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11.
Biosensors designed for environmental and food quality control based on screen-printed graphite electrodes with different configurations 总被引:3,自引:0,他引:3
Avramescu A Andreescu S Noguer T Bala C Andreescu D Marty JL 《Analytical and bioanalytical chemistry》2002,374(1):25-32
Graphite electrodes fabricated by screen-printing have been used as amperometric detectors in biosensors based on NAD(+)-dependent dehydrogenases, tyrosinase, or genetically modified acetylcholinesterases. The mono-enzyme sensors have been optimized as disposable or reusable devices for detection of a variety of substrates important in the food industry ( D-lactic acid, L-lactic acid, acetaldehyde) or in environmental pollution control (phenols and dithiocarbamate, carbamate and organophosphorus pesticides). The sensors were prepared in four configurations differing in enzyme confinement, enzyme immobilization and location of the immobilization agent in the biosensor assembly. Tests on real samples have been performed with the biosensors; D-lactic acid and acetaldehyde have been detected in wine and phenols in air. 相似文献
12.
Sionkowska A 《Journal of photochemistry and photobiology. B, Biology》2005,80(2):87-92
The thermal stability of UVB irradiated collagen in bovine lens capsules and in bovine cornea has been investigated by differential scanning calorimetry (DSC). During UVB irradiation the lens capsules and cornea were immersed in water to keep the collagen in a fully hydrated condition at all times. UV irradiation induced changes in collagen which caused both stabilization and destabilization of the collagen structure. The helix-coil transition for non-irradiated collagen in cornea occurred near 66 degrees C, instead for the irradiated one for 3h it occurred at 69 degrees C. After irradiating for longer times (20-96h) the helix-coil transition peak occurred at much lower temperatures. The peak was very broad and suggested that collagen was reduced by UV to different polypeptides of different molecular weight and different lower thermal stabilities. The irradiation of lens capsules with UVB light in vitro resulted in changes in the thermal properties of type-IV collagen consistent with increased cross-linking. DSC of lens capsules showed two major peaks at melting temperatures at 54 degrees C Tm1 and 78 degrees C Tm2, which can be attributed to the denaturation of the triple helix and 7S domains, respectively. UVB irradiation of lens capsules in vitro for 6 h caused an increase in Tm1 from 54 to 57 degrees C. The higher temperature required to denature the type-IV collagen after irradiation in vitro suggested an increase of intermolecular cross-linking. 相似文献
13.
Zamfir AD Lion N Vukelic Z Bindila L Rossier J Girault HH Peter-Katalinic J 《Lab on a chip》2005,5(3):298-307
A thin chip polymer-based microsprayer has been coupled to a hybrid quadrupole time-of-flight mass spectrometer (QTOF MS) and introduced in carbohydrate research. The feasibility of the approach is demonstrated for mapping, sequencing and structural elucidation of glycoconjugates originating from human body fluids and tissues such as a glycopeptide mixture from normal human urine and an isolated and purified GT1 ganglioside fraction from normal adult human brain. The optimization procedure required by each glycoconjugate category is described and the advantages of the system in terms of flexibility and adaptability to QTOF MS, stability of the ESI MS signal, carbohydrate ionization and sequencing, sensitivity, speed of analysis and sample consumption are discussed. 相似文献
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Frontispiece: Facile Conversion of Red Phosphorus into Soluble Polyphosphide Anions by Reaction with Potassium Ethoxide 下载免费PDF全文
16.
Alina Adriana Minea 《Heat and Mass Transfer》2012,48(11):1837-1845
In this paper an investigation was conducted to study the suitability of inserting radiant panels for industrial heating. The study involved heat transfer enhancement in an oval and a classical semi-industrial furnace. The experiment suggests an optimal panel position at 10–15 degrees inclination. A maximum energy saving of 22.5?% for the oval furnace was noticed and the most suitable case is to use panels as thick as is possible. 相似文献
17.
Predicting unsteady flows and aerodynamic forces for large displacement motion of microstructures requires transient solution of Boltzmann equation with moving boundaries. For the inclusion of moving complex boundaries for these problems, three immersed boundary method flux formulations (interpolation, relaxation, and interrelaxation) are presented. These formulations are implemented in a 2‐D finite volume method solver for ellipsoidal‐statistical (ES)‐Bhatnagar‐Gross‐Krook (BGK) equations using unstructured meshes. For the verification, a transient analytical solution for free molecular 1‐D flow is derived, and results are compared with the immersed boundary (IB)‐ES‐BGK methods. In 2‐D, methods are verified with the conformal, non‐moving finite volume method, and it is shown that the interrelaxation flux formulation gives an error less than the interpolation and relaxation methods for a given mesh size. Furthermore, formulations applied to a thermally induced flow for a heated beam near a cold substrate show that interrelaxation formulation gives more accurate solution in terms of heat flux. As a 2‐D unsteady application, IB/ES‐BGK methods are used to determine flow properties and damping forces for impulsive motion of microbeam due to high inertial forces. IB/ES‐BGK methods are compared with Navier–Stokes solution at low Knudsen numbers, and it is shown that velocity slip in the transitional rarefied regime reduces the unsteady damping force. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
18.
Fanny Danton Dr. Mohamed Othman Dr. Ata Martin Lawson Dr. Ján Moncol Dr. Alina Ghinet Prof. Benoît Rigo Prof. Adam Daïch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(24):6113-6118
An efficient domino transformation using a phenyliodine(III) diacetate (PIDA)/I2 combination towards Morin 1,4-thiazine compounds has been developed starting from N,S-acetals. The latter leads to “one-step” regioselective methylene insertion without the need for traditional sulfoxide intermediates in good yields. The reaction involves easily accessible N,S-acetals obtained from cost-effective basic ketones and cysteamine as starting materials. This process ultimately leads to 1,4-thiazines related to natural product and fused derivatives necessary for further QSAR study. 相似文献
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Mihaela Pascu Daniela-Elena Pascu Gina Alina Trăistaru Aurelia Cristina Nechifor Andrei A. Bunaciu Hassan Y. Aboul-Enein 《Journal of the Iranian Chemical Society》2014,11(2):315-321
The present study investigates the antioxidant activities of some Romanian plants, using different spectrophotometric methods (FRAP I, FRAP II, and CUPRAC). The plants investigated are hawthorn (Crataegus oxyacantha), bilberry (Vaccinium myrtillus L.), rosehip (Rosa canina), and chokeberries (Aronia melanocarpa). Hawthorn is used to treat a wide variety of inflammatory conditions, but the primary use is generally restricted for treating hypertension, ischemic heart disease, congestive heart failure, and arrhythmia. Investigations have proved the safe and reliable use of plant and plant extracts for treatment of cardiovascular disorders. 相似文献