bluuebunny/crossref_metadata_2025_split huggingface dataset:
AFM observation of collapse and expansion of phosphoric acid‐demineralized dentin
Authors: Nakabayashi Nobuo , Watanabe Akihiko , Igarashi Kayo 
Published: January 2004

AbstractThe objective of this study is to provide additional data regarding morphological changes that occur to dentin matrices following demineralization with etchants. Our understanding of the mechanism of diffusion of comonomers into the demineralized substrate is very limited. It has been hypothesized that certain water‐soluble polyelectrolytes (acidic proteins) and neutral proteins in dentin can influence the collapse of demineralized dentin when it is air dried. Some of these solubilized substances are thought to aggregate by the action of Ca cations, which become dissolved during H3PO4 etching, ultimately resulting in some degree of collapse. In the current study, dentin surfaces were examined by atomic force microscopy (AFM) before and after treatment by 10% H3PO4containing increasing concentrations of CaHPO4. Reversal of matrix collapse by aqueous 30% 2‐hydroxyethyl methacrylate (HEMA) was evaluated by AMF for 60 min. The results demonstrate two forms of matrix collapse; we speculate that one form is induced by acidic noncollagenous polyelectrolytes and the other by neutral peptides. Our data indicate that further evaluation of the influence of endogenous noncollagenous proteins must be studied to understand the mechanism of the collapse and reexpansion dynamics of demineralized dentin networks. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 558–565, 2004
Scaled interfacial activity of proteins at the liquid–vapor interface
Authors: Krishnan Anandi , Sturgeon Jacqueline , Siedlecki Christopher A. , Vogler Erwin A. 
Published: January 2004

AbstractA principal conclusion drawn from observations of time‐ and concentration‐dependent liquid–vapor (LV) interfacial tension γlv of a diverse selection of proteins ranging from albumin to ubiquitin spanning nearly three decades in molecular weight (MW) is that concentration scaling substantially alters perception of protein interfacial activity as measured by reduction in γlv. Proteins appear more similar than dissimilar on a weight/volume basis, whereas molarity scaling reveals a “Traube‐rule” ordering by MW, suggesting that adsorption is substantially driven by solution concentration rather than diversity in protein amphilicity. Scaling as a ratio‐to‐physiological‐concentration demonstrates that certain proteins exhibit the full possible range of interfacial activity at and well‐below physiological concentration, whereas others are only weakly surface active within this range, requiring substantially higher solution concentration to achieve reduction in γlv. Important among this latter category of proteins are the blood factors XII and XIIa, assumed by the classical biochemical mechanism of plasma coagulation to adsorb to procoagulant surfaces, even in the presence of overwhelming concentrations of other blood constituents such as albumin and immunoglobulin that are shown by this work to be among the class of highly surface‐active proteins at physiologic concentration. A comparison of pendant drop and Wilhelmy balance tensiometry as tools for assessing protein interfacial activity shows that measurement conditions employed in the typical Wilhelmy plate approach fails to achieve the steady‐state adsorption condition that is accessible to pendant drop tensiometry. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 544–557, 2004
Improved wet bonding of methyl methacrylate‐tri‐n‐butylborane resin to dentin etched with ten percent phosphoric acid in the presence of ferric ions
Authors: Iwasaki Yasuhiko , Toida Tetsuya , Nakabayashi Nobuo 
Published: January 2004

AbstractThe objective of this study was to determine the influence of dissolved dentinal substances in demineralized dentin on the hybridization of resin for bonding to dentin. It was hypothesized that these substances, including polyelectrolytes, significantly change the substrates, which could then be assessed by the addition of Na+, Ca2+, or Fe3+ in 10% phosphoric acid. Bovine dentin specimens were etched for 10 s with a solution of 10% phosphoric acid (control) or of 22.0 mM dissolved sodium chloride (10P‐Na), calcium chloride (10P‐Ca), or ferric chloride (10P‐Fe). The specimens were then rinsed, blot‐dried, and primed three times with 5% 4‐methacryloyloxyethyl trimellitate anhydride in acetone for 60 s. Methyl methacrylate‐tri‐n‐butylborane resin was then applied. The tensile bond strength of each of the dumbbell‐shaped specimens was then measured. The fractured surfaces and modified cross‐sections were examined by scanning electron microscopy. The cross‐sections were soaked in 6N HCl for 10 s and then in 1% sodium hypochlorite for 30 min to determine the resin content in the hybridized specimens. Shrinkage of the demineralized dentins upon drying was assessed by atomic force microscopy. The tensile bond strengths were 10.8 ± 4.5 (control), 15.0 ± 7.0 (10P‐Na), 19.3 ± 5.5 (10P‐Ca), and 27.8 ± 8.1 (10P‐Fe) MPa. The atomic force microscopy studies showed that Fe3+ minimized the shrinkage by drying for 10 s but Ca2+ and Na+ did not decrease the shrinkage the same as the control. The results support the hypothesis that the monomer permeability of wet demineralized dentin is effectively improved by dissolving ferric ions in the phosphoric acid, resulting in a greater bond strength and higher resin content in the hybridized dentin. The dissolved dentinal substances, including the polyelectrolytes, had a significant influence on the characteristics of the demineralized dentin, changing the degree of hybridization and bonding. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 566–572, 2004
Effects of end boundary conditions and specimen geometry on the viscoelastic properties of cancellous bone measured by dynamic mechanical analysis
Authors: Dong X. Neil , Yeni Yener N. , Les Clifford M. , Fyhrie David P. 
Published: January 2004

AbstractThe viscoelastic properties of cancellous bone can be measured nondestructively in compression testing using a dynamic mechanical analyzer. In this study, we examined the effects of end boundary conditions and specimen geometry on the viscoelastic properties of cancellous bone measured by dynamic mechanical analysis. During dynamic compression testing, the cancellous bone specimens may be mechanically fixed (e.g., glued) to the loading platens or they may be free to expand across the platen surface. When specimens of cancellous bone were tested between platens with gluing, the dependence of loss tangent on frequency was not consistent with previously observed strain‐rate‐dependent mechanical behavior of cancellous bone. When long specimens of cancellous bone (length = 10 mm, diameter = 8 mm) were tested without gluing, the relationship between loss tangent and frequency depended on the level of load applied. For short specimens (length = 5 mm, diameter = 8 mm) tested without gluing, however, the frequency dependence of loss tangent agreed with existing data reported for the strain‐rate‐dependent behavior of cancellous bone and also with the frequency dependence of cortical bone viscoelasticity. Therefore, we recommend that short cancellous bone cylinders with a length of 5 mm and a diameter of 8 mm should be used without gluing in the dynamic mechanical analysis of cancellous bone. This is consistent with the American Society for Testing and Materials testing recommendations for plastics, but different from current practice for unimodal mechanical testing of cancellous bone. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 573–583, 2004
Trochophora larvae: Cell‐lineages, ciliary bands, and body regions. 1. Annelida and Mollusca
Authors: Nielsen Claus 
Published: January 2004

AbstractThe trochophora concept and the literature on cleavage patterns and differentiation of ectodermal structures in annelids (“polychaetes”) and molluscs are reviewed. The early development shows some variation within both phyla, and the cephalopods have a highly modified development. Nevertheless, there are conspicuous similarities between the early development of the two phyla, related to the highly conserved spiral cleavage pattern. Apical and cerebral ganglia have almost identical origin in the two phyla, and the cell‐lineage of the prototroch is identical, except for minor variations between species. The cell‐lineage of the metatrochs is almost unknown, but the telotroch of annelids and the “telotroch” of the gastropod Patella originate from the 2d‐cell, as does the gastrotroch in the few species which have been studied. The segmented annelid body, i.e. the region behind the peristome, develops through addition of new ectoderm from a ring of 2d‐cells just in front of the telotroch. This whole region is thus derived from 2d‐cells. Conversely, the mollusc body is covered by descendants of cells from both the C and D quadrants and a growth zone is not apparent. This supports the notion that the molluscs are not segmented like the annelids, and that the repeated structures seen in polyplacophorans and monplacophorans do not represent a segmentation homologous to that of the annelids. J. Exp. Zool. (Mol. Dev. Evol.) 302B: 35–68, 2004. © 2004 Wiley‐Liss, Inc.
Evo‐Devo aspects of classical and molecular data in a historical perspective
Authors: Sander Klaus , Schmidt‐Ott Urs 
Published: January 2004

AbstractWe discuss the interplay between evolution and development as reflected in data and concepts since about 1800. Darwin and his “continental apostle” Haeckel put the striking similarity between early vertebrate embryos in an evolutionary context. Haeckel's partly illicit generalizations discredited evolutionary thinking among early experimental embryologists who moreover noted riddles incompatible with contemporary concepts of homology and evolution. Relevant solutions were suggested by the more recent concept of ontogenetic networks that embody complex regulatory properties and genes with partly overlapping functions. Molecular data on development increasingly reveal evolutionary opportunism, for instance when a widespread signaling chain involved in primitive immune defense was apparently recruited later on for dorso‐ventral axis determination in some evolutionarily advanced insect groups. Recently, Rickettsia‐related bacteria colonizing many arthropod species were found to “manipulate” the first steps of host development to the advantage of their own propagation, but by ways that could also promote host speciation. Molecular genetics can now document evolutionary steps in ontogenetic networks. In the fruit fly for instance, the novel bicoid gene has superseded a crucial patterning function within a pre‐existing network—a case of “molecular caenogenesis.” The expression patterns of conserved genes that antagonistically determine dorso‐ventral polarity support a literal revolution envisioned almost 200 years ago. This is the dorso‐ventral inversion of the body plan in some metazoans—ascribed then to the Articulata, now to the Chordata. The final section posits that the opportunistic character of evolutionary innovations is detrimental to parsimony in development. J. Exp. Zool. (Mol. Dev. Evol.) 302B:69–91, 2004. © 2004 Wiley‐Liss, Inc.
Rupert riedl and the re‐synthesis of evolutionary and developmental biology: Body plans and evolvability
Authors: Wagner Günter P. , Laubichler Manfred D. 
Published: January 2004

AbstractThis paper reviews the scientific career of Rupert Riedl and his contributions to evolutionary biology. Rupert Riedl, a native of Vienna, Austria, began his career as a marine biologist who made important contributions to the systematics and anatomy of major invertebrate groups, as well as to marine ecology. When he assumed a professorship at the University of North Carolina in 1968, the predominant thinking in evolutionary biology focused on population genetics, to the virtual exclusion of most of the rest of biology. In this atmosphere Riedl developed his “systems theory” of evolution, which emphasizes the role of functional and developmental integration in limiting and enabling adaptive evolution by natural selection. The main objective of this theory is to account for the observed patterns of morphological evolution, such as the conservation of body plans. In contrast to other “alternative” theories of evolution, Riedl never denied the importance of natural selection as the driving force of evolution, but thought it necessary to contextualize natural selection with the organismal boundary conditions of adaptation. In Riedl's view development is the most important factor besides natural selection in shaping the pattern and processes of morphological evolution. J. Exp. Zool. (Mol. Dev. Evol.) 302B: 92‐104, 2004. © 2004 Wiley‐Liss, Inc.
Solid‐state glycation of β‐lactoglobulin by lactose and galactose: localization of the modified amino acids using mass spectrometric techniques
Authors: Fenaille François , Morgan François , Parisod Véronique , Tabet Jean‐Claude , Guy Philippe A. 
Published: January 2004

AbstractThe Maillard reaction is commonly encountered during food processing or storage, and also in human nutrition, hence there is a need for analytical methodologies to identify and characterize the modified proteins. This paper reports specific methods using mass spectrometric techniques to localize protein modifications induced by lactose and galactose on β‐lactoglobulin (β‐Lg) under solid‐state glycation conditions. The extent of glycation was first determined by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI‐MS). The specific identification of lactose‐modified amino acid residues was realized using both NanoESI‐MS, NanoESI‐MS/MS (neutral loss scanning modes) and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) (with and without guanidination of lysine residues) on unfractionated digests. The results indicated that, after 8.25 h of incubation, the lysine residues were the main targets of lactose‐induced modification. In addition to the 15 lysine residues, Leu1 (NH2 terminal) and the Arg124 were also found to be modified, thus leading to a total of 17 different modified amino acid residues (versus 15 found by LC/ESI‐MS measurement). In a second set of experiments, different strategies consisting of constant neutral loss and precursor ion scanning were compared to characterize galactose‐induced modifications. Owing to the high level of β‐Lg glycation, the combined use of these different strategies appeared to be necessary for determining the galactose‐modified sites after 8.25 h of incubation. Thus, among the 22 galactose adducts deduced from the LC/ESI‐MS measurement, apart from the N‐terminal and classical lysine residues, we also observed a few arginine residues (Arg40, Arg124 and Arg148) that were modified, and also dialkylations on specific lysine residues (Lys47, Lys75). Copyright © 2003 John Wiley & Sons, Ltd.
Qualitative study of in vivo melphalan adduct formation in the rat by miniaturized column‐switching liquid chromatography coupled with electrospray mass spectrometry
Authors: Van den Driessche Bart , Lemière Filip , Van Dongen Walter , Van der Linden Annemie , Esmans Eddy L. 
Published: January 2004

AbstractIn a general study of DNA adduct formation with melphalan, rats were intravenously injected with a single high dose (10 mg kg−1). Adduct formation was studied at the nucleoside level in the target organs liver, bone marrow, kidney and blood with the use of 2D liquid chromatography/tandem mass spectrometry (LC/MS/MS). Adducts of dGuo and dAdo were detected under selected reaction monitoring in liver and bone marrow 10 h after administration of melphalan. In the DNA hydrolysates from kidney and blood a Gua–melphalan adduct was found, although in very low abundance. These first results of the search for in vivo‐formed melphalan adducts in the rat showed that our miniaturized LC/MS technique is useful for investigating this type of compound. More experiments will be performed in this area to gather more information about the pharmacokinetics and the quantity of adducts formed. Copyright © 2003 John Wiley & Sons, Ltd.
Measurement of the malondialdehyde–2′‐deoxyguanosine adduct in human urine by immuno‐extraction and liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry
Authors: Hoberg Anne‐Mette , Otteneder Michael , Marnett Lawrence J. , Poulsen Henrik E. 
Published: January 2004

AbstractThe major adduct of malondialdehyde with guanine, M1G, was measured in human urine from non‐smoking healthy individuals. M1G is a mutagenic DNA lesion and a terminal product of lipid peroxidation in vivo that may be implicated in cancer related to lifestyle and diet. On the basis of a recently developed method for the quantification of M1G as an excreted deoxynucleoside using immuno‐extraction purification, chemical NaBH4 reduction and liquid chromatography combined with atmospheric pressure chemical ionization tandem mass spectrometry, we demonstrate that the average 24 h excretion rate of M1G‐dR is about 12 ± 3.8 fmol kg−1 (n = 5). Copyright © 2004 John Wiley & Sons, Ltd.
Effects of ion‐pairing reagents on the electrospray signal suppression of sulphonated dyes and intermediates
Authors: Holčapek M. , Volná K. , Jandera P. , Kolářová L. , Lemr K. , Exner M. , Církva A. 
Published: January 2004

AbstractHigh‐performance liquid chromatography/mass spectrometry (HPLC/MS) analysis of anionic species such as sulphonic acid dyes and intermediates requires volatile ion‐pairing mobile phase additives. Six di‐ and trialkylammonium acetates were compared with tetraalkylammonium salts and ammonium acetate in the concentration range 0–20 mmol l−1 as mobile phase additives for HPLC/MS of polysulphonated compounds. The effects of the structure and concentration of the ion‐pairing reagents on the electrospray response of mono‐, di‐ and tetrasulphonic aromatic acids and acid dyes were studied in detail. Further, five different mass analysers and instrument geometries were compared. A higher signal decrease is observed with linear geometry instruments in comparison to orthogonal or even Z‐spray geometry mass spectrometers. The concentration of mobile phase additives has a significant influence on the abundance ratios of multiply charged ions in the mass spectra of polysulphonated compounds. The competing ions of sulphonic acids may also cause significant signal suppression. Copyright © 2004 John Wiley & Sons, Ltd.
Identification of chlorinated fatty acids in fish by gas chromatography/mass spectrometry with negative ion chemical ionization of pentafluorobenzyl esters
Authors: Zhuang Wenshan , McKague A. Bruce , Reeve Douglas W. , Carey John H. 
Published: January 2004

AbstractThis paper reports the development of a technique for identifying and confirming chlorinated fatty acids previously detected in fish by gas chromatography (GC) with halogen‐specific detection (XSD). Fatty acid methyl esters (FAMEs) including chlorinated FAMEs within fractions of reversed‐phase high‐performance liquid chromatography of transesterified fish extracts were derivatized to pentafluorobenzyl esters, which were subjected to GC/mass spectrometry (MS) with negative ion chemical ionization (NICI). Pentafluorobenzyl esters displayed reasonably good GC characteristics, a very high ionization efficiency and a low degree of fragmentation. Chloride ion chromatograms extracted at m/z 35 and 37 from full scans were utilized for locating traces of chlorinated unknowns in the GC elution profile so that their mass spectra could be readily displayed. Significant ions displayed in the mass spectrum scanned in a narrow range of retention time where a chlorinated unknown was located were evaluated using ion chromatograms extracted at the m/z of these ions. The chromatographic peaks of those ions derived from the analyte were expected to center at that specific retention time, whereas those originating from matrix compounds were not. The isotopic patterns of chlorinated ions were also examined against their theoretical relative abundances. Using this approach, three metabolism‐related dichloro fatty acids previously identified by GC/XSD in filet extracts of white sucker sampled downstream from a bleached kraft pulp mill were confirmed: dichlorooctadecanoic, dichlorohexadecanoic and dichlorotetradecanoic acids. In addition, an isomer of dichlorotetradecanoic acid was found in a reference fish sample. As sample preparation is critical in this application, improved conditions for hydrolysis and pentafluorobenzyl esterification are also discussed Copyright © 2003 John Wiley & Sons, Ltd.
Identification and assay of wild‐type and modified nucleoside mixtures by turbo ionspray ionization tandem mass spectrometry
Authors: Benincasa Cinzia , Maiuolo Loredana , Mazzotti Fabio , Perri Enzo , Sindona Giovanni , Urso Elena 
Published: January 2004

AbstractA method is presented which allows the identification and assay of a nucleoside in the presence of other analogues and homologues. The method is based on the conventional multiple reaction monitoring approach performed on the [M + H]+ ions of wild‐type and modified nucleosides produced by the turbo ionspray ionization method on a triple‐quadrupole mass spectrometer. The accuracy of the quantitative determination relies on the evaluation of a response factor ρ, which takes into account the kinetics of dissociation of the parent ions into the protonated [B + 2H]+ nucleobase ions. The evaluation of the absolute concentration of each analyte in the examined mixture does not require any previous chromatographic separation. Copyright © 2003 John Wiley & Sons, Ltd.
Structural studies of the allelic wheat glutenin subunits 1Bx7 and 1Bx20 by matrix‐assisted laser desorption/ionization mass spectrometry and high‐performance liquid chromatography/electrospray ionization mass spectrometry
Authors: Cunsolo Vincenzo , Foti Salvatore , Saletti Rosaria , Gilbert Simon , Tatham Arthur S. , Shewry Peter R. 
Published: January 2004

AbstractStructural studies of the high molecular mass (HMM) glutenin subunits 1Bx7 (from cvs Hereward and Galatea) and 1Bx20 (from cv. Bidi17) of bread wheat were conducted using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) and reversed‐phase high‐performance liquid chromatography/electrospray ionization mass spectrometry (RP‐HPLC/ESI‐MS). For all three proteins, MALDI‐TOFMS analysis showed that the isolated fractions contained a second component with a mass about 650 Da lower than the major component. The testing and correction of the gene‐derived amino acid sequences of the three proteins were performed by direct MALDI‐TOFMS analysis of their tryptic peptide mixture. Analysis of the digest was performed by recording several MALDI mass spectra of the mixture at low, medium and high mass ranges, optimizing the matrix and the acquisition parameters for each mass range. Complementary data were obtained by RP‐HPLC/ESI‐MS analysis of the tryptic digest. This resulted in coverage of about 98% of the sequences. In contrast to the gene‐derived data, the results obtained demonstrate the insertion of the sequence QPGQGQ between Trp716 and Gln717 of subunit 1Bx7 (cv. Galatea) and a possible single amino acid substitution within the T20 peptide of subunit 1Bx20. Moreover, the mass spectrometric data demonstrated that the lower mass components present in all the fractions correspond to the major components but lack about six amino acid residues, which are probably lost from the protein C‐terminus. Finally, the results obtained provide evidence for the lack of glycosylation or other post‐translational modifications of these subunits. Copyright © 2004 John Wiley & Sons, Ltd.