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51.
As a continuation of our project aimed at the search for new antiviral agents, the synthesis and biological evaluation of N-thia-carba-thymidine ((1R,2S,4S,5S)-5-methyl-1-{6-thia-4-hydroxy-5-[(hydroxy)-methyl]bicyclo[3.1.0]hex-2-yl}-1,3-dihydropyrimidine-2,4-dione; compound 8) was carried out employing the carbocyclic enantioenriched intermediate (1R,4S)-4-phenylmethoxy-3-[(phenylmethoxy)methyl]cyclopent-2-en-1-ol, which in turn was prepared from (3R,4S) phenylmethoxy-3-[(phenylmethoxy)methyl]-cyclopent-1-ene. The title compound resulted to be a very potent antiherpetic agent exhibiting a similar potency to acyclovir as shown. The synthetic approach to obtain this carbanucleoside required a novel strategy to introduce a thiirane group fused to a functionalized five-membered ring. 相似文献
52.
Tosi G Conti C Giorgini E Ferraris P Garavaglia MG Sabbatini S Staibano S Rubini C 《The Analyst》2010,135(12):3213-3219
Fourier transform infrared (FTIR) microspectroscopy has been employed to investigate benign (ordinary dermal and Reed nevi), dysplastic and malignant (invasive melanoma) skin lesions through the analysis of spectral changes of melanocytes as well as in the evaluation of the presence of melanin. Hierarchical cluster analysis and principal component analysis led to a satisfactory separation of malignant from dysplastic and normal melanocytes. Also, on enlarging the clustering with spectra from Reed and dermal nevi, the multivariate analysis segregated well the spectral data into discrete clusters, allowing the obtaining of reliable average spectra for analysis at the molecular level of the main groups or components responsible for the biological and biochemical changes. The most significant spectral characteristics appear to be related to differences in secondary protein structures, in nucleic acid conformation, in intra- and intermolecular bonding. In all cases, supervised and unsupervised spectral analyses resulted in satisfactory agreement with histopathological findings. 相似文献
53.
Dr. Daniele Fazzi Dr. Eleonora V. Canesi Prof. Fabrizia Negri Dr. Chiara Bertarelli Prof. Chiara Castiglioni 《Chemphyschem》2010,11(17):3685-3695
The quinoidal versus biradicaloid character of the ground state of a series of thiophene‐based heterophenoquinones is investigated with quantum‐chemical calculations. The role of the ground‐state electronic character on molecular structure and vibrational properties is emphasized. The vibrational activities are experimentally determined and their analysis is performed by taking advantage of the definition of a collective vibrational coordinate (the
54.
Giorgini E Conti C Ferraris P Sabbatini S Tosi G Rubini C Vaccari L Gioacchini G Carnevali O 《Analytical and bioanalytical chemistry》2010,398(7-8):3063-3072
The aim of this study was to verify the effects of probiotic Lactobacillus rhamnosus on zebrafish oocyte maturation using FPA (focal plane array) FTIR imaging together with specific biochemical assays (SDS-PAGE, real-time PCR and enzymatic assay). Oocyte growth is prevalently due to a vitellogenic process which consists of the hepatic synthesis of vitellogenin and its selective uptake during maturation. The administration of L. rhamnosus IMC 501 for 10 days induced chemical changes to oocyte composition, promoting the maturation process. Some interesting biochemical features, linked to protein secondary structure (amide I band) and to phospholipidic and glucidic patterns, were detailed by vibrational analysis. The spectroscopic results were supported by the early increase of the lysosomal enzyme involved in the final oocyte maturation, the cathepsin L. This enzyme increases during follicle maturation, with the highest levels in class IV oocytes. In treated females, class III oocytes showed higher cathepsin L gene expression and enzymatic activity, with levels comparable to class IV oocytes isolated from controls; this can be related to the proteolytic cleavage of the higher molecular mass yolk protein components, as evidenced by SDS-PAGE. 相似文献
55.
Bronstein LM Shtykova EV Malyutin A Dyke JC Gunn E Gao X Stein B Konarev PV Dragnea B Svergun DI 《The journal of physical chemistry. C, Nanomaterials and interfaces》2010,114(50):21900-21907
Iron oxide nanoparticles (NPs) with a diameter 21.6 nm were coated with poly(maleic acid-alt-1-octadecene) (PMAcOD) modified with grafted 5,000 Da poly(ethyelene glycol) (PEG) or short ethylene glycol (EG) tails. The coating procedure utilizes hydrophobic interactions of octadecene and oleic acid tails, while the hydrolysis of maleic anhydride moieties as well as the presence of hydrophilic PEG (EG) tails allows the NP hydrophilicity. The success of the NP coating was found to be independent of the degree of grafting which was varied between 20 and 80% of the -MacOD-units, but depended on the length of the grafted tail. The NP coating and hydrophilization did not occur when the modified copolymer contained 750 Da PEG tails independently of the grafting degree. To explain this phenomenon the micellization of the modified PMAcOD copolymers in water was analyzed by small angle x-ray scattering (SAXS). The PMAcOD molecules with the grafted 750 Da PEG tails form compact non-interacting disk-like micelles, whose stability apparently allows for no interactions with the NP hydrophobic shells. The PMAcOD containing the 5,000 Da PEG and EG tails form much larger aggregates capable of an efficient coating of the NPs. The coated NPs were characterized using transmission electron microscopy, dynamic light scattering, ζ-potential measurements, and thermal gravimetry analysis. The latter method demonstrated that the presence of long PEG tails in modified PMAcOD allows the attachment of fewer macromolecules (by a factor of ~20) compared to the case of non-modified or EG modified PMAcOD, emphasizing the importance of PEG tails in NP hydrophilization. The NPs coated with PMAcOD modified with 60% (towards all -MAcOD- units) of the 5,000 PEG tails bear a significant negative charge and display good stability in buffers. Such NPs can be useful as magnetic cores for virus-like particle formation. 相似文献
56.
Levina EV Kalinovsky AI Dmitrenok PS Martyyas EA Stonik VA 《Natural product communications》2010,5(11):1737-1742
New steroid glycosides, hylodoside A (1) and novaeguinoside Y (2), along with previously known polyhydroxylated steroids (3-7) were isolated from the ethanolic extracts of the starfish Leptasterias hylodes reticulata and Culcita novaeguineae (juvenile). The structures have been elucidated using 1D and 2D NMR spectra (1H, 13C, DEPT, COSY-45, 1D-TOCSY, HSQCGP, ROESY, HSQC and HMBCGP) and mass spectrometry. Compound 3 was shown to inhibit the growth of Staphylococcus aureus up to 10% from the control at a concentration of 1 mg/mL. Steroids 1, 2 and 5 showed moderate hemolytic activity in the mouse erythrocytes assay. Compounds 3, 4 and 6 displayed pH-depended hemolytic properties. 相似文献
57.
Fabio Gosetti Ugo Chiuminatto Davide Zampieri Eleonora Mazzucco Emilio Marengo Maria Carla Gennaro 《Journal of chromatography. A》2010,1217(20):3427-3434
The study investigates the natural photodegradation pathway of mono-chloroanilines in river waters, with the aim to identify the predominant photoproducts formed. At this purpose a new sensitive on-line SPE HPLC–MS/MS method has been developed with LOQ values equal or lower than the legal threshold concentration levels allowed for mono-chloroanilines in waters. The degradation processes of o-, m- and p-chloroaniline have been investigated subjecting their solutions, prepared both in ultrapure and in river water, to sun light irradiation simulated by a solar box system. The SPE HPLC–MS/MS methodology allowed to evaluate the degradation kinetics, to identify the predominant photodegradation products and to propose the chemical structures. Two photoproducts (aniline and 3-aminophenol), for which standards are available, have also been quantified. 相似文献
58.
Bogdan Tiţa Eleonora Marian Adriana Fuliaş Tunde Jurca Dumitru Tiţa 《Journal of Thermal Analysis and Calorimetry》2013,112(1):367-374
The application of thermal method is of great importance regarding the pharmaceutical problems such as the control of raw materials, the determination of purity, the qualitative and quantitative analysis of drug formulation, tests of thermal stability and compatibility and the determination of kinetic parameters etc. The purpose of a kinetic investigation is to calculate the kinetic parameters and the determination of the kinetic model for the studied process. The results are further used to predict the system’s behaviour in various circumstances. A kinetic study regarding the piroxicam—active substance’s thermal decomposition was performed under isothermal conditions and nitrogen atmosphere, for the temperature steps: 200, 205, 210, 215 and 220 °C. The TG/DTG data were processed by three differential methods: isothermal—isoconversional, Friedman’s isothermal isoconversional and isothermal model-fitting. The obtained results are in good accord between them, as well as with those obtained under non-isothermal conditions from a previous work and confirm the necessity of the kinetic parameters determining in different thermal conditions, by the adequate calculation methods. 相似文献
59.
60.
The X-ray photoelectron spectra of a series of Co(II) dithiocarbamate complexes have been studied. Data confirmed the substantial identity of the electronic structure of the chromophores throughout the series, and Co2P3/2 BE values of 780.1 eV are in good agreement with the expectation on the base of Feltham-Brant scale. Shake-up satellites associated with the Co2P3/2 photoelectron line have been investigated and compared with magnetic moments. 相似文献