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排序方式: 共有357条查询结果,搜索用时 812 毫秒
41.
Quinton D Girard A Thi Kim LT Raimbault V Griscom L Razan F Griveau S Bedioui F 《Lab on a chip》2011,11(7):1342-1350
In this work we report on the design, microfabrication and analytical performances of a new electrochemical sensor array (ESA) which allows for the first time the simultaneous amperometric detection of nitric oxide (NO) and peroxynitrite (ONOO(-)), two biologically relevant molecules. The on-chip device includes individually addressable sets of gold ultramicroelectrodes (UMEs) of 50 μm diameter, Ag/AgCl reference electrode and gold counter electrode. The electrodes are separated into two groups; each has one reference electrode, one counter electrode and 110 UMEs specifically tailored to detect a specific analyte. The ESA is incorporated on a custom interface with a cell culture well and spring contact pins that can be easily interconnected to an external multichannel potentiostat. Each UME of the network dedicated to the detection of NO is electrochemically modified by electrodepositing thin layers of poly(eugenol) and poly(phenol). The detection of NO is performed amperometrically at 0.8 V vs. Ag/AgCl in phosphate buffer solution (PBS, pH = 7.4) and other buffers adapted to biological cell culture, using a NO-donor. The network of UMEs dedicated to the detection of ONOO(-) is used without further chemical modification of the surface and the uncoated gold electrodes operate at -0.1 V vs. Ag/AgCl to detect the reduction of ONOOH in PBS. The selectivity issue of both sensors against major biologically relevant interfering analytes is examined. Simultaneous detection of NO and ONOO(-) in PBS is also achieved. 相似文献
42.
M. Abdolzadeh M.A. MehrabianG. Zahedi A. Soltani Goharrizi 《International Journal of Heat and Fluid Flow》2011,32(3):670-679
In this study a modified version of v2-f turbulence model (φ-α), is applied to simulate a non-isothermal air-flow. The φ-α model and a two-phase Eulerian approach complement each other to predict the rate of particle deposition on a tilted surface. The φ-α model can accurately calculate the normal fluctuations, which mainly represent the non-isotropic nature of turbulence regime near the wall. The Eulerian model was modified considering the most important mechanism in the particle deposition rate when compared to the experimental data. The model performance is examined by comparing the rate of particle deposition on a vertical surface with the experimental data in a turbulent channel flow available in the literature. The effects of lift force, turbophoretic force, thermophoreric force, electrostatic force, gravitational force and Brownian/turbulent diffusion were examined on the particle deposition rate. The results show that, using the φ-α model predicts the rate of deposition with reasonable accuracy. The results of modified particle model are in good agreement with the experimental data. This study highlights the paramount effect of thermophoretic force on the particle deposition rate and clearly shows that when the temperature difference exceeds a certain limit, the electrostatic force has insignificant effect on the particle deposition rate. Furthermore, it is indicated that even at small temperature differences, the effect of tilt angle on the particle deposition rate for intermediate-size particles is negligible. 相似文献
43.
We consider periodically correlated autoregressive processes in Hilbert spaces. Our studies on these processes involve existence,
covariance structure, estimation of the covariance operators, strong law of large numbers and central limit theorem. 相似文献
44.
Marie-Christine Costa Fethi Jarray Christophe Picouleau 《4OR: A Quarterly Journal of Operations Research》2006,4(1):73-85
This paper studies the days off scheduling problem when the demand for staffing fluctuates from day to another and when the
number of total workdays is fixed in advance for each employee. The scheduling problem is then to allocate rests to employees
with different days off policies: (1) two or three consecutive days off for each employee per week and (2) at least three
consecutive days off for each employee per month. For each one, we propose a polynomial time algorithm to construct a solution
if it exists.
Received: April 2005 / Revised version: October 2005
AMS classification:
60K25, 60K30 相似文献
45.
Fethi Bouzeffour 《Applicable analysis》2013,92(4):761-779
In this work, we establish a Babenko–Beckner-type inequality for the Dunkl transform of a radial function and Dunkl transform associated to a finite reflection group generated by the sign changes. As applications, we establish a new version of Young’s-type inequality and uncertainty relation for Renyi entropy. 相似文献
46.
Fethi Bouzeffour 《Journal of Difference Equations and Applications》2013,19(5):513-529
In this paper, we establish a sampling theorem related to the nonterminating version of the Wilson polynomials and we give a generalization of the de Branges–Wilson integral. 相似文献
47.
In this paper, the photocatalytic degradation of Reactive Black 5 (RB5) was investigated with ferrite bismuth synthesized via ultrasound under direct sunlight irradiation. The intensity of absorption peaks of RB5 gradually decreased by increasing the irradiation time and finally vanished in 50 min in acidic medium. The formation of new intermediate was observed in basic medium. The relative concentration of RB5 in solution and on the surface of ferrite bismuth (BiFeO3) nanoparticles was considered during the experiment in acidic and basic media. The effects of various parameters such as amount of catalyst, concentration of dye, and pH of the solution have been studied on the dye degradation. The adsorption isotherm and the kinetic of photocatalytic degradation of RB5 were investigated. The adsorption constants in the dark and in the presence of sunlight irradiation were compared. The photocatalytic degradation mechanism of RB5 has been evaluated through the addition of some scavengers to the solution. In addition, the stability and reusability of the catalyst were examined in this work. 相似文献
48.
S. Tavakol M. R. Nikpour A. Amani M. Soltani S. M. Rabiee S. M. Rezayat P. Chen M. Jahanshahi 《Journal of nanoparticle research》2013,15(1):1-16
Surface morphology, surface wettability, and size distribution of biomaterials affect their in vitro and in vivo bone regeneration potential. Since nano-hydroxyapatite has a great chemical and structural similarity to natural bone and dental tissues, incorporated biomaterial of such products could improve bioactivity and bone bonding ability. In this research, nano-hydroxyapatite (23 ± 0.09 nm) and its composites with variety of chitosan content [2, 4, and 6 g (45 ± 0.19, 32 ± 0.12, and 28 ± 0.12 nm, respectively)] were prepared via an in situ hybridization route. Size distribution of the particles, protein adsorption, and calcium deposition of powders by the osteoblast cells, gene expression and percentage of new bone formation area were investigated. The highest degree of bone regeneration potential was observed in nano-hydroxyapatite powder, while the bone regeneration was lowest in nano-hydroxyapatite with 6 g of chitosan. Regarding these data, suitable size distribution next to size distribution of hydroxyapatite in bone, smaller size, higher wettability, lower surface roughness of the nano-hydroxyapatite particles and homogeneity in surface resulted in higher protein adsorption, cell differentiation and percentage of bone formation area. Results obtained from in vivo and in vitro tests confirmed the role of surface morphology, surface wettability, mean size and size distribution of biomaterial besides surface chemistry as a temporary bone substitute. 相似文献
49.
We study the dual Dunkl-Sonine operator tSk,? on ?d, and give expression of tSk,?, using Dunkl multiplier operators on ?d. Next, we study the extremal functions f*λ, λ >0 related to the Dunkl multiplier operators, and more precisely show that {f*λ} λ >0 converges uniformly to tSk,?(f) as λ → 0+. Certain examples based on Dunkl-heat and Dunkl-Poisson kernels are provided to illustrate the results. 相似文献
50.