Search results for " Chemistry"
showing 10 items of 41321 documents
Controlling the crystal growth of potassium iodide with a 1,1'-bis(pyridin-4-ylmethyl)-2,2'-biimidazole ligand (L) – formation of a linear [K4I4L4]n …
2018
The crystal growth of potassium iodide was controlled by using the neutral organic 1,1′-bis(pyridin-4-ylmethyl)-2,2′-biimidazole (L) ligand as a modifier. The selected modifier allows the preservation of original cubic [K4I4] units and their arrangement into a linear ligand-supported 1D chain. The supported [K4I4] cubes are only slightly distorted compared to the cubes found in pure KI salt. The N–K binding of the ligand to the KI salt, as well as weak I⋯H, N⋯H, and N⋯I interactions, stabilizes the structure to create a unique 1D polymer of neutral potassium iodide ionic salt inside the [K4I4L4]n complex.
Combined effect of low-molecular-weight organic acids and creosote on phosphatase activities in sandy soil
2018
This paper assesses the impact of creosote and low-molecular-weight organic acids (LMWOAs) on the activity of acid phosphomonoesterase, alkaline phosphomonoesterase, phosphotriesterase, and inorganic pyrophosphatase in soil. The experiment was carried out on loamy sand samples with organic carbon content of 8.71 g · kg -1 , with the following variable factors: dosages of creosote: 0, 0.5%, and 2.5%; type of LMWOAs: oxalic acid, tartaric acid, and citric acid in the amount of 50 mmol · kg -1 of soil; days of experiment: 1, 7, 14, 28, 56, 112. Obtained results showed that contamination with creosote caused decrease in the activity of soil phosphatases. The observed effect did not always incre…
Trait Hedonism and the Distribution of Savoring and Positive Emotion States in Everyday Life.
2022
International audience; The present study aimed at (1) identifying the emotion regulation processes that can explain the trait hedonism positive emotions relationship, and (2) determining whether this relationship varies according to which part of the distribution of positive emotions is considered. To this end, the intensity of the positive emotions felt by 84 adult participants, and the intensity of their engagement in savoring, were assessed twice a day over a month period, using an Experience Sampling Method. Participants’ distributions of these variables were then related to their level of trait hedonism, assessed with a common questionnaire. Results suggested that, as expected, the tr…
Psychrophiles: A source of cold-adapted enzymes for energy efficient biotechnological industrial processes
2021
Biocatalysts are the backbone of bioprocessing industries that are going through a phase of transition with reference to the requirement of extraordinary enzymes for various biochemical processes. This transition is well reported and documented by various researchers through elucidation of different features and applications of mesophilic and thermophilic enzymes. However, there is little information available about psychrophilic enzymes and their involvement in industrial processes. Therefore, understanding the features and functions of psychrophilic enzymes could suggest some of their novel applications in various industries such as food, agriculture, chemicals, pharmaceuticals, and waste…
Implementing kiva antibullying program in pioner schools in Spain
2022
This study analyzes the implementation of the KiVa Antibullyiing program in Spain with 10 pioneer schools. This research has two aims. The first is a preliminary evaluation of the KiVa program’s implementation in the pioneer schools in Spain. To do so, the perceived levels of bullying and victimization have been analyzed through the surveys done anonymously by the students of 10 KiVa schools before and after the program’s implementation. The second is to identify the factors which explain the phenomenon with a view to knowing the background of the victims and the bullies and proposing courses of action. To do so, the school environment (atmosphere in the classroom and in the school), the pe…
Science education and the “state of the world”: a programme of activities to enhance teacher’s perception of global problems and possible remedies
2003
A literatura sobre formação de professores de ciências não tem tratado suficientemente a situação do mundo quanto a uma percepção global de seus graves problemas atuais. O presente artigo consiste essencialmente de um programa de atividades a ser desenvolvido com professores em formação e em exercício, que visa favorecer uma reflexão coletiva e conscientização sobre essa problemática. Nesta perspectiva é apontado um conjunto de referências e questões para um debate fundamentado sobre vários dos fatores associados à degradação da vida e sobre possíveis medidas para o enfrentamento da emergência planetária. Investigações preliminares sobre a utilização do programa proposto têm revelado result…
Testing the Modified Sediment Delivery Model (MOSEDD) at SPA2 Experimental Basin, Sicily (Italy)
2017
A new version of a spatially distributed sediment delivery model taking into account the hillslope sediment transport efficiency, named MOSEDD, is presented. This model gives estimates of basin sediment yield at event scale, which are more reliable than those obtained by the original SEDD. For SPA2 basin discretized into morphological units, four different calculation schemes of MOSEDD, including the original SEDD version, were applied. All parameterization schemes of the model were calibrated using 15 events measured at the outlet of the experimental basin in the period February 2005–February 2010. The model calibration was used to determine a relationship between the coefficient βe of the…
Formation, Structural Characterization, and Calculated NMR Chemical Shifts of Selenium-Nitrogen Compounds from SeCl4 and ArNHLi (Ar = supermesityl, m…
2004
Supermesityl selenium diimide [Se{N(C6H2tBu3-2, 4, 6)}2; Se{N(mes*)}2] can be prepared in a good yield from the reaction of SeCl4 and (mes*)NHLi. The molecule adopts an unprecedented anti, anti-conformation, as deduced by DFT calculations at PBE0/TZVP level of theory and supported by 77Se NMR spectroscopy and a crystal structure determination. An analogous reaction involving (C6H2Me3-2, 4, 6)NHLi [(mes)NHLi] unexpectedly lead to the reduction of selenium and afforded the selenium diamide Se{NH(mes)}2 that was characterized by X-ray crystallography and 77Se NMR spectroscopy. The Se-N bonds of 1.847(3) and 1.852(3) A show normal single bond lengths. The <NSeN bond angle of 109.9(1)° also indi…
Influence of a Thiolate Chemical Layer on GaAs (100) Biofunctionalization: An Original Approach Coupling Atomic Force Microscopy and Mass Spectrometr…
2013
International audience; Widely used in microelectronics and optoelectronics; Gallium Arsenide (GaAs) is a III-V crystal with several interesting properties for microsystem and biosensor applications. Among these; its piezoelectric properties and the ability to directly biofunctionalize the bare surface, offer an opportunity to combine a highly sensitive transducer with a specific bio-interface; which are the two essential parts of a biosensor. To optimize the biorecognition part; it is necessary to control protein coverage and the binding affinity of the protein layer on the GaAs surface. In this paper; we investigate the potential of a specific chemical interface composed of thiolate molec…
Entrapment of a linear water pentamer into a uranyl-salophen dimer in the solid state
2019
In the solid state, uranyl-salophen complex 1, decorated with bipyridyl sidearms, self-assembles from moist acetonitrile into dimeric species displaying a confined water pentamer, as observed by X-...