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101.
Determination of the Anticancer Drug Sorafenib in Serum by Adsorptive Stripping Differential Pulse Voltammetry Using a Chitosan/Multiwall Carbon Nanotube Modified Glassy Carbon Electrode 下载免费PDF全文
Nurgul Karadas‐Bakirhan Stéphanie Patris Sibel A. Ozkan Alp Can Jean‐Michel Kauffmann 《Electroanalysis》2016,28(2):358-365
Adsorptive stripping differential pulse voltammetry (AdSDPV) was applied to the assay of sorafenib in human serum sample. Cyclic voltammetry at a carbon based screen printed electrode (SPE) permitted to detect the irreversible oxidation of SOR with formation of a new compound reversibly oxidized at a lower potential. Quantitative assays were realized using a chitosan/carboxylic acid functionalized multiwalled carbon nanotube modified glassy carbon electrode in 0.1 M phosphate buffer pH 7.0 in the presence of 50 % methanol. The AdSDPV method provided two linear responses within the concentration ranges 1×10?8–8×10?8 M and 1×10?7–8×10?7 M in serum with LOQ and LOD of 3.2×10?9 and 9.6×10?10 of lower linear range, respectively. The recovery of sorafenib in spiked serum was 97.5 %. 相似文献
102.
We study a selective and periodic inventory routing problem (SPIRP) and develop an Adaptive Large Neighborhood Search (ALNS) algorithm for its solution. The problem concerns a biodiesel production facility collecting used vegetable oil from sources, such as restaurants, catering companies and hotels that produce waste vegetable oil in considerable amounts. The facility reuses the collected waste oil as raw material to produce biodiesel. It has to meet certain raw material requirements either from daily collection, or from its inventory, or by purchasing virgin oil. SPIRP involves decisions about which of the present source nodes to include in the collection program, and which periodic (weekly) routing schedule to repeat over an infinite planning horizon. The objective is to minimize the total collection, inventory and purchasing costs while meeting the raw material requirements and operational constraints. A single-commodity flow-based mixed integer linear programming (MILP) model was proposed for this problem in an earlier study. The model was solved with 25 source nodes on a 7-day cyclic planning horizon. In order to tackle larger instances, we develop an ALNS algorithm that is based on a rich neighborhood structure with 11 distinct moves tailored to this problem. We demonstrate the performance of the ALNS, and compare it with the MILP model on test instances containing up to 100 source nodes. 相似文献
103.
Atas Sibel S. Ali Karmina K. Sulaiman Tukur Abdulkadir Bulut Hsan 《Optical and Quantum Electronics》2022,54(11):1-14
Optical and Quantum Electronics - A series of barium zinc borophosphate glasses doped with copper oxide was prepared for optical filters. The phosphate network exhibited P–O bonds in... 相似文献
104.
Cliff Konold Anthony Harradine Sibel Kazak 《International Journal of Computers for Mathematical Learning》2007,12(3):217-230
In current curriculum materials for middle school students in the US, data and chance are considered as separate topics. They
are then ideally brought together in the minds of high school or university students when they learn about statistical inference.
In recent studies we have been attempting to build connections between data and chance in the middle school by using a modeling
approach made possible by new software capabilities that will be part of TinkerPlots 2.0 (TinkerPlots is published by Key Curriculum Press and has been developed with grants from the National Science Foundation (ESI-9818946, REC-0337675, ESI-0454754). Opinions
expressed here are our own and not necessarily those of the Foundation.). Using a new Sampler object, students build “factories”
to model not only prototypical chance events, but also distributions of measurement errors and of heights of people. We provide
the rationale for having students model a wide range of phenomena using a single software tool and describe how we are using
this capability to help young students develop a robust, statistical perspective. 相似文献
105.
A series of novel N-, S-, and O-substituted p-chloranil derivatives were synthesized from the reactions of p-chloranil (1) and related nucleophiles in sodium carbonate (Na2CO3) solution of acetonitrile or in chloroform with Et3N. The structures of novel compounds were characterized by using microanalysis, Fourier transform–infrared, 1H NMR, 13C NMR, and mass spectrometry. 相似文献
106.
A new, rapid, selective, cheap and simple RP-LC method has been developed and validated for the simultaneous determination of clobetasol propionate and calcipotriol mixtures in bulk drugs (raw materials) and in a novel-fixed dose emulgel formulation. Separation was carried out using a NovaPak C18 column with methanol:water (74:26 v/v) as mobile phase for isocratic elution at a flow rate of 1.0 mL min?1. The column temperature was set at 25 °C. Calibration curves were established ranging between 0.5 and 20 μg mL?1 and 0.5 and 10 μg mL?1 for clobetasol propionate and calcipotriol, respectively. Limit of detection and limit of quantification values of the method was found as 0.16 and 0.48 μg mL?1 for clobetasol propionate and 0.10 and 0.30 μg mL?1 for calcipotriol, respectively. The method was validated in accordance with ICH guidelines and obtained results proved that the proposed method was precise, accurate, selective and sensitive for the simultaneous analysis of clobetasol propionate and calcipotriol. The proposed method can be easily applied for the simultaneous determination of clobetasol propionate and calcipotriol in prepared emulgel formulations. The obtained validation results showed that the RP-LC method is suitable for routine quantification of clobetasol propionate and calcipotriol in emulgel formulations with high precision and accuracy. 相似文献
107.
Burcin Bozal-Palabiyik Burcu Dogan-Topal Bengi Uslu Alp Can Sibel A. Ozkan 《Journal of Solid State Electrochemistry》2013,17(11):2815-2822
A sensitive electroanalytical method for the determination of anticancer drug etoposide (ETP) using adsorptive stripping differential pulse voltammetry (AdSDPV) at a multi-walled carbon nanotube-modified glassy carbon electrode (MWCNT-modified GCE) is presented. The surface morphology of modified electrode was characterized by scanning electron microscopy. The effects of accumulation time and potential, pH, scan rate, and amount of MWCNT suspension were investigated. The calibration curve was linear in the concentration range of 2.0?×?10?8–2.0?×?10?6 M with the detection limit of 5.4?×?10?9 M. The reproducibility of the peak current was found at 1.55 % (n?=?5) RSD value in pH 6.0 Britton–Robinson buffer for the MWCNT-modified GCE. The method was then successfully utilized for the determination of ETP in pharmaceutical dosage form, and a recovery of 99.55 % was obtained. The possible oxidation mechanism of ETP was also discussed. The proposed electroanalytical method using MWCNT-modified GCE is the most sensitive method for the determination of ETP with lowest limit of detection in the previously published electrochemical methods. 相似文献
108.
The O-methyl oxime grouping in the antibiotic cefepime is reduced in aqueous buffer solution at pH<8 at a carbon electrode. The reduction of the protonated form of the oxime occurs in a single two-electron step. By comparison with anodic wave of 2-aminothiazole it was furthermore shown that the oxidation of cefepime involves the 2-amino group located on the thiazole ring in the side chain on C-7. Both reduction and oxidation peaks can be used for analytical purposes. 相似文献
109.
Simultaneous Estimation of Ceftazidime and Ceftizoxime in Pharmaceutical Formulations by HPLC Method
Senem Sanli Nurullah Sanli Mehmet Gumustas Sibel A. Ozkan Nurgul Karadas Hassan Y. Aboul-Enein 《Chromatographia》2011,74(7-8):549-558
The aim of the present study was to develop a fast, sensitive and reliable method for rapid screening of cephalosporin injectable dosage forms namely ceftazidime and ceftizoxime to the detection of counterfeit and substandard drugs that might be illegally commercialized. Ceftazidime, ceftizoxime and cefixime (IS) were separated in a X-Terra RP-18 column (250 × 4.60 mm ID × 5 ??) and DAD detector set at 290 and 260 nm. The mobile phase consisted of a mixture of methanol:water 20:80 (v/v) at a flow rate of 1.0 mL min?1. Additionally, in order to find the optimum pH value of separation the pK a values of studied compounds were determined by using two different methodologies. Aqueous pK a values of studied compounds have been determined by UV-spectrophotometry and liquid chromatography were used for the determination and direct characterization of the dissociation constants by using the dependence of the capacity factor on the pH of the mobile phase in 20% (v/v) methanol?Cwater binary mixture in which separation was performed. The pH of the mobile phase was adjusted with 25 mM H3PO4 to 3.2. The method was shown to be linear, sensible, accurate, and reproducible over the range of analysis and it can be used to pharmaceutical formulations containing a single active ingredient within a short analysis time. 相似文献
110.
The first use of electrospun nanofibrous materials as highly responsive fluorescence quenching-based optical CO2 sensors is reported. Poly(methyl methacrylate) and ethyl cellulose were used as polymeric materials. Sensing slides were
fabricated by electrospinning technique. A fiber-optic bundle was used for the gas detection. CO2 sensors based on the change in the fluorescence signal intensity of ion pair form of 8-hydroxypyrene-1,3,6-trisulfonic acid
(HPTS). The sensor slides showed high sensitivities due to the high surface area-to-volume ratio of the nanofibrous membrane
structures. The preliminary results of Stern-Volmer analysis show that the sensitivities of electrospun nanofibrous membranes
to detect CO2 are 24 to 120 fold higher than those of the thin film based sensors. The response times of the sensing reagents were short
and the signal changes were fully reversible. The stability of ion pair form of HPTS in the employed matrix materials was
excellent and when stored in the ambient air of the laboratory there was no significant drift in signal intensity after 7 months.
Our stability tests are still in progress. 相似文献