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排序方式: 共有223条查询结果,搜索用时 31 毫秒
61.
Eleftheria Roumeli Angelina Tsiapranta Eleni Pavlidou Georgios Vourlias Kyriakos Kachrimanis Dimitrios Bikiaris Konstantinos Chrissafis 《Journal of Thermal Analysis and Calorimetry》2013,111(3):2109-2115
Thermal analysis is an essential, analytic tool used in preliminary studies and preparation of new pharmaceutical formulations. This study was performed to investigate the possible interactions between trandolapril and three commonly used natural excipients, namely α-lactose monohydrate, microcrystalline cellulose, and pregelatinized starch. The compatibility studies were carried out using thermoanalytic along with other complementary techniques. Differential scanning calorimetry and thermogravimetric analysis have proved that trandolapril is fully compatible with all the studied excipients until 100 °C. The complementary techniques used in this study were X-ray powder diffraction, Fourier transform-infrared spectroscopy, and scanning electron microscopy which confirmed the findings of thermal analysis. 相似文献
62.
Eleni Dimitriadou Julia Stephanidou-Stephanatou Constantinos A. Tsoleridis Dimitra J. Hadjipavlou-Litina Christos Kontogiorgis George E. Kostakis 《Tetrahedron》2014
A new aspect concerning chromone chemistry leading to the one-pot synthesis of functionalized novel ABCD-fused chromenopyrazolopyridines has been described. The synthesis involves a multicomponent reaction of chromone-3-benzoylhydrazones with isocyanides and acetylenedicarboxylates, whereupon novel complex tetracyclic benzopyrone derivatives containing three stereogenic centres were formed. The structure elucidation of the products was accomplished by 1D and 2D NMR experiments and confirmed by X-ray crystallographic analysis. Full assignment of all 1H and 13C NMR chemical shifts has been unambiguously achieved. The reaction mechanism is also discussed. In addition, eight chromenopyrazolopyridine derivatives were tested for possible biological activity (antioxidant and lipid peroxidation inhibition). 相似文献
63.
Stella Manta Dimitra-Niki Gkaragkouni Eleni Kaffesaki Petros Gkizis Dimitra Hadjipavlou-Litina Eleni Pontiki Jan Balzarini Wim Dehaen Dimitri Komiotis 《Tetrahedron letters》2014
A novel, two-step, facile route for the synthesis of pyrrolo[2,3-b]quinoxalines via 2,3-dioxopyrroles, enhanced by microwave irradiation, is presented. The newly synthesized 2,3-dioxo-5-halophenyl pyrrolo precursors 4a–c as well as the non-aromatized ethyl 2-(4-halophenyl)-1-methyl-2,4-dihydro-1H-pyrrolo[2,3-b]quinoxaline-3-carboxylates 6a–c and the aromatized ethyl 2-(4-halophenyl)-1-methyl-1H-pyrrolo[2,3-b]quinoxaline-3-carboxylates 7a–c were evaluated for their antioxidant, cytostatic, and antiviral properties. Most of them proved to be potent hydroxyl radical scavengers and inhibited in vitro lipid peroxidation. The compounds showed moderate antiproliferative activity, while 6a inhibited vaccinia virus at an EC50 value of 2 μM, and 4c and 6c inhibited Sindbis virus at EC50 values of 4 μM. 相似文献
64.
Panagiotis Theodosis-Nobelos Georgios Papagiouvannis Paraskevi Tziona Panos N. Kourounakis Eleni A. Rekka 《Molecules (Basel, Switzerland)》2021,26(13)
A series of L-serine amides of antioxidant acids, such as Trolox, (E)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid (phenolic derivative of cinnamic acid) and 3,5-di-tert-butyl-4-hydroxybenzoic acid (structurally similar to butylated hydroxytoluene), was synthesized. The hydroxy group of serine was esterified with two classical NSAIDs, ibuprofen and ketoprofen. The Trolox derivatives with ibuprofen (7) and ketoprofen (10) were the most potent inhibitors of lipid peroxidation (IC50 3.4 μΜ and 2.8 μΜ), several times more potent than the reference Trolox (IC50 25 μΜ). Most of the compounds decreased carrageenan-induced rat paw edema (37–67% at 150 μmol/kg). They were moderate inhibitors of soybean lipoxygenase, with the exception of ibuprofen derivative 8 (IC50 13 μΜ). The most active anti-inflammatory compounds exhibited a significant decrease in lipidemic indices in the plasma of Triton-induced hyperlipidemic rats, e.g., the most active compound 9 decreased triglycerides, total cholesterol and low-density lipoprotein cholesterol by 52%, 61% and 70%, respectively, at 150 μmol/kg (i.p.), similar to that of simvastatin, a well-known hypocholesterolemic drug. Since the designed compounds seem to exhibit multiple pharmacological actions, they may be of use for the development of agents against inflammatory and degenerative conditions. 相似文献
65.
Modern Synthetic Tools Toward the Preparation of Sophisticated Phthalocyanine‐Based Photoactive Systems 下载免费PDF全文
Phthalocyanines are ideal components in a variety of electronic applications due to their extraordinary photophysical characteristics combined with their synthetic versatility and robustness. They have attracted substantial attention in recent decades and are now established building blocks of sophisticated molecular materials. Synthetically, a great deal of this progress is attributed to the use of modern synthetic tools, which gave rise to phthalocyanine‐based systems that could not have been envisaged in the past. In particular, Pd‐catalyzed cross‐coupling reactions, together with other transition‐metal‐catalyzed procedures, “click” chemistry, and ruthenium metathesis have been employed extensively en route to an abundant range of elaborate phthalocyanine mono‐ and multicomponent photoactive architectures. Herein, we describe the synthesis of a selection of key examples that are representative in certain optoelectronic applications. 相似文献
66.
Evangelos I. Tolis Evangelos I. Gkanas Eleni Pavlidou Athina Skemperi Jorge Pey Noemi Pérez John G. Bartzis 《Central European Journal of Chemistry》2014,12(10):1081-1090
Scientists are interested in knowing more about the control of sources which contribute to environmental pollution. Air pollution has two main sources: anthropogenic and natural sources. The natural contributions to environmental pollution can be assessed, but cannot be totally controlled. while the emissions from the anthropogenic sources can be controlled. These air pollutants can be dispersed and transferred by winds in the atmosphere. The focus area of this study is the Mediterranean basin. The most important winds in this area are the land and sea breezes. Scanning Electron Microscopy (SEM) was applied to characterize the morphology of the PM10 samples in order to identify possible emission sources for the occuring pollution. Energy Dispersive X-ray Spectroscopy (EDS) was performed for the elemental analysis and chemical characterization of the PM10 samples. The analysis showed that the PM10 samples can be divided into three different groups: the samples containing mineral phases, the compounds from combustion processes and the particles emitted from high-temperature processes. 相似文献
67.
A multi-method approach has been developed for the characterisation of the proteinaceous binding media, drying oils and pigments present in samples from the panel paintings of the Church of the Assumption in Cephalonia (Ionian Islands, Greece). The analytical protocol involved the use of scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX), Raman spectroscopy and gas chromatography. The identification of the pigments was achieved by SEM/EDX and Raman spectroscopy. The latter technique was also used for the detection of the binding media, while their characterisation was achieved by gas chromatographic analysis of ethyl chloroformate derivatives. The aim of this multi-method protocol was to obtain as much information as possible from the panel paintings of the Church of the Assumption, through non-destructive methods, before proceeding to gas chromatography. Little scientific information is available for the understanding of the construction technique and the materials used by the post-Byzantine artists and whatever is available comes mainly from artists’ manuals. One of the aims of this paper is to provide a scientific background to the technology of the Ionian post-Byzantine icons. 相似文献
68.
A rapid and sensitive analytical method was developed for the residue analysis of ten quinolones (enoxacin (ENO), ofloxacin (OFL), norfloxacin (NOR), ciprofloxacin (CIP), danofloxacin (DAN), enrofloxacin (ENR), sarafloxacin (SAR), oxolinic acid (OXO), nalidixic acid (NAL), and flumequine (FLU)) in cow's milk. The analytes were extracted from milk by a deproteinization step followed by a simple SPE cleanup procedure using LiChrolut RP-18 Merck cartridges. Recoveries varied between 75 and 92%. HPLC separation was performed at 25 degrees C using an ODS-3 PerfectSil Target (250 x 4 mm(2)) 5 microm analytical column (MZ-Analysentechnik, Germany). The mobile phase consisted of a mixture of TFA 0.1%-CH(3)CN-CH(3)OH, delivered by a gradient program at the flow rate of 1.2 mL/min. Elution of the ten analytes and the internal standard (caffeine, 7.5 ng/microL) was completed within 27 min. Column effluent was monitored using a photodiode array detector, set at 275 and 255 nm. The developed method was validated according to the criteria of Commission Decision 2002/657/EC. The LODs of the specific method of quinolones' determination in milk varied between 1.5 and 6.8 ng/microL. 相似文献
69.
Zheng Niu Elke Prade Eleni Malideli Kathleen Hille Alexander Jussupow Yonatan G. Mideksa Li-Mei Yan Chen Qian Markus Fleisch Ana C. Messias Riddhiman Sarkar Michael Sattler Don C. Lamb Matthias J. Feige Carlo Camilloni Aphrodite Kapurniotu Bernd Reif 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(14):5820-5830
Designed peptides derived from the islet amyloid polypeptide (IAPP) cross-amyloid interaction surface with Aβ (termed interaction surface mimics or ISMs) have been shown to be highly potent inhibitors of Aβ amyloid self-assembly. However, the molecular mechanism of their function is not well understood. Using solution-state and solid-state NMR spectroscopy in combination with ensemble-averaged dynamics simulations and other biophysical methods including TEM, fluorescence spectroscopy and microscopy, and DLS, we characterize ISM structural preferences and interactions. We find that the ISM peptide R3-GI is highly dynamic, can adopt a β-like structure, and oligomerizes into colloid-like assemblies in a process that is reminiscent of liquid–liquid phase separation (LLPS). Our results suggest that such assemblies yield multivalent surfaces for interactions with Aβ40. Sequestration of substrates into these colloid-like structures provides a mechanistic basis for ISM function and the design of novel potent anti-amyloid molecules. 相似文献
70.
Tsiafoulis CG Exarchou V Tziova PP Bairaktari E Gerothanassis IP Troganis AN 《Analytical and bioanalytical chemistry》2011,399(6):2285-2294
The rapid and accurate determination of specific metabolites present in biofluids is a very demanding task which is essential
in both medicine and chemistry. l-carnitine (3-hydroxy-4-N-trimethylammonium butyrate) is an important metabolite which participates in a series of biological paths and therefore its
determination is of diagnostic importance. A single quantum coherence filtering 1H NMR methodology was used for the accurate and rapid determination of l-carnitine in human serum samples. The methodology is based on spectral simplification, and specifically on the distinction
of the N-methyl proton signal of l-carnitine that is greatly overlapped in the 1H-NMR spectrum of serum. The quantitative results provided by the proposed method are in excellent agreement with those obtained
by the enzymatic method, which is widely used. The proposed method is rapid (~20 min of experimental time), selective, sensitive,
and has good analytical characteristics (accuracy, reproducibility). Selected protein precipitation methods were also investigated
and sample pretreatment with EtOH is suggested. 相似文献