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111.
112.
Carolina Menna Natalia Calonghi Lanfranco Masotti Paolo Neyroz 《Journal of fluorescence》1993,3(1):33-43
This report describes a method to conjugate lucifer yellow to the external surface of liposomes. The heterobifunctional cross-linking reagentN-succinimidyl 3-(2-pyridyldithio)propionate has been used to activate DMPE molecules. The DMPE-dithiopyridine product has been mixed with DMPC to prepare liposome vesicles. These have been reduced by DTT and finally reacted with lucifer yellow-iodoacetamide to produce the fluorescence-labeled vesicles. The quenching of their fluorescence intensity by Kl is consistent with fully exposed fluorophores. The decay of the fluorescence intensity of the lipid-bound lucifer yellow is biexponential (1=7.9 ns; 2=1.1 ns), with a relative yield of 0.16. When the fluorescent liposomes are mixed with cells, the lucifer yellow-DMPE derivative is transferred. Boar spermatozoa and peripheral human blood lymphocytes have been used as cellular models. The extent of incorporation is dependent on the incubation time and temperature. At 36°C, lucifer yellow fluorescence appears in the spermatozoa cells after 10 min of incubation and reaches its maximum at about 60 min. The fluorescent phospholipid derivative seems to incorporate specifically into membrane structures. The highest labeling ratio is observed with integer, scarcely motile, spermatozoa. A poorer labeling yield (15%) is found with lymphocytes. Interestingly, photobleaching due to epiillumination of the labeled cells is apparently negligible and cells are clearly visible after irradiation times ranging from several minutes to few hours.A preliminary account of this work was presented at the Quarto Simposio su Biotecnologie Biochimiche, Capri, 28–30 June 1992. 相似文献
113.
苦味酸水浴液对固定在增塑的聚氯乙烯(PVC)膜中的蒽有可逆荧光熄灭作用,据此研制了测定苦味酸的荧光光化学传感器。该传感器的敏感膜的最佳组成为6~8mg蒽、50mgPvC粉、100mg邻苯二甲酸二异辛酯。测定苦味酸的浓度范围为3.04×10 ̄(-6)~6.16×10 ̄(-3)mol/L,重现性良好,响应时间为5~40秒,该传感器选择性好,许多常见亲脂明离子不干扰测定,可用于药物奎宁及辛可宁的间接测定。 相似文献
114.
Molecular switches that are controllable, reversible and readable at molecular level are an essential compo-nent of molecular electronics1 and chemical sensors.2-6 Of particular interest are the molecules which show dramatic and reversible changes in color and/or lumi-nescence in visible spectral region upon exposure to specific substrates. A number of chromophore- spacer-receptor systems that can selectively recognize specific guest molecules at their receptor site and pro-duce measurable col… 相似文献
115.
Klaus Rose Vlastimil MatĚjec Milos Hayer Marie PospiŠilovÁ 《Journal of Sol-Gel Science and Technology》1998,13(1-3):729-733
Various types of UV-curable organically modified siloxanes have been synthesized by the sol-gel method with the aim of fabricating chemically sensitive coatings for silica optical fibers. The refractive index of the coating material can be tailored in the range from 1.46 to 1.56 and sensitivity towards CO2 is achieved by incorporation of amino groups. The interaction of the cured layers with CO2 or with hydrocarbons has been studied in immersion experiments. Both the reaction of CO2 with incorporated amino groups and the penetration of hydrocarbons into the layer induce changes of the light absorption coefficient and the refractive index of the coating which are detected by measuring the output light intensity from the fiber. 相似文献
116.
Yi-Lu Sun Ren-Jang Wu Yu-Ching Huang Pi-Guey Su Murthy Chavali Yi-Zhen Chen Chu-Chieh Lin 《Talanta》2007,73(5):857-861
In situ preparation of polypyrrole (Ppy) by photo-polymerization coated on a quartz crystal microbalance (QCM) as a low humidity sensor was reported. Different concentrations of Ppy films say 0 wt.% (as blank), 0.1, 1, and 10 wt.% were investigated to measure humidity concentrations between 14.7 and 5412.5 ppmv. The adsorption/desorption behavior was also examined at humidity concentration 510.2 ppmv. The sensitivities of 0, 0.1 and 1 wt.% Ppy films at 51.5 ppmv were 0.143, 0.219 and 0.427, respectively. For 1 wt.% Ppy, the highest sensitivity was obtained. The slope and correlation coefficients (R2) for 1 wt.% Ppy at the ranges of 14.7–898.6 ppmv were 0.0646 and 0.9909, respectively. A series of molecular simulations have been carried out to calculate bond energy for the water molecule interaction with Ppy, which was found to be 3 kcal/mol indicating the existence of hydrogen bonding during the sorption process. Based on Langmuir isotherm adsorption assumption, for 0.1 and 1 wt.% Ppy films, the association constants were 2606.30 and 5792.98, respectively. This larger association constant for 1 wt.% Ppy film explains higher sensitivity. 相似文献
117.
Thereza Christina Vessoni Penna Marina Ishii Adalberto Pessoa Junior Laura de Oliveira Nascimento Luciana Cambricoli de Souza Olivia Cholewa 《Applied biochemistry and biotechnology》2004,114(1-3):453-468
To determine the influence of various culture conditions, transformed cells of Escherichia coli expressing recombinant green fluorescent protein (GFPuv) were grown in nine cultures with four variable conditions (storage
of inoculated broth at 4°C prior to incubation, agitation speed, isopropyl-β-d-thiogalactopyranoside [IPTG] concentration, and induction time). The pelleted cells were resuspended in extraction buffer
and subjected to the three-phase partitioning (TPP) extraction method. To determine the most appropriate purification resin,
protein extracts were eluted through one of four types of HiTrap hydrophobic interaction chromatography (HIC) columns prepacked
with methyl, butyl, octyl, or phenyl resins and analyzed further on a 12% sodium dodecylsulfatepolyacrylamidegel. With Coomassie
staining, a single band between 27 (standard GFPuv) and 29 kDa (molecular weight standard) was visualized for every HIC column
sample. TPP extraction with HIC elution provided about 90% of the GFPuv recovered and eight-fold GFPuv enrichment related
to the specific mass. Rotary speed and IPTG concentration showed, respectively, greater negative and positive influences on
GFPuv expression at the beginning of the logarithmic phase for the set culture conditions (37°C, 24-h incubation). 相似文献
118.
报道了一种用于定量分析易爆气体混合物丙烷和异丁烷的基于碳酸锶纳米材料的催化发光传感器。基于该传感器在不同温度下对两种气体的灵敏度不同,在320℃和342℃两个工作温度下,两种气体的浓度范围均为1000mL/m^3~10000mL/m^3时,分别建立了混合组分浓度相对催化发光强度的两个线性回归方程。在342℃时,丙烷和异丁烷的检出限(3σ)分别为50mL/m^3和20mL/m^3。可通过解上述两个联立方程式求得未知混合物中两组分的浓度。外来物质甲烷、乙烷、CO、氨气通过传感器时,甲烷和乙烷分别引起5.6%和17.2%的干扰,其它气体不干扰测定。20000mL/m^3的水蒸气不干扰2000mL/m^3丙烷和异丁烷气体的测定。用该法分析了人工合成样品中两种气体的浓度。 相似文献
119.
Yuri Vlasov 《Mikrochimica acta》1991,104(1-6):363-377
MOSFET-sensors can be considered as membrane-oxide-semiconductor field-effect transistors. MOSFETs can be divided into ISFETs, GasFETs, BioFETs, these sensors being sensitive to ion, gas, biomolecules respectively and there is also a possibility to fabricate MOSFET reference electrode (RefFET). The development and theoretical treatment of various type of MOSFET-sensors are presented in this paper. 相似文献
120.
Tin dioxide SnO2−δ is a pronounced n-type electron conductor due to its oxygen deficiency. This study investigates the rate of chemical diffusion of oxygen in SnO2−δ single crystals, which is a crucial step in the overall stoichiometry change of the material. The chemical diffusion coefficient Dδ was determined from conductivity- and EPR-relaxation methods. The temperature dependence was found to be . The dependence on crystal orientation, dopant content and oxygen partial pressure was below experimental error. The latter observation leads to the conclusion that the chemical diffusion coefficient is close to the diffusion coefficient of oxygen vacancies. Along with the relaxation process resulting from the chemical diffusion of oxygen, additional processes were observed. One of these was attributed to complications in the defect chemistry of the material. The relevance of the results for the kinetics of drift processes of Taguchi sensors is discussed. 相似文献