Determination of micro-amounts of zirconium in mixed aqueous organic medium by normal and first-derivative spectrophotometry

Normal and first-derivative spectrophotometric methods have been applied to the determination Zr(IV) with Arsenazo-III in mixed aqueous organic medium. Zirconium (IV) has been determined in presence and in absence of U(VI). For the determination of Zr(IV) in presence of U(VI) no prior separation is needed. The suggested method was also applied to the individual and simultaneous determinations of Zr(IV) and U(VI) in different environmental samples and alloys without separation processes. The method has advantages of simplicity, accuracy and versatility over other conventional methods. The molar absorptivities of U(VI) and Zr(IV) complexes with Arsenazo-III increased to 7.24 × 10⁴ and 1.8 × 10⁵ L/mol cm, respectively, in comparison with values of 5.0 × 10⁴ and 1.2 × 10⁵ L/mol cm cited in literature.     

Using molecular dynamic simulation data of calcite in a wide pressure range to calculate some of its thermodynamic properties via some universal equations of state

Molecular dynamics, MD, simulation of calcite (CaCO₃) is selected to compare the p-v-T behaviour of some universal equations of state, UEOS, for the temperature range 100 K ≤ T ≤ 800 K, and pressures up to 3000 kbar. The isothermal sets of p-v-T data generated by simulation were each fitted onto some three- and two-parameter EOSs including Parsafar and Mason (PM), Linear Isotherm Regularity (LIR), Birch-Murnaghan (BM), Shanker, Vinet, Baonza and Modified generalized Lennard–Jones (MGLJ) EOSs. It is found that the MD data satisfactorily fit these UEOS with reasonable precision. Some features for a good UEOS criteria such as temperature dependencies of coefficients, pressure deviation, isothermal bulk modulus and its derivative at the zero pressure limit, isobaric thermal expansion, pressure spinodal values and divergence of pseudo critical exponent either near to or far from the spinodal condition, and some regularities for calcite are investigated.     

Bearing Fault Diagnosis Using Refined Composite Generalized Multiscale Dispersion Entropy-Based Skewness and Variance and Multiclass FCM-ANFIS

Bearing vibration signals typically have nonlinear components due to their interaction and coupling effects, friction, damping, and nonlinear stiffness. Bearing faults affect the signal complexity at various scales. Hence, measuring signal complexity at different scales is helpful to diagnosis of bearing faults. Numerous studies have investigated multiscale algorithms; nevertheless, multiscale algorithms using the first moment lose important complexity data. Accordingly, generalized multiscale algorithms have been recently introduced. The present research examined the use of refined composite generalized multiscale dispersion entropy (RCGMDispEn) based on the second moment (variance) and third moment (skewness) along with refined composite multiscale dispersion entropy (RCMDispEn) in bearing fault diagnosis. Moreover, multiclass FCM-ANFIS, which is a combination of adaptive network-based fuzzy inference systems (ANFIS), was developed to improve the efficiency of rotating machinery fault classification. According to the results, it is recommended that generalized multiscale algorithms based on variance and skewness be examined for diagnosis, along with multiscale algorithms, and be used to achieve an improvement in the results. The simultaneous usage of the multiscale algorithm and generalized multiscale algorithms improved the results in all three real datasets used in this study.     

Thiazolidinedione Derivatives: In Silico,In Vitro,In Vivo,Antioxidant and Anti-Diabetic Evaluation

This work aimed to synthesize a new antihyperglycemic thiazolidinedione based on the spectral data. The DFT\B3LYP\6-311G** level of theory was used to investigate the frontier molecular orbitals (FMOs), chemical reactivity and map the molecular electrostatic potentials (MEPs) to explain how the synthesized compounds interacted with the receptor. The molecular docking simulations into the active sites of PPAR-γ and α-amylase were performed. The in vitro potency of these compounds via α-amylase and radical scavenging were evaluated. The data revealed that compounds (4–6) have higher potency than the reference drugs. The anti-diabetic and anti-hyperlipidemic activities for thiazolidine-2,4-dione have been investigated in vivo using the alloxan-induced diabetic rat model along with the 30 days of treatment protocol. The investigated compounds didn’t show obvious reduction of blood glucose during pre-treatments compared to diabetic control, while after 30 days of treatments, the blood glucose level was lower than that of the diabetic control. Compounds (4–7) were able to regulate hyperlipidemia levels (cholesterol, triglyceride, high-density lipoproteins and low- and very-low-density lipoproteins) to nearly normal value at the 30th day.     

Novel fused 1,2,3-triazolo-benzodiazepine derivatives as potent anticonvulsant agents: design,synthesis, in vivo,and in silico evaluations

Molecular Diversity - A novel series of 1,2,3-triazolo-benzodiazepine derivatives 6a–o has been synthesized and evaluated in vivo for their anticonvulsant activities using by...     

Nucleophilic substitutions at the pyridine ring: Kinetics of the reaction of 2-chloro-3-nitro and 2-chloro-5-nitropyridines with piperidine and morpholine in methanol and benzene

The kinetics of the reactions of 2-chloro-3-nitropyridine (ortho-like) and 5-nitro (para-like) isomer with morpholine and piperidine were studied in methanol and benzene at several amine concentrations and temperatures in the range 25–45°C. The data show that k/k ratios are less than unity in methanol. The steric hindrance in the transition state of the 3-nitro (ortho-like) isomer retards o-substitution while the stability of p-quinonoid structure of the 5-nitro (para-like) isomer favors p-substitution. In benzene, the k_3-NO2/k_5-NO2 ratios are greater than unity. The hydrogen bonding formation between the ammonium hydrogen and the ortho-nitro group in the transition state of 3-nitro isomer favors the o-substitution. © 1997 John Wiley & Sons, Inc.