bluuebunny/crossref_metadata_2025 huggingface dataset:
The Activation of Electrophile, Nucleophile and Leaving Group during the Reaction Catalysed by pI258 Arsenate Reductase
Authors: Roos Goedele , Loverix Stefan , Brosens Elke , Van Belle Karolien , Wyns Lode , Geerlings Paul , Messens Joris
Published: April 2006

The reduction of arsenate to arsenite by pI258 arsenate reductase (ArsC) combines a nucleophilic displacement reaction with a unique intramolecular disulfide cascade. Within this reaction mechanism, the oxidative equivalents are translocated from the active site to the surface of ArsC. The first reaction step in the reduction of arsenate by pI258 ArsC consists of a nucleophilic displacement reaction carried out by Cys10 on dianionic arsenate. The second step involves the nucleophilic attack of Cys82 on the Cys10–arseno intermediate formed during the first reaction step. The onset of the second step is studied here by using quantum chemical calculations in a density functional theory context. The optimised geometry of the Cys10–arseno adduct in the ArsC catalytic site (sequence motif: Cys10–Thr11–Gly12–Asn13–Ser14–Cys15–Arg16–Ser17) forms the starting point for all subsequent calculations. Thermodynamic data and a hard and soft acids and bases (HSAB) reactivity analysis show a preferential nucleophilic attack on a monoanionic Cys10–arseno adduct, which is stabilised by Ser17. The P‐loop active site of pI258 ArsC activates first a hydroxy group and subsequently arsenite as the leaving group, as is clear from an increase in the calculated nucleofugality of these groups upon going from the gas phase to the solvent phase to the enzymatic environment. Furthermore, the enzymatic environment stabilises the thiolate form of the nucleophile Cys82 by 3.3 pH units through the presence of the eight‐residue α helix flanked by Cys82 and Cys89 (redox helix) and through a hydrogen bond with Thr11. The importance of Thr11 in the pKa regulation of Cys82 was confirmed by the observed decrease in the kcat value of the Thr11Ala mutant as compared to that of wild‐type ArsC. During the final reaction step, Cys89 is activated as a nucleophile by structural alterations of the redox helix that functions as a pKa control switch for Cys89; this final step is necessary to expose a Cys82–Cys89 disulfide.
Induced‐Fit Recognition of DNA by Small Circular Oligonucleotides
Authors: Escaja Núria , Gómez‐Pinto Irene , Viladoms Júlia , Rico Manuel , Pedroso Enrique , González Carlos
Published: April 2006

We have investigated the molecular interaction between cyclic and linear oligonucleotides. We have found that short cyclic oligonucleotides can induce hairpinlike structures in linear DNA fragments. By using NMR and CD spectroscopy we have studied the interaction of the cyclic oligonucleotide d with d, as well as with its two linear analogs d(GTCCCTCA) and d(CTCAGTCC). Here we report the NMR structural study of these complexes. Recognition between these oligonucleotides occurs through formation of four intermolecular Watson–Crick base pairs. The three‐dimensional structure is stabilized by two tetrads, formed by facing the minor‐groove side of the Watson–Crick base pairs. Overall, the structure is similar to those observed previously in other quadruplexes formed by minor‐groove alignment of Watson–Crick base pairs. However, in this case the complexes are heterodimeric and are formed by two different tetrads (G:C:A:T and G:C:G:C). These complexes represent a new model of DNA recognition by small cyclic oligonucleotides, increasing the number of potential applications of these interesting molecules.
Synthesis and Biological Evaluation of SERMs with Potent Nongenomic Estrogenic Activity
Authors: Tobias Sandra C. , Qiu Jian , Kelly Martin J. , Scanlan Thomas S.
Published: April 2006

We have synthesized novel SERMs that activate a rapid response in CNS neurons, but which lack the ability to bind to the nuclear estrogen receptors (ERα and ERβ). These compounds are analogues of 4‐hydroxytamoxifen, but unlike 4‐hydroxytamoxifen, they do not exist as a mixture of E/Z isomers. They contain a carboxamide insertion between the olefin and basic phenyl side chain, which results in more stable geometric isomers. The amide insertion also eliminates their ability to bind to the nuclear estrogen receptors, and hence, they are unable to modulate ER‐mediated gene transcription as do classical estrogens and SERMs. We show that one of these analogues, ST‐X, elicits a potent nongenomic estrogen response in the CNS by rapidly inhibiting GIRK activation in hypothalamic γ‐aminobutyric acid (GABA) and proopiomelanocortin (POMC) neurons. To our knowledge, ST‐X is the only SERM that modulates rapid estrogen responses, but which lacks nuclear ER activity.
Hydrogen Electrocatalysis
Authors: Kibler Ludwig A.
Published: April 2006

A selection of recent theoretical and experimental studies on electrolytic hydrogen evolution is presented. It is demonstrated with well‐defined model surfaces that this reaction is a very structure‐sensitive process. Crystallographic orientation, defect density and surface composition are parameters that determine the local geometric and electronic surface structure, and are thus crucial for the electrocatalytic activity as characterised by the exchange current density. The observed trends can be understood within a recent theory by J. K. Nørskov et al., which is based on density functional calculations and which emphasises the impact of hydrogen chemisorption energies on the reaction rate, that is, on the exchange current density. The particular electrocatalytic activities of ultrathin metal films and of nanostructures are addressed.
Dynamic Light‐Scattering Analysis of the Electrostatic Interaction of Hexahistidine‐Tagged Cytochrome P450 Enzyme with Semiconductor Quantum Dots
Authors: Ipe Binil Itty , Shukla Anuj , Lu Huachang , Zou Bo , Rehage Heinz , Niemeyer Christof M.
Published: April 2006

Currently, there is great interest in the development of methods suitable for determining the stoichiometry of biomolecules attached to nanoparticles. We describe the use of the dynamic light‐scattering technique (DLS) to determine the stoichiometry of the protein cytochrome P450BSβattached to CdS and CdSe quantum dots (QDs). The enzyme‐conjugated QDs have different diffusion characteristics compared to the QD and enzyme precursors, expressed in their size, scattering intensity as well as zeta‐potential values. The significant enhancement of the scattering intensity of QDs observed upon conjugation with the P450BSβdue to the refractive‐index increment and the systematic variation in zeta potential resulting from charge neutralization of the anionic QDs by the cationic histidine‐tagged P450BSβhave been used for stoichiometry determination.
Regular use of low‐phosphorus milk significantly improves dietary satisfaction of patients without changing their serum phosphorus
Authors: Oliverio Sandra , Atcher Leah
Published: April 2006

Background

Control of serum phosphorus has become one of the most critical issues in the management and welfare of the population of those with stage 5 chronic kidney disease (CKD). Milk is a food staple desired by many in this population, yet it is a food especially high in phosphorus. This study was designed to test the acceptance of DairyDelicious low‐phosphorus milk by CKD stage 5 patients and to evaluate its effect on their serum phosphorus levels.

Methods

Twenty CKD stage 5 patients who liked milk but avoided it because of its high phosphorus content were given a 1‐month supply of DairyDelicious low‐phosphorus (116 mg/8 fl oz), low‐potassium (197 mg/8 fl oz) milk. The serum phosphorus, calcium, and albumin levels of the patients were measured at the beginning and end of the study. Baseline and poststudy questionnaires were used to survey patient satisfaction.

Results

The serum phosphorus levels of the participants were not significantly changed at the end of the study. All study participants reported that they enjoyed the low‐phosphorus milk; most stated that they were generally happier with their diet and that they used fewer high‐phosphorus foods during the month.

Conclusions

DairyDelicious low‐phosphorus milk is an important adjunct to the diet of most CKD stage 5 patients who use or drink milk. Use of this product permits expansion of food choices and promotes patient diet satisfaction without increasing serum phosphorus.
Two‐stage anterotransposition of the brachial vein as the new option for native vascular access for hemodialysis: A report of 3 cases
Authors: Przywara Stanislaw , Wronski Jacek , Terlecki Piotr , Zubilewicz Tomasz , Feldo Marcin , Skublewska‐Bednarek Anna
Published: April 2006

Background

We present 3 cases of 2‐stage anterotransposition of the brachial vein to be considered the last option for native vascular access for hemodialysis before forearm/upper arm graft placement.

Methods

Three patients with chronic renal insufficiency were admitted for the creation of vascular access for hemodialysis. Physical examination, confirmed by ultrasonography, revealed the absence of adequate cephalic and basilic veins. In each case, precise color Doppler ultrasound examination showed a brachial artery with the appropriate diameter and 2 wide brachial veins joining into 1 axillary vein in the axillary fossa. Surgery was performed in 2 stages. In the first stage, one of the brachial veins was anastomosed with the brachial artery end to side in the cubital fossa. The fistula was left for 4 weeks to mature, with the brachial vein in its anatomical location. During the second stage, the entire length of the brachial vein was exposed via 1 longitudinal incision from cubital fossa up to armpit. Mobilized vein was subcutaneously transposed to an anterior location.

Results

At present, 8–20 months after the procedure, venous pressures are within accepted ranges and hemodialysis is adequate.

Conclusions

Our technical report confirms that the brachial vein can be utilized as the last option for the creation of native vascular access on the upper arm. We recommend that the surgery be performed in 2 stages. Maturation of the vein in its anatomical location, which occurs between the first and second stages of surgery, assures proper dilatation and thickening of the vein, making it better able to resist the extensive dissection and transposition during the second stage.
Low risk of sexual transmission of hepatitis C virus to spouses of infected hemodialysis patients
Authors: Fadil‐Romão Maria Aparecida , Pomar Luciana Navarro , Romão João Egidio
Published: April 2006

Background

Sexual transmission of hepatitis C virus (HCV) is still debated. The aim of this study was to evaluate the role of sexual transmission of HCV among hemodialysis patients and their partners.

Methods

We investigated intrafamilial spread of HCV between 53 married hemodialysis patients reporting stable monogamous sexual activity and their partners, using an epidemiological questionnaire on risk factors for HCV, a third‐generation ELISA to determine anti‐HCV status, and a PCR test to detect HCV RNA. An additional 84 single patients with no reported regular sexual activity were considered the control group.

Results

Of the 53 married patients, 16 (30.2%) were anti‐HCV positive (all HCV‐RNA positive), and 37 were anti‐HCV negative (all HCV‐RNA negative). There were no statistically significant differences between anti‐HCV‐positive and anti‐HCV‐negative married patients in mean age, gender, blood transfusion, and mean time on dialysis. None of the husbands or wives of the 16 anti‐HCV‐positive hemodialysis patients had antibodies to HCV. Similarly, of the 37 partners of anti‐HCV‐negative patients, none was anti‐HCV positive.

Conclusion

Our data suggest a very low risk of heterosexual transmission of HCV between hemodialysis patients and their partners.
Performance comparison of optical modulation formats for 40 Gbit/s systems from the viewpoint of frequency utilization efficiency and tolerance for fiber nonlinearities
Authors: Norimatsu Seiji , Ito Kenichi
Published: April 2006

In wavelength division multiplex (WDM) systems for long distance and large capacity, it is desirable that the modulation format be tolerant to degradation by nonlinear effects and achieve high frequency utilization efficiency. This paper compares modulation formats by numerical calculation from the viewpoints of frequency utilization efficiency and tolerance for fiber nonlinearities. It is shown that duobinary, RZ‐DQPSK (0.5) and CSRZ‐DQPSK achieve high transmission performance in DWDM (dense WDM). It is also shown that NRZ‐DBPSK, RZ‐DBPSK (0.5), and CSRZ‐DQPSK achieve high transmission performance in CWDM (coarse WDM). Before concluding, various methods of bit‐error rate calculation are compared and discussed, aiming at the correct evaluation of the bit‐error rate. The application of theQmethod to the differential quadrature phase‐shift keying format is shown to be feasible. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(8): 50–64, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20236
Development and experimental study of a network‐based RTK‐GPS positioning system using a satellite communication line
Authors: Namie Hiromune , Okamoto Osamu , Fan Chunming , Tanaka Shinji , Yasuda Akio
Published: April 2006

The geostationary satellite system will be able to disseminate data to a wider area and a greater number of users simultaneously. The authors tested the network‐based RTK‐GPS positioning using the area correction parameter (FKP) via the geostationary satellite‐based communication line. They investigated network‐based RTK‐GPS positioning at several fixed points located inside the GPS reference station network area. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(9): 1–9, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20298
An Analogous Solution‐Liquid‐Solid (ASLS) Growth Route to InP Hollow Spheres and a Honeycomb‐Like Macroporous Framework
Authors: Zheng Xiuwen , Liu Changzeng , Xie Yi
Published: April 2006

Hollow spheres and a honeycomb‐like macroporous framework structure of InP have been successfully fabricated by employing Au/In core/shell composite colloid droplets formed in situ as the template and catalyst for a simple analogous solution‐liquid‐solid (ASLS) growth route. SEM images show that the morphology of the obtained InP is mostly micrometer‐scale hollow spheres (>80 %) accreted with honeycomb‐like structures (<5 %). These hollow spheres have well‐defined voids and homogeneous walls, and the surface of the obtained InP hollow spheres is porous, which indicates that the building blocks are InP nanoparticles formed by solidification on the surface of Au/In core/shell droplets. A possible growth mechanism for the micrometer hollow spheres and honeycomb‐like macroporous framework is proposed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis, Characterisation and Molecular Hyperpolarisabilities of Pseudo‐Octahedral Hydrido(nitrile)iron(II) Complexes for Nonlinear Optics: X‐ray Structure of [Fe(H)(dppe)2(4‐NCC6H4NO2)][PF6]·CH2Cl2
Authors: Robalo Maria Paula , Teixeira António P. S. , Garcia Maria Helena , Minas da Piedade M. Fátima , Duarte M. Teresa , Dias Alberto Romão , Campo Jochen , Wenseleers Wim , Goovaerts Etienne
Published: April 2006

A series of ionic pseudo‐octahedral trans‐hydrido(nitrile)iron(II) complexes with the general formula [Fe(H)(dppe)2(4‐NCR)][PF6] [dppe = 1,2‐bis(diphenylphosphanyl)ethane; R = acceptor‐substituted conjugated ligand] have been synthesised by chloride abstraction from the starting compound trans‐[FeHCl(dppe)2] and fully characterised. First hyperpolarisabilities (β) have been determined by hyper‐Rayleigh scattering (HRS) at the fundamental wavelength of 1072 nm and the high near‐resonant values obtained (up to 1130 × 10–30 esu) are interpreted in terms of the two‐level model (TLM) and are correlated with IR and NMR spectroscopic data. Wavelength‐dependent HRS has been performed in the 1072–1580 nm range for two of the compounds, namely [Fe(H)(dppe)2{4‐NC(CH)(CH)C6H4NO2}][PF6] and [Fe(H)(dppe)2{4‐NCC6H4(CH)(CH)C6H4NO2}][PF6]. These results clearly show the two‐photon resonance but also the shortcomings of the TLM when it comes to deriving reliable static β values. A structural study of the compound [Fe(H)(dppe)2(4‐NCC6H4NO2)][PF6] by X‐ray diffraction shows that it crystallises in the centrosymmetric monoclinic space groupP21/n, with four molecules in the unit cell and a pairwise antiparallel alignment of the dipoles. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Mesoporous Aluminium Organophosphonates Functionalized with ChiralL‐Proline Groups in the Pore
Authors: Shi Xin , Yang Jie , Yang Qihua
Published: April 2006

Mesoporous aluminium organophosphonates with chiral L‐proline groups in the pore were synthesized for the first time through surfactant‐assisted one‐pot co‐condensation of Al(OsBu)3 with a mixture of 1‐phosphonomethylproline (S)‐H2PO3CH2NC4H7COOH (H3PMP) and phosphoric acid (H3PO4) [H3PMP/(H3PMP + H3PO4) = 50, 75, 100 mol‐%] under basic conditions in the presence of cetyltrimethylammonium bromide. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Tetranuclear Complexes Containing a Luminescent Ru2M2 Core [M = CuI, (allyl)PdII]: Synthesis, Structures and Electrochemical Properties
Authors: Walther Dirk , Böttcher Lars , Blumhoff Jörg , Schebesta Sebastian , Görls Helmar , Schmuck Katrin , Rau Sven , Rudolph Manfred
Published: April 2006

The reaction between [(tbbpy)2Ru(tmbiH2)](PF6)2 (tbbpy = 4,4′‐di‐tert‐butyl‐2,2′‐bipyridine; tmbiH2 = 5,5′,6,6′‐tetramethyl‐2,2′‐dibenzimidazole) and LiMe/CuI affords the tetranuclear complex 1 containing the dication [{(tbbpy)2Ru(tmbi)}2Cu2]2+. The X‐ray structure of 1 shows that the two [(tbbpy)2Ru(tmbi)] units coordinate the two Cu atoms in a twofold monodentate manner. Each copper atom is surrounded by two N‐donor atoms of different ruthenium(II) units with N–Cu–N angles of 167.3°. The Cu···Cu separation (2.72 Å) indicates intranuclear contacts. LiMe/[(allyl)PdCl]2 reacts with the starting Ru complex to form 2, which contains the tetranuclear dication [{(tbbpy)2Ru(tmbi)}2{Pd(η3‐allyl)}2]2+. Its crystal structure shows that the RuII units act as twofold monodentate ligands as well. Each PdII is in an essentially planar coordination environment containing two nitrogen atoms of two different dibenzimidazolates in the cis position with the η3‐bonded allyl group occupying the two remaining positions. In contrast to 1, where the Ru–Cu–Cu–Ru unit forms an essentially planar structure, a strongly bent structure is formed in compound 2. ESI mass spectra of 1 and 2 clearly show that the tetranuclear complexes are present in solution as well. Both complexes are luminescent. In addition, 2 catalyses the Heck coupling at 120 °C in N,N‐dimethylacetamide. In contrast to 1 and 2, the homodinuclear complex [(tbbpy)2Ru(tmbi)Ru(tbbpy)2] (3) contains the dibenzimidazolate as a twofold chelating ligand that forms two five‐membered chelate rings with the Ru centres. Electrochemical measurements of 2 show two reversible, one‐electron oxidation steps, the difference between which (ΔE = 89 mV) is distinctly larger than the pure entropic effect. Furthermore, four reduction steps are observed, the first two of which are fully reversible. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Hypersilylphosphanylidene: A Facile Low‐Temperature Generation and Formation of Bis(hypersilyl)diphosphene and the Bis(hypersilyl)triphosphaallyl Anion
Authors: Cappello Vittorio , Baumgartner Judith , Dransfeld Alk , Flock Michaela , Hassler Karl
Published: April 2006

The reaction of hypersilyl(trimethylsilyl)chlorophosphane (SiMe3)3SiP(SiMe3)Cl (1) with tBuOK in THF at –60 °C proceeds by Si–P bond cleavage of the trimethylsilyl group and formation of tBuOSiMe3/KCl and bis(hypersilyl)phosphanylidene. The phosphanylidene dimerizes to form bis(hypersilyl)diphosphene (2) in excellent yields (≥95%). X‐ray diffraction experiments reveal the simultaneous presence of two rotamers in the solid state that differ in their SiSiPP torsion angles. Ab initio calculations for the parent diphosphene (SiH3)3SiP=PSi(SiH3)3 at the DFT/6‐31+G(d) level predict an energy difference of 2.3 kJ mol–1. A cis arrangement of the two Si(SiH3)3 groups raises the energy by about 45 kJ mol–1. In the UV/Vis spectrum the n → π* excitation is observed at 622 nm, which is in excellent agreement with the ab initio results. In the Raman spectrum, the P=P stretching vibration is easily identified as a strong line at 591 cm–1. When a solution of 1 in THF is added to a solution of KOtBu inTHF, maintaining an excess of KOtBu during the reaction, the deep‐violet bis(hypersilyl)triphosphenide anion [HypPPPHyp]– (4) forms in excellent yields. This anion is also formed when 2 is treated with KOtBu. Compound 2 can be derivatized with 2,3‐dimethylbutadiene to give a cyclic diphosphane 5 by [4+2] addition. When a solution of 2 in toluene is heated to 110 °C for 4 h, bis(hypersilyl)cyclotriphosphane (Hyp2P3H, 6) is formed, besides some HypPH2 as a by‐product. As an aid for the interpretation of 31P NMR spectra, equilibrium structures and phosphorus chemical shifts have been calculated at the DFT and MP2 level for a large number of molecules with phosphorus‐containing backbones, which are closely related to those described in the present work. Calculations for disilyldiphosphenes reveal a close correlation between PPSi bond angles and 31P NMR chemical shifts, which is useful for predicting NMR spectra. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A Hydrothermal Reduction Route to Single‐Crystalline Hexagonal Cobalt Nanowires
Authors: Xie By‐Qin , Qian Yitai , Zhang Shuyuan , Fu Shenquan , Yu Weichao
Published: April 2006

Hexagonal close‐packed (hcp) cobalt nanowires with diameters of 150–300 nm and lengths of up to several hundreds of micrometers have been synthesized by a hydrothermal reduction method. These cobalt nanowires were generated by the reduction of cobalt(II) citrate complexes by hypophosphite (H2PO2–) in basic solution at 160 °C. High‐resolution TEM and SAED reveal that the as‐prepared Co nanowires have a single‐crystalline structure with a [001] growth direction. The room‐temperature hysteresis loop of these nanowires shows a ferromagnetic behavior with enhanced coercivity. A formation mechanism for these Co nanowires is proposed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Catalytic Adsorptive Stripping Voltammetric Procedure for Determination of Total Chromium in Environmental Materials
Authors: Grabarczyk Małgorzata , Tyszczuk Katarzyna , Korolczuk Mieczyslaw
Published: April 2006

A sensitive catalytic adsorptive stripping voltammetric procedure for determination of traces of total chromium in environmental samples is reported. The method is based on the preconcentration of a Cr(III)H2DTPA complex by adsorption at the HMDE from an acetate buffer solution at the potential −1.0 V vs. Ag/AgCl. Total chromium was determined as Cr(III) after reduction of Cr(VI) to Cr(III) by NaHSO3. In order to stabilize the signal of Cr(III) the measurements were performed at 5 °C. The calibration graph for chromium for an accumulation time of 60 s was linear in the range from 5×10−10 to 5×10−8 mol L−1. The relative standard deviation for a chromium concentration of 1×10−8 mol L−1 was 3.9% (n=5). The detection limit for accumulation time of 60 s was about 8×10−11 mol L−1. The validation of the procedure was performed by the analysis of the certified reference materials.
A Homogenous Assay of FAD Using a Binding Between Apo‐Glucose Oxidase and FAD Labeled with an Electroactive Compound
Authors: Sugawara Kazuharu , Kamiya Naoto , Hirabayashi George , Kuramitz Hideki
Published: April 2006

A homogenous assay of FAD using a binding between glucose oxidase (apo‐GOD) and FAD labeled with an electroactive compound was developed. Because daunomycin is sensitively detected with voltammetry, daunomycin was connected to FAD with a cross‐linker. The peak current decreased due to the apo‐GOD‐labeled FAD binding. Competitive reaction to the apo‐GOD between FAD and the labeled FAD produces the increase of peak current. Accordingly, FAD is detected on the basis of the reaction. The merit of this method is that the influence from FMN and riboflavin in the measurement of FAD can be suppressed by the high selective binding.
Increased expression and phosphorylation of liver glutamine synthetase in well‐differentiated hepatocellular carcinoma tissues from patients infected with hepatitis C virus
Authors: Kuramitsu Yasuhiro , Harada Toshio , Takashima Motonari , Yokoyama Yuuichirou , Hidaka Isao , Iizuka Norio , Toda Tosifusa , Fujimoto Masanori , Zhang Xiulian , Sakaida Isao , Okita Kiwamu , Oka Masaaki , Nakamura Kazuyuki
Published: April 2006

Hepatocellular carcinoma (HCC) is one of the most common fatal cancers, and chronic infection with hepatitis C virus (HCV) is thought to be one of the main causes in Japan. To identify diagnostic or therapeutic biomarkers for HCC associated with HCV (HCV‐HCC), we tried to elucidate the factors related to the products from cancerous tissues of HCV‐infected patients. From proteomic differential display analysis of liver tissue samples from HCV‐HCC cancerous tissues and corresponding non‐cancerous tissues from patients, three protein spots of the same molecular mass (42 kDa), whose expression increased in well‐differentiated cancerous tissues, were detected. Although their pI were different, they were identified as glutamine synthetase (GS) by PMF with MALDI‐TOF MS and by Western blotting using anti‐GS specific mAb. Immunohistochemical analysis showed that tumor tissue consists of two parts, GS‐positive cell and GS‐negative cell regions, suggesting that GS‐producing cells grew in the tumor tissue as a nodule in nodules. The tryptic peptides of the most acidic GS isoform lost the signal of 899.5 Da, corresponding a peptide of SASIRIPR, and gained a signal of 1059.5 Da, which was submitted to PSD analysis. PSD analysis showed the neutral loss by elimination of two phosphate groups, supposed to be on serine residues of the 899.5‐Da peptide, from serine 320 to arginine 327 in GS. PMF followed by PSD analysis is thought to be useful for the determination of phosphorylation sites of proteins showing molecular heterogeneity.
Protein expression dynamics during replicative senescence of endothelial cells studied by 2‐D difference in‐gel electrophoresis
Authors: Eman Michael R. , Regan‐Klapisz Elsa , Pinkse Martijn W. H. , Koop Inge M. , Haverkamp Johan , Heck Albert J. R. , Verkleij Arie J. , Post Jan A.
Published: April 2006

Endothelial senescence contributes to endothelium dysfunctionality and is thereby linked to vascular aging. A dynamic proteomic study on human umbilical vein endothelial cells, isolated from three umbilical cords, was performed. The cells were cultured towards replicative senescence and whole cell lysates were subjected to 2‐D difference gel electrophoresis (DIGE). Despite the biological variability of the three independent isolations, a set of proteins was found that showed senescence‐dependent expression patterns in all isolations. We focused on those proteins that showed significant changes, with a paired analysis of variance (RM‐ANOVA) p‐value of ≤0.05. Thirty‐five proteins were identified with LC‐Fourier transform MS, and functional annotation revealed that endothelial replicative senescence is accompanied by increased cellular stress, protein biosynthesis and reduction in DNA repair and maintenance. Nuclear integrity becomes affected and cytoskeletal structure is also changed. Such important changes in the cell infrastructure might accelerate endothelium dysfunctionality. This study provides biological information that will initiate studies to further unravel endothelial senescence and gain more knowledge about the consequences of this process in the in vivo situation.
Microscale analysis of proteins in inner ear tissues and fluids with emphasis on endolymphatic sac, otoconia, and organ of Corti
Authors: Thalmann Isolde , Hughes Inna , Tong Benton D. , Ornitz David M. , Thalmann Ruediger
Published: April 2006

Here we describe preparatory techniques adapted for the study of proteins of inner ear tissues and fluids that have allowed us to apply state‐of‐the‐art analytical techniques in spite of the minute size and anatomical complexities of this organ. Illustrative examples address unresolved issues of functional and clinical significance. First, we demonstrate how quick‐freezing and freeze drying prevents artifacts that arise from sampling endolymphatic sac (ES) content in the liquid state. This set the stage for the generation of the first protein profile of the ES. Identification of crucial proteins will help elucidate mechanisms of endolymph volume regulation and pathogenesis of Meniere's disease. Second, we show how a unique situation allowed identification of otoconial proteins by mass spectrometric analysis without prior separation and we discuss possible roles for these minor otoconins in otoconial development and prevention of degenerative diseases that affect balance. Finally, we demonstrate techniques for the precise dissection of organ of Corti and its substructures, while preserving their near normal chemical state. We extended an earlier study in which we identified a novel calcium‐binding protein by IEF, oncomodulin, localized in the outer hair cells and show here the applicability of prefractionation for the screening of calcium‐binding proteins of organ of Corti. These studies demonstrate how advanced preparatory and analytical techniques can be applied to studies of the inner ear.
Effect of organic cosolvents on the free solution mobility of curved and normal DNA molecules
Authors: Lu Yongjun , Stellwagen Earle , Stellwagen Nancy C.
Published: April 2006

The free solution mobilities of curved and normal 199‐bp DNA fragments have been measured in buffer solutions containing various quantities of the organic cosolvents methanol, ethanol, 2‐propanol, 2‐methyl‐2,4‐pentanediol (MPD), ethylene glycol, and ACN, using CE. The curved fragment, taken from the VP1 gene of SV40, contains five unevenly spaced A‐ and T‐tracts in a centrally located “curvature module”; the A‐ and T‐tracts have been mutated to other sequences in the normal 199‐bp fragment. The free solution mobility of the curved 199‐bp fragment is significantly lower than that of its normal counterpart in aqueous solutions [Stellwagen, E., Lu, Y. J., Stellwagen, N. C., Nucleic Acids Res. 2005, 33, 4425–4432]. The mobilities of both the curved and normal fragments decrease with increasing cosolvent concentration, due to the effect of the cosolvent on the viscosity and dielectric constant of the solution. The mobility differences between the curved and normal 199‐bp fragments and the mobility ratios decrease approximately linearly with the increasing mole fraction of cosolvent in the solution. Hence, MPD and other organic cosolvents affect DNA electrophoretic mobility by a common mechanism, most likely the preferential hydration of the DNA surface that occurs in aqueous cosolvents. The gradual loss of the anomalously slow mobility of the curved 199‐bp fragment with increasing cosolvent concentration, combined with other data in the literature, suggests that preferential hydration gradually widens the narrow A‐tract minor groove, releasing site‐bound counterions in the minor groove and shifting the conformation toward that of normal DNA.
Seasonal changes in ground‐penetrating radar signature observed at a polythermal glacier, Bylot Island, Canada
Authors: Irvine‐Fynn T. D. L. , Moorman B. J. , Williams J. L. M. , Walter F. S. A.
Published: April 2006

In recent years, ground‐penetrating radar (GPR) has been increasingly used for characterization of subglacial and englacial environments at polythermal glaciers. The geophysical method is able to exploit the dielectric difference between water, air, sediment and ice, allowing delineation of subsurface hydrological, thermal and structural conditions. More recent GPR research has endeavoured to examine temporal change in glaciers, in particular the distribution of the cold ice zone at polythermal glaciers. However, the exact nature of temporal change that can be identified using GPR has not been fully examined. This research presents the results of three GPR surveys conducted over the course of a summer ablation season at a polythermal glacier in the Canadian Arctic. A total of approximately 30 km of GPR profiles were collected in 2002 repeatedly covering the lower 2 km of Stagnation Glacier, Bylot Island (72°58′ N 78°22′ W). Comparison between profiles indicated changes in the radar signature, including increased noise, appearance and disappearance of englacial reflections, and signal attenuation in the latter survey. Further, an area of chaotic returns in up‐glacier locations, which was interpreted to be a wet temperate ice zone, showed marked recession over the course of the ablation season. Combining all the temporal changes that were detected by GPR, results indicate that a polythermal glacier may exhibit strongly seasonal changes in hydrological and thermal characteristics throughout the ice body, including the drainage of 17 000 m3 of temporarily stored intra‐glacial meltwater. It is also proposed that the liquid water content in the temperate ice zone of polythermal glaciers can be described as a fraction of a specific retention capacity. Copyright © 2006 John Wiley & Sons, Ltd.
Preparation of undecamethylated and hexamethylated 1‐halocarba‐closo‐dodecaborate anions
Authors: Vyakaranam Kamesh , Janoušek Zbyněk , Eriksson Ludvig , Michl Josef
Published: April 2006

We report an improved synthesis of 1‐halocarba‐closo‐dodecaborate anions 1‐Hal–CB11H and their efficient conversion to the undecamethylated anions 1‐Hal–CB11Me (Hal = Cl, Br, I) and the hexamethylated anions 1‐Hal‐(7–12)‐(CH3)6–CB11H (Hal = F, Cl) by treatment with methyl triflate in sulfolane in the presence of calcium hydride to remove the triflic acid byproduct. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:217–223, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20224
(π+σ)‐double aromatic and π,σ‐mixed aromatic boron compounds with two electrons delocalized over three centers
Authors: Hofmann Matthias , Berndt Armin
Published: April 2006

Using Schleyer's measure for aromaticity, computed nuclear independent chemical shifts (NICS), we review molecules with two electrons delocalized cyclically over three centers: one class with two π‐ as well as two σ‐electrons, i.e. (π + σ)‐double aromatics and a second class with two electrons intermediate between π and σ, i.e. π,σ‐mixed aromatics. These classes show distinctly different patterns of NICS values. On this basis, sila‐, germa‐, and stannaboriranes, recently presented by Jemmis et al., are shown to be the first π,σ‐mixed aromatics which are not homoaromatics. “Improvement of overlap by pyramidalization” a building principle introduced by Haddon in 1988, is the key to understanding the structure of π,σ‐mixed aromatics. New representatives with large aromatic stabilization energies (up to 60 kcal mol−1) and very strong pyramidalizations at tricoordinate B, C, and Si centers (up to 63°) are designed by computations. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:224–237, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20225
Effect of the plate thermal resistance on the heat transfer performance of a corrugated thin plate heat exchanger
Authors: Iwai Hiroshi , Tatsumi Kazuya , Suzuki Kenjiro
Published: April 2006

Two‐dimensional conjugate conduction/convection numerical simulations were carried out for flow and thermal fields in a unit model of a counter‐flow‐type corrugated thin plate heat exchanger core. The effects of the thermal resistance of the solid plate, namely the variation of the plate thickness and the difference of the plate material, on the heat exchanger performance were examined in the Reynolds number range of 100<Re<400. Higher temperature effectiveness was obtained for a thicker plate at any Reynolds number, which was a unique feature of corrugated thin plate geometry. Detailed discussions on the thermal fields revealed that restricting the heat conduction along the plate by making the plate thinner or choosing a low thermal conductivity material causes a larger plate temperature variation along the plate, and, consequently, a smaller amount of thermal energy exchanged between two fluids. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(3): 209–223, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20110
The heat transfer and pressure drop characteristics of the finned tube banks in forced convection (effects of fin height on heat transfer characteristics)
Authors: Kawaguchi Kiyoshi , Okui Kenichi , Asai Toshihiro , Hasegawa Yutaka
Published: April 2006

In recent years the requirement for the reduction of energy consumption has been increasing to solve the problems of global warming and the shortage of petroleum resources. For example, in the power generation field, as thermal power generation occupies 60% of the power generation demand, considerable improvement of thermal efficiency is required. This paper describes the heat transfer characteristics of finned tube banks used for the heat exchanger in thermal power generation that were clarified by testing serrated finned tube banks with different fin heights for improved higher heat transfer and conventional spiral finned tube banks with different fin height. Then an equation to predict the heat transfer coefficient which is necessary for the design of the heat exchanger was proposed. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(3): 194–208, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20111
The role of the Madden–Julian Oscillation in the El Niño and Indian drought of 2002
Authors: Saith Neena , Slingo Julia
Published: April 2006

In 2002 India experienced a severe drought, one among the five worst droughts since records began in 1871, notable for its countrywide influence. The drought was primarily due to an unprecedented break in the monsoon during July, which persisted for almost the whole month and affected most of the sub‐continent. The failure of the monsoon in 2002 was not predicted and India was not prepared for the devastating impacts on, for example, agriculture. This paper documents the evolution of the 2002 Indian summer monsoon and considers the possible factors that contributed to the drought and the failure of the forecasts.

The development of the 2002/2003 El Niño and the unusually high levels of Madden–Julian Oscillation (MJO) activity during the monsoon season are identified as the central players. The 2002/2003 El Niño was characterised by very high sea‐surface temperatures (SSTs) in the central Pacific that developed rapidly during the monsoon season. It is suggested that the unusual character of the developing El Niño was associated with the MJO and was a consequence of the eastward extension of the West Pacific Warm Pool, brought about primarily by a series of westerly wind events (WWEs) as part of the eastward movement of the active phase of the MJO.

During the boreal summer, the MJO is usually characterised by northward movement, but in 2002 the northward component of the MJO was weak and the MJO was dominated by a strong eastward component, probably driven by the abnormally high SSTs in the central Pacific. It is suggested that a positive feedback existed between the developing El Niño and the eastward component of the MJO, which weakened the active phases of the monsoon. In particular, the unprecedented monsoon break in July could be associated with the juxtaposition of strong MJO activity with a developing El Niño, both of which interfered constructively with each other to produce major perturbations to the distribution of tropical heating. Subsequently, the main impact of the developing El Niño was a modulation of the Walker circulation that led to the overall suppression of the Indian monsoon during thess latter part of the season.

It is argued that the unique combination of a rapidly developing El Niño and strong MJO activity, which was timed within the seasonal cycle to have maximum impact on the Indian summer monsoon, meant that prediction of the prolonged break in July and the seasonally deficient rainfall was a challenge for both the empirical and dynamical forecasting systems. Copyright © 2006 Royal Meteorological Society
In vivo study on the healing of bone defects treated with bone marrow stromal cells, platelet‐rich plasma, and freeze‐dried bone allografts, alone and in combination
Authors: Dallari D. , Fini M. , Stagni C. , Torricelli P. , Nicoli Aldini N. , Giavaresi G. , Cenni E. , Baldini N. , Cenacchi A. , Bassi A. , Giardino R. , Fornasari P.M. , Giunti A.
Published: April 2006

The repair of confined trabecular bone defects in rabbits treated by autologous bone marrow stromal cells (BMSC), platelet‐rich plasma (PRP), freeze‐dried bone allografts (FDBA) alone and in combination (BMSC + PRP; FDBA + BMSC; FDBA + PRP; FDBA + PRP + BMSC) was compared. A critical size defect was created in the distal part of the femurs of 48 adult rabbits. Histology and histomorphometry were used in the evaluation of healing at 2, 4, and 12 weeks after surgery. The healing rate (%) was calculated by measuring the residual bone defect area. Architecture of the newly formed bone was compared with that of bone at the same distal femur area of healthy rabbits. The defect healing rate was higher in PRP + BMSC, FDBA + PRP, FDBA + BMSC, and FDBA + PRP + BMSC treatments, while lower values were achieved with PRP treatment at all experimental times. The highest bone‐healing rate at 2 weeks was achieved with FDBA + PRP + BMSC treatment, which resulted significantly different from PRP (p < 0.05) and BMSC (p < 0.05) treatments. At 4 weeks, the bone‐healing rate increased except for PRP treatment. Finally, the bone‐healing rate of FDBA + PRP, FDBA + BMSC, and FDBA + PRP + BMSC was significantly higher than that of PRP at 12 weeks (p < 0.05). At 12 weeks, significant differences still existed between PRP, BMSC, and FDBA groups and normal bone (p < 0.05). These results showed that the combination of FDBA, BMSC and PRP permitted an acceleration in bone healing and bone remodeling processes. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Histological and scanning electron microscopy analyses of bone/implant interface using the novel Bonelike® synthetic bone graft
Authors: Gutierres M. , Hussain N. Sooraj , Lopes M.A. , Afonso A. , Cabral A.T. , Almeida L. , Santos J.D.
Published: April 2006

Synthetic bone grafts provide an alternative to autografts and allografts. Bonelike® is a patented synthetic bone graft that mimics the mineral composition of bone. The aim of the present work was to assess the biological behavior of Bonelike® graft in humans, before using the material in orthopedic applications of bone regeneration, for example, in opening wedge high tibial osteotomies for medial knee osteoarthritis. Bonelike® granules were implanted in cortical bone of 11 patients undergoing osteotomies, and new bone formation, osteoconductive properties, and resorption characteristics of the granules were analyzed. The granules ranged from 500 to 1000 µm and were implanted in the lateral aspect of the tibia. The patients' mean age was 59 years (range 48 to 70 years); there were eight women and three men, all suffering from medial compartment osteoarthritis of the knee. At surgery, a 1 × 1 × 1‐cm cortical defect was created 3 cm distal to the entry point of the screws, in line with the long axis of tibia. The implanted Bonelike® graft sample was extracted for analysis during removal of the metallic prosthesis after implantation times of 6, 9, and 12 months. Radiological follow‐up, scanning electron microscopy, histological analysis, and histomorphometric measurements were conducted on the retrieved samples to assess bone regeneration in the defect area. Osteoconductive capacity was demonstrated by extensive mature bone formation around the implanted granules and high levels of percentage bone‐to‐graft contact (from 67–84%). Bonelike® acted as an excellent bioactive scaffold, allowing the migration, proliferation, and differentiation of bone cells on its surface, and therefore regeneration of the defects was achieved in a rapid, controlled manner. Our results suggest that Bonelike® graft is an excellent candidate for orthopedic applications where rapid new bone formation is a fundamental requirement. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res
Safety of, and biological and functional response to, a novel metallic implant for the management of focal full‐thickness cartilage defects: Preliminary assessment in an animal model out to 1 year
Authors: Kirker‐Head Carl A. , Van Sickle David C. , Ek Steve W. , McCool John C.
Published: April 2006

Focal full‐thickness cartilage lesions of the human medial femoral condyle (MFC) can cause pain and functional impairment. Affected middle‐aged patients respond unpredictably to existing treatments and knee arthroplasty may be required, prompting risk of revision. This study assesses the safety of, and biological and functional response to, a metallic resurfacing implant which may delay or obviate the need for traditional arthroplasty. The anatomic contour of the surgically exposed MFC of six adult goats was digitally mapped and an 11 mm diameter full‐thickness osteochondral defect was created. An anchor‐based Co–Cr resurfacing implant, matching the mapped articular contour, was implanted. Each goat's contralateral unoperated femorotibial joint was used as a control. Postoperative outcome was assessed by lameness examination, radiography, arthroscopy, synoviocentesis, necropsy, and histology up to 26 (n = 3) or 52 (n = 3) weeks. By postoperative week (POW) 4, goats demonstrated normal range of motion, no joint effusion, and only mild lameness in the operated limb. By POW 26 the animals were sound with only occasional very mild lameness. Arthroscopy at POW 14 revealed moderate synovial inflammation and a chondral membrane extending centrally across the implant surface. Radiographs at POWs 14 to 52 implied implant stability in the operated joints, as well as subchondral bone remodeling and mild exostosis formation in the operated and contralateral unoperated joints of some goats. By POW 26, histology revealed new trabecular bone abutting the implant. At POWs 26 and 52 MFC cartilage was metachromatic and intact in the operated and unoperated femorotibial joints. Proximal tibiae of some operated and unoperated limbs demonstrated limited subchondral bone remodeling and foci of articular cartilage fibrillation and thinning. The chondral membrane crossing the prosthesis possessed a metachromatic matrix containing singular and clustered chondrocytes. Our data imply the safety, biocompatibility, and functionality of the implant. Focal articular damage was documented in the operated joints at POWs 26 and 52, but lesions were much reduced over those previously reported in untreated defects. Expanded animal or preclinical human studies are justified. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res