No abstract

Various derivatives of 1,2-dihydro-6-(4-hydroxy-5-isopropyl-2-methylphenyl)-2-oxo-4-arylpyridine-3-carbonitrile (IVa-m) were synthesized and characterized. Their antioxidant and antimicrobial properties were evaluated by measuring their activity in vitro. Among the newly synthesized derivatives IVg, IVh, IVi, IVj, IVk, IVl, and IVm showed good antioxidant activity. However, all derivatives show better antibacterial and antifungal properties than that of parent thymol. The probable mechanism, particularly for antioxidant properties of these compounds is proposed.

A series of novel 3-methyl-N"-(2-oxoindolin-3-ylidene)-4H-benzo [b][1,4]thiazine-2-carbohyrazides have been synthesized and studied on their in vitro antimicrobial activity potency to establish structure-activity relationship. Several compounds demonstrated promising antifungal and antibacterial activity; however, other tested compounds exhibited moderate to poor antimicrobial activity with respect to the reference drug against the test strains.

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Purpose This paper aims to present 3D finite element (FE) simulations of impact loading on a construction safety helmet over a headform to improve the ventilation slots profile in helmet design. Design/methodology/approach Impact response on headforms in three different studies considering ventilation slots of varied profiles and dimensions in helmets with rectangular elliptical and circular slots is compared and analysed. Head injury criteria (HIC) and safety regulations from past literature have been considered to evaluate the impact responses. Findings Simulation results show that a helmet with rectangular ventilation slots achieves a lowest peak impact force of 5941.3 N for a slot area of 170 mm2 as compared to elliptical and circular slots. Research limitations/implications Ventilation slots of simple geometry (rectangular, elliptical and circular) have been considered in this work. Other/complex geometry slots can also be chosen to predict its effect during impact response on a helmet–headform model. Biofidelic head–neck FE model can be developed to achieve precise results. Practical implications The presented work gives a clear idea to design engineers for the selection of ventilation slot profiles to design a construction safety helmet. Social implications Construction safety (CS) helmets are used to reduce injuries on heads of workers at construction sites in the event of free-falling objects. Rectangular ventilation slots in CS helmets as suggested in the work may reduce the risk of injury. Originality/value Results are found in good agreement with the past numerical simulation of impact response on a construction safety helmet over a validated biofidelic head FE model.