bluuebunny/crossref_metadata_2025 huggingface dataset:
Multinuclear Magnetic Resonance Imaging as a Multifunctional Tool for the Investigation of the Properties of Materials, Transport Processes and Catalytic Reactions
Authors: Koptyug I. V. , Lysova A. A. , Kovtunov K. V. , Zhivonitko V. V. , Khomichev A. V. , Sagdeev R. Z.
Published: October 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Molecular Aspects on the Interaction of Protoberberine, Benzophenanthridine, and Aristolochia Group of Alkaloids with Nucleic Acid Structures and Biological Perspectives
Authors: Maiti Motilal , Kumar Gopinatha Suresh
Published: October 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Automated Screening of Cationic Lipid Formulations for Transfection
Authors: Massing Ulrich , Jantscheff Peter
Published: October 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Fluorescence Microscopy: Bridging the Phase Gap in Catalysis
Authors: Roeffaers Maarten B. J. , Hofkens Johan , De Cremer Gert , De Schryver Frans C. , Jacobs Pierre A. , De Vos Dirk E. , Sels Bert F.
Published: October 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis and Characterization of New Macrocyclic Cu(II) Complexes from Various Diamines, Copper(II) Nitrate and 1,4‐Bis(2‐formylphenoxy)butane
Authors: ILHAN Salih , TEMEL Hamdi , KILIC Ahmet
Published: October 2007

Six new macrocyclic complexes were synthesized by a template reaction of 1,4‐bis(2‐formylphenoxy)butane with diamines and Cu(NO3)2·3H2O and their structures were proposed on the basis of elemental analysis, FT‐IR, UV‐Vis, magnetic susceptibility measurements, molar conductivity measurements and mass spectra. The metal to ligand molar ratios of the Cu(II) complexes were found to be 1:1. The Cu(II) complexes are 1:2 electrolytes as shown by their molar conductivities (Λm) in DMF at 10−3 mol·L−1. Due to the existence of free ions the Cu(II) complexes are electrically conductive. Their configurations were proposed to be probably distorted octahedral.
Curcumin‐Derived Pyrazoles and Isoxazoles: Swiss Army Knives or Blunt Tools for Alzheimer's Disease?
Authors: Narlawar Rajeshwar , Pickhardt Marcus , Leuchtenberger Stefanie , Baumann Karlheinz , Krause Sabine , Dyrks Thomas , Weggen Sascha , Mandelkow Eckhard , Schmidt Boris
Published: October 2007

Curcumin binds to the amyloid β peptide (Aβ) and inhibits or modulates amyloid precursor protein (APP) metabolism. Therefore, curcumin‐derived isoxazoles and pyrazoles were synthesized to minimize the metal chelation properties of curcumin. The decreased rotational freedom and absence of stereoisomers was predicted to enhance affinity toward Aβ42 aggregates. Accordingly, replacement of the 1,3‐dicarbonyl moiety with isosteric heterocycles turned curcumin analogue isoxazoles and pyrazoles into potent ligands of fibrillar Aβ42 aggregates. Additionally, several compounds are potent inhibitors of tau protein aggregation and depolymerized tau protein aggregates at low micromolar concentrations.
Hyrtiosal, from the Marine Sponge Hyrtios erectus, Inhibits HIV‐1 Integrase Binding to Viral DNA by a New Inhibitor Binding Site
Authors: Du Li , Shen Liangliang , Yu Zhiguo , Chen Jing , Guo Yuewei , Tang Yun , Shen Xu , Jiang Hualiang
Published: October 2007

HIV‐1 integrase (IN) is composed of three domains, the N‐terminal domain (NTD, residues 1–50), the catalytic core domain (CCD, residues 51–212), and the C‐terminal domain (CTD, residues 213–288). All the three domains are required for the two known integration reactions. CCD contains the catalytic triad and is believed to bind viral DNA specifically, and CTD binds viral DNA in a nonspecific manner. As no clear evidence has confirmed the involvement of NTD in DNA binding directly, NTD has not been seriously considered and less is known about its function in viral replication. In the current work, using a SPR technology‐based assay, the HIV‐1 viral DNA was determined to bind directly to NTD with a KD value of 8.8 μM, suggesting that the process of preintegrated complex formation for HIV‐1 IN might involve the direct interaction of NTD with viral DNA in addition to binding of viral DNA to the catalytic core domain and C‐terminal domain. Moreover, such viral DNA/IN binding could be inhibited by the marine product hyrtiosal from the marine sponge Hyrtios erectus with an IC50 of 9.60±0.86 μM. Molecular dynamic analysis correlated with a site‐directed mutagenesis approach further revealed that such hyrtiosal‐induced viral DNA/IN binding inhibition was caused by the fact that hyrtiosal could bind HIV‐1 NTD at Ser17, Trp19, and Lys34. As hyrtiosal was recently discovered by us as a protein tyrosine phosphatase 1B (PTP1B) inhibitor,1 this work might also supply multiple‐target information for this marine product, and the verified HIV‐NTD/HIV‐1 IN interaction model could have further implications for new HIV‐1 IN inhibitor design and evaluation.
Self‐Assembly of Amphiphilic Hexapyridinium Cations at the Air/Water Interface and on HOPG Surfaces
Authors: Gong Haofei , Bredenkötter Björn , Meier Christoph , Hoffmann‐ Richter Carola , Ziener Ulrich , Kurth Dirk G. , Volkmer Dirk
Published: October 2007

Mono‐ and multilayers of a novel amphiphilic hexapyridinium cation with six eicosyl chains (3) are spread at the air/water interface as well as on highly ordered pyrolytic graphite (HOPG). On water, the monolayer of 3 is investigated by recording surface pressure/area and surface potential/area isotherms, and by Brewster angle microscopy (BAM). Self‐organized tubular micelles with an internal edge‐on orientation of molecules form at the air/water interface at low surface pressure whereas multilayers are present at high surface pressure, after a phase transition. Packing motifs suggesting a tubular arrangement of the constituting molecules were gleaned from atomic force microscopy (AFM) investigations of Langmuir–Blodgett (LB) monolayers being transferred on HOPG at different surface pressures. These LB film structures are compared to the self‐assembled monolayer (SAM) of 3 formed via adsorption from a supersaturated solution, which is studied by scanning tunnelling microscopy (STM). On HOPG the SAM of 3 consists of nanorods with a highly ordered edge‐on packing of the aromatic rings and an arrangement of alkyl chains which resembles the packing of molecules at the air/water interface at low surface pressure. Additional details of the molecular packing were gleaned from single‐crystal X‐ray structure analysis of the hexapyridinium model compound 2b, which possesses methyl instead of eicosyl residues.
Marshmallows used as saliva stimulant do not affect cortisol concentrations: Finally a palatable alternative for toddler saliva collection
Authors: D. Clements Andrea , Parker C. Richard , Dixon Wallace E. , Salley Brenda
Published: October 2007

Two studies were conducted to validate marshmallows as a saliva stimulant for use with toddlers. First, cortisol concentrations from 14 subjects (ages 6–46 years) were compared using three saliva collection methods: (1) plain cotton dental roll, (2) dental roll with one mini‐marshmallow, and (3) expectorating into a collection tube using no cotton or stimulant. EIA was used for analyses. There were no significant differences among cortisol concentrations. Second, saliva collection compliance rate was compared for 21‐month‐olds (n = 51) using either flavored drink crystal‐ (compliance rate = 16.7%) or marshmallow‐flavored (compliance rate = 60%) dental rolls for saliva collection (χ2 )1) = 4.02, p = .045). These studies indicate that marshmallow is a viable option for saliva stimulation to determine toddler cortisol concentrations using EIA. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 702–707, 2007.
Maternal anesthesia via isoflurane or ether differentially affects pre‐and postnatal behavior in rat offspring
Authors: Ronca April E. , Abel Regina A. , Alberts Jeffrey R.
Published: October 2007

Our understanding of prenatal behavior has been significantly advanced by techniques for direct observation and manipulation of unanesthetized, behaving rodent fetuses with intact umbilical connections to the mother. These techniques involve brief administration of an inhalant anesthesic, enabling spinal transection of the rat or mouse dam, after which procedures can continue with unanesthetized dams and fetuses. Because anesthetics administered to the mother can cross the placental barrier, it is possible that fetuses are anesthetized to varying degrees. We compared in perinatal rats the effects of prenatal maternal exposure to two inhalant anesthetics: ether and isoflurane. Fewer spontaneous fetal movements and first postpartum nipple attachments were observed following maternal exposure to ether as compared to isoflurane. Neonatal breathing frequencies and oxygenation did not account for group differences in nipple attachment. Our results provide evidence that the particular inhalant anesthetic employed in prenatal manipulation studies determines frequencies of perinatal behavior. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 675–684, 2007.
Synapses, circuits, and the ontogeny of learning
Authors: Hunt Pamela S. , Fanselow Michael S. , Richardson Rick , Mauk Michael D. , Freeman John H. , Stanton Mark E.
Published: October 2007

This article summarizes the proceedings of a symposium organized by Mark Stanton and Pamela Hunt and presented at the annual meeting of the International Society for Developmental Psychobiology. The purpose of the symposium was to review recent advances in neurobiological and developmental studies of fear and eyeblink conditioning with the hope of discovering how neural circuitry might inform the ontogenetic analyses of learning and memory, and vice versa. The presentations were: (1) Multiple Brain Regions Contribute to the Acquisition of Pavlovian Fear by Michael S. Fanselow; (2) Expression of Learned Fear: Appropriate to Age of Training or Age of Testing by Rick Richardson; (3) Trying to Understand the Cerebellum Well Enough to Build One by Michael D. Mauk; and (4) The Ontogeny of Eyeblink Conditioning: Neural Mechanisms by John H. Freeman. Taken together, these presentations converge on the conclusions that (1) seemingly simple forms of associative learning are governed by multiple “engrams” and by temporally dynamic interactions among these engrams and other circuit elements and (2) developmental changes in these interactions determine when and how learning emerges during ontogeny. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 649–663, 2007.
Analysis of lightning surge propagation in wind farm
Authors: Yasuda Yoh , Hara Takehisa , Funabashi Toshihisa
Published: October 2007

Wind power generation is expected to become more important in future distribution systems. Although several prospective reports such as IEC 61400‐24 and NREL SR‐500‐31115 indicate an insulation scheme and grounding design for lighting protection, there still seems to be too few investigations on the problems. This paper therefore discusses lightning surge analysis using a wind farm model with 2 or 10 ideal wind turbines. Changing parameters such as grounding resistance and lightning strike points, several cases were studied. As a result of the analysis using digital simulator ARENE, it is clear that the surge tends to propagate toward the end of a distribution line in a wind farm and there is the possibility of insulation accidents at the other wind turbines when lightning attacks a wind turbine. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(2): 30– 38, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20364
Matrix converter control using direct AC/AC conversion approach to reduce output voltage harmonics
Authors: Takeshita Takaharu , Shimada Hiroshi
Published: October 2007

This paper presents a control scheme for matrix converters for reducing the output voltage harmonics. The proposed control scheme is based on the direct AC/AC conversion approach and the carrier‐based PWM control to obtain the constant switching frequency. The proposed scheme can achieve simultaneous control of both the output voltage and the input power factor. A feature of the proposed control scheme is the reduction of both the output voltage harmonics and the number of instances of commutations. The effectiveness of the proposed control algorithm for a matrix converter has been verified by simulations. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(2): 61–72, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20550
Ion extraction from magnetically driven shunting‐arc plasma and density estimation at sheath boundary
Authors: Kumagai Osamu , Mukaigawa Seiji , Takaki Koichi , Fujiwara Tamiya , Yukimura Ken , Ego Kenichi
Published: October 2007

Ion extraction from a magnetically driven shunting arc plasma and the plasma density at the sheath boundary are described in this paper. The plasma density is obtained using current and voltage waveforms for a target which is immersed in the plasma to extract the carbon ions. A 40‐mm‐long carbon rod which is 2 mm in diameter is employed as a solid‐state plasma source. A large current of more than 1 kA is supplied from a charged‐up 20‐µF capacitor to heat the carbon rod and to vaporize the rod materials. The shunting arc plasma generated along the rod surface is driven by the Lorenz force and is accelerated toward the muzzle of a plasma launcher which consists of a pair of 100‐mm‐long carbon plates. A 64‐mm‐diameter brass disk is placed 100 mm away from the carbon rod and is used as the target. A 10‐µs‐wide negative pulse bias voltage is applied to the target for the extraction of the carbon ions from the shunting arc plasma. The ion density near the sheath boundary around the target is obtained using two procedures: utilization of the stationary target current to determine the ion current and/or utilization of the target bias voltage waveforms. The ion density is obtained as 1.1×1015m−3 at µs after the arc ignition using the target current. The density is larger than the density of 5.1×1014m−3 obtained using the waveform of the target voltage. The plasma density is also predicted using a Bohm equation and a momentum conservation equation. The plasma density is 1.6×1015m−3 at 100 µs after the arc ignition. The density decreases as the time from arc ignition increases. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(2): 1– 9, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20553
Parameter design of event‐driven logic controller for two‐wheeled vehicle
Authors: Konaka Eiji , Mutou Takashi , Suzuki Tatsuya
Published: October 2007

Programmable Logic Controllers (PLCs) are widely used in industry. In PLC‐based control systems, low‐resolution (especially ON‐/OFF) sensors are inexpensive, and actuators are commonly used because they are compatible with programming languages used in PLCs.

PLC switches the actuators ON/OFF as the state of the sensor changes between ON/OFF. In designing PLC‐based systems, the design of the parameters of these sensors and actuators (e.g., position of limit switches and torque of motors) is an important problem because they affect the overall performance of the system. This problem, however, has not yet been fully discussed. In the present paper, a systematic design method for this problem is developed. The main concept is to express the model of the system as a Mixed Logical Dynamical System (MLDS) and to formulate the problem as a mathematical programming problem. The developed idea is applied to the line‐following control of a two‐wheeled vehicle. The usefulness of the proposed method is demonstrated through simulation and experiments. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(2): 51–60, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20584
Transient stability considering dynamic load in bulk power system with high DG penetration
Authors: Ueda Tomoyuki , Komami Shintaro
Published: October 2007

Transient stability may be seriously affected when a large number of distributed generators (DG) stop simultaneously during voltage sag. It is necessary to analyze accurately the dynamics of bulk power systems with high DG penetration. In this paper, transient stability is studied by analyzing power‐angle curves of generators while considering load dynamics and model order reduction at lower voltages. Based on the analysis, a decrease in the load internal resistance after voltage sag causes transient instability of generators. The phenomenon is confirmed through simulation using a one‐machine and one‐load model. This paper also suggests that the simulation results might be misled by traditional bulk power system modeling such as using the static load model and ignoring impedance at lower voltages. As for the numerical simulation, a large level of DG stoppage leads to transient step out in a bulk power system, and the stability is greatly improved by DG voltage regulation. © 2007 Wiley Periodicals, Inc. Electr Eng Jpn, 162(2): 20– 29, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20608
Synthesis, Crystal Structures, and Photophysical Properties of Lanthanide Complexes Containing Pyrrole‐Derivatized Carboxylate Ligands
Authors: Law Ga‐Lai , Wong Ka‐Leung , Lau Kok‐Kin , Tam Hoi‐Lam , Cheah Kok‐Wai , Wong Wing‐Tak
Published: October 2007

Two pyrrole‐deriviatized carboxylic acids [L1 = 1‐methylpyrrole‐2‐carboxylate] and [L2 = N‐methyl‐3‐indoleglyoxylate] were used as ligands to prepare six lanthanide coordination compounds [(L1)3Ln]n (Ln = Eu, 1; Gd, 2; Tb, 3) and [(L2)nLn(NO3)(MeOH)2]n (Ln = Eu, 4; Gd, 5; Tb, 6). These complexes have been synthesized and structurally characterized by single‐crystal X‐ray diffraction. The phosphorescence behavior of the ligands in the Gd3+ complexes show that modification of the ligands can tune the triplet energy levels of the ligands so that they match the 5D0 energy level of Eu3+ and the 5D4 energy level of Tb3+; thus, the energy transfer efficiency from antenna to Eu3+ and Tb3+ is improved, and the Eu3+ and Tb3+ emission intensity is enhanced. This concept can be applied towards improving the luminescent properties of Ln3+ complexes by the modification of coordinating ligands. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
First NiII–LnIII Coordination Polymers Constructed by Using [Ni(bpca)2] as a Building Block [Hbpca = bis(2‐pyridylcarbonyl)amine]: Synthesis, Crystal Structures and Magnetic Properties
Authors: Madalan Augustin M. , Bernot Kevin , Pointillart Fabrice , Andruh Marius , Caneschi Andrea
Published: October 2007

Three new heterobimetallic 1D coordination polymers have been obtained by assembling the [Ni(bpca)2] complex, as a building block, with lanthanide cations: [{Ln(O2NO)(H2O)3}{Ni(bpca)2}](NO3)2·3H2O (Ln Gd 1; Tb 2; Dy 3). The three compounds are isostructural and their structure consists of infinite cationic chains with LnIII ions connected by [Ni(bpca)2] complexes acting as bridging bis‐bidentate ligands. The charge of the chains is counterbalanced by uncoordinated nitrate ions. The LnIII ions display a coordination number of nine: four oxygen atoms from the carbonyl groups of the bpca ligands belonging to two {Ni(bpca)2} moieties, two oxygen atoms from a chelating nitrato ion and three water molecules. The magnetic investigation of the gadolinium derivative 1 revealed very weak intrachain NiII–GdIII‐ferromagnetic interactions (θ = +0.15 K). The weak intrachain‐exchange interactions, as well as the bad magnetic isolation of the chains in the crystals, preclude the single‐chain magnet behaviour of compounds 2 and 3. The out‐of‐phase, χ″, signal observed with compounds 2 and 3 can be ascribed to the magnetic slow relaxation of the lanthanide ions (TbIII, DyIII).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
A New Donor‐Stabilized Ditungsten Amido Alkoxido Species: Synthesis, Crystal Structure, Fluxionality, and Grafting onto Silica
Authors: Coutelier Olivier , Gauvin Régis M. , Nowogrocki Guy , Trébosc Julien , Delevoye Laurent , Mortreux André
Published: October 2007

A new dimeric tungsten(III) complex containing amidoand chelating pyridine–alkoxido ligands was synthesized through protonolysis of [W2(NMe2)6] by 2‐(2‐pyridyl)propan‐2‐ol and fully characterized by X‐ray diffraction and infrared and NMR spectroscopy. Intramolecular exchange processes were studied by variable‐temperature NMR spectroscopy. The compound was grafted onto dehydroxylated silica by protonolysis of an amido–tungsten bond, and the structure of the supported species was investigated by infrared and solid‐state (bidimensional) NMR spectroscopy. The reactivity of the molecular and grafted species toward alkynes was probed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
The Structure of Potassium and Tetramethylammonium Salts of the Cyclic Organohydroborate Anion [H2BC8H14]– with Different Solvent Ligands
Authors: Chen Xuenian , Liu Shengming , Du Bin , Meyers Edward A. , Shore Sheldon G.
Published: October 2007

Solvated potassium salts of the 9‐BBN hydroborate anion have been prepared and their structures have been determined by single‐crystal X‐ray diffraction analyses. A tetrameric complex {LK[(μ‐H)2BC8H14]}4 is formed when L is toluene, MeTHF, toluene/THF, THF/Et2O mixtures. The basic framework consists of a distorted K4B4 cube in which potassium and boron are at alternate corners of the cube linked by bridging hydrogen atoms and α‐C–H hydrogen atoms from the 9‐BBN hydroborate that appear to form agostic interactions with potassium. There are two types of bridging hydrogen atoms: one is connected to three potassium atoms and one boron atom in a μ4‐coordination arrangement, and the other one is connected to two potassium atoms and one boron atom in a μ3‐coordination arrangement. There are four μ4‐hydrogen arrangements in the structure. They are located inside of the K4B4 cube. The four μ3‐hydrogen arrangements are located outside of the distorted K4B4 cube. The coordination number of potassium is 8 with the three μ4‐, two μ3‐bridging hydrogen atoms, two α‐C–H hydrogen atoms, and one oxygen atom of the solvent, L (there is a weak π‐η6 interaction when the solvent is toluene). On the other hand, in the chelating solvent DME, a dimeric structure is formed in which the inner part is planar with potassium and boron located at alternate corners. The potassium is connected to four μ3‐bridging hydrogen atoms, two apparent agostic α‐C–H bonding hydrogen atoms, and four oxygen atoms of two DME molecules. Its coordination number is 10 including the agostic interactions. The structure of the uncoordinated [H2BC8H14]– anion is observed in the tetramethylammonium salt. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Chiral separability of hydrophobic boron cluster anions with native cyclodextrins in water–methanol background electrolytes
Authors: Horáková Hana , Vespalec Radim
Published: October 2007

Cluster anions of boron are built up on three‐center two‐electron bonds in contrast to naturally occurring compounds and their synthetic analogs. Methanol works as a solvent and as a competing agent, which advantageously adjusts reasonable strength of their interaction with native CDs in water–organic BGE. The highest methanol concentration preserving chiral discrimination of atropoisomers of individual anions is approximately 35, 55 and 75% v/v for α‐, β‐ and γ‐CD, respectively. α‐CD separates anionic 7, 8‐nido‐dicarbaundecaborate clusters with small exo‐skeletal substituents. β‐CD separates anions of all four tested structural types. The efficiency of separation of a compound with α‐ or β‐CD is always markedly lower than the separation efficiency at the absence of a CD in BGE. The efficiency of separation of a compound with β‐CD is always lower than the efficiency of separation of the compound with α‐CD. γ‐CD was proved to be unsuitable as a chiral selector because in BGEs with γ‐CD, effective mobilities of analytes as well as their differences continuously decrease. The decrease was ascribed to the decomposition of the γ‐CD. The assessment of analytical prospect of α‐ and β‐CDs as chiral selectors for chiral separations of boron cluster anions requires knowledge of stability of individual CDs at the conditions of analyses and recognition of the chance to eliminate low separation efficiency.
Analysis of sub‐ppb levels of Fe(II), Co(II), and Ni(II) by electrokinetic supercharging preconcentration, CZE separation, and in‐capillary derivatization
Authors: Urbanek Marek , Delaunay Nathalie , Michel Régis , Varenne Anne , Gareil Pierre
Published: October 2007

The analysis of sub‐ppb levels of Fe(II), Co(II), and Ni(II) in heat exchanger fluids of nuclear power plants is needed to monitor corrosion. A method involving preconcentration with electrokinetic supercharging (electrokinetic injection with transient ITP), CZE separation, and in‐capillary derivatization with ortho‐phenanthroline (o‐Phe) for direct UV detection was thus developed. First, a multizone BGE was loaded into the capillary by successive hydrodynamic introduction of zones of (i) o‐Phe‐containing BGE, (ii) BGE for the zonal separation, and (iii) ammonium‐based leading electrolyte. Metal cations were electrokinetically injected and stacked at the capillary inlet behind this last leading zone. Finally, a terminating electrolyte zone was hydrodynamically introduced. When a constant voltage was applied, metal ions kept on concentrating isotachophoretically, then separated in CZE mode, were complexed by migrating through an o‐Phe zone, and finally detected by direct absorbance. To detect extremely thin peaks, it was attempted for the first time to focus the derivatization reagent by inducing a second transient ITP, before labeling analytes, already separated in CZE mode. With this arrangement, LODs were about 30 ppt in pure water. In heat exchanger fluid matrices containing 1000 ppm bore and 2 ppm lithium, only Fe(II) cation was detected among the three cations of interest at the 1 ppb level using the present method, and its LOD was about ten times higher, due to the lower loading rate during electrokinetic injection.
A rapid CE‐potential gradient detection method for determination of quinolones
Authors: Fan Yongxia , Gan Xiao , Li Shuo , Qin Weidong
Published: October 2007

A rapid CE coupled with potential gradient detection (PGD) for the separation and detection of four quinolones, namely, enoxacin, ofloxacin (OFL), fleroxacin, and pazufloxacin, was described. Separation was performed in a fused‐silica capillary (75 μm×8.5 cm) using a buffer of 30 mM Tris and 4 mM phosphoric acid at pH 8.9. Under the separation voltage of 3 kV, the quinolones were separated within 2.8 min with good linearity (r2 ≥ 0.985). The method was successfully applied in determining OFL in a pharmaceutical formulation. Also, a liquid–liquid extraction (LLE) method was developed and coupled to CE‐PGD in determining quinolones that spiked in milk samples. With dichloromethane and hexane for enrichment and purification, the LLE recoveries of the four quinolones were in the range of 77–106%. The detection limits of the quinolones with LLE‐CE‐PGD were from 23 to 65 ng/mL. The proposed CE‐PGD method was validated with an HPLC method, and the results indicated consistency between the two methods.
Enhanced pH‐mediated stacking of anions for CE incorporating a dynamic pH junction
Authors: Arnett Stacy D. , Lunte Craig E.
Published: October 2007

A technique has been developed to enhance analyte focusing for CE for the analysis of physiological samples. High‐ionic‐strength samples are titrated to low‐ionic‐strength on‐line using pH‐mediated sample stacking in conjunction with a dynamic pH junction. This method concentrates analytes by reducing their electrophoretic mobility during field‐amplification. Parameters responsible for enhanced focusing were investigated, and an enhanced pH‐mediated stacking method was optimized for anionic nucleosides. The process results in ultra‐narrow peak widths, for example, 0.28 s for thymidine with a 10 min analysis time. Peak width and resolution with the enhanced stacking method were also compared to normal base stacking and electrokinetic injection. With this technique, mass‐loading capacity can be increased without degradation in peak shape and resolution is dramatically improved.
Determination of iodine and bromine compounds in foodstuffs by CE‐inductively coupled plasma MS
Authors: Chen Jing‐Huan , Wang Kai‐en , Jiang Shiuh‐Jen
Published: October 2007

A CE‐inductively coupled plasma mass spectrometric (CE‐ICP‐MS) method for iodine and bromine speciation analysis is described. Samples containing ionic iodine (I− and IO3−) and bromine (Br− and BrO3−) species are subjected to electrophoretic separation before injection into the microconcentric nebulizer (CEI‐100). The separation has been achieved in a 50 cm length×75 μm id fused‐silica capillary. The electrophoretic buffer used is 10 mmol/L Tris (pH 8.0), while the applied voltage is set at −8 kV. Detection limits are 1 and 20–50 ng/mL for various I and Br compounds, respectively, based on peak height. The RSD of the peak areas for seven injections of 0.1 μg/mL I−, IO3− and 1 μg/mL Br−, BrO3− mixture is in the range of 3–5%. This method has been applied to determine various iodine and bromine species in NIST SRM 1573a Tomato Leaves reference material and a salt and seaweed samples obtained locally. A microwave‐assisted extraction method is used for the extraction of these compounds. Over 87% of the total iodine and 83% of the total bromine are extracted using a 10% m/v tetramethylammonium hydroxide (TMAH) solution in a focused microwave field within a period of 10 min. The spike recoveries are in the range of 94–105% for all the determinations. The major species of iodine and bromine in tomato leaves, salt, and seaweed are Br−, IO3−, I−, and Br−, respectively.
Peak splitting in the CE separation of enantiomers caused by organic solvents in the sample
Authors: Stapf Fabian I. , Oehme Michael , Kiessig Steffen , Schwarz Maria A. , Kálmán Franka
Published: October 2007

Two robust chiral standard separation systems were developed for the analysis of the chiral purity of chemically different model compounds applied in homogeneous asymmetric hydrogenation catalysis. Sulfated CDs were used as chiral selectors as they allow the analysis of neutral, acidic as well as basic compounds in the same electrophoretic system. Poorly water‐soluble amines were dissolved in different organic solvent/buffer mixtures. Reproducibly, depending on the amount of organic solvent in the sample solution, peak splitting occurred and/or more peaks than expected were observed, implying impure model compounds. The dependence of the “chiral purity” on experimental parameters, e.g., kind and amount of sample solvent, length of injection plug, inner surface modification of the capillary, kind of sulfated CD, hydrophobicity, and basicity of the analytes, etc. was investigated. It is gathered that different equilibrium constants of the strong binding basic analytes and highly sulfated CD complex in the organic phase of the injection plug and the aqueous electrolyte phase are resulting in two different mobility zones for each enantiomer. It follows that each enantiomer is showing two peaks instead of one. Experimental strategies are shown to avoid these peak splitting/artificial impurity effects and obtain the “real” chiral purity picture of the samples.
Assay of aromatic amino acid enantiomers in rice‐brewed suspensions by chiral ligand‐exchange CE
Authors: Qi Li , Liu Meirong , Guo Zhenpeng , Xie Mingyi , Qiu Changgui , Chen Yi
Published: October 2007

The aim of this work was to assay seasoning D‐ or L‐aromatic amino acids (AAs) in rice‐brewed suspensions, Laozao in Chinese, by chiral ligand‐exchange CE with UV detection and Zn(II) complex as a chiral selecting system. Resolution and peak retention were found to be parallel to the basicity of the AA chiral ligands, and basic L‐Arg was known to work the best at pH 8.20 compared with L‐Lys and other AA ligands. Baseline separation of DL‐aromatic AAs and partially separation of some FMOC‐labeled nonaromatic AAs have been achieved using a running buffer of 5 mM ammonium acetate, 100 mM boric acid, 3 mM ZnSO4, and 6 mM L‐Arg at pH 8.20. The aromatic amino acids in four brands of Laozao were measured in a range of 0.25–20 μg/mL for Typ, 1.00–120 μg/mL for Phe, and 2.50–200 μg/mL for Tyr, with linear regression coefficient all over 0.999. The LOD (S/N = 3) was 0.15 μg/mL for Typ, 0.50 μg/mL for Phe, and 1.25 μg/mL for Tyr. The recovery of the method determined by spiking with the supernates of Laozao as background was 94.0–112.9%. The RSDs of migration time and peak area measured from six injections of tyrosine were 0.2 and 2.7%, respectively, for run‐to‐run, and 1.6 and 3.2%, respectively for day‐to‐day. Interestingly, there were only L‐Trp, D‐Tyr, and L‐Tyr found in the assayed four brands of Laozao. They may serve as an index to recognize the brand of Laozao.
Reliable electrophoretic mobilities free from Joule heating effects using CE
Authors: Evenhuis Christopher J. , Hruska Vlastimil , Guijt Rosanne M. , Macka Miroslav , Gaš Bohuslav , Marriott Philip J. , Haddad Paul R.
Published: October 2007

Ionic electrophoretic mobilities determined by means of CE experiments are sometimes different when compared to generally accepted values based on limiting ionic conductance measurements. While the effect of ionic strength on electrophoretic mobility has been long understood, the increase in the mobility that results from Joule heating (the resistive heating that occurs when a current passes through an electrolyte) has been largely overlooked. In this work, a simple method for obtaining reliable and reproducible values of electrophoretic mobility is described. The electrophoretic mobility is measured over a range of driving powers and the extrapolation to zero power dissipation is employed to eliminate the effect of Joule heating. These extrapolated values of electrophoretic mobility can then be used to calculate limiting ionic mobilities by making a correction for ionic strength; this somewhat complicated calculation is conveniently performed by using the freeware program PeakMaster 5. These straightforward procedures improve the agreement between experimentally determined and literature values of limiting ionic mobility by at least one order of magnitude. Using Tris‐chromate BGE with a value of conductivity 0.34 S/m and ionic strength 59 mM at a modest dissipated power per unit length of 2.0 W/m, values of mobility for inorganic anions were increased by an average of 12.6% relative to their values free from the effects of Joule heating. These increases were accompanied by a reduction in mobilities due to the ionic strength effect, which was 11% for univalent and 28% for divalent inorganic ions compared to their limiting ionic mobilities. Additionally, it was possible to determine the limiting ionic mobility for a number of aromatic anions by using PeakMaster 5 to perform an ionic strength correction. A major significance of this work is in being able to use CE to obtain reliable and accurate values of electrophoretic mobilities with all its benefits, including understanding and interpretation of physicochemical phenomena and the ability to model and simulate such phenomena accurately.
Determination of olive oil acidity by CE
Authors: Balesteros Manoela R. , Tavares Marina F. M. , Ribeiro Sidney J. L. , Polachini Ferminio C. , Messaddeq Younes , de Oliveira Marcone A. L.
Published: October 2007

In this work, a CE method for the determination of olive oil acidity was proposed. The method was based on an ethanolic extraction (at 60°C) of the oil long‐chain free fatty acids (LC‐FFAs) components followed by CE determination in pH 6.86 phosphate buffer at 15 mmol/L concentration containing 4 mmol/L sodium dodecylbenzenesulfonate (SDBS), 10 mmol/L polyoxyethylene 23 lauryl ether (Brij 35®), 2% v/v 1‐octanol and 45% v/v ACN under indirect UV detection at 224 nm. Although this electrolyte promoted baseline separation of myristic acid (C14:0) (internal standard (IS)) and olive oil major components (palmitic acid (C16:0), oleic acid (C18:1c) and linoleic acid (C18:2cc)) in less than 8 min, after a few injections, the electropherogram profiles were severely altered (peak broadening, migration time shifts, etc.) and the current increased substantially. An adsorption study was conducted revealing that the dissolution of the capillary external polyimide coating during the electrophoretic run caused the detrimental effect. After removal of the capillary tip coating, ten consecutive injections could be performed without any disturbances and this simple procedure was, therefore, implemented during quantitative purposes. The reliability of the proposed method was further investigated by the determination of acidity of an extra virgin olive oil sample in comparison to the established methodology (AOCS method Ca 5a‐40, alkaline volumetric titration (AVT)). No statistical differences were found within 95% confidence level. A % acidity of 0.39 ± 0.02 was found for the olive oil sample under consideration.
Mixture‐designed electrolytes for the MEKC separation of natural and synthetic steroids
Authors: Silva Claudinei A. , Pereira Elisabete A. , Micke Gustavo A. , Farah João P. S. , Tavares Marina F. M.
Published: October 2007

In this work, the separation of 11 natural and synthetic steroids was studied using MEKC electrolytes modified by property‐selected organic solvents: ethanol, ACN, and THF. The interplay between electrophoretic behavior and structural features was disclosed and the effects of organic modifiers to modulate retention and to alter selectivity were discussed in terms of system linear solvation energy relationships (LSER). The LSER indicated the total organic solvent percentage in the electrolyte as a major parameter to control retention and as a minor contribution, the hydrogen bond acidity. By evaluating the electropherograms obtained from mixture‐designed electrolytes, a favorable separation condition for all solutes was achieved in ca. 25 min with an electrolyte composed of 20 mmol/L sodium tetraborate at pH 9.4, 20 mmol/L SDS and 20% EtOH (0.80% CV for migration time and 2.5% CV for peak area, n = five consecutive injections). The applicability of the proposed separation condition was demonstrated by the inspection of estrogens in urine sample (puberty stage).
A new game theory‐based solution methodology for generation maintenance strategy
Authors: Jia Dexiang , Cheng Haozhong , Zhang Wenjun , Hu Zechun , Yan Jianyong , Chen Ming
Published: October 2007

A new maintenance scheduling of generating units (MSU) game in competitive electricity markets is presented to analyze strategic behaviors of generating companies (Gencos). The payoff of each player comprises the revenues from the energy auction market, production cost, maintenance cost, and risk loss over the horizon, which involves the compensation fee of interruptible load and the forced outage of generator. A simplified offer price methodology and a stochastic programming one are adopted to determine player's optimal bidding strategies for the day‐ahead market, whose trends of game result are similar. The maximal payoff of each Genco is obtained by tabu search algorithm. The solutions of non‐equilibrium, unique equilibrium, and multiple equilibria are coordinated. Numerical results for a two‐Genco system and a realistic system are used to illustrate the applicability of the proposed method. Copyright © 2007 John Wiley & Sons, Ltd.
Improvement of grounding resistances using a deep‐ground‐well method for indoor‐type substations located in complex soils
Authors: Chang Cheng‐Nan , Lee Chien‐Hsing , Wang Yaw‐Juen
Published: October 2007

The purpose of this paper is to investigate the performance of a deep‐ground‐well method used for improving the grounding resistances of indoor‐type substations located in complex soils in the system of Taiwan Power Company (TPC). Three and two ground wells are installed at Kungchia and Kuoan 161/23.9 ∼ 11.95 kV substations as examples for assessing the improvement. The grounding resistances of ground wells are calculated by one‐ and equivalent n‐layer soil models with the image method and the current distribution electromagnetic grounding and soil structure analysis (CDEGS) program. On the other hand, the grounding resistances of ground wells are measured by the fall‐of‐potential method. As a result, the calculated grounding resistances of ground wells based on an equivalent two‐layer soil model are approximately equal to the measured grounding resistances of ground wells. Moreover, the grounding resistances of Kungchia and Kuoan indoor‐type substations after installing ground wells are improved about 70.29 and 58.40%, respectively. Copyright © 2007 John Wiley & Sons, Ltd.
Somatic KIT mutations occur predominantly in seminoma germ cell tumors and are not predictive of bilateral disease: Report of 220 tumors and review of literature
Authors: Coffey Jerome , Linger Rachel , Pugh Julia , Dudakia Darshna , Sokal Michael , Easton Douglas F. , Timothy Bishop D. , Stratton Michael , Huddart Robert , Rapley Elizabeth A.
Published: October 2007

Mutations in the KIT gene occur in ∼8% of all testicular germ cell tumors (TGCT) and KIT is the most frequently mutated known cancer gene. One report has shown that 93% of patients with bilateral disease have a mutation at codon 816 of the KIT gene. Importantly, this suggests that the identification of a mutation in KIT is predictive of the development of a contralateral TGCT. We investigated the frequency and type of mutations in KIT in a series of 220 tumors from 211 patients with TGCTs and extragonadal germ cell tumors. In 170 patients with unilateral TGCT and no additional germ cell tumour, we identified one exon 11 mutation in a patient with unilateral TGCT and eight activating KIT mutations in exon 17 (9/175, 5.1%). In 32 patients with bilateral TGCT, one patient had an activating KIT mutation in exon 17 (3.1%). The incidence of activating KIT mutations in sporadic TGCT vs. familial TGCT was not significantly different. All mutations were identified in seminomas. Three extragonadal primary germ cell tumors were examined and in one tumor an activating KIT mutation was demonstrated in the pineal germinoma. Interestingly, this mutation was also seen in the patient's testicular seminoma. We find no evidence for an increased frequency of KIT mutations in bilateral TGCT. © 2007 Wiley‐Liss, Inc.
In vivo differentiation and genomic evolution in adult male germ cell tumors
Authors: Korkola J. E. , Heck S. , Olshen A. B. , Reuter V. E. , Bosl G. J. , Houldsworth J. , Chaganti R. S. K.
Published: October 2007

Germ cell tumors (GCTs) are the most common solid malignancy in young adult men, but the genes and genomic regions involved in their etiology are not fully defined. We report here an investigation of DNA copy number changes in GCTs using 1 Mb BAC arrays. As expected, 12p gain was the defining genomic alteration, occurring in 72/74 GCTs. Parallel expression profiling of these tumors identified potential oncogenes from gained regions (LYN and RAB25) and potential tumor suppressor genes in regions of loss (SYNPO2, TTC12, IGSF4, and EPB41L3). Notably, we observed specific genomic alterations associated with histology, including gain of 17p11.2‐q21.32 and loss of 2p25.3 in embryonal carcinoma, gain of 8p23.3‐12 and loss of 5p15.33‐35.3, 11q23.1‐25, and 13q12.11‐34 in seminoma, and gain of 1q31.3‐42.3, 3p, 14q11.2‐32.33, and 20q and loss of 8q11.1‐23.1 in yolk sac tumors (YST). Many significant genes that mapped to these regions had previously been associated with specific histologies, such as EOMES (chr3) and BMP2 (chr20) in YST and SPRY2 (chr13) and SOX17 (chr8) in seminomas. Additionally, our results suggest a model in which histologic differentiation of GCTs may drive genomic evolution. © 2007 Wiley‐Liss, Inc.
Upregulation of HMGA2 in thyroid carcinomas: A novel molecular marker to distinguish between benign and malignant follicular neoplasias
Authors: Belge Gazanfer , Meyer Anke , Klemke Markus , Burchardt Käte , Stern Corinna , Wosniok Werner , Loeschke Siegfried , Bullerdiek Jörn
Published: October 2007

The identification of molecular markers allowing to differentiate between benign and malignant thyroid tumors remains a diagnostic challenge. Herein, we have used the expression of the high mobility group protein gene HMGA2 and its protein, respectively, as a possible marker detecting malignant growth of thyroid tumors. HMGA2 belongs to the high mobility group proteins, i.e. small, highly charged DNA‐binding proteins. While HMGA2 is highly expressed in most embryonic tissues, its expression in adult tissues is very low. However, a reactivation of HMGA2 expression has been described for various malignant tumors and often correlates with the aggressiveness of the tumors. The aim of this study was to investigate whether the HMGA2 expression can be used to detect malignant thyroid tumors. RNA from 64 formalin‐fixed paraffin‐embedded thyroid tissues including normal tissue (n = 3), thyroiditis (n = 2), and follicular adenomas (n = 19) as well as follicular (n = 9), papillary (n = 28), and anaplastic (n = 3) carcinomas was reverse transcribed. Finally, real‐time quantitative RT‐PCR was performed. Expression differences of up to 400‐fold were detected between benign and malignant thyroid tumors. Based on HMGA2 expression alone, it was possible to distinguish between benign and malignant thyroid tissues with a sensitivity of 95.9% and a specificity of 93.9%. There was a highly significant (P < 0.001) difference with histology of the tumors being the gold standard between the benign lesions and malignant tumors. Our results show that even as a stand‐alone marker HMGA2 expression has a high potential to improve diagnoses of follicular neoplasms of the thyroid. © 2007 Wiley‐Liss, Inc.
FLT3 mutations in a 10 year consecutive series of 177 childhood acute leukemias and their impact on global gene expression patterns
Authors: Andersson Anna , Paulsson Kajsa , Lilljebjörn Henrik , Lassen Carin , Strömbeck Bodil , Heldrup Jesper , Behrendtz Mikael , Johansson Bertil , Fioretos Thoas
Published: October 2007

During 1995–2004, 209 children/adolescents were diagnosed with acute lymphoblastic or myeloid leukemia (ALL, AML) in Southern Sweden, of which 177 (85%), comprising 128 B‐lineage ALL, 34 AML, and 15 T‐cell ALL, could be analyzed for internal tandem duplications (ITD) and activating point mutations in the second tyrosine kinase domain (ATKD) of FLT3. Seventeen (10%) FLT3 mutations (6 ITD, 11 ATKD; mutually exclusive) were detected. None of the T‐cell ALL harbored any mutations. ITD and ATKD were found in 2% and 6% of the B‐lineage ALL and in 12% and 9% of the AML, being particularly common in high hyperdiploid ALL (14%), ALL (20%), and AML (23%) with 11q23/MLL rearrangements, and in AML with a normal karyotype (60%). All ATKD‐positive AML with MLL rearrangements harbored the t(9;11)(p21;q23). Global gene expression data were available for 76 of the B‐lineage ALL and 19 of the AML, of which 6 (8%) and 3 (16%) had FLT3 mutations, respectively. No distinct expression pattern associated with FLT3 mutations was identified. © 2007 Wiley‐Liss, Inc.