Voltammetric studies of some azo compounds derived from 4-methyl-6,7-dihydroxy coumarin in microemulsion and aqueous media

The cyclic voltammetric(CV) behavior of some azo compounds based on coumarin derivatives  was investigated in microemulsion systems and in aqueous solutions. The obtained results indicated that these compounds undergo an irreversible 4-electron reduction step leading to cleavage of the N=N center with the formation of amine compounds in all media. The effect of medium on the CV parameters was discussed. The total number of electrons involved in the reduction process was determined by controlled potential coulometry. Also, The effect of substituents on the electrode reaction pathway and the kinetic parameters of the electrode process were calculated and discussed. Based on the data obtained the electroreduction mechanism was suggested and discussed

Improvement of drought tolerance in five different cultivars of Vicia faba with foliar application of ascorbic acid or silicon

Aim of study: To explore the role of ascorbic acid (AsA) or silicon (Si) in improving drought tolerance in five faba bean cultivars under irrigation water deficit (IWD).Area of study: The experimental farm; 30° 36′ N, 32° 16′ E, Egypt.Material and methods: Three drip irrigation regimes (WW, well-watered, 4000 m3 water ha-1; MD, moderate drought, 3000 m3 water ha-1; and SD, severe drought, 2000 m3 water ha-1) were applied to plants, which were sprayed 25, 40, and 55 days after sowing with 1.5 mM AsA or 2.0 mM Si vs distilled water as a control.Main results: Drought negatively affected physiological attributes (photosynthetic pigments, gas exchange parameters, relative water content, membrane stability index, electrolyte leakage (EL), and lipid peroxidation), which restricted plant growth and yields, and stimulated alterations in both enzymatic and non-enzymatic antioxidant activities. However, AsA or Si application mitigated drought effects on physiological attributes, improving growth, yields and water use efficiency by raising antioxidant activities and suppressing lipid peroxidation and EL in stressful cultivars. The mitigating effects of AsA and Si were more pronounced under MD.Research highlights: ‘Nubaria-2’, ‘Giza-843’, and ‘Sakha-3’ were more tolerant than ‘Giza-716’ and ‘Sakha-4’, suggesting the use of AsA or Si to ameliorate the IWD effects on stressful cultivars. Certain physiological traits exhibited positive association with growth and seed yield, demonstrating their importance in enhancing seed yield under irrigation treatments

Monotonic Positive Solutions of Nonlocal Boundary Value Problems for a Second-Order Functional Differential Equation

We study the existence of at least one monotonic positive solution for the nonlocal boundary value problem of the second-order functional differential equation x′′(t)=f(t,x(ϕ(t))), t∈(0,1), with the nonlocal condition ∑k=1makx(τk)=x0, x′(0)+∑j=1nbjx′(ηj)=x1, where τk∈(a,d)⊂(0,1), ηj∈(c,e)⊂(0,1), and x0,x1>0. As an application the integral and the nonlocal conditions ∫adx(t)dt=x0, x′(0)+x(e)-x(c)=x1 will be considered

Síntesis y evaluación de compuestos heterocíclicos derivados de ?-hidroxiácidos con interés industrial potencial.

The reaction of 2-hydroxyheptadecanoyl chloride (2) and anthranilic acid gave 2-(1-hydroxyheptadecyl)-4H-3,1-benzoxazin-4-one (3) which was used as starting material to synthesize some condensed and non-condensed heterocyclic compounds by a reaction with nitrogen nucleophiles (e.g., hydrazine hydrate, and formamide). The subsequent reaction of the synthetic products with different amounts of propylene oxide gave a novel group of nonionic compounds having a double function as antibacterial and surface active agents which may serve in the manufacturing of drugs, cosmetics, pesticides or as antibacterial and/or antifungal products. The surface active properties such as surface and interfacial tensions, cloud point, foaming height, wetting time, and emulsification power were determined. Antimicrobial and biodegradability were also screened.La reacción de cloruro de 2-hidroxiheptadecanoilo (2) con ácido antranílico produjo 2-(1-hidroxiheptadecil)-4H-3,1-benzoxazin-4-ona (3) que fue usada como material de partida en la síntesis de compuestos heterocíclicos condensados y no condensados por reacción con nucleófilos nitrogenados (hidracina y formamida). La reacción de los productos sintetizados con distintas cantidades de óxido de propileno dio un grupo nuevo de compuestos no iónicos con una función doble como antibacterianos y agentes tensioactivos que pueden servir en la manufactura de medicamentos, cosméticos, pesticidas, o como productos antibacterianos y/o antifúngicos. Se determinaron las propiedades tensioactivas así como la capacidad antimicrobiana y la biodegrabilidad de los compuestos sintetizados

Hind-foot correction and stabilization by pins in plaster after surgical release of talipes equino varus feet in older children

Congenital talipes equino varus (CTEV) is a three dimensional deformity and is one of the most common congenital abnormalities affecting the lower limb and can be challenging to manage. Hind-foot deformity is considered the most difficult to treat. Unfortunately, the calcaneus is often small and thus difficult to control during casting after surgical release in severe or relapsed cases. We used three pins to control and maintain the hind foot correction, after surgical release, during casting in 47 cases (59 feet). We introduced a modified, coronal plane, transverse calcaneal pin. This pin is inserted from medial to lateral through the calcaneus to correct the varus mal-positioning of the calcaneus in the sagittal plane and to provide a better control on the small sized, hind-foot during casting. We paid special attention to the final hind-foot deformity after surgery, and the results were favorable after the application of this transverse pin