The impact of ozone on the (15)n incorporation and nitrogen assimilation of wheat and maize

Abstract Young wheat (C3) and maize (C4) plants were exposed to near-ambient concentrations of ozone in open-top chambers in order to investigate the possible effects of ozone on nitrogen metabolism. Nitrogen was supplied to the plants by adding (15)N-labelled tracer substances via the soil substrate. Enzyme activities (NADH nitrate reductase, nitrite reductase, glutamine synthetase and NADH glutamate dehydrogenase) and the incorporation of (15)N were determined. The findings show that nitrogen metabolism was affected by O(3), however, there were distinct differences between the two species. In plants treated with O(3), NADH nitrate reductase activity in maize leaves was reduced, while NR activity in wheat leaves only slightly declined. Only minor changes were observed with respect to the activities of nitrite reductase, glutamine synthetase and NADH glutamate dehydrogenase. Feeding experiments using (15)NO(3) (-) showed that the incorporation of nitrate nitrogen in wheat plants exposed to ozone remains virtually unchanged, whereas in maize plants reduced incorporation rates were observed for nitrate nitrogen. The incorporation of ammonium nitrogen was distinctly increased in wheat and maize by the impact of ozone. When investigating pigment contents, reduced levels of chlorophyll a and b and carotenoids were observed, whereas the pigment content of wheat leaves remained unchanged. These results indicate that young maize plants are more susceptible than wheat plants to short-term ozone exposure.     

Evaluation of the Alzheimer’s disease clinical stages under the optics of hybrid approaches in Verbal Decision Analysis

The decision making process is present in every moment of personal life, but other decisions need a further analysis of a considerable number of factors is involved. The impact of each decision is analyzed mainly from two points of view, being one for it and one against it. It is intended to determine in this research which of the tests are relevant and would detect whether the patient is developing the early diagnosis of diseases like Alzheimer’s. The tests should be applied in two stages. Initially, a classification method will be implemented to determine which questionnaires from a set would, themselves, detect the Alzheimer’s disease. After, the questionnaires classified as the ones that would give this diagnosis will be ordered by means, from the most likely one to lead to the diagnosis faster, to the least, considering an ordination methodology. This paper presents a hybrid model for the early diagnosis of Alzheimer’s disease by applying methods of Verbal Decision Analysis structured considering the methods ARACE and NORCLASS.     

Simulation models to support the preliminary electoral results program for the Mexican Electoral Institute

On July 1st, 2018, federal elections for president, senators and deputies took place in Mexico. In most states, elections for state governors and representatives took also place in the same polling booths. The Technical Unit for Information Services (UNICOM) of the National Electoral Institute (INE) of Mexico has the responsibility for planning and implementation of the Preliminary Electoral Results Program (PREP) for federal elections. For the 2018 elections UNICOM developed forecasting models for the performance of PREP based on simulation models that were developed using a special purpose simulation software and C++ subroutines for fast simulation of queues. These simulation models were a valuable tool for planning, scheduling and allocation of the main resources that participated in the operational process of the PREP. In this article we report the main features, applications and results obtained by using these simulation models.

     

Reaction of N-amino-4,6-dimethylpyrimidinium mesitylene sulfonate with nucleophiles . A 15n-study

Reaction of N-amino-4, 6-dimethylpyrimidinium mesitylene sulfonate with liquid ammonia, with an aqueous solution of sodium hydroxide or with hydrazine leads to 3, 5-dimethylpyrazole. Reaction of this salt with ¹⁵N-labelled hydrazine gave incorporation of nitrogen-15 in 3,5-dimethylpyrazole and in recovered starting material. Evidence has been presented that the initial step in the ring contraction with hydrazine is the addition of the nucleophile to C-2 and C-6. It is suggested that in the presence of a base the reactive species is probably 4,6-dimethylpyrimidinio amide.     

REACTIVITY OF CHLOROPHYLL a/b-PROTEINS AND MICELLAR TRITON X-100 COMPLEXES OF CHLOROPHYLLS a OR b WITH BOROHYDRIDE

The reaction of several plant chlorophyll-protein complexes with NaBH₄ has been studied by absorption spectroscopy. In all the complexes studied, chlorophyll b is more reactive than Chi a, due to preferential reaction of its formyl substituent at C-7. The complexes also show large variations in reactivity towards NaBH₄ and the order of reactivity is: LHCI > PSII complex > LHCII > PSI > P700 (investigated as a component of PSI). Differential pools of the same type of chlorophyll have been observed in several complexes.
Parallel work was undertaken on the reactivity of micellar complexes of chlorophyll a and of chlorophyll b with NaBH₄ to study the effect of aggregation state on this reactivity. In these complexes, both chlorophyll a and b show large variations in reactivity in the order monomer > oligomer > polymer with chlorophyll b generally being more reactive than chlorophyll a. It is concluded that aggregation decreases the reactivity of chlorophylls towards NaBH₄ in vitro, and may similarly decrease reactivity in naturally-occurring chlorophyll-protein complexes.     

Tungsten Biscorroles: New Chiral Sandwich Compounds

The oxidative metalation method, involving the interaction of free‐base meso‐triarylcorroles and W(CO)₆ in refluxing decalin, led to a set of three tungsten(VI) biscorroles, the first homoleptic sandwich compounds involving corroles. Single‐crystal X‐ray structures of two of the complexes revealed square‐antiprismatic coordination and strongly domed corroles with long W?N distances of 2.15–2.22 Å and a substantial displacement of ～1.17 Å of the metal relative to the mean N₄ planes of the ligands. The structures correspond to approximate C₂ symmetry and are thus chiral. DFT calculations strongly indicate that the enantiomers are configurationally stable and hence amenable to chiral resolution. Their other notable properties include a strongly blueshifted Soret band at (357±2) nm, a relatively intense π→W(d ) near‐IR feature at (781±3) nm, and a low electrochemical HOMO–LUMO gap of approximately 1.3 V. The results obtained herein suggest that metallobiscorroles may emerge as a new class of inherently chiral chromophores with novel optical and electrochemical properties.     

Stabilization of the Columnar Mesophase of Perylenediimide by Racemic Triple Tails

Whereas perylene tetracarboxdiimides derived from amino‐n‐alkanes if at all only show monotropic (thermodynamically unstable) mesogenic self‐assembly, the hexagonal columnar liquid crystalline state can be stabilized over a broad temperature range with doubly branched, doubly racemic alkyl residues. An improved tendency to homeotropic surface orientation is observed, and the orientation of the liquid crystalline domains is maintained upon cycling through the crystalline state at room temperature.     

Characterization and compatibility of dry extract from Annona muricata L. and pharmaceutical excipients

Journal of Thermal Analysis and Calorimetry - The aim of this study was to characterize and evaluate the compatibility of the dry extract (DE) of leaves of Annona muricata L. with pharmaceutical...