Search results for "RELATIONSHIP"

Application of molecular topology in the prediction of new compounds with anti-trypanosomal cytotoxic activity

2021

La enfermedad de Chagas es una antropozoonosis parasitaria de transmisión mayoritariamente vectorial. Si bien afecta principalmente a América, constituye una de las mayores enfermedades desatendidas a nivel mundial. Solamente dos fármacos con un alto grado de toxicidad se encuentran disponibles para su tratamiento, por lo que es preciso aunar esfuerzos en pos del desarrollo de nuevas drogas antitripanosomales eficaces y con escasos efectos adversos. En este estudio, se aplicó la topología molecular para el desarrollo de un modelo QSAR capaz de predecir la actividad citotóxica antitripanosomal de un grupo de 39 compuestos. El modelo desarrollado mediante análisis lineal discriminante permiti…

Synthesis and inhibitory activity of dimethylamino-chalcone derivatives on the induction of nitric oxide synthase.

2002

A series of nine dimethylamino-chalcone derivatives (1,3-diaryl-propenones) was synthesized and screened as potential inhibitors of NO and PGE(2) production in the RAW 264.7 macrophage cell line. 4-Dimethylamino-2',5'-dimethoxychalcone (6) was found to be the most potent and dual inhibitor (IC(50s) in the submicromolar range) of NO and PGE(2) production. 2',6'-Dimethoxylation appeared to be an effective requirement for selective and potent inhibition of nitric oxide synthase induction as it was confirmed by Western blot analysis. Chalcone (6) at 25 mg kg(-1) by oral route, inhibited significantly the formation of oedema in the carrageenan-induced model of inflammation in mice.

Phenylsulphonyl urenyl chalcone derivatives as dual inhibitors of cyclo-oxygenase-2 and 5-lipoxygenase

2005

Two series of phenylsulphonyl urenyl chalcone derivatives (UCH) with various patterns of substitution were tested for their effects on nitric oxide (NO) and prostaglandin E2 (PGE2) overproduction in RAW 264.7 macrophages. None of the tested compounds reduced NO production more than 50% at 10 microM but most of them inhibited the generation of PGE2 with IC50 values under the micromolar range. Me-UCH 1, Me-UCH 5, Me-UCH 9, Cl-UCH 1, and Cl-UCH 9 were selected to evaluate their influence on human leukocyte functions and eicosanoids generation. These derivatives selectively inhibited cyclo-oxygenase-2 (COX-2) activity in human monocytes being Me-UCH 5 the most potent (IC50 0.06 microM). Selecte…

Synthesis and anti-inflammatory activity of chalcone derivatives

1998

Chalcones and their derivatives were synthesized and evaluated for their anti-inflammatory activity. In vitro, chalcones 2, 4, 8, 10 and 13 inhibited degranulation and 5-lipoxygenase in human neutrophils, whereas 11 behaved as scavenger of superoxide. Only four compounds (4-7) inhibited cyclo-oxygenase-2 activity. The majority of these samples showed anti-inflammatory effects in the mouse air pouch model.

Evaluation of the anti-inflammatory and analgesic activity of Me-UCH9, a dual cyclooxygenase-2/5-lipoxygenase inhibitor

2007

Abstract Recently, we reported the dual inhibition of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO) activity by some phenylsulphonyl urenyl chalcone derivatives. 2,4-dichloro-4′ N [ N ′(4″methylphenylsulphonyl)urenyl] chalcone (Me-UCH9), was selected in the present study to determine its potential anti-inflammatory and analgesic effect after oral administration in several animal models related to the activation of COX-2 and 5-LO pathways. In the zymosan stimulated mouse air pouch model, Me-UCH9, reduced in a dose-dependent manner leukotriene B 4 (LTB 4 ) levels in pouch exudates obtained at 4 h, as well as prostaglandin E 2 (PGE 2 ) generated through COX-2 activation at 24 h. Tumor nec…

Longitudinal associations of student–teacher relationships and behavioural and emotional strengths on academic achievement

2017

Positive student–teacher relationships are related to students’ academic achievement and behavioural and emotional adjustment. How a student’s behavioural and emotional strengths are associated with these relationships and how the relationships influence students’ academic performance remains unknown. We examined this framework using a cross-lagged panel model with a group of Finnish students and their parents from Grade 5 to Grade 7. The results revealed that the parents rated behavioural and emotional strengths are stable over a 1-year (r = .78) and 2-year (r = .71) period and that students’ perceptions of student–teacher relationships demonstrated greater change over time (r’s = .54, .35…

Opinion dynamics in coalitional games with transferable utilities

2014

This paper studies opinion dynamics in a large number of homogeneous coalitional games with transferable utilities (TU), where the characteristic function is a continuous-time stochastic process. For each game, which we can see as a “small world”, the players share opinions on how to allocate revenues based on the mean-field interactions with the other small worlds. As a result of such mean-field interactions among small worlds, in each game, a central planner allocates revenues based on the extra reward that a coalition has received up to the current time and the extra reward that the same coalition has received in the other games. The paper also studies the convergence and stability of op…

Effect of EDTA and citrate on the functional activity of the first component of complement, C1, and the C1q subcomponent.

1985

The first component of complement, C1, is a calcium-dependent complex of the three distinct subcomponents, C1q, C1r, and C1s. Earlier observations revealed that treatment of C1 with EDTA led to a loss of hemolytic C1 activity even after recalcification. Therefore, it was of interest to study whether EDTA has an additional effect on C1 and its subcomponents, beside its chelating capacity. The chelating effect of EDTA was compared to that of citrate. It was found that treatment of C1 or C1 with EDTA followed by addition of Ca++ led to a loss of hemolytic activity up to 90%, depending on EDTA concentration. Even pretreatment of EDTA with varying amounts of Ca++ did not prevent the inactivation…

Solving Chemical Problems with a Mixture of Quantum-Mechanical and Molecular Mechanics Calculations: Nobel Prize in Chemistry 2013

2013

STUDENT TEACHERS’ PROBLEMS IN TEACHING ‘ELECTROLYSIS’ WITH A KEY DEMONSTRATION

2002

This study is concerned with student teachers’ conceptions about teaching the topic of electrolysis and difficulties they encounter. The aim of the study was also to find out how the student teachers understand the meaning of a key demonstration that would show the main features of the phenomenon. During this study eight chemistry student teachers were invited to write a lesson plan on the topic of electrolysis for lower secondary level, grade 8 pupils (age 14 to 15). The written lesson plans and the semi-structured interviews were collected and analysed by using a set of analytical categories. Only two of the eight student teachers had a clear view that electrolysis is a process where an e…