bluuebunny/crossref_metadata_2025 huggingface dataset:
TLR9 activation is a key event for the maintenance of a mycobacterial antigen‐elicited pulmonary granulomatous response
Authors: Ito Toshihiro , Schaller Matthew , Hogaboam Cory M. , Standiford Theodore J. , Chensue Stephen W. , Kunkel Steven L.
Published: September 2007

Type 1 (Th1) granulomas can be studied in mice sensitized with mycobacterium antigens followed by challenge of agarose beads covalently coupled to purified protein derivative. TLR9 is known to play a role in the regulation of Th1 responses; thus, we investigated the role of TLR9 in granuloma formation during challenge with mycobacterium antigens and demonstrated that mice deficient in TLR9 had increased granuloma formation, but a dramatically altered cytokine phenotype. Th1 cytokine levels of IFN‐γ and IL‐12 in the lungs were decreased in TLR9–/– mice when compared to wild‐type mice. In contrast, Th2 cytokine levels of IL‐4, IL‐5, and IL‐13 were increased in TLR9–/– mice. The migration of CD4+ T cells in the granuloma was impaired, while the number of F4/80+ macrophages was increased in TLR9–/– mice. Macrophages in the lungs of the TLR9‐deficient animals with developing granulomas expressed significantly lower levels of the classically activated macrophage marker, nitric oxide synthase, but higher levels of the alternatively activated macrophage markers such as ‘found in inflammatory zone‐1′ antigen and Arginase‐1. These results suggest that TLR9 plays an important role in maintaining the appropriate phenotype in a Th1 granulomatous response.
Square‐Planar Diacetatopalladium Complexes with trans‐Configured Secondary Amine Ligands that Avoid Orthometalation: Ligand Synthesis, Coordination, Molecular Structure and Catalytic Potential for Suzuki Cross‐Coupling Reactions
Authors: Chahen Ludovic , Therrien Bruno , Süss‐Fink Georg
Published: September 2007

The trans‐configured square‐planar palladium complexes [Pd(OAc)2(LNtBu)2] (1), [Pd(OAc)2(η2‐LN∩NtBu)] (2), [Pd(OAc)2(LNPh)2] (3), and [Pd(OAc)2(η2‐LN∩NPh)] (4), have been synthesized by treating palladium acetate with the amines NHtBuCH2‐2,4,6‐Me3C6H2 (LNtBu) or NHPhCH2‐2,4,6‐Me3C6H2 (LNPh) or with the diamines NHtBuCH2‐2,4,6‐Me3C6H‐CH2‐2,4,6‐Me3C6H‐CH2‐NHtBu (LN∩NtBu) or NHPh‐CH2‐2,4,6‐Me3C6H‐CH2‐2,4,6‐Me3C6H‐CH2‐NHPh (LN∩NPh). The single‐crystal X‐ray structure analysis of complexes 1–3 confirms a trans arrangement of the two acetato groups and of the two nitrogen atoms. Orthometalation leading to palladacycles is impossible in all cases as the ortho positions in the benzylic rings are blocked by methyl substituents. All complexes are found to catalyze Suzuki cross‐coupling reactions of deactivated and even sterically hindered arene substrates. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Cyclodiphosphazane cis‐{(o‐MeOC6H4O)P(μ‐NtBu)}2 as a Bridging Bidentate Ligand: Synthesis, Structures of Heterometallic Complexes, and Halogen Exchange Between Rh–Cl and Cu–X (X = Br, I)
Authors: Chandrasekaran P. , Mague Joel T. , Venkateswaran Ramalingam , Balakrishna Maravanji S.
Published: September 2007

The mononuclear rhodium complexes of cyclodiphosphazane [(cod)RhCl{L‐κP}] (1a) (L = cis‐{(o‐MeOC6H4O)P(μ‐NtBu)}2) and trans‐[Rh(CO)Cl{L‐κP}2] (1b) react in a 1:1 molar ratio with [AuCl(SMe2)] to form the heteronuclear complexes [(cod)RhCl{μ‐L‐κP,κP}AuCl] (2) and trans‐[Rh(CO)Cl{μ‐L‐κP,κP}2(AuCl)2] (7), respectively, in quantitative yield. The reaction between 1a and CuCl afforded a tetranuclear complex [(cod)RhCl{μ‐L‐κP,κP}Cu(μ‐Cl)]2 (3). Under similar reaction conditions 1 reacts with 2 equiv. of CuX (X = Br, I) to produce the heteronuclear complexes [(cod)RhBr{μ‐L‐κP,κP}Cu(μ‐Br)]2 (4) and [((cod)RhI{μ‐L‐κP,κP})2Cu(μ‐X)2Cu] (X ≈ 1:1 mixture of Cl and I disordered over both sites) (5), respectively, in which two molecules of 1a are bridged by the rhombic, disordered, mixed halide [Cu(μ‐X)2Cu] (5: X = Br; 6: X = Cl, I) unit. The crystal structures of 4 and 5 confirm the halogen exchange between the Rh–Cl and CuX (X = Br, I) moieties which leads to the formation of Rh–Br and Rh–I bonds. The heterodinuclear RhI/PdII complex [(cod)RhCl{μ‐L‐κP,κP}PdCl(η3‐C3H5)] (6) was synthesized by the reaction of 1a with [PdCl(η3‐C3H5)]2 in a 2:1 ratio. Reaction of 1b with CuI leads to the formation of the tetranuclear complex [Rh(CO)I{μ‐L‐κP,κP}2Cu(μ‐I)]2 (8) containing two terminal uncoordinated phosphorus(III) centers irrespective of reactant ratio and reaction conditions. Halogen exchange reaction which leads to the formation of the Rh–I bond was also observed during the preparation of complex 8. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Expanding the Range of “Daniphos”‐Type P∩P‐ and P∩N‐Ligands: Synthesis and Structural Characterisation of New [(η6‐arene)Cr(CO)3] Complexes
Authors: Alberico Elisabetta , Braun Wolfgang , Calmuschi‐Cula Beatrice , Englert Ulli , Salzer Albrecht , Totev Daniel
Published: September 2007

New P∩P‐ and P∩N‐ligands have been synthesised whose core structure is an [(η6‐arene)Cr(CO)3] unit. These new ligands, which extend the range of “Daniphos” ligands, are endowed with central and planar chirality and have been prepared through a stereoselective synthetic strategy from optically pure benzylamines bearing a second substituent on the arene other than the benzyldimethylamino group. Because the two faces of unsymmetrically 1,2‐ and 1,3‐disubstituted benzylamine are diastereotopic, which means that diastereomeric complexes arise upon coordination of theCr(CO)3 fragment to either of these two faces, the synthetic plan has been adjusted by exploiting the trimethylsilyl group as a temporary steric modulator in order to access both complexes with high diastereoselectivity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Formation of Boronate Ester Polymers with Efficient Intrastrand Charge‐Transfer Transitions by Three‐Component Reactions
Authors: Christinat Nicolas , Croisier Emmanuel , Scopelliti Rosario , Cascella Michele , Röthlisberger Ursula , Severin Kay
Published: September 2007

The three‐component reaction of aryl boronic acids with 1,2,4,5‐tetrahydroxybenzene and 1,2‐bis(4‐pyridyl)ethylene or 4,4′‐bipyridine leads to the formation of dark‐purple boronate ester polymers. Crystallographic analyses show that the polymer strands have a zig–zag geometry, and the bis(dioxaborole) units are connected by dipyridyl linkers through dative B–N interactions. Upon dissolution of the polymers in hot chloroform, most of the B–N connections are broken, which indicates that polymer formation is a reversible process. A computational study provides evidence that the strong color of the polymers is due to efficient intrastrand charge‐transfer excitations from the tetraoxobenzene to the dipyridyl linker.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Palladium‐Catalyzed Alkynylcarbonylation of Aryl Iodides with the Use of Mo(CO)6 in the Presence of tBu3P Ligand
Authors: Iizuka Muneaki , Kondo Yoshinori
Published: September 2007

Palladium‐catalyzed alkynylcarbonylation of aryl iodides was accomplished by using Mo(CO)6 as a CO source. The reaction was conducted at room temperature with the use of tBu3P as a ligand, which was found to be essential for smooth carbonylation. One‐pot construction of pyrazoles by using aryl iodides with electron‐withdrawing groups was also accomplished under these reaction conditions in the presence of methylhydrazine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Palladium Biosensor
Authors: Adam Vojtech , Hanustiak Pavel , Krizkova Sona , Beklova Miroslava , Zehnalek Josef , Trnkova Libuse , Horna Ales , Sures Bernd , Kizek Rene
Published: September 2007

In this paper we proposed a palladium(II) biosensor. The biosensor is based on determining of interactions between palladium(II) and metallothionein modified hanging mercury drop electrode by means of differential pulse voltammetry. We studied influence of two supporting electrolytes (potassium or sodium chloride) on the signals of the biosensor. Based on the results obtained we found potassium chloride (0.05 M) as the most suitable supporting electrolyte to determine palladium(II). The detection limit of the biosensor for palladium ions was evaluated as 100 nM with RSD about 10%. Moreover, we utilized the biosensor for measurement of the target molecule in the presence of human blood serum and human urine.
Square‐Wave Voltammetry Applied to the Analysis of the Dye Marker, Solvent Blue 14, in Kerosene and Fuel Alcohol
Authors: Trindade Magno Aparecido Gonçalves , Boldrin Zanoni Maria Valnice
Published: September 2007

The purpose of this paper is to develop an electroanalytical method based on square‐wave voltammetry (SWV) for the determination of the solvent blue 14 (SB‐14) in fuel samples. The electrochemical reduction of SB‐14 at glassy carbon electrode in a mixture of Britton‐Robinson buffer withN,N‐dimethylformamide (1 : 1, v/v) presented a well‐defined peak at−0.40 V vs. Ag/AgCl. All parameters of the SWV technique were optimized and the electroanalytical method presented a linear response from 1.0×10−6to 6.0×10−6 mol L−1(r=0.998) with a detection limit of 2.90×10−7 mol L−1. The developed method was successfully utilized in the quantification of the dye SB‐14 in kerosene and alcohol samples with average recovery from 93.00 to 98.10%.
Determination of Folic Acid by Adsorptive Stripping Voltammetry at a Lead Film Electrode
Authors: Korolczuk Mieczyslaw , Tyszczuk Katarzyna
Published: September 2007

An adsorptive stripping voltammetric procedure for the determination of folic acid at an in situ plated lead film electrode was described. Formation of lead film on a glassy carbon substrate and accumulation of folic acid was performed simultaneously from an acetate buffer solution of pH 5.6 at the potential −0.88 V. The measurements were carried out from aerated solutions. The calibration graph for an accumulation time of 300 s was linear from 2×10−9 to 5×10−8 mol L−1. The detection limit was 7×10−10 mol L−1, the relative standard deviation for 2×10−8 mol L−1 of folic acid was 3.9%. The proposed procedure was applied to folic acid determinations in pharmaceutical preparations.
Electrocatalysis and Amperometric Detection of the Reduced Form of Nicotinamide Adenine Dinucleotide at Toluidine Blue/Zinc Oxide Coated Electrodes
Authors: Kumar S. Ashok , Chen Shen‐Ming
Published: September 2007

Thin toluidine blue (TBO) and zinc oxide (ZnO) hybrid films have been grown on glassy carbon electrode (GCE) and indium tin oxide coated (SnO2) glass electrodes by using cyclic voltammetry (CV). Scanning electron microscopy (SEM) images revealed spherical and beads‐like shape of highly oriented TBO/ZnO hybrid films. Energy dispersive spectrometry (EDS) results declared that the films composed mainly of Zn and O. Moreover, TBO/ZnO hybrid films modified electrode is electrochemically active, dye molecules were not easily leached out from the ZnO matrix and the hybrid films can be considered for potential applications as sensor for amperometric determination of reduced nicotinamide adenine dinucleotide (NADH) at 0.0 V. A linear correlation between electrocatalytic current and NADH concentration was found to be in the range between 25 μM and 100 μM in phosphate buffer. In addition, we observed that dopamine, ascorbic acid and uric acid are not interference in amperometric detection of NADH in this proposed method. In addition, TBO/ZnO hybrid film modified electrode was highly stable and its response to the NADH also remained relentless.
Silver Amalgam Film Electrode of Prolonged Application in Stripping Chronopotentiometry
Authors: Kapturski Paweł , Bobrowski Andrzej
Published: September 2007

The utility of the cylindrical silver‐based mercury film electrode of prolonged analytical application in stripping chronopotentiometry (SCP) was examined. This electrode allowed us to obtain good reproducibility of results owing to the special electrode design, which enables regeneration of the thin layer before each measurement cycle. The accessible potential window in KNO3 (pH 2), acetate and ammonia buffers was defined, and the optimal conditions (i.e., stripping current, deposition potential and deposition time) for the determination of Cd and Pb traces were selected. The detection limits, obtained for an accumulation time of 60 s, were 0.023 μg/L for Cd and 0.075 μg/L for Pb. The response increases linearly with Cd, Pb and Zn concentration, up to at least 100 μg/L. It was also shown that the proposed procedure ensures excellent separation of the In and Tl, Pb and Tl or the In and Cd signals. The method was tested with dolomite and lake sediment samples, and good agreement with reference values was achieved. The obtained results showed good reproducibility (RSD=5–6%) and reliability.
A comparison of the hierarchical likelihood and Bayesian approaches to spatial epidemiological modelling
Authors: Jang Myoung Jin , Lee Youngjo , Lawson Andrew B. , Browne William J.
Published: September 2007

Recently Bayesian methods have been widely used in disease mapping. Hierarchical (h‐) likelihood methods allow reliable likelihood inference in random‐effect models and it is therefore interesting to compare h‐likelihood and Bayesian methods. For comparison we consider three examples: low birth weight and cancer mortality data in South Carolina and lip cancer data in Scotland. Mean estimates from both h‐likelihood and Bayesian approaches are almost identical, while variance‐component estimates can be somewhat different, depending upon choice of priors. Copyright © 2007 John Wiley & Sons, Ltd.
One‐day forward premiums and the impact of virtual bidding on the New York wholesale electricity market using hourly data
Authors: Hadsell Lester , Shawky Hany A.
Published: September 2007

This study examines one‐day forward premiums at the hourly level on the New York independent systems operator wholesale electricity market for the period 2001–2005. Examining two representative zones, the authors show that premiums vary by hour of day, day of week, and month. We report differences in the level and volatility of the premium across zones. We measure the impact of opening the market to outsiders through the introduction of virtual bidding. Results indicate that virtual bidding is associated with lower premiums in off‐peak or near‐off‐peak hours; it is associated with higher premiums during peak hours. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27: 1107–1125, 2007
Forecasting performance of extreme‐value volatility estimators
Authors: Vipul  , Jacob Joshy
Published: September 2007

This study evaluates the forecasting performance of extreme‐value volatility estimators for the equity‐based Nifty Index using two‐scale realized volatility. This benchmark mitigates the effect of microstructure noise in the realized volatility. Extreme‐value estimates with relatively simple forecasting methods provide substantially better short‐term and long‐term forecasts, compared to historical volatility. The higher efficiency of extreme‐value estimators is primarily responsible for this improvement. The extent of possible improvement in forecasts is likely to be economically significant for applications like options pricing. By including extremevalue estimators, the forecasting performance of generalized autoregressive conditional heteroscedasticity (GARCH) can also be improved. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27: 1085–1105, 2007
A new look at hedging with derivatives: Will firms reduce market risk exposure?
Authors: Bali Turan G. , Hume Susan R. , Martell Terrence F.
Published: September 2007

This study examines derivatives use of foreign exchange, interest rate, and commodities risk by nonfinancial firms across multiple industries, using data from 1995 to 2001. This work considers the interaction of a firm's risk exposures, derivatives use, and real operations simultaneously, and considers how these factors change over time using a consistent database. Hedging with derivatives is only signi.cantly related to commodity risk exposure during most years of the study, and to a more limited degree to interest rate exposure. Further, a strong correlation was found between risk exposures for some years using a new technique, suggesting that univariate modeling is not always appropriate. The implications are that hedging with derivatives is not always important to a firm's rate of return and is linked to other nonfinancial and economic factors. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27: 1053–1083, 2007
Inferential testing for linkage with GENEHUNTER‐MODSCORE: The impact of the pedigree structure on the null distribution of multipoint MOD scores
Authors: Mattheisen Manuel , Dietter Johannes , Knapp Michael , Baur Max P. , Strauch Konstantin
Published: September 2007

The asymptotic distribution of [MOD] scores under the null hypothesis of no linkage is only known for affected sib pairs and other types of affected relative pairs. We have extended the GENEHUNTER‐MODSCORE program to allow for simulations under the null hypothesis of no linkage to determine the empirical significance of MOD‐score results in general situations. We performed simulations with families of different size (one million replicates of 500 families per simulation setting) to thoroughly investigate the impact of the pedigree size on the null distribution of multipoint MOD scores. It is shown that the distribution is dependent on the size and structure of the pedigrees under study. By performing simulations in the context of MOD‐score analysis, our new tool efficiently explores the linkage data in a comprehensive way and also provides a valid method to inferentially test for linkage. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
A principal components regression approach to multilocus genetic association studies
Authors: Wang Kai , Abbott Diana
Published: September 2007

With the rapid development of modern genotyping technology, it is becoming commonplace to genotype densely spaced genetic markers such as single nucleotide polymorphisms (SNPs) along the genome. This development has inspired a strong interest in using multiple markers located in the target region for the detection of association. We introduce a principal components (PCs) regression method for candidate gene association studies where multiple SNPs from the candidate region tend to be correlated. In this approach, the total variance in the original genotype scores is decomposed into parts that correspond to uncorrelated PCs. The PCs with the largest variances are then used as regressors in a multiple regression. Simulation studies suggest that this approach can have higher power than some popular methods. An application to CHI3L2 gene expression data confirms a significant association between CHI3L2 gene expression level and SNPs from this gene that has been previously reported by others. Genet. Epidemiol. 2008. © 2007 Wiley‐Liss, Inc.
Astrocyte membrane responses and potassium accumulation during neuronal activity
Authors: Meeks Julian P. , Mennerick Steven
Published: September 2007

Older studies suggest that astrocytes act as potassium electrodes and depolarize with the potassium efflux accompanying neuronal activity. Newer studies suggest that astrocytes depolarize in response to neuronal glutamate release and the activity of electrogenic glial glutamate transporters, thus casting doubt on the fidelity with which astrocytes might sense extracellular potassium rises. Any K+‐induced astrocyte depolarization might reflect a spatial buffering effect of astrocytes during neuronal activity. For these reasons, we studied stimulus‐evoked currents in hippocampal CA1 astrocytes. Hippocampal astrocytes exhibited stimulus‐evoked transient glutamate transporter currents and slower Ba2+‐sensitive inward rectifier potassium (Kir) currents. In whole‐cell astrocyte recordings, Ba2+ blocked a very weakly rectifying component of the astrocyte membrane conductance. The slow stimulus‐elicited current, like measurements from K+‐sensitive electrodes under the same conditions, predicted small bulk [K+]o increases (<0.5 mM) following the termination of short‐stimulus trains. These currents indicate the potential for astrocyte spatial K+ buffering. However, Ba2+ did not significantly affect resting [K+]o or the [K+]o rises detected by the K+‐sensitive electrode. To test whether local K+ rises may be significantly higher than those detected by glial recordings or by K+ electrodes, we assayed EPSCs and fiber volleys, two measures very sensitive to K+ increases. We found that Ba2+ had little effect on neuronal axonal or synaptic function during short‐stimulus trains, indicating that Kirs do not influence local [K+]o rises enough, under these conditions to affect synaptic transmission. In conclusion, our results indicate that hippocampal astrocytes are faithful sensors of [K+]o rises, but we find little evidence for physiologically relevant spatial K+ buffering during brief bursts of presynaptic activity. © 2007 Wiley‐Liss, Inc.
Memory for familiar environments learned in the remote past: fMRI studies of healthy people and an amnesic person with extensive bilateral hippocampal lesions
Authors: Rosenbaum R. Shayna , Winocur Gordon , Grady Cheryl L. , Ziegler Marilyne , Moscovitch Morris
Published: September 2007

Preserved remote spatial memory in amnesic people with bilateral hippocampal damage, including the well‐studied case K.C., challenges spatial theories, which assume that the hippocampus is needed to support all allocentric spatial representations, old or new. It remains possible, however, that residual hippocampal tissue is functional and contributes to successful performance. Here, we examine brain activity with fMRI during the retrieval of spatial information in K.C. and in healthy controls using landmark and route stimuli from a premorbidly familiar neighborhood that K.C. can navigate normally. In all participants, activity was found in the parahippocampal cortex, but not in the hippocampus itself, during all navigational tasks on which K.C. performs well, even though part of his hippocampus remains viable. The opposite pattern was observed on a house recognition task, which is inconsequential to navigation, and on which K.C. performed poorly. On that task, K.C. recruited the right hippocampus presumably because even “familiar” houses were treated as novel by him, whereas controls recruited occipitotemporal cortex, including parahippocampal cortex. The distinction between recent and remote memory, therefore, may apply as much to spatial theories of hippocampal function as it does to theories emphasizing the role of the hippocampus in other types of explicit memory. © 2007 Wiley‐Liss, Inc.
An examination of fatigue striations in human dentin: In vitro and in vivo
Authors: Bajaj D. , Sundaram N. , Arola D.
Published: September 2007

Although striations are often used in evaluating fatigue crack growth in engineering materials, they have not been used in studying the mechanics of fracture in hard tissues. The primary objective of this study was to evaluate the striations resulting from fatigue crack growth in the dentin of human teeth. Compact tension (CT) specimens obtained from the coronal dentin of molars from young (17 ≤ age ≤ 37 years) and senior (age ≥ 50 years) patients were subjected to cyclic Mode I loads. Striations evident on the fracture surfaces were examined using a scanning electron microscope (SEM) and contact profilometer. Fatigue crack growth striations that developed in vivo were also examined on fracture surfaces of restored molars. A power spectrum analysis of surface profiles from the CT specimens showed that the striation spacing ranged from 50 to 170 μm. The average spacing in the dentin of seniors (130 ± 23 μm) was significantly larger (p < 0.001) than that in young dentin (88 ± 13 μm). Fatigue striations in the restored teeth exhibited features that were consistent with those that developed in vitro and a spacing ranging from 59 to 95 μm. Unlike metals, the striations in dentin developed after a period of cyclic loading that ranged from 1 × 103 to 1 × 105 cycles. A quantitative evaluation of the striation spacing using the Bates‐Clark equation suggested that cyclic crack growth within the restored teeth occurred at a stress intensity range near 0.7 MPa·m0.5, and a stress range of ∼12 MPa. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Calcium phosphate‐based coatings on titanium and its alloys
Authors: Narayanan R. , Seshadri S. K. , Kwon T. Y. , Kim K. H.
Published: September 2007

Use of titanium as biomaterial is possible because of its very favorable biocompatibility with living tissue. Titanium implants having calcium phosphate coatings on their surface show good fixation to the bone. This review covers briefly the requirements of typical biomaterials and narrowly focuses on the works on titanium. Calcium phosphate ceramics for use in implants are introduced and various methods of producing calcium phosphate coating on titanium substrates are elaborated. Advantages and disadvantages of each type of coating from the view point of process simplicity, cost‐effectiveness, stability of the coatings, coating integration with the bone, cell behavior, and so forth are highlighted. Taking into account all these factors, the efficient method(s) of producing these coatings are indicated finally. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Human tooth culture: A study model for reparative dentinogenesis and direct pulp capping materials biocompatibility
Authors: Téclès Odile , Laurent Patrick , Aubut Virginie , About Imad
Published: September 2007

In a previous work, based on an in vitro entire tooth culture model of human immature third molars, we demonstrated that perivascular progenitor cells can proliferate and migrate to the injury site after pulp exposure. In this work, we investigated the differentiation of cells after direct capping with biomaterials classically used in restorative dentistry. Histological staining after direct pulp capping with Calcium Hydroxide XR® or MTA revealed early and progressive mineralized foci formation containing BrdU‐labeled sequestered cells. The molecular characterization of the matrix and the sequestered cells by immunohistochemistry (Collagene type I, Dentin sialoprotein, and Nestin) clearly demonstrates that these areas share common characteristics of the mineralized matrix of reparative dentin formed by odontoblast‐like cells. This reproduces some features of the pulp responses after applying these materials in vivo and demonstrates that the entire tooth culture model reproduces a part of the early steps of dentin regeneration in vivo. Its future development may be useful in studying the effects of biomaterials on this process. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
The human micro‐vascular endothelial cells in vitro interaction with atomic‐nitrogen‐doped diamond‐like carbon thin films
Authors: Okpalugo T. I. T. , Ogwu A. A. , Okpalugo A. C. , McCullough R. W. , Ahmed W.
Published: September 2007

This paper reports the initial response of atomic nitrogen doped diamond like carbon (DLC) to endothelial cells in vitro. The introduction of nitrogen atoms/molecules to the diamond like carbon structures leads to an atomic structural change favorable to the attachment of human micro‐vascular endothelial cells. Whilst the semi‐conductivity induced by nitrogen in DLC is thought to play a part, the increase in the non‐bonded N atoms and N2 molecules in the atomic doped species (with the exclusion of the charged species) seems to contribute to the improved attachment of human microvascular endothelial cells. The increased endothelial attachment is associated with a lower work function and slightly higher water contact angle in the atomic doped films, where the heavy charged particles are excluded. The films used in the study were synthesized by the RF PECVD technique followed by post deposition doping with nitrogen, and afterwards the films were characterized by XPS, Raman spectroscopy, SIMS and Kelvin probe. The water contact angles were measured, and the counts of the adherent endothelial cells on the samples were carried out. This study is relevant and contributory to improving biocompatibility of surgical implants and prostheses. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
High‐resolution water window X‐ray imaging of in vivo cells and their products using LiF crystal detectors
Authors: Bonfigli Francesca , Faenov Anatoly , Flora Francesco , Francucci Massimo , Gaudio Pasqualino , Lai Antonia , Martellucci Sergio , Montereali Rosa Maria , Pikuz Tania , Reale Lucia , Richetta Maria , Vincenti Maria Aurora , Baldacchini Giuseppe
Published: September 2007

High contrast imaging of in vivo Chlorella sorokiniana cells with submicron spatial resolution was obtained with a contact water window X‐ray microscopy technique using a point‐like, laser‐plasma produced, water‐window X‐ray radiation source, and LiF crystals as detectors. This novel type of X‐ray imaging detectors is based on photoluminescence of stable electronic point defects, characterized by high intrinsic resolution. The fluorescence images obtained on LiF crystals exposed in single‐shot experiments demonstrate the high sensitivity and dynamic range of this new detector. The powerful performances of LiF crystals allowed us to detect the exudates of Chlorella cells in their living medium and their spatial distribution in situ, without any special sample preparation. Microsc. Res. Tech., 2008. © 2007 Wiley‐Liss, Inc.
Comparative modeling of marsupial MHC class I molecules identifies structural polymorphisms affecting functional motifs
Authors: Daly Kerry , Bret Church W. , Nicholas Kevin , Williamson Peter
Published: September 2007

Major histocompatibility complex (MHC) class I molecules are transmembrane glycoproteins that present antigenic peptides to CD8+ T cells and are subsequently important for the initiation of an immune response. In this study novel MHC class I sequences from the tammar wallaby (Macropus eugenii) have been characterized. Analysis and comparative modeling of these and existing marsupial molecules reveals potential functional polymorphisms within peptide‐binding grooves, MHC assembly motifs and the T cell receptor recognition interface. In addition, we show that a previously identified marsupial‐specific insertion is within a region, which is known as a putative NK cell receptor (Ly49A) binding site in the mouse, suggesting that this site may be functionally active in marsupials. Further, the analysis highlighted differences in structural and sequence based grouping of marsupial MHC class I molecules. J. Exp. Zool. 307A:611–624, 2007. © 2007 Wiley‐Liss, Inc.
Osteoinductive effect of bone bank allografts on human osteoblasts in culture
Authors: de la Piedra Concepción , Vicario Carlos , de Acuña Lucrecia Rodríguez , García‐Moreno Carmen , Traba Maria Luisa , Arlandis Santiago , Marco Fernando , López‐Durán Luis
Published: September 2007

Incorporation of a human bone allograft requires osteoclast activity and growth of recipient osteoblasts. The aim of this work was to study the effects produced by autoclavated and −80°C frozen bone allografts on osteoblast proliferation and synthesis of interleukin 6 (IL6), activator of bone resorption, aminoterminal propeptide of procollagen I (PINP), marker of bone matrix formation, and osteoprotegerin (OPG), inhibitor of osteoclast activity and differentiation. Allografts were obtained from human femoral heads. Human osteoblasts were cultured in the presence (problem group) or in the absence (control group) of allografts during 15 days. Allografts produced a decrease in osteoblast proliferation in the first week of the experiment, and an increase in IL6 mRNA, both at 3 h and 2 days, and an increase in the IL6 released to the culture medium the second day of the experiment. We found a decrease in OPG released to the culture on the 2nd and fourth days. These results suggest an increase in bone resorption and a decrease in bone formation in the first week of the experiment. In the second week, allografts produced an increase in osteoblast proliferation and PINP release to the culture medium, indicating an increase in bone formation; an increase in OPG released to the culture medium, which would indicate a decrease in bone resorption; and a decrease in IL6, indicating a decrease in bone resorption stimulation. These results demonstrate that autoclavated and −80°C frozen bone allografts produce in bone environmemt changes that regulate their own incorporation to the recipient bone. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:200–207, 2008
Interface membrane fibroblasts around aseptically loosened endoprostheses express MMP‐13
Authors: Wagner Susanne , Gollwitzer Hans , Wernicke Dirk , Langer Rupert , Siebenrock Klaus A. , Hofstetter Willy
Published: September 2007

The objective of this article was to assess whether matrix metalloproteinase‐13 (MMP‐13) is produced by cells of the peri‐implant interface tissues and to further characterize these cells. Tissue specimens were collected from the bone–prosthesis interface at the time of revision surgery of clinically loosened hip and knee arthroplasties (n = 27). Synovial tissues from osteoarthritic patients and young patients with mild joint deformity were used as controls (n = 6). Tissue samples were fixed in 4% PFA, decalcified with EDTA, and embedded in paraffin. Sections (4 µm) were stained with hematoxylin/eosin and for the osteoclastic marker enzyme tartrate resistant acid phosphatase. Monocytes/macrophages were characterized with a monoclonal antibody against CD68 and mRNAs encoding MMP‐13 and α1 collagen I (COL1A1) were detected by in situ hybridization. Cells expressing transcripts encoding MMP‐13 were found in 70% of the interface tissues. These cells colocalized with a cell population expressing COL1A1 mRNA, and were fibroblastic in appearance. MMP‐13 expressing cells were found in the close vicinity of osteoclasts and multinuclear giant cells. No signals for transcripts encoding MMP‐13 were detected in multinuclear giant cells or in osteoclasts. Control tissues were negative for transcripts encoding MMP‐13 mRNA. Fibroblasts of the interface from aseptically loosened endoprostheses selectively express MMP‐13. By the expression and the release of MMP‐13, these fibroblastic cells may contribute to the local degradation of the extracellular matrix and to bone resorption. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:143–152, 2008
Clonal T‐cell response against autologous pleomorphic malignant fibrous histiocytoma antigen presented by retrieved HLA‐A*0206
Authors: Kimura Shigeharu , Kozakai Yuriko , Kawaguchi Satoshi , Tsukahara Tomohide , Ida Kazunori , Murase Masaki , Matsumura Tadaki , Kaya Mitunori , Torigoe Toshihiko , Wada Takuro , Sato Noriyuki , Yamashita Toshihiko
Published: September 2007

Towards the goal of identifying tumor‐rejection antigens on eradicated tumors in bone and soft tissue sarcomas, we evaluated the immune response against antigens presented by lost HLA class I molecules. Tumor specimens and peripheral blood samples were obtained from a 70‐year‐old woman with pleomorphic malignant fibrous histiocytoma. Over 1‐year culture, a tumor cell line (MFH2004) was established. A B‐cell line infected with Epstein–Barr virus (B2004‐EBV) was developed from the blood samples. HLA genotypes of B2004‐EBVcells were A*0206/2402, B*4006/4601, and C*0102/0801, whereas MFH2004 cells were defective for A*0206, B*4006, and C*0102. Loss of HLA‐A2 expression was also proved immunohistochemically in the primary tumor tissues. Lost HLA‐A2 in MFH2004 cells was retrieved by transfection of HLA‐A*0206 cDNA to develop MFH2004‐A2. Attempts to induce CTLs by mixed culture with autologous T cells and MFH2004 cells resulted in failure. In contrast, those with MFH2004‐A2 induced CTL clones CTL2004‐c6 and CTL2004‐c17. These CTL clones specifically killed MFH2004‐A2 but not MFH2004 or B2004‐EBV in an HLA‐A2‐restricted manner. These findings suggest that CTL2004‐c6 and CTL2004‐c17 recognize autologous tumor‐rejection antigens presented by HLA‐A*0206, which may have been expressed by tumor cells that had been eradicated by the host's immunosurveillance system. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:271–278, 2008
Inhibition effect of {surfactant–substrate} aggregation on the rate of oxidation of reducing sugars by alkaline hexacyanoferrate(III)
Authors: Shukla Ratna , Upadhyay Santosh K.
Published: September 2007

The effect of cationic (cetyltrimethylammonium bromide, CTAB), anionic (sodium lauryl sulfate, NaLS), and nonionic (Brij‐35) surfactants on the rate of oxidation of some reducing sugars (xylose, glucose, and fructose) by alkaline hexacyanoferrate(III) has been studied in the temperature range from 35 to 50°C. The rate of oxidation is strongly inhibited in the presence of surfactant. The inhibition effect of surfactant on the rate of reaction has been observed below critical micelle concentration (CMC) of CTAB. In case of NaLS and Brij‐35, the inhibition effect was above CMC, at which the surfactant abruptly associates to form micelle. The kinetic data have been accounted for by the combination of surfactant molecule(s) with a substrate molecule in case of CTAB and distribution of substrate into micellar and aqueous pseudophase in case of NaLS and Brij‐35. The binding parameters (binding constants, partition coefficients, and free‐energy transfer from water to micelle) in case of NaLS and Brij‐35 have been evaluated with the help of Menger and Portnoy model reported for micellar inhibition. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 595–604, 2007
Estimation of homogeneous rate constants of reaction of electrochemically generated ortho‐benzoquinones with 1,3‐indandione
Authors: Nematollahi Davood , Ardakani Mohammad Mazloum , Shekarlab Nastaran
Published: September 2007

Electrochemical oxidation of some catechol derivatives has been studied in the presence of 1,3‐indandione as nucleophile in aqueous solution, by means of cyclic voltammetry and controlled‐potential coulometry. The results indicate the participation of electrochemically produced o‐benzoquinones in the Michael reaction with 1,3‐indandione to form the corresponding new catechol derivatives. On the basis of the EC mechanism, the observed homogeneous rate constants (kobs) of reaction of produced o‐benzoquinones with 3‐indandione were estimated by comparing the experimental cyclic voltammograms with the digitally simulated results. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 605–613, 2007
Kinetics of OH radical reaction with phenanthrene: New absolute rate measurements and comparison with other PAHs
Authors: Ananthula Rajeshwar , Yamada Takahiro , Taylor Philip H.
Published: September 2007

Using an in situ pulsed laser photolysis/pulsed laser‐induced fluorescence/technique, the OH reaction kinetics of a three‐ring polycyclic aromatic hydrocarbon (PAH), phenanthrene (and its deuterated form), was investigated over the temperature range of 373–1000 K. This study represents the first examination of the OH kinetics for phenanthrene at elevated temperatures using the absolute rate technique. The phenanthrene results indicate a temperature dependence similar to its isomer anthracene, reported previously in R. Ananthula, T. Yamada, and P. H. Taylor, J Phys Chem A 2006, 100, 3559–3566, over a similar temperature range. The phenanthrene rate constants are similar to anthracene at high temperature (ca. 1000 K) and a factor of ca. 2 lower at low temperatures (373–700 K). The rate measurements were best fitted by the following two‐parameter expression of the form ATn: k1(373–1000 K) = 4.98 ± 2.96 × 10−6 * T−1.97±0.10 (in units of cm3 molecule−1 s−1, error limits ±1σ). Rate measurements with deuterated phenanthrene below 725 K were indistinguishable from the phenanthrene rate measurements, within random error limits, providing strong evidence for an OH‐addition mechanism. The effects of PAH size on their reactivity with OH radicals based on selected data over the temperature range of 243–1200 K are discussed. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 629–637, 2007
Kinetics of the alkaline hydrolysis of fenuron in aqueous and micellar media
Authors: Gangwar S. K. , Rafiquee M. Z. A.
Published: September 2007

The kinetics of the hydrolysis of fenuron in sodium hydroxide has been investigated spectrometrically in an aqueous medium and in cationic micelles of cetyltrimethylammonium bromide (CTAB) medium. The reaction follows first‐order kinetics with respect to [fenuron] in both the aqueous and micellar media. The rate of hydrolysis increases with the increase in [NaOH] in the lower concentration range but shows a leveling behavior at higher concentrations. The reaction followed the rate equation, 1/kobs = 1/k + 1/(kK[OH−]), where kobs is the observed rate constant, k is rate constant in aqueous medium, and k is the equilibrium constant for the formation of hydroxide addition product. The cationic CTAB micelles enhanced the rate of hydrolytic reaction. In both aqueous and micellar pseudophases, the hydrolysis of fenuron presumably occurs via an addition–elimination mechanism in which an intermediate hydroxide addition complex is formed. The added salts decrease the rate of reaction. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 638–644, 2007
Liquid chromatography combined with mass spectrometry for 13C isotopic analysis in life science research
Authors: Godin Jean‐Philippe , Fay Laurent‐Bernard , Hopfgartner Gérard
Published: September 2007

Among the different disciplines covered by mass spectrometry, measurement of 13C/12C isotopic ratio crosses a large section of disciplines from a tool revealing the origin of compounds to more recent approaches such as metabolomics and proteomics. Isotope ratio mass spectrometry (IRMS) and molecular mass spectrometry (MS) are the two most mature techniques for 13C isotopic analysis of compounds, respectively, for high and low‐isotopic precision. For the sample introduction, the coupling of gas chromatography (GC) to either IRMS or MS is state of the art technique for targeted isotopic analysis of volatile analytes. However, liquid chromatography (LC) also needs to be considered as a tool for the sample introduction into IRMS or MS for 13C isotopic analyses of non‐volatile analytes at natural abundance as well as for 13C‐labeled compounds. This review presents the past and the current processes used to perform 13C isotopic analysis in combination with LC. It gives particular attention to the combination of LC with IRMS which started in the 1990's with the moving wire transport, then subsequently moved to the chemical reaction interface (CRI) and was made commercially available in 2004 with the wet chemical oxidation interface (LC‐IRMS). The LC‐IRMS method development is also discussed in this review, including the possible approaches for increasing selectivity and efficiency, for example, using a 100% aqueous mobile phase for the LC separation. In addition, applications for measuring 13C isotopic enrichments using atmospheric pressure LC‐MS instruments with a quadrupole, a time‐of‐flight, and an ion trap analyzer are also discussed as well as a LC‐ICPMS using a prototype instrument with two quadrupoles. © 2007 Wiley Periodicals, Inc., Mass Spec Rev 26:751–774, 2007
Preparation and Characterization of pH‐Sensitive Microgels of Poly((2‐dimethylamino) ethyl methacrylate)
Authors: Emileh Ali , Vasheghani‐Farahani Ebrahim , Imani Mohammad
Published: September 2007

Summary: pH‐sensitive microgels of poly((2‐dimethylamino) ethyl methacrylate) (PDMAEMA) were prepared by dispersion polymerization of 2‐dimethylamino ethyl methacrylate in a mixed solvent of water/ethanol. 1HNMR, FTIR and SEM were used to confirm the chemical structure and morphological properties of the resulting microgels. Dynamic Light Scattering (DLS) was used to measure the hydrodynamic diameter of the particles. SEM micrographs showed that the microgel particles have a diameter of about 100–200 nm in dry state. Mean hydrodynamic diameter of the particles at their collapsed state at pH = 9.5 was found to be about 150 nm. DLS measurements at various pH values showed that the prepared microgels have a volume phase transition around pH = 8 at which the hydrodynamic diameter decreased from about 470 nm to around 150 nm corresponding to a 32 fold change in the mean volume of a microgel particle.
Preparation of Magnetite‐Polystyrene Core‐Shell Hybrid Nanoparticles, Initiated by a Covalently Bonded Azo Compound
Authors: Hartmann Patrice C. , Sanderson Ronald D.
Published: September 2007

Summary: Magnetite nanoparticles (MNP), onto which the radical initiator 4,4′ azobis (4‐cyanovaleric acid) (ACV) was grafted, were used as a macro‐initiators in the polymerization of styrene. Bulk and emulsion polymerizations were performed. Core‐shell nanoparticles with a magnetite core and a polystyrene (PS) shell were obtained by emulsion polymerizations. A simple geometrical model was proposed to correlate the size of the final PS shell to the styrene/MNP ratio. The diameter of the shell of the prepared core‐shell nanoparticles was found to be greater than expected. This was due to the fact that most of the PS shell contained several MNP cores. This feature was confirmed by transmission electron microscopy (TEM) imaging of the stable latexes obtained. Particles of nearly mono‐disperse size were obtained by emulsion polymerization, and their diameters decreased as the ratio of MNP/styrene increased. Films were cast from the core‐shell nanoparticles dissolved in chloroform. Due to the superparamagnetic properties of the MNP, a change in their organization in the polymer matrix was obtained by applying a magnetic field at a temperature above the Tg of the PS shell.
Synthesis, Characterisation of Novel Polyaniline Nanomaterials and Application in Amperometric Biosensors
Authors: Michira I. , Akinyeye R. , Somerset V. , Klink M. J. , Sekota M. , Al‐Ahmed A. , Baker P. G. L. , Iwuoha E.
Published: September 2007

Summary: Anthracene sulfonic acid doped polyaniline nanomaterials were prepared through the chemical oxidative polymerisation process. Ammonium peroxydisulfate (APS) was employed as oxidant. Scanning electron microscopy (SEM) results show the resultant polyaniline (PANi) materials exhibited nanofibrillar morphology with diameter sizes less than 300 nm. Using the nanofibrillar PANI, amperometric biosensors for H2O2 and erythromycin were constructed through the drop‐coating technique. Anthracene sulfonic acid (ASA) doped PANi and the test enzymes horseradish peroxidase, (HRP), or cytochrome P450 3A4, (CYP4503A4) were mixed in phosphate buffer solution before drop coating onto the electrode. The resultant biosensors displayed typical Michaelis‐Menten behaviour. The apparent Michaelis‐Menten constant obtained was 0.18 ± 0.01 mM and 0.80 ± 0.02 µM L−1 for the peroxide and erythromycin biosensor respectively. The sensitivity for the peroxide sensor was 3.3 × 10−3 A · cm−2 · mM−1, and the detection limit was found to be 1.2 ×  10−2 mM respectively. Similarly, the sensitivity for the erythromycin sensor was in the same order at 1.57 × 10−3 A · cm−2 · mM−1 and detection limit was found to be 7.58 × 10−2 µM.
CMC and Phase Separation Studies of RAFT Mediated Amphiphilic Diblock Glycopolymers with Methyl Acrylate and Styrene
Authors: Ramiah V. , Matahwa H. , Weber W. , McLeary J. B. , Sanderson R. D.
Published: September 2007

Summary: Interesting new CMC and phase separation data of carbohydrate‐based self‐assembling core‐shell nanoparticles which were synthesized via the Reversible Addition‐Fragmentation Transfer (RAFT) process. The macro‐RAFT agent, poly(3‐O‐ Methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐D‐glucofuranose) (PMAlpGlc), was prepared by RAFT polymerization of the glycomonomer with cumyl phenyl dithioacetate as the chain transfer agent. Chain extension with styrene and methyl acrylate afforded the diblock copolymers (PMAlpGlc‐b‐styrene and PMAlpGlc‐b‐methyl acrylate) having predetermined molecular weight and narrow molecular weight distributions. Acidolysis of these diblock copolymers were undertaken and confirmed by NMR. Core‐shell nanoparticles were observed by TEM.