Dynamic flight stability of hovering insects

The equations of motion of an insect with flapping wings are derived and then simplified to that of a flying body using the “rigid body” assumption. On the basis of the simplified equations of motion, the longitudinal dynamic flight stability of four insects (hoverfly, cranefly, dronefly and hawkmoth) in hovering flight is studied (the mass of the insects ranging from 11 to 1,648 mg and wingbeat frequency from 26 to 157 Hz). The method of computational fluid dynamics is used to compute the aerodynamic derivatives and the techniques of eigenvalue and eigenvector analysis are used to solve the equations of motion. The validity of the “rigid body” assumption is tested and how differences in size and wing kinematics influence the applicability of the “rigid body” assumption is investigated. The primary findings are: (1) For insects considered in the present study and those with relatively high wingbeat frequency (hoverfly, drone fly and bumblebee), the “rigid body” assumption is reasonable, and for those with relatively low wingbeat frequency (cranefly and howkmoth), the applicability of the “rigid body” assumption is questionable. (2) The same three natural modes of motion as those reported recently for a bumblebee are identified, i.e., one unstable oscillatory mode, one stable fast subsidence mode and one stable slow subsidence mode. (3) Approximate analytical expressions of the eigenvalues, which give physical insight into the genesis of the natural modes of motion, are derived. The expressions identify the speed derivative M _u (pitching moment produced by unit horizontal speed) as the primary source of the unstable oscillatory mode and the stable fast subsidence mode and Z _w (vertical force produced by unit vertical speed) as the primary source of the stable slow subsidence mode. The project supported by the National Natural Science Foundation of China (10232010 and 10472008).     

线性Fuzzy方程组(A~)(x~)=(b~)的解

重点研究线性Fuzzy方程组Ax=b的解,其中矩阵A和向量5均以有限Fuzzy数为其元素。文中首先指出,使用扩展原理和Fuzzy数运算规则有时会导致Ax=b没有解。本文以实广义逆矩阵为工具,给出了Ax=b的六个解,证明了它们都是R^n上的Fuzzy向量。     

模糊关系几何规划

提出一类目标函数为正项式,约束是模糊关系方程的优化问题。阐述模糊关系方程解集的结构以及求解的方法,基于目标函数中每个单项式的指数取值情况讨论最优解,并且给出解决此类优化问题的一个程序,为了说明该方法的有效性给出具体例子。     

In-silico profiling,design, molecular docking computation,and drug kinetic model evaluation of novel curcumin derivatives as potential anticancer agents

The alarming trend of leukemia cell lines that are multidrug-resistant has prompted scientists to scramble for effective new anticancer treatments. Therefore, it remains an intriguing scientific task to optimize curcumin by trying to introduce molecular alteration to its vital structure to improve the biological effect against the P388 cell line or get around resistance phenomena. Regardless of the wide range of medications that are now being studied, Prednisone remains the most important and efficient part of chemotherapy that the WHO recommends. This article discusses the QSAR-oriented model and in silico assessment of some potent curcumin derivatives' anticancer activity against the P388 cell line. The solidity and propensity for prediction of the model were ensured by using stringent validation procedures. The activity of these derivatives was shown to be unrelated to lipophilicity, while shorter N-N distances and short substituents result in quite bioactive molecules. This information was used to design potent molecules that demonstrate good quality as per the assessment based on the Lead-Like Soft rule is acceptable for drug-like molecules. Also, molecule d2 does not possess any toxic effects risk alerts, suggesting drug-adherent conduct. While Prednisone the reference drug has a toxicity risk alert in red, suggesting non-adherent conduct for Prednisone. Hence, the novel molecules are promising anticancer agents.     

Improving antioxidant scavenging effect of fruit peel waste extracts and their applicability in biodiesel stability enhancement

The increasing popularity of fruit peel extracts as effective sources of natural antioxidants is primarily attributed to their affordability, easy availability, and high phenolic contents that readily dissolve in solutions. However, most natural antioxidants demonstrate a lesser free radical scavenging effect when applied in mono blends compared to their synthetic counterparts. To address this problem, this work aims to improve the antioxidant capacities of palm fruit, banana, and mango peel liquid extracts recovered using supercritical fluid extraction (SFE). Firstly, a reverse-phase high-performance liquid chromatography (RP-HPLC) was used to isolate three (3) target bioactive compounds from the extracts, whose estimated quantities ranged between 1.2983–4.6841, 1.1469–3.6987, and 0.0254–0.0489 mg/g for quercetin, beta-carotene, and gallic acid respectively. Subsequently, blends of the recovered extracts were formulated in mono, binary, and ternary dosage ratios (S.₁–S.₁₀) to assess their free radical scavenging efficiency (RSE) in terms of inhibitory concentration at 50% (IC₅₀) using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, total phenolic content (TPC), total flavonoid content (TFC), and total carotenoid content (TCC). Based on the results obtained, the highest RSE was exhibited by the ternary blend (S.₉), with an IC₅₀ value of 76.21 ± 032 µg/mL and a TPC value of 242.38 ± 0.26 mg gallic acid equivalent (GAE/g). The fastest kinetics for the extracts’ reaction with DPPH corresponding to a rate constant (K) of 1.2351 M^−1.min⁻¹ and activation energy ($E_a)$ of 0.55 KJ/mol were presented by the same sample blend (S.₉), indicating the ease of hydrogen atom release for radical scavenging. Finally, the peel extracts demonstrate an improved antioxidative performance by prolonging the biodiesel’s induction period of the extracts-blended samples as obtained from Rancimat analysis.     

A New Efficient Transform Mechanism with Convergence Analysis of the Space-Fractional Telegraph Equations

This article"s goal is to investigate the space-fractional telegraph equation using an effective method called the Adomian natural decomposition method (ANDM), which is a combination of the Adomian decomposition method (ADM) and the natural transform method (NTM). Using the Banach fixed point theorem, we explore proofs for the existence and uniqueness theorems applying it to a nonlinear differential equation. Using our method, exact solutions of the space-fractional telegraph equation and time-fractional diffusion problems have been obtained. To demonstrate the effectiveness of the suggested scheme, four examples are provided.