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61.
Jiménez-Hernández ME Orellana G Montero F Portolés MT 《Photochemistry and photobiology》2000,72(1):28-34
The capability of the new luminescent probe (dibenzo[h,j] dipyrido[3,2-a:2',3'-c]phenazine)bis(2,2'-bipyridine)ruthenium(II) dication, (RB2Z), to discriminate live and dead cells has been tested on rat hepatocytes and mouse lymphocytes. RB2Z-stained cells were analyzed using flow cytometry, fluorescence (confocal) microscopy and time-resolved luminescence measurements. The established viability probes propidium iodide (PI) and SYTOX green (SG) were used as controls. The intense luminescence of RB2Z at 606 nm is localized in the nucleus of nonviable cells. Viability measurements by flow cytometry and fluorescence microscopy using RB2Z as dead-cell marker yield the same results as PI and SG. The luminescence lifetime of RB2Z also displays sensitivity to cell viability (0.45 and 0.82 microsecond in presence of fully viable and dead cells, respectively). This ruthenium complex is photostable under laser sources and its 200 nm Stokes shift facilitates multicolor labeling experiments in flow cytometry and fluorescence microscopy. Unlike the currently available probes, the long-lived excited state of RB2Z also allows assays based on luminescence decay measurements. 相似文献
62.
1,3-Cyclopentanedione bis(4-methylthiosemicarbazone) monohydrochloride produces colored solutions with chlorate ions in strongly acid medium. The yellow color obtained has been used to propose a spectrophotometric method of C103? determination in the concentration range 0.5–6.0 ppm (molar absorptivity 1.26 × 104 liters mol?1 cm?1 at a wavelength of 397 nm). 相似文献
63.
Francesco Frusteri Lorenzo Spadaro Claudia Espro Adolfo Parmaliana Francesco Arena 《天然气化学杂志》2002,(Z2)
The liquid-phase partial oxidation of propane in the presence of the Fen+/H2O2 Fenton system at 70℃ and 1.4 atm on silica supported Nafion catalysts has been investigated. The reaction proceeds via a radical reaction path the efficiency of which is improved by silica-supported Nafion catalysts. Because of the direct relationship between reaction rate and concentration of sulphonic acid sites of Nafion catalysts, it is inferred that the active phase enahnces the kinetics of propane conversion by promoting the rate of active radicals generation. 相似文献
64.
Giampaolo Primofiore Anna Maria Marini Federico Da Settimo Silvia Salerno Daniele Bertini Lisa Dalla Via Sebastiano Marciani Magno 《Journal of heterocyclic chemistry》2003,40(5):783-788
The synthesis of new planar derivatives characterized by the presence of a pyridothiopyranopyrazole or pyridothiopyranopyrimidine nucleus, carrying a substituted aryl group, is reported. The novel 1,4‐dihydropyrido[3′,2′:5,6]thiopyrano[4,3‐c]pyrazole derivatives were obtained by condensation of 2,3‐dihydro‐3‐hydroxymethylenethiopyrano[2,3‐b]pyridin‐4(4H)‐ones with appropriate hydrazines. The preparation of 2‐substituted pyrido[3′,2′:5,6]thiopyrano[4,3‐d]pyrimidines was accomplished from the intermediate 2,3‐dihy‐dro‐3‐dimethylaminomethylenethiopyrano[2,3‐b]pyridin‐4(4H)‐ones by reaction with the appropriate binucleophile amidines. The antiproliferative activity of some new products was tested by an in vitro assay on human tumour cell lines (HL‐60 and HeLa), but none of them showed any significant effects in the tests performed. Accordingly, linear flow dichroism measurements indicated their inability to form a molecular complex with DNA. 相似文献
65.
Martin JN Muñoz EM Schwergold C Souard F Asensio JL Jiménez-Barbero J Cañada J Vicent C 《Journal of the American Chemical Society》2005,127(26):9518-9533
Sugar-oligoamides have been designed and synthesized as structurally simple carbohydrate-based ligands to study carbohydrate-DNA interactions. The general design of the ligands 1-3 has been done as to favor the bound conformation of Distamycin-type gamma-linked covalent dimers which is a hairpin conformation. Indeed, NMR analysis of the sugar-oligoamides in the free state has indicated the presence of a percentage of a hairpin conformation in aqueous solution. The DNA binding activity of compounds 1-3 was confirmed by calf thymus DNA (ct-DNA) NMR titration. Interestingly, the binding of the different sugar-oligoamides seems to be modulated by the sugar configuration. Semiquantitative structural information about the DNA ligand complexes has been derived from NMR data. A competition experiment with Netropsin suggested that the sugar-oligoamide 3 bind to DNA in the minor groove. The NMR titrations of 1-3 with poly(dA-dT) and poly(dG-dC) suggested preferential binding to the ATAT sequence. TR-NOE NMR experiments for the sugar-oligoamide 3-ct-DNA complex both in D(2)O and H(2)O have confirmed the complex formation and given information on the conformation of the ligand in the bound state. The data confirmed that the sugar-oligoamide ligand is a hairpin in the bound state. Even more relevant to our goal, structural information on the conformation around the N-glycosidic linkage has been accessed. Thus, the sugar asymmetric centers pointing to the NH-amide and N-methyl rims of the molecule have been characterized. 相似文献
66.
Gierczak T Jiménez E Riffault V Burkholder JB Ravishankara AR 《The journal of physical chemistry. A》2005,109(4):586-596
Rate coefficients for the gas-phase thermal decomposition of HO(2)NO(2) (peroxynitric acid, PNA) are reported at temperatures between 331 and 350 K at total pressures of 25 and 50 Torr of N(2). Rate coefficients were determined by measuring the steady-state OH concentration in a mixture of known concentrations of HO(2)NO(2) and NO. The measured thermal decomposition rate coefficients k(-)(1)(T,P) are used in combination with previously published rate coefficient data for the HO(2)NO(2) formation reaction to yield a standard enthalpy for reaction 1 of Delta(r)H degrees (298K) = -24.0 +/- 0.5 kcal mol(-1) (uncertainties are 2sigma values and include estimated systematic errors). A HO(2)NO(2) standard heat of formation, Delta(f)H degrees (298K)(HO(2)NO(2)), of -12.6 +/- 1.0 kcal mol(-1) was calculated from this value. Some of the previously reported data on the thermal decomposition of HO(2)NO(2) have been reanalyzed and shown to be in good agreement with our reported value. 相似文献
67.
Stephen B. Colbran Brian H. Robinson Jim Simpson 《Journal of organometallic chemistry》1984,265(2):199-204
The nitrosyl clusters PPN[YCCo3(CO)7(NO)] (Y = Me, Ph, COOH, (C5H5)Fe(C5H4)) have been prepared in high yield from the reaction of YCCo3(CO)9 with PPN(NO2) in THF, acetone or acetonitrile. Spectroscopic evidence indicates the structure of the nitrosyl anions is derived from that of YCCo3(CO)9 by the replacement of two CO ligands on one cobalt atom by a linear, terminal nitrosyl group. The nitrosyl metallates are extremely sensitive to oxidation and attempts to protonate the anions resulted in the reformation of the parent YCCo3(CO)9, molecules. The oxidative electrochemistry of the ferrocene complex, PPN[(C5H5)Fe(C5H4CCo3(CO)7(NO)] is also discussed. 相似文献
68.
69.
Jim Ho 《Analytica chimica acta》2002,457(1):125-148
Biological aerosol detection in real time is an urgent civilian and military requirement. Such detection capability will be useful in environmental monitoring, for example, in gathering information in perceived hazardous areas such as housing developments downwind of sewage treatment plants. To be truly functional, the instrument has to operate continuously, 24 h a day and 7 days a week with minimal maintenance and few false alarms. A novel concept is proposed. The system employs a rapid front-end warning/alarming mechanism based on optical technologies that provides useful information for protection decision makers. This is connected to a sample collector that feeds a slower back-end liquid chemistry system that provides analytical results to the medical personnel to assist in prophylaxis and therapy decisions. Experience gained from measuring fluorescence signals of single bacterial spores under flow cytometry (FCM) using UV excitation at 340-360 nm, was applied to concept testing of a prototype instrument, built to do the same for aerosols. This machine was capable of resolving particle size as well as fluorescence intensity of each particle under laboratory and field conditions; it was called the fluorescent aerodynamic particle sizer (FLAPS). This paper describes practical aspects of measuring biological aerosols when the results must be compared to reference samplers that provide culturable or “live” data. Treatment of particle size and fluorescence information is discussed with respect to FLAPS and reference data fidelity. Along with an objective method to evaluate FLAPS data correlation to reference data, an approach for determining limit of detection in the field is discussed. In addressing the back-end detector chemistry, we have prioritized a number of important biological characteristics that must be given to a clinician to help in prophylaxis and therapy decisions. A series of biochemical measurements are proposed to define the threat of a sample and different solutions are given to implement these tests. We predict that the future for biological detection looks promising for fluorescence in situ hybridization (FISH) techniques in identifying microorganisms. A conceptual instrument based on merging FCM and microchip-based analysis is described. 相似文献
70.
Valle-Algarra FM Medina A Gimeno-Adelantado JV Llorens A Jiménez M Mateo R 《Talanta》2005,66(1):194-201
Various solid-phase extraction (SPE) procedures for clean-up, two perfluoroacylation reagents (pentafluoropropionic anhydride (PFPA) and heptafluorobutyric anhydride (HFBA)) and two chromatographic columns (HP-1701 and HP-5) have been assessed comparatively to achieve the determination of type B trichothecenes (deoxynivalenol (DON), nivalenol (NIV), 3- and 15-acetyldeoxynivalenol (3- and 15-ADON)) in wheat grain by gas chromatography (GC)-electron-capture detection (ECD). Spiked wheat samples were extracted with acetonitrile-water (84:16, v/v). Tested SPE procedures were MycoSep 225 column, Florisil and different cartridges prepared in the laboratory with mixtures of various sorbents like alumina, Celite 545, C18, silica and charcoal. We propose MycoSep 225 column, and cartridges made with alumina-charcoal-silica and alumina-charcoal-C18 silica mixtures as clean-up procedures on the basis of recovery values (89.6, 87.3 and 86.1% for deoxynivalenol, respectively, at 1.0 mg/kg spiking level). The two last procedures are less expensive. Pentafluoropropionic anhydride was more stable against moisture and less expensive, while recoveries were similar to those obtained with heptafluorobutyric anhydride. HP-1701 column can separate 3- and 15-acetyldeoxynivalenol derivatives while HP-5 cannot, although this last column provided lower bleed and better sensitivity. 相似文献