bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solution Equilibria. A Unified Mathematical Treatment of Experimental Polarographic and Potentiometric Data from AcidBase and Ligand Titrations. A Polarographic and Ion Selective Electrode Study of CdII(N‐(2‐hydroxyethyl)iminodiacetic acid)OH System
Authors: Cukrowski Ignacy , Maseko Nontombi 
Published: September 2003

AbstractIt has been demonstrated that potentiometric and polarographic data coming from either acidbase or ligand titrations can be evaluated by the same set of equations and mathematical procedures involving mass‐balance equations written for any metalligand model, including polynuclear species. It is shown that the concept of the complex formation curves, used previously in modeling and refinement of stability constants in acid‐base titration, is of general nature and can be successfully used in polarographic and potentiometric experiments conducted as a function of pH or an excess of a ligand. It appears that the linear relationship ΔE vs. log [M], typical for potentiometric studies with ISE, holds also in the case of the study of kinetically mixed metal‐ligand system studied by polarography when the corrected shift in the polarographic signal is used. The relationship ΔE vs. log [M] applies equally to the acid‐base and ligand titration for both experimental techniques employed (potentiometry and polarography). The significance of the corrected shift is discussed and its meaning in the study of kinetically fast or slow metalligand systems is elaborated. Advantages of the acid‐base titration over the ligand titration are discussed. The generalized mathematical data treatment was successfully employed in the study of the CdII(N‐(2‐hydroxyethyl)iminodiacetic acid) system. Results obtained from both analytical techniques (potentiometry with the use of an ion selective electrode, and two polarographic techniques) and analytical procedures (acidbase and ligand titrations) compare well with each other and with the literature data (the formation and stability constants of ML and ML2). In addition, a new complex M(HL) was identified and its stability constant is reported.
Alternating Current Tensammetry of Tetraphenylborate (TPB) and its Application for Potassium Determination
Authors: Ion Ana , Costache Madalina Beatrice , Grecu I. V. , Banica F. G. 
Published: September 2003

AbstractAlternating‐current polarography of tetraphenylborate ion (TPB) in acetate buffer (pH 4 to 5) or 0.1 to 0.5 M NaCl produces a characteristic tensammetric (pseudocapacitive) peak at −0.95 V (vs. SCE). Within a limited range (till about 0.2 mM), the tensammetric peak current is proportional to the TPB concentration but it levels off at higher concentration. TPB concentration can also be determined within 5 to 50 μM by measuring the capacity current at −0.4 V or the differential pulse polarographic peak current at −0.85 V. The tensammetric peak current was used to determine the solubility of potassium tetraphenylborate in acetate buffer and sodium chloride solutions. Also, a method for amperometric back‐titration of potassium ion was worked out and applied to the analysis of mineral water.
Characteristics of Subtractive Anodic Stripping Voltammetry of Lead, Cadmium and Thallium at Silver‐Gold Alloy Electrodes
Authors: Bonfil Y. , Brand M. , Kirowa‐Eisner E. 
Published: September 2003

AbstractSilver‐gold alloy electrodes have been studied for the purpose of the quantitative determination of heavy metals by subtractive anodic stripping voltammetry, (SASV). The results have been compared with those obtained with the silver and gold electrodes. The 50/50 a/o Ag/Au alloy electrode is the most suitable for quantifying thallium in the presence of lead and cadmium. The separation of its peak from those of lead and cadmium is 200 mV, which is about twice the separation obtained on the pure metal electrodes and is also better than on mercury. The silver electrode is suitable for the simultaneous determination of thallium, lead and cadmium. The peaks of lead and cadmium overlap on the 50/50 alloy. Pure silver or pure gold can be used for simultaneous quantification of these two metals. The use of gold for quantifying lead and cadmium is more limited because the peak potential of cadmium is shifted in the negative direction as its concentration increases and at [Cd2+]>200 nM, the two peaks merge. SASV enables correction for background currents and is of utmost importance for obtaining well‐defined peaks. The peaks of lead, cadmium and thallium appear over a relatively narrow potential range (ca. 200 mV) on all the electrodes presented in this work. For this reason, the quantifying of a peak is based on the derivative at the inflection point of only one of its branches (ascending or descending). All SASV measurements were carried out without removal of oxygen.
Using the Aggregation of Latex Polymers in the Fabrication of Reproducible Enzyme Electrodes
Authors: Rahmat Wibowo , Fischer Joshua , Hibbert D. Brynn , Gilbert Robert G. , Gooding J. Justin 
Published: September 2003

AbstractAn enzyme electrode for glucose is described as a model system to demonstrate a fabrication method using latex aggregation and entrapment of enzyme. Electrosterically‐stabilized latex particles synthesized by emulsion polymerization in batch from acrylic acid, methyl methacrylate and butyl acrylate, and glucose oxidase were coagulated together at pH 5.5 with ethanol. A platinum disk electrode dipped in the solution becomes coated with latex/enzyme. The relative thickness of the film and relative amount of enzyme may be controlled by the time the electrode is in contact with the solution. The enzyme was then immobilized by covalent attachment of amine groups to carboxylic moieties in the polymer using 1‐ethyl‐3(3‐dimethylaminopropyl)‐carbodiimide hydrochloride and N‐hydroxysuccinimide. Five minutes contact with the latex/enzyme solution and subsequent amide coupling, gave electrodes with a reproducibility of 5.7% RSD, a wide dynamic range (0–100 mM) and good storage properties.
Electroanalysis at Diamond‐Like and Doped‐Diamond Electrodes
Authors: Compton Richard G. , Foord John S. , Marken Frank 
Published: September 2003

AbstractDiamond as a high performance material occupies a special place due to its in many ways extreme properties, e.g., hardness, chemical inertness, thermal conductivity, optical properties, and electric characteristics. Work mainly over the last decade has shown that diamond also occupies a special place as an electrode material with interesting applications in electroanalysis. When made sufficiently electrically conducting for example by boron‐doping, ‘thin film' and ‘free–standing' diamond electrodes exhibit remarkable chemical resistance to etching, a wide potential window, low background current responses, mechanical stability towards ultrasound induced interfacial cavitation, a low ‘stickiness' in adsorption processes, and a high degree of ‘tunability' of the surface properties. This review summarizes some of the recent work aimed at applying conductive (boron‐doped) diamond electrodes to improve procedures in electroanalysis.
Quantification of analytes in overlapping peaks from capillary electrophoresis using multivariate curve resolution‐alternating least squares methods
Authors: Li Hua , Zhang Fang , Havel Josef 
Published: September 2003

AbstractApplication of multivariate curve resolution with alternating least squares (ALS) methods to second‐order data from capillary electrophoresis diode array detector (CE‐DAD) is shown. Second‐order data are easily obtained by setting individual data matrix of CE run one in top of the other. Initial qualitative solutions obtained by evolving factor analysis can be further optimized by simultaneous analysis of multiple electrophoresis run data with ALS regression. Quantification is achieved by the comparison of the analyte peak areas with that of pure standards. During the ALS regression procedure, the following constraints were applied: (i) both concentrations and unit pure spectra of the resolved components must be positive; (ii) elution profiles have an unimodal shape; (iii) correspondence exists between common species in the different data matrices; (iv) the pure spectrum of each species is the same in all runs where it is present. The above methods were applied for the determination of dinitrotoluene (DNT) isomeric compounds in overlapping peaks from CE.
Monitoring of chemical reactions within microreactors using an inverted Raman microscopic spectrometer
Authors: Fletcher Paul D. I. , Haswell Stephen J. , Zhang Xunli 
Published: September 2003

AbstractAn inverted Raman microscope spectrometer has been used to profile the spatial evolution of reactant and product concentrations for a chemical reaction within a microreactor operating under hydrodynamic flow control. The Raman spectrometer was equipped with a laser source at wavelength of 780 nm, confocal optics, a holographic transmission grating, and a charge‐coupled device (CCD) detector. The microreactor consisted of a T‐shaped channel network etched within a 0.5 mm thick glass bottom plate that was thermally bonded to a 0.5 mm thick glass top plate. The ends of the channel network were connected to reagent reservoirs that were linked to a syringe pump for driving the solutions by hydrodynamic pumping within the channels. The microchannels were 221 μm wide and 73 μm deep. The synthesis of ethyl acetate from ethanol and acetic acid was investigated as a model system within the microreactor as Raman scattering bands for each reactant and product species were clearly resolved. Raman spectral intensities of each band were proportional to concentration for each species and hence all concentrations could be quantitatively measured after calibration. By scanning specific Raman bands within a selected area in the microchannel network at given steps in the X‐Y plane, spatially resolved concentration profiles were obtained under steady‐state flow conditions. Under the flow conditions used, different positions within the concentration profile correspond to different times after contact and mixing of the reagents, thereby enabling one to observe the time dependence of the product formation. Raman microscopy provides a useful complementary technique to UV/VIS absorbance and fluorescence methods for the in situ monitoring and analysis of chemical reaction species having their lowest S0‐S1 absorption bands too far in the UV to be of use, due to their probable overlap with the bands from other reactant, product and solvent molecules.
Direct tris(2,2'‐bipyridyl)ruthenium (II) electrochemiluminescence detection of polyamines separated by capillary electrophoresis
Authors: Liu Jifeng , Yang Xiurong , Wang Erkang 
Published: September 2003

AbstractCapillary electrophoresis (CE) with tris(2,2`‐bipyridyl) ruthenium (II) (Ru(bpy)32+) electrochemiluminescence (ECL) detection technique was developed for the analysis of four polyamines (putrescine (Put), cadaverine (Cad), spermidine (Spd), and spermine (Spm)) analysis. The four polyamines contain different amine groups, which have different ECL activity. There are several parameters which influence the resolution and ECL peak intensities, including the buffer pH and concentrations, separation voltage, sample injection, electrode materials, and Ru(bpy)32+ concentrations. Polyamines are separated by capillary zone electrophoresis in an uncoated fused‐silica capillary (50 cm×25 μm (ID) filled with acidic phosphate buffer (200 mmol/L phosphate, pH 2.0) – 1mol/L phosphoric acid (9:1 v/v) and a separation voltage of 5 kV (25 μA), with end‐column Ru(bpy)32+ ECL detection. A 5 mmol/L Ru(bpy)32+ solution plus 200 mmol/L phosphate buffer (pH 11.0) is added into the reagent reservoir. The calibration curve is linear over a concentration range of two or three orders of magnitude for the polyamines. The analysis time is less than 25 min. Detection limits for Put and Cad are 1.9×10−7 mol/L and 7.6×10−9 mol/L for Spd and Spm, respectively. Intraday and interday relative standard deviations of ECL peak intensities are less than 8%. The main advantages of this CE‐ECL detection technique for polyamines analysis presented herein are the omission of chemical derivatization of the analytes and the high selectivity.
Influence of pH on electrophoretic behavior of phenothiazines and determination of pKa values by capillary zone electrophoresis
Authors: Lin Ching‐Erh , Liao Wei‐Ssu , Chen Kuo‐Hsing , Lin Wann‐Yin 
Published: September 2003

AbstractThe influence of buffer pH on the electrophoretic behavior of 13 structurally related phenothiazines and determination of pKa values by capillary zone electrophoresis (CZE) were investigated. The results indicate that phenothiazines with a piperazine substituent behave quite differently from those with substituents having an aliphatic side chain or a piperidine moiety over the pH range studied. To separate these phenothiazines, it is preferable to select buffer pH in the range of 2.5–3.5. The pKa values of phenothiazines with three different types of substituents attached at the 10‐position of the phenothiazine ring were determined. The determination of pKa values of phenothiazines allows us to rationalize the influence of buffer pH on the migration behavior of these compounds in CZE.
Comprehensive two‐dimensional separation system by coupling capillary reverse‐phase liquid chromatography to capillary isoelectric focusing for peptide and protein mapping with laser‐induced fluorescence detection
Authors: Mao Yu , Zhang Xiangmin 
Published: September 2003

AbstractA comprehensive two‐dimensional (2‐D) separation system, coupling capillary reverse‐phase liquid chromatography (cRPLC) to capillary isoelectric focusing (CIEF), is described for protein and peptide mapping. cRPLC, the first dimension, provided high‐resolution separations for salt‐free proteins. CIEF, the second dimension with an orthogonal mechanism to cRPLC afforded excellent resolution capability for proteins with efficient protein enrichment. Since all sample fractions in cRPLC effluents could be transferred to the CIEF dimensions, the combination of the two high‐efficiency separations resulted in maximal separation capabilities of each dimension. Separation effectiveness of this approach was demonstrated using complex protein/peptide samples, such as yeast cytosol and a BSA tryptic digest. A peak capacity of more than 10 000 had been achieved. A laser‐induced fluorescence (LIF) detector, developed for this system, allowed for high‐sensitive detection, with a fmol level of peptide detection for the BSA digest. FITC and BODIPY maleimide were used to tag the proteins, and the latter was found better both for separation and detection in our 2‐D system.
Separation and determination synchronously by multichannel mode‐filtered light capillary electrochromatography
Authors: Zuo Xinbing , Wang Kemin , Zhou Leiji , Huang Shasheng 
Published: September 2003

AbstractMode‐filtered light capillary electrophoresis (CE) was developed for capillary electrochromatography (CEC) by applying annular columns of different size (250, 320, and 530 μm) and a bovine serum albumin (BSA)‐modified chiral stationary phase. BSA was encapsulated on the pretreated surface of an optic fiber and the inner wall of a capillary using sol‐gel technique with a resultant larger active stationary phase area. The coating was examined by atomic force microscopy (AFM) and Fourier transform infrared (FT‐IR). The separation of DL‐tryptophan (10 mM) was investigated under different voltage/current conditions.
Direct immunoassay of estrone by capillary electrophoresis with laser‐induced fluorescence detection
Authors: Su Ping , Zhang Xin‐Xiang , Chang Wen‐Bao 
Published: September 2003

AbstractAn immunoassay for estrone (E1) in women's serum, based on the competitive reaction between fluorescein‐labeled complete antigen and E1 with limited amount of anti‐estrone monoclonal antibody is described. A thermally reversible hydrogel, poly‐N‐isopropylacrylamide (pNIPA), was added to the buffer to improve the reproducibility. With a laser‐induced fluorescence (LIF) detector, the capillary electrophoretic immunoassay (CEIA) can be applied to determine E1 at a concentration lower than 19.6 pg/mL. The E1 levels in ten normal women's serum were measured at the range of 118.6–222.0 pg/mL.
Critical factors for reproducible capillary electrophoresis of Escherichia coli cells
Authors: Dai Dongsheng , Chen Yi , Qi Li , Yu Xiao 
Published: September 2003

AbstractSharp peaks of Escherichia coli JM 109 (up to 1 300 000 theoretical plates) were recorded with either extremely diluted (< 5 mM) or extremely concentrated (ca. 150 mM) Tris‐borate (TB) running buffers. However, under the conditions of yielding sharp peaks, migration time of E. coli was irreproducible. Critial factors influencing reproducibility were found to include bacterial growth phase, storage condition, cell pretreatment before injection, and concentration of running buffer. Buffer concentrations in the range of 20–100 mM TB were essential for reproducibility. E. coli JM 109 was shown to be sensitive to ultrasonification. Bacterial growth and storage conditions could be monitored by CE, with results comparable to those obtained with optical methods.
Direct computation of thermodynamic properties of chemically reacting air with consideration to CFD
Authors: Iannelli Joe 
Published: September 2003

AbstractThis paper details a two‐equation procedure to calculate exactly mass and mole fractions, pressure, temperature, specific heats, speed of sound and the thermodynamic and jacobian partial derivatives of pressure and temperature for a five‐species chemically reacting equilibrium air. The procedure generates these thermodynamic properties using as independent variables either pressure and temperature or density and internal energy, for CFD applications. An original element in this procedure consists in the exact physically meaningful solution of the mass‐fraction and mass‐action equations. Air‐equivalent molecular masses for oxygen and nitrogen are then developed to account, within a mixture of only oxygen and nitrogen, for the presence of carbon dioxide, argon and the other noble gases within atmospheric air. The mathematical formulation also introduces a versatile system non‐dimensionalization that makes the procedure uniformly applicable to flows ranging from shock‐tube flows with zero initial velocity to aerothermodynamic flows with supersonic/hypersonic free‐stream Mach numbers. Over a temperature range of more than 10000 K and pressure and density ranges corresponding to an increase in altitude in standard atmosphere of 30000 m above sea level, the predicted distributions of mole fractions, constant‐volume specific heat, and speed of sound for the model five species agree with independently published results, and all the calculated thermodynamic properties, including their partial derivatives, remain continuous, smooth, and physically meaningful. Copyright © 2003 John Wiley & Sons, Ltd.
Molecular analysis of t(X;11)(q24;q23) in an infant with AML‐M4
Authors: Fu Jen‐Fen , Liang Der‐Cherng , Yang Chao‐Ping , Hsu Jia‐Jong , Shih Lee‐Yung 
Published: September 2003

Abstractt(X;11)(q24;q23) is a recurring chromosomal translocation in pediatric acute myeloid leukemia. The rearrangement results in fusion of MLL at 11q23 with SEPT6 at Xq24. Here, we report the identification of an MLL‐SEPT6 fusion transcript in an infant with acute myeloid leukemia (AML)‐M4. Reverse transcription–polymerase chain reaction confirmed the presence of an MLL‐SEPT6 fusion transcript composed of exon 8 of MLL and exon 2 of SEPT6, but the absence of the reciprocal SEPT6‐MLL fusion transcript. Sequence analysis of the genomic break junctions in MLL and SEPT6 suggested that the rearrangement in this case was the result of an insertion of the inverted Xq24 segment, which contained the 3′ region of SEPT6 intron 1 and up to 950 kb centromeric to SEPT6, into MLL intron 8. This is a novel type of chromosomal rearrangement leading to the MLL‐SEPT6 fusion. The presence of deletions, duplications, and non‐template DNA sequence at the break junctions suggested that the DNA damage‐repair machinery is likely to be involved in the translocation events. © 2003 Wiley‐Liss, Inc.
High‐resolution mapping of amplifications and deletions in pediatric osteosarcoma by use of CGH analysis of cDNA microarrays
Authors: Squire Jeremy A. , Pei Jianming , Marrano Paula , Beheshti Ben , Bayani Jane , Lim Gloria , Moldovan Laura , Zielenska Maria 
Published: September 2003

AbstractConventional cytogenetic and comparative genomic hybridization (CGH) studies have shown that osteosarcomas (OSs) are characterized by complex structural and numerical chromosomal alterations and gene amplification. In this study, we used high‐resolution CGH to investigate recurrent patterns of genomic imbalance by use of DNA derived from nine OS tumors hybridized to a 19,200‐clone cDNA microarray. In six OSs, there was copy number gain or amplification of 6p, with a minimal region of gain centering on segment 6p12.1. In seven OSs, the pattern of amplification affecting chromosome arm 8q showed high‐level gains of 8q12–21.3 and 8q22–q23, with amplification of the MYC oncogene at 8q24.2. Seven OSs showed copy number gain or amplification of 17p between the loci bounded by GAS7 and PMI (17p11.2–17p12), and three of these tumors also showed small losses at 17p13, including the region containing TP53. An in silico analysis of the distribution of segmental duplications (duplicons) in this region identified a large number of tracts consisting of paralogous sequences mapping to the 17p region, encompassing the region of deletions and amplifications in OS. Interestingly, within this same region there were clusters of duplicons and several genes that are expressed during bone morphogenesis and in OS. In summary, microarray CGH analysis of the chromosomal imbalances of OS confirm the overall pattern observed by use of metaphase CGH and provides a more precise refinement of the boundaries of genomic gains and losses that characterize this tumor. © 2003 Wiley‐Liss, Inc.
Molecular cytogenetic characterization of the KG‐1 and KG‐1a acute myeloid leukemia cell lines by use of spectral karyotyping and fluorescence in situ hybridization
Authors: Mrózek Krzysztof , Tanner Stephan M. , Heinonen Kristiina , Bloomfield Clara D. 
Published: September 2003

AbstractThe KG‐1 cell line, established from bone marrow cells of a patient with erythroleukemia evolving to acute myelogenous leukemia, and its less differentiated variant, KG‐1a, are widely used in research worldwide. However, to our knowledge, neither cell line was studied by use of molecular‐cytogenetic techniques such as spectral karyotyping (SKY) and fluorescence in situ hybridization (FISH). Our G‐banding, SKY, and FISH analyses revealed a complex karyotype with a pseudodiploid modal chromosome number in both the KG‐1 and KG‐1a cell lines. The lines shared several identical structural aberrations, including der(4)t(4;8), del(7q), der(8)t(8;12), idic(8)(p11), der(17)t(5;17), and der(20)t(12;20), but also differed with regard to other chromosome rearrangements. In contrast to KG‐1, the KG‐1a line lost one of the two copies of idic(8)(p11) present in KG‐1 cells and gained a der(8;22)(q24;q13), an i(11)(q10), and a der(19)t(14;19)(q13;q13.4). Notably, we have shown that the KG‐1 cells harbor a partial hexasomy of the long arm of chromosome 8, which may explain in part the previously reported significantly higher rate of formation of the AML1‐ETO fusion gene in KG‐1 cells subjected to high‐dose gamma irradiation compared with the rates of formation of the BCR‐ABL or the DEK‐CAN fusion gene. Our detailed description of chromosome rearrangements in KG‐1 and KG‐1a will be useful for the cytogenetic authentication of the lines, and provide clues as to the regions of the genome that could be studied further to explain the differences in phenotypic properties between KG‐1 and KG‐1a cells. © 2003 Wiley‐Liss, Inc.