Memorial University of Newfoundland

About: Memorial University of Newfoundland is a education organization based out in St. John's, Newfoundland and Labrador, Canada. It is known for research contribution in the topics: Population & Gadus. The organization has 13818 authors who have published 27785 publications receiving 743594 citations. The organization is also known as: Memorial University & Memorial University of Newfoundland and Labrador.

A reaction-diffusion SIS epidemic model in a time-periodic environment

Abstract: In this paper, we consider a susceptible–infected–susceptible (SIS) reaction–diffusion model, where the rates of disease transmission and recovery are assumed to be spatially heterogeneous and temporally periodic and the total population number is constant. We introduce a basic reproduction number and establish threshold-type results on the global dynamics in terms of . In particular, we obtain the asymptotic properties of with respect to the diffusion rate dI of the infected individuals, which exhibit the delicate influence of the time-periodic heterogeneous environment on the extinction and persistence of the infectious disease. Our analytical results suggest that the combination of spatial heterogeneity and temporal periodicity tends to enhance the persistence of the disease.

(Ru(bpy) 3 ) 2+ * and other remarkable metal-to- ligand charge transfer (MLCT) excited states*

Abstract: In 1974, the metal-to-ligand charge transfer (MLCT) excited state, (Ru(bpy) 3 ) 2+ *, was shown to undergo electron transfer quenching by methylviologen dication (MV 2+ ), inspiring a new approach to artificial photosynthesis based on molecules, molecular-level phenomena, and a "modular approach". In the intervening years, application of synthesis, excited-state measurements, and theory to (Ru(bpy) 3 ) 2+ * and its relatives has had an outsized impact on photochemistry and photophysics. They have provided a basis for exploring the energy gap law for nonradiative decay and the role of molecular vibrations and solvent and medium effects on excited-state properties. Much has been learned about light absorption, excited-state electronic and molecular structure, and excited-state dynamics on timescales from femtoseconds to milliseconds. Excited-state properties and reactivity have been exploited in the investigation of electron and energy transfer in solution, in molecular assem- blies, and in derivatized polymers and oligoprolines. An integrated, hybrid approach to solar fuels, based on dye-sensitized photoelectrosynthesis cells (DSPECs), has emerged and is being actively investigated.

Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants

Abstract: Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA) cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (citrate valve), while malate is accumulated and participates in the redox balance in different cell compartments (via malate valve). This results in malate and citrate frequently being the most accumulated acids in plants. However, the intensity of reactions linked to the conversion of these compounds can cause preferential accumulation of other organic acids, e.g., fumarate or isocitrate, in higher concentrations than malate and citrate. The secondary reactions, associated with the central metabolic pathways, in particularly with the TCA cycle, result in accumulation of other organic acids that are derived from the intermediates of the cycle. They form the additional pools of fixed carbon and stabilize the TCA cycle. Trans-aconitate is formed from citrate or cis-aconitate, accumulation of hydroxycitrate can be linked to metabolism of 2-oxoglutarate, while 4-hydroxy-2-oxoglutarate can be formed from pyruvate and glyoxylate. Glyoxylate, a product of either glycolate oxidase or isocitrate lyase, can be converted to oxalate. Malonate is accumulated at high concentrations in legume plants. Organic acids play a role in plants in providing redox equilibrium, supporting ionic gradients on membranes, and acidification of the extracellular medium.

Influence of maternal diet during lactation and use of formula feeds on development of atopic eczema in high risk infants.

Abstract: OBJECTIVE--To examine the effects of maternal diet during lactation and the use of formula feeds on the development of atopic eczema in infants at risk. DESIGN--Mothers who planned to breast feed exclusively were randomly allocated to either a restricted diet (avoiding milk and other dairy products, eggs, fish, peanuts, and soybeans) or a diet without restrictions. Mothers who did not plan to breast feed were randomly allocated to using one of three formula feeds. SETTING--Child health centre in Canada. SUBJECTS--97 Mothers who chose to breast feed and 124 mothers who did not. INTERVENTIONS--Restricted diet for 49 mothers who breast fed. Casein hydrolysate formula, soy milk formula, or cows' milk formula for infants not breast fed. MAIN OUTCOME MEASURE--Development of eczema in babies. RESULTS--Infants were followed up over 18 months and examined for eczema. Eczema was less common and milder in babies who were breast fed and whose mothers were on a restricted diet (11/49 (22%) v 21/48 (48%)). In infants fed casein hydrolysate, soy milk, or cows' milk 9/43 (21%), 26/41 (63%), and 28/40 (70%), respectively, developed atopic eczema. CONCLUSIONS--In families with a history of atopic disease [corrected] mothers who breast feed should avoid common allergenic foods during lactation. If they choose not to breast feed a hydrolysate formula should be used.