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81.
An Ethanol Biosensor Based on Simple Immobilization of Alcohol Dehydrogenase on Fe3O4@Au Nanoparticles
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Anchalee Samphao Kanjana Kunpatee Sanchai Prayoonpokarach Jatuporn Wittayakun Ľubomír Švorc Dalibor M. Stankovic Kristina Zagar Miran Ceh Kurt Kalcher 《Electroanalysis》2015,27(12):2829-2837
An ethanol biosensor based on alcohol dehydrogenase (ADH) attached to Au seeds decorated on magnetic nanoparticles (Fe3O4@Au NPs) is presented. ADH was immobilized on Fe3O4@Au NPs, which were subsequently fixed by a magnet on a carbon paste electrode modified with 5 % (m : m) MnO2. Optimum conditions for the amperometric determination of ethanol with the biosensor were as follows: working potential +0.1 V (vs. Ag/AgCl); supporting electrolyte: 0.1 M phosphate buffer solution at pH 6.8 containing 0.25 mM of the coenzyme (NAD+); working electrode: carbon paste with magnetically attached Fe3O4@Au NPs (0.012 mg ? cm?2 electrode area) with immobilized alcohol dehydrogenase (120 units per cm2 of electrode area). Linearity between signal and concentration was found for the range from 0.1 to 2.0 M ethanol (r2=0.995) with a detection limit of 0.07 M, a sensitivity of 0.02 µA ? mM?1 ? cm?2, a reproducibility of 4.0 % RSD, and a repeatability of 2.7 % RSD. The results for the determination of ethanol in alcoholic beverages showed good agreement with gas chromatography (GC) with recovery of 96.0 – 108.8 %. 相似文献
82.
Dalibor Pražák 《Applications of Mathematics》2011,56(1):161-172
We are concerned with the uniqueness problem for solutions to the second order ODE of the form x″+f(x, t) = 0, subject to appropriate initial conditions, under the sole assumption that f is non-decreasing with respect to x, for each t fixed. We show that there is non-uniqueness in general; on the other hand, several types of reasonable additional assumptions
make the problem uniquely solvable. 相似文献
83.
Jamali S Milić D Kia R Mazloomi Z Abdolahi H 《Dalton transactions (Cambridge, England : 2003)》2011,40(37):9362-9365
The preparation of two new bis(N-heterocyclic carbene) platinum(II) complexes, in which NHC rings are joined by a CH(2) linker group, is described. While, the chelate complex [PtMe(2)(bis-NHC1)], 1, was formed with large tert-butyl wingtips, the iso-propyl N-substituent analogue favors formation of the cluster complex [Pt(2)Me(4)(μ-SMe(2))(μ-bis-NHC2)](2)(μ-Ag(2)Br(2)), 2, in which two binuclear platinum(II) complexes are linked together by an Ag(2)Br(2) unit. The chelating platinum complex 1 undergoes aerial CO(2) fixation and forms platinum(II) carbonate complex [Pt(CO(3))(bis-NHC1)], 3. 相似文献
84.
The main aim of this work was to study the dependence of oligoadenine isolation efficiency on the chain length by using paramagnetic particles covered by homo-deoxythymidines ((dT)25) with subsequent detection by adsorptive transfer technique coupled with square wave voltammetry. For this purpose, the oligonucleotides of the length A5, A10, A15, A20, A25, A30, A35, A40 and poly(A) in various concentrations were chosen. We determined that the isolation efficiency defined as “isolated oligonucleotide concentration”/“given oligonucleotide concentration” was about 55% on average. Sequence A25 demonstrated the best binding onto microparticles surface. 相似文献
85.
Dirk C. de Graaf Wolfgang Ritter Frans J. Jacobs Marleen Brunain Hein Imberechts Koen Mintiens Yves Van der Stede Bart Verheyden Aud Kari Fauske Patrick Boujon Gabriela Chioveanu Daniel Dezmirean Giovanni Formato Franco Mutinelli Hendrik-Jan Roest Dalibor Titĕra Stephen F. Pernal Katia Knapen 《Accreditation and quality assurance》2009,14(5):273-276
We report on the first proficiency test in the context of honey bee disease testing on a broad international scale. Honey
samples were distributed to 12 participating laboratories for isolation and identification of spores of the etiological agent
of American foulbrood, Paenibacillus larvae. Of the 11 laboratories responding to this proficiency testing event, only 6 (54%) provided data that were in full agreement
with the previously determined status of the honey samples; eight (72%) laboratories fell within the threshold for qualification
as defined a priori in this proficiency test (=level of agreement of at least 90%). Some lessons can now be drawn from the
organizational point of view and will certainly improve new initiatives to be taken. 相似文献
86.
Easy, efficient and low demanding separation of mRNA from biological material is needed to study gene expression and to use in chip technologies. It is common knowledge that each mRNA molecule contains sequence of 25 adenines. This feature can be used for binding mRNA on the surface of the particles coated by thymine chains. The present work reports on suggesting and optimizing of mRNA separation and detection from biological material via paramagnetic microparticles coupled with electrochemical detection. Primarily we optimized cyclic and square wave voltammetric conditions to detect poly(A), which was used as standard to mimic behaviour of mRNA. Under the optimized square wave voltammetric conditions (frequency 280 Hz, accumulation time 200 s, supporting electrolyte and its temperature: acetate buffer 4.6 and 35 °C) we estimated detection limit down to 1 ng of poly(A) per ml. To enhance effectiveness and repeatability of isolation of nucleic acid automated approach for rinsing and hybridizing was proposed. We optimized the whole procedure and experimental conditions. Using automated way of isolation and under optimized conditions the yield of poly(A) (isolated concentration of poly(A)/given concentration of poly(A)*100) was approximately 75%. The suggested and optimized method for poly(A) isolation and detection was utilized for the analysis of brain tissues of patients with traumatic brain injury. The total amount of isolated mRNA varied from 40 to 760 g of mRNA per g of brain tissue. The isolation of mRNA from six samples per run was not longer than 2.5 h. Moreover, we applied the optimized procedure on fully automated pipetting instrument to isolate mRNA. The instrument was successfully tested on the analysis of extracts from roots of maize plants treated with cadmium(II) ions. 相似文献
87.
Robust static output feedback control was applied to a continuous stirred tank reactor with parametric uncertainty and multiple
steady states in which exothermic reaction takes place. The problem of robust controller design was converted to a solution
of linear matrix inequalities and a computationally simple non-iterative algorithm is presented. The possibility of using
robust static output feedback for stabilization of reactors with uncertainty and comparison of robust P and PI controllers
with an optimal controller is demonstrated by simulation results. 相似文献
88.
Jungang Hou Yuanfang Qu Dalibor Krsmanovic R. V. Kumar 《Journal of nanoparticle research》2010,12(5):1797-1805
Well-dispersed bismuth titanate (BIT) nanocrystals with an average size ranged from 3 to 60 nm were synthesized via a peroxide-based
route assisted with an inverse microemulsion process. The crystallite size and lattice parameter of BIT upon variable-temperature
were determined by X-ray diffraction (XRD). The particle size was confirmed by transmission electron microscopy (TEM). Thermal
decomposition behaviour of Ti-peroxy and BIT gel and crystallization kinetics of BIT nanocrystals were investigated by differential
scanning calorimetry/thermogravimetry (DSC/TG) and Fourier-Transform infrared spectroscopy (FTIR). Analysis of nonisothermal
DSC data yielded a value of 220.84 ± 2.73 KJ/mol and 2.25 ± 0.26 for the activation energy of crystallization (E
a) and the Avrami exponent (n), respectively. 相似文献
89.
Dalibor M. Stankovi Milo Ognjanovi Milica Jovi Valentina Cupli Andreas Lesch Hubert H. Girault Marija GavroviJankulovi Bratislav Anti 《Electroanalysis》2019,31(8):1517-1525
A disposable acetaminophen biosensor based on inkjet‐printed CNT electrodes (IJPCNT) modified with amidase/cerium dioxide@graphene nanoribbons composite was developed (ACeO2@GNR/IJPCNT). The enzyme amidase A was used for the first time as a recognition element. Inkjet‐printed CNT electrodes served as a basis for the construction of a biosensor that enables droplet detection using 5 μL sample volume. The biosensor showed high selectivity, sensitivity, a low detection limit of 0.18 μM and a wide working linear range from 1 to 100 μM. The proposed approach allows fast and reliable detection of acetaminophen in biological fluids with negligible matrix effect and remarkable reproducibility. 相似文献
90.