26 research outputs found
Chemical constituents and antimicrobial activity of Goniothalamus macrophyllus (Annonaceae) from Pasoh Forest Reserve, Malaysia
The essential oils from the twig and root of Goniothalamus macrophyllus were obtained by hydrodistillation and subjected to Gas Chromatography (GC-FID) and Gas Chromatography/Mass Spectrometry (GC-MS) using CBP-5 capillary column in order to determine their chemical composition. Both twig and root oils and four reference standard compounds (-pinene, linalool, geraniol and geranyl acetate) were evaluated for their antimicrobial properties against gram positive and gram negative bacteria, yeast and dermatophyte fungi using broth microdilution methods. The GCMS analysis revealed twenty-one and fourteen compounds from twig and root oils which represented 90.0 and 42.5% of the total oils, respectively. The oils were found to possess the following major components: twig: geranyl acetate (45.5%), geraniol (17.0%), linalool (12.7%) and camphene (7.5%); root: cyperene (9.8%), geranyl acetate (9.4%), geraniol (3.4%) and linalool (2.6%). Other components present in appreciable amounts in both essential oils were -pinene (0.8%) and benzaldehyde (0.5%). The root oil exhibited the most notable inhibitory activity (0.3 mg/ml) against Vancomycin intermediate-resistance Staphylococcus aureus (VISA 24), Staphylococcus epidermidis and Candida albicans. -pinene meanwhile inhibited the bacteria and fungal growth at 0.3 and 2.5 mg/ml. With regards to antimicrobial potential, -pinene superceeds linalool, geraniol and geranyl acetate, respectively.Keywords: Goniothalamus macrophyllus, Annonaceae, essential oils, geranyl acetate, cyperene, geraniol, linalool, -pinene, antimicrobial activityAfrican Journal of Biotechnology Vol. 9(34), pp. 5511-5515, 23 August, 201
Alleviating staff stress in care homes for people with dementia: protocol for stepped-wedge cluster randomised trial to evaluate a web-based Mindfulness- Stress Reduction course
Composition Screening of Lithium- and Sodium-Rich Anti-Perovskites for Fast-Conducting Solid Electrolytes
Li-
and Na-rich anti-perovskites are receiving increasing attention
as high-performance solid electrolytes for applications within all-solid-state
batteries. The defect chemistry and ionic transport in a wide range
of Li3âxNaxOCl1âyBry compositions are
examined using advanced materials modeling techniques. Our calculations
indicate that alkali-halide Schottky defect pairs are the dominant
type of intrinsic disorder in these materials. Li-ion conductivity
is shown to significantly exceed Na-ion conductivity, with the highest
conductivities found for Li3OCl and Li3OBr.
The effect of Cl/Br mixing on conductivity is shown to be small but
could be used to fine-tune the activation energy. Both low conductivities
and high activation energy barriers are found for the mixed Li/Na
systems, which suggests that they would make poor solid electrolytes.
The results presented here will aid the future optimization of anti-perovskite
materials for solid electrolyte applications
Mechanisms of Lithium Intercalation and Conversion Processes in Organic-Inorganic Halide Perovskites
Mechanochemical synthesis and ion transport properties of Na<sub>3</sub>OX(X = Cl, Br, I and BH<sub>4</sub>) antiperovskite solid electrolytes
Under pressure: Mechanochemical effects on structure and ion conduction in the sodium-ion solid electrolyte Na<sub>3</sub>PS<sub>4</sub>
Technical Education in Jeopardy? Assessing the Interdisciplinary Faculty Structure in a University Merger
The social responsibility of universities is to contribute to solving the âwicked problemsâ facing humanity, including climate change, poverty, conflicts and the lack of energy resources. Interdisciplinarity is an approach that enables solving these problems and helps higher education institutions become more socially responsible while meeting the requirements of their stakeholders. In this chapter, we analyse a multidisciplinary and sector-breaking merger of three higher education institutions in Finland, where the merger is justified by its contribution to solving wicked problems through increased structural interdisciplinarity. We examine the suggested faculty structures and views of staff and students to understand how interdisciplinarity and addressing the needs of stakeholders are seen from the perspective of technical education. The interdisciplinary faculty structure is heavily criticised by the internal stakeholders, who claim that it does not meet the needs of the universityâs external stakeholders. However, there is debate on whose interests and identities are at risk when the disciplinary boundaries of technical education are transgressed.peerReviewe
Cooperative mechanisms of fast-ion conduction in gallium-based oxides with tetrahedral moieties.
NoThe need for greater energy efficiency has garnered increasing support for the use of fuel-cell technology, a prime example being the solid-oxide fuel cell1, 2. A crucial requirement for such devices is a good ionic (O2- or H+) conductor as the electrolyte3, 4. Traditionally, fluorite- and perovskite-type oxides have been targeted3, 4, 5, 6, although there is growing interest in alternative structure types for intermediate-temperature (400¿700 °C) solid-oxide fuel cells. In particular, structures containing tetrahedral moieties, such as La1-xCaxMO4-x/2(M=Ta,Nb,P) (refs 7,8), La1-xBa1+xGaO4-x/2 (refs 9,10) and La9.33+xSi6O26+3x/2 (ref. 11), have been attracting considerable attention recently. However, an atomic-scale understanding of the conduction mechanisms in these systems is still lacking; such mechanistic detail is important for developing strategies for optimizing the conductivity, as well as identifying next-generation materials. In this context, we report a combined experimental and computational modelling study of the La1-xBa1+xGaO4-x/2 system, which exhibits both proton and oxide-ion conduction9, 10. Here we show that oxide-ion conduction proceeds via a cooperative 'cog-wheel'-type process involving the breaking and re-forming of Ga2O7 units, whereas the rate-limiting step for proton conduction is intra-tetrahedron proton transfer. Both mechanisms are unusual for ceramic oxide materials, and similar cooperative processes may be important in related systems containing tetrahedral moieties