Search results for "Substitution"
showing 10 items of 536 documents
Mutant p53 gain of function can be at the root of dedifferentiation of human osteosarcoma MG63 cells into 3AB-OS cancer stem cells
2014
Osteosarcoma is a highly metastatic tumor affecting adolescents, for which there is no second-line chemotherapy. As suggested for most tumors, its capability to overgrow is probably driven by cancer stem cells (CSCs), and finding new targets to kill CSCs may be critical for improving patient survival. TP53 is the most frequently mutated tumor suppressor gene in cancers and mutant p53 protein (mutp53) can acquire gain of function (GOF) strongly contributing to malignancy. Studies thus far have not shown p53-GOF in osteosarcoma. Here, we investigated TP53 gene status/role in 3AB-OS cells-a highly aggressive CSC line previously selected from human osteosarcoma MG63 cells-to evaluate its involv…
Promoting self-employment: Does it create more employment and business activity?
2021
International audience; We assess the economic impact of reforms promoting self-employment in the three countries that have implemented such reforms since the early 2000s: the Netherlands, the United Kingdom and France. To that end, we use an unbalanced cross country-industry dataset of 4,226 observations, including 12 OECD countries and 20 market industries, over the 1995-2016 period. We first observe, using country-level data, that the share of self-employed workers in total employment is quite stable or declines over the period in all countries in our dataset, except in the three countries where large reforms promoting self-employment have been implemented, and only after these reforms. …
Arylated phenols, aroxyl radicals and aryloxenium ions syntheses and properties
1985
Development of Kesterite (Cu2ZnSnS4) absorber material for solar cell application.
2021
Kesterite-based solar cells still suffer from limited efficiency due to various problems related to the absorber and device interfaces. Absorber defects and non-ideal band alignment at the absorber/buffer hetero-interface, resulting in a cliff-like conduction band offset (CBO), and non-ideal absorber/back contact interfaces are the main factors limiting efficiency.This thesis focuses mainly on the absorber-related problems such as the secondary phases and the band alignment at the absorber-buffer heterojunction as well as the back interface.In the first part, the properties of the absorber layer were studied. Thin layers of Cu2ZnSnS4 (CZTS) were obtained by chemical route. This study reveal…
Structure and function of the vacuolar Ccc1/VIT1 family of iron transporters and its regulation in fungi
2020
Iron is an essential micronutrient for most living beings since it participates as a redox active cofactor in many biological processes including cellular respiration, lipid biosynthesis, DNA replication and repair, and ribosome biogenesis and recycling. However, when present in excess, iron can participate in Fenton reactions and generate reactive oxygen species that damage cells at the level of proteins, lipids and nucleic acids. Organisms have developed different molecular strategies to protect themselves against the harmful effects of high concentrations of iron. In the case of fungi and plants, detoxification mainly occurs by importing cytosolic iron into the vacuole through the Ccc1/V…
NUCLEOPHILIC SUBSTITUTIONS IN ISOINDOLE SERIES AS VALUABLE TOOL TO SYNTHESIZE DERIVATIVES WITH ANTITUMOR ACTIVITY
2009
The evolution of the heat-shock protein GroEL from Buchnera, the primary endosymbiont of aphids, is governed by positive selection
2002
The heat-shock protein GroEL is a double-ring-structured chaperonin that assists the folding of many newly synthesized proteins in Escherichia coli and the refolding in vitro, with the cochaperonin GroES, of conformationally damaged proteins. This protein is constitutively overexpressed in the primary symbiotic bacteria of many insects, constituting approximately 10% of the total protein in Buchnera, the primary endosymbiont of aphids. In the present study, we perform a maximum likelihood (ML) analysis to unveil the selective constraints in GroEL. In addition, we apply a new statistical approach to determine the patterns of evolution in this highly interesting protein. The main conclusion d…
Synthesis of Fluorinated Indazoles Through ANRORC-Like Rearrangement of 1,2,4-Oxadiazoles with Hydrazine.
2006
A series of 6-substituted fluorinated indazoles has been obtained through an ANRORC-like rearrangement (Addition of Nucleophile, Ring-Opening and Ring-Closure) of 5-tetrafluorophenyl-1,2,4-oxadiazoles with hydrazine. The initial addition of the bidentate nucleophile to the electrophilic C(5) of the 1,2,4-oxadiazole ring, followed by ring opening and ring closure, leads to the formation of fluorinated indazoles in high yield under mild experimental conditions. Functionalization of the C(6) in the final indazole nucleus was preliminarily achieved through a nucleophilic aromatic substitution on the starting 5-pentafluorophenyl-1,2,4-oxadiazole.
Nucleophilic reactions in the indole series: displacement of bromine under phase transfer catalysis
2008
A novel synthetic approach for the synthesis of 3-substituted indoles by nucleophilic substitution of 3-bromo derivatives under phase transfer catalysis (PTC) was reported.
Polycondensed nitrogen heterocycles. Part13. Pyrrolo[3,2-b]indole by intramolecular nucleophilic substitution reaction in the pyrrole series
1984
An intramolecular nucleophilic substitution in the pyrrole series has been generalized. The behaviour of nitro, chlorine, bromine and iodine as leaving groups towards the nucleophilic amino group was observed. An acid catalyzed mechanism has been proposed.