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Stefan Bucur Marius Niculaua Catalina Ionica Ciobanu Neculai Catalin Lungu Ionel Mangalagiu 《Molecules (Basel, Switzerland)》2021,26(18)
This communication reports a novel synthesis route for the preparation of monofunctionalized β-cyclodextrin in a single stage. The approach involves only the in-situ protection of secondary hydroxyl groups as an excellent alternative to the classical procedure involving a series of five steps of protection and deprotection of hydroxyl groups (both primary and secondary ones) belonging to β-cyclodextrin. 相似文献
53.
Anton A. Ciucu Mihaela Buleandră Tatiana Ciurea Vlad N. Stoica Cristian D. Ştefanescu Adela Ciobanu 《Electroanalysis》2021,33(6):1389-1392
A new linear sweep voltammetric method for quantitative lamotrigine (LMT) determination based on an electrochemically pre-treated pencil graphite electrode (PGE*) is presented. Response characteristics of the PGE* toward the mentioned compound were investigated by cyclic voltammetry and linear sweep voltammetry. The quantitative determination of LMT revealed a wide linear range of 2.5 ⋅ 10−5–1.0 ⋅ 10−3 M with a detection limit of 1.94 ⋅ 10−5 M. The method was used successfully for LMT determination in a pharmaceutical formulation. 相似文献
54.
Dan Rosu Constantin Ciobanu Liliana Rosu Carmen-Alice Teaca 《Applied Surface Science》2009,255(23):9453-9457
A polyurethane elastomer was synthesized starting from 4,4′ diphenylmethane diisocyanate and poly(ethyleneadipate)diol. Butylene glycol was used as chain extender. Surface properties after photo-degradation of the elastomer under the action of the radiation with λ > 300 nm was monitored by FT-IR spectroscopy and contact angle measurements. The quality of polymer surface was observed under optical microscope. The formation of photo-Fries rearrangement and Norrish II reaction products during irradiation was associated with the gloss loss (from 100% for non-irradiated sample to 27% after 200 h irradiation time) and modification of wettability. There were also found significant modifications with irradiation time of both the glass transition temperature (Tg decreases from 64 °C for non-irradiated sample to 53 °C after 200 h irradiation) and the swelling coefficient (an increase from 1.2% up to 2.5% is observed after 200 h irradiation). 相似文献
55.
Identification and specificity profiling of protein prenyltransferase inhibitors using new fluorescent phosphoisoprenoids 总被引:4,自引:0,他引:4
Dursina B Reents R Delon C Wu Y Kulharia M Thutewohl M Veligodsky A Kalinin A Evstifeev V Ciobanu D Szedlacsek SE Waldmann H Goody RS Alexandrov K 《Journal of the American Chemical Society》2006,128(9):2822-2835
Posttranslational modification of proteins with farnesyl and geranylgeranyl isoprenoids is a widespread phenomenon in eukaryotic organisms. Isoprenylation is conferred by three protein prenyltransferases: farnesyl transferase (FTase), geranylgeranyl transferase type-I (GGTase-I), and Rab geranylgeranyltransferase (RabGGTase). Inhibitors of these enzymes have emerged as promising therapeutic compounds for treatment of cancer, viral and parasite originated diseases, as well as osteoporosis. However, no generic nonradioactive protein prenyltransferase assay has been reported to date, complicating identification of enzyme-specific inhibitors. We have addressed this issue by developing two fluorescent analogues of farnesyl and geranylgeranyl pyrophosphates {3,7-dimethyl-8-(7-nitro-benzo[1,2,5]oxadiazol-4-ylamino)-octa-2,6-diene-1}pyrophosphate (NBD-GPP) and {3,7,11-trimethyl-12-(7-nitro-benzo[1,2,5]oxadiazo-4-ylamino)-dodeca-2,6,10-trien-1} pyrophosphate (NBD-FPP), respectively. We demonstrate that these compounds can serve as efficient lipid donors for prenyltransferases. Using these fluorescent lipids, we have developed two simple (SDS-PAGE and bead-based) in vitro prenylation assays applicable to all prenyltransferases. Using the SDS-PAGE assay, we found that, in contrast to previous reports, the tyrosine phosphatase PRL-3 may possibly be a dual substrate for both FTase and GGTase-I. The on-bead prenylation assay was used to identify prenyltransferase inhibitors that displayed nanomolar affinity for RabGGTase and FTase. Detailed analysis of the two inhibitors revealed a complex inhibition mechanism in which their association with the peptide binding site of the enzyme reduces the enzyme's affinity for lipid and peptide substrates without competing directly with their binding. Finally, we demonstrate that the developed fluorescent isoprenoids can directly and efficiently penetrate into mammalian cells and be incorporated in vivo into small GTPases. 相似文献
56.
The present article deals with novel compounds comprising a redox‐active group as core and a nucleobase in the peripheries, linked covalently via a spacer. The new derivatives 1,1′,1″‐(benzene‐1,3,5‐triyltrimethanediyl)tris{1′‐[3‐(3,4‐dihydro‐5‐methyl‐2,4‐dioxopyrimidin‐1(2H)‐yl)propyl]‐4,4′‐bipyridinium} hexafluorophosphate ( 1 ), 1,1′,1″‐(benzene‐1,3,5‐triyltrimethanediyl)tris{1′‐[2‐(4‐chloro‐7H‐pyrrolo[2,3‐d]pyrimidine‐7‐yl)ethyl]‐4,4′‐bipyridinium} hexachloride ( 2a ) 1 1 The numbering of the pyrrolo[2,3‐d]pyrimidine system follows the IUPAC rules and is different from that of the purine ring system. , and 1,1′,1″‐(benzene‐1,3,5‐triyltrimethanediyl)tris{1′‐[2‐(2‐amino‐4‐chloro‐7H‐pyrrolo[2,3‐d]pyrimidine‐7‐yl)ethyl]‐4,4′‐bipyridinium} hexabromide ( 2b )1) were synthesized by nucleobase‐anion alkylation and linked to the 4,4′‐bipyridinium core. UV and CV analyses of these compounds were performed and revealed significantly different properties. 相似文献
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59.
The influence of non-magnetic impurities on band ferromagnetism for an electron gas withδ-function interaction is investigated in the framework of the quantum field theory applied to phase transitions. The Hartree-Fock approximation is used for non-zero temperatures. An equation for the magnetizationM and the critical temperatureT Fc is obtained. It is found that the transition temperature is lowered by increasing impurity concentration. There exists a critical concentration which vanishes the ferromagnetism. 相似文献
60.
Cotton fabrics were treated with a hybrid organic–inorganic coating obtained through a dual-cure process, i.e. a photopolymerization
reaction followed by a thermal treatment for promoting the formation of silica phases through a sol–gel process. To this aim,
different amounts of a silica precursor were added to an acrylic UV-curable formulation in the presence of a suitable coupling
agent. The thermo-mechanical properties of the treated fabrics were investigated and correlated to the composition and morphology
of the hybrid organic–inorganic system. Furthermore, their flame retardancy and combustion behavior were evaluated by flammability
tests and cone calorimetry and compared with the performances of pure cotton. 相似文献