTX is beneficial in the management of rheumatoid arthritis with fewer side effects on liver function, as well as the possibility of the leaf extract to stand alone as an effective natural anti-arthritic agent.

This paper is devoted to study a new four- parameter additive model. The newly suggested model is referred to as the flexible Weibull extension-Burr XII distribution. It is derived by considering a serial system with one component following a flexible Weibull extension distribution and another following a Burr XII distribution. The usefulness of the model stems from the flexibility of its failure rate which accommodates bathtub and modified bathtub among other risk patterns. These two patterns have been widely accepted in several fields, especially reliability and engineering fields. In addition, the importance of the new distribution is that it includes new sub-models which are not known in the literature. Some statistical properties of the proposed distribution such as quantile function, the mode, the rth moment, the moment generating function and the order statistics are discussed. Moreover, the method of maximum likelihood is used to estimate the parameters of the model. Also, to evaluate the performance of the estimators, a simulation study is carried out. Finally, the performance of the proposed distribution is compared through a real data set to some well-known distributions including the new modified Weibull, the additive Burr and the additive Weibull distributions. It is shown that the proposed model provides the best fit for the used real data set.

Purpose This paper presents economic and economic–statistical designs of the adaptive exponentially weighted moving average (AEWMA) control chart for monitoring the process mean. It also aims to compare the effect of estimated process parameters on the economic performance of three charts, which are Shewhart, exponentially weighted moving average and AEWMA control charts with economic–statistical design. Design/methodology/approach The optimal parameters of the control charts are obtained by applying the Lorenzen and Vance’s (1986) cost function. Comparisons between the economic–statistical and economic designs of the AEWMA control chart in terms of expected cost and statistical measures are performed. Also, comparisons are made between the economic performance of the three competing charts in terms of the average expected cost and standard deviation of expected cost. Findings This paper concludes that taking into account the economic factors and statistical properties in designing the AEWMA control chart leads to a slight increase in cost but in return the improvement in the statistical performance is substantial. In addition, under the estimated parameters case, the comparisons reveal that from the economic point of view the AEWMA chart is the most efficient chart when detecting shifts of different sizes. Originality/value The importance of the study stems from designing the AEWMA chart from both economic and statistical points of view because it has not been tackled before. In addition, this paper contributes to the literature by studying the effect of the estimated parameters on the performance of control charts with economic–statistical design.

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