bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative analysis of laccase‐isozymes patterns of several related Polyporaceae species under different culture conditions
Authors: AranaCuenca Ainhoa , Roda Arantxa , Téllez Alejandro , Loera Octavio , Carbajo José M. , Terrón María C. , González Aldo E. 
Published: April 2004

AbstractThe study of isozymes has to date been successfully applied in the identification of a number of different microorganisms, particularly fungi. Trametes sp. I‐62 (CECT20197) is a white‐rot fungus with potential biotechnological applications. It has been identified as Trametes on the basis of the mycelium morphology, but the features observed are not sufficient for its classification at the species level. Given that this strain produces a very characteristic laccase isozyme pattern, in the present work we compared its isozyme profile with the profiles produced by ten other very closely phylogenetically related fungi from the Polyporaceae family. The data indicates that Trametes sp. I‐62 could not be included in any of the taxonomically related species which were analysed in the present work. Extracellular laccases were detected in nine of the fungi studied and in four of them namely Trametes subectypus, Trametes pavonia, Trametes ochracea and Trametes gallica, this is the first report of such activity. Given that phylogenetically related fungi growing in the same culture conditions exhibit different laccase patterns, these isozymes could be used as an additional criterion for fungal identification. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dimensionality estimate of the manifold in chemical composition space for a turbulent premixed H2 + air flame
Authors: Tonse Shaheen R. , Brown Nancy J. 
Published: April 2004

AbstractThe dimensionality (${\cal D}$) of manifolds of active chemical composition space has been measured using three different approaches: the Hausdorff geometrical binning method, Principal Component Analysis, and the Grassberger‐Procaccia cumulative distribution method. A series of artificial manifolds is also generated using a Monte Carlo approach to discern the advantages and limitations of the three methods. Dimensionality is quantified for different levels of turbulent intensity in a simulation of the interactions of a 2D premixed hydrogen flame with a localized region of turbulence superimposed over the cold region upstream of the flame front. The simulations are conducted using an adaptive mesh refinement code for low Mach number reacting flows. By treating the Ns species and temperature of the local thermo‐chemical state as a point in multidimensional chemical composition space, a snapshot of a flame region is mapped into chemical composition space to generate the manifold associated with the 2‐D flame system. An increase in ${\cal D}$ was observed with increasing turbulent intensity for all three methods. Although each method provides useful information, the Grassberger‐Procaccia method is subject to fewer artifacts than the other two thereby providing the most reliable quantification of ${\cal D}$. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 326–336, 2004
Cover Picture: Macromol. Rapid Commun. 7/2004
Authors: Maupin Paul H. , Gilman Jeffrey W. , Harris Richard H. , Bellayer Severine , Bur Anthony J. , Roth Steven C. , Murariu Marius , Morgan Alexander B. , Harris Joseph D. 
Published: April 2004

Cover: The pictures show melt processed polyamide‐6 nanocomposites at 1 min (left) and 7 min (right) processing. The structure on the right is of Nile Blue A. Below each is the respective TEM of the nanocomposites and the graph at the bottom illustrates their fluorescence spectra.Further details can be found in the Communication by P. H. Maupin,* J. W. Gilman, R. H. Harris, Jr., S. Bellayer, A. J. Bur, S. C. Roth, M. Murariu, A. B. Morgan, and J. D. Harris on page 788.
Comparison of different methods for the preparation of porous bone substitution materials and structural investigations by synchrotron μ‐computer tomography
Authors: Tadic D. , Beckmann F. , Donath T. , Epple M. 
Published: April 2004

AbstractThe preparation of porous biomaterials for bone substitution is an important clinical issue in current biomedical technology because the ingrowth of bone can only occur if a suitable number of sufficiently large pores is available. Different procedures are compared here: The combined chemical‐thermal treatment of bovine and human cancellous bone, the calcination of bovine cancellous bone, mechanical hole‐drilling, and the extraction of porogens (in this case: salt crystals). The inner structure and the porosity of all samples were studied using high‐resolution synchrotron μ‐computer tomography.
Functional Materials for Bone Regeneration from Beta‐Tricalcium Phosphate
Authors: Peters F. , Reif D. 
Published: April 2004

AbstractBiodegradable ceramics of β‐tricalcium phosphate (β‐TCP, Ca3(PO4)2) are widely used as bone regeneration materials. The goal is a complete regeneration of the bony defect (restitutio ad integrum = full recovery). Different bioceramics made of β‐TCP show fundamental differences in terms of phase purity, primary particle size, stability, porosity, solubility and therefore biodegradation of the material.Cerasorb® is a bioceramic consisting of phase pure β‐TCP. The primary particle size in connection with a stable sinter structure forms a porous biomaterial which is optimised in the functional surface, porosity and resorption/degradation behaviour. Different forms of Cerasorb® are available: granular materials with high and low porosity optimised for specific indications as well as block forms shapeable by the surgeon for various bony defects.
Individuelle Implantate aus biodegradierbarem Kompositmaterial zur Versorgung von Schädeldefekten
Authors: Weihe S. , Rasche C. , Schiller C. , Wehmöller M. , Böckmann R. , Eufinger H. , Epple M. 
Published: April 2004

AbstractTitan ist ein etabliertes Knochenersatzmaterial für die Versorgung komplexer Schädeldefekte mittels individuell geplanter CAD/CAM‐Implantate. Zur Verbesserung der durch Patientenkontrollstudien evaluierten thermischen und psychischen Belastungsfaktoren wurde in der vorliegenden Studie ein gradiertes Kompositmaterial aus Polymeren und Calciumphosphat bzw. Calciumcarbonat entwickelt. Biokompatibilitätsuntersuchungen auf Basis des ISO‐Standards 10993‐5 erlaubten zunächst die Auswahl geeigneter Materialien sowie nachfolgend die Feststellung der verbesserten pH‐Charakteristika der Kompositmaterialien gegenüber den reinen Polymeren. Für die geometrisch korrekte Herstellung der Implantate aus Kompositmaterialien wurden zwei unterschiedliche Verarbeitungsmethoden gewählt und kombiniert. Diese Implantate konnten bereits durch in‐vivo Versuche an einem eigens entwickelten Großtiermodell getestet werden und zeigten post mortem bei einem Nachbeobachtungszeitraum von zwei Monaten keine histologischen Reaktionen außerhalb der Norm und eine beginnende Knochenbildung. Klinisch ergaben sich bei den lebenden Schafen auch nach einem Zeitraum von bisher 11 Monaten keinerlei Komplikationen.
Verbesserung der knöchernen Integration von Schanz’ Schrauben durch eine Poly(D,L‐laktid) Beschichtung
Authors: Duda G. N. , Partale K. , Klein P. , Schell H. , Schiller R. A. , Wildemann B. , Schmidmaier G. , Bail H. 
Published: April 2004

AbstractSchraubenkanal‐Infektionen und Schraubenlockerungen sind wesentliche Komplikationen bei der Fixateur externe‐Osteosynthese. In dieser Studie wurde der Einfluss einer Poly(D,L‐laktid)‐Beschichtung auf die ossäre Integration der Schrauben während der Frakturversorgung analysiert.An 16 Schafen wurden Osteotomien der rechten Tibia mit einem monolateralen Fixateur externe stabilisiert. Zusätzlich wurden mechanisch unbelastete Schanz' Schrauben eingebracht. Die Hälfte der implantierten Schrauben wurde mit Poly(D,L‐laktid) beschichtet. Nach neun Wochen wurden die Schrauben entnommen, auf Blutagar‐Platten ausgerollt und mikrobiologisch untersucht. Es erfolgte die histologische Aufarbeitung der Pintrakts und eine anschließende histochemische und histomorphometrische Analyse. Obwohl klinisch keine Anzeichen für Infektionen beobachtet wurden, zeigte die mikrobiologische Bewertung bei 15 % der beschichteten Schrauben versus 29 % der unbeschichteten Schrauben eine Kontamination durch Staphylococcus aureus. Die histologische Auswertung zeigte, dass beschichtete Schrauben eine bessere Osteointegrität (p=0,0006) als unbeschichtete Implantate aufwiesen. In der Histomorphometrie wurde in der Gruppe der unbeschichteten Schrauben ein höheres knöchernes Remodeling (p = 0,006) und eine höhere Osteoklastenaktivität (p = 0,019) festgestellt. Belastete Schrauben zeigten mehr Kallus am Schraubenaustritt (p = 0,048). Eine Poly(D,L‐laktid)‐Beschichtung bei Schanz' Schrauben scheint die ossäre Integration durch eine Verminderung des kortikalen Remodelings und der Osteoklastenaktivität zu verbessern.
Defining hormone replacement therapy in longitudinal studies: impact on measures of effect
Authors: Csizmadi Ilona , Collet Jean‐Paul , Benedetti Andrea , Boivin Jean‐François , Hanley James A. 
Published: April 2004

AbstractData from a nested case‐control study, designed to examine the effect of hormone replacement therapy (HRT) on colorectal cancer risk, were analyzed to determine the effect of exposure definition on the estimation of risk ratios (RR). A prescription drug plan database was used to ascertain HRT prescriptions dispensed prior to index dates to cases (n = 3059) and age‐matched controls (n = 12 116). HRT exposure was defined as ‘prescription’ and ‘tablet’ counts, ‘conjugated estrogen only’ and a method based on proportions of minimum exposure to a number of estrogens (SUM‐P3 and SUM‐P12). The effect of HRT was described with reference to ‘ever’, < 5 and ≥ 5 years of HRT use. Conditional logistic regression was used to estimate ORs and 95% confidence intervals (CI). Adjusted ORs for ‘ever use’ of HRT ranged from 0.72 (95%CI: 0.60–0.88) to 0.86 (95%CI: 0.76–0.99); for <5 years use, from 0.70 (95%CI: 0.56–0.88) to 0.89 (95%CI: 0.78–1.01) and for ≥5 year of HRT use, from 0.74 (95%CI: 0.59–0.92) to 0.98 (95%CI: 0.42–2.26). Various methods used to define HRT exposure produce a range of estimated ORs that vary in magnitude similar to results reported in the literature from observational studies investigating the association between HRT and colorectal cancer. Copyright © 2003 John Wiley & Sons, Ltd.
What is prescription labeling communicating to doctors about hepatotoxic drugs? A study of FDA approved product labeling
Authors: Willy Mary E. , Li Zili 
Published: April 2004

AbstractPurposeThe objective of this study was to evaluate the informativeness and consistency of product labeling of hepatotoxic drugs marketed in the United States.MethodsWe searched the Physicians' Desk Reference—2000 for prescription drugs with hepatic failure and/or hepatic necrosis listed in the labeling. We used a six‐item checklist to evaluate the ‘informativeness’ and consistency of the labeling content. An informativeness score equaled the proportion of checklist items present in each drug's labeling.ResultsNinety‐five prescription drugs were included in the study. Eleven (12%) of the drugs had information related to hepatic failure in a Black Boxed Warning, 52 (54%) in the Warnings section and 32 (34%) in the Adverse Reactions section of the label. The mean informativeness score was 35%; the score was significantly higher, 61%, when the risk was perceived to be high. The informativeness of labeling was not affected by the time of the labeling, but differed across the Center for Drug Evaluation and Research (CDER) Review Division responsible for the labeling.ConclusionsThe information provided in labeling is variable and affected by many factors, including the perceived level of risk and review division strategy. Product labeling may benefit from current FDA initiatives to improve the consistency of risk‐related labeling. Published in 2003 by John Wiley & Sons, Ltd.
Protein secondary structure assignment through Voronoï tessellation
Authors: Dupuis Franck , Sadoc Jean‐François , Mornon Jean‐Paul 
Published: April 2004

AbstractWe present a new automatic algorithm, named VoTAP (Voronoï Tessellation Assignment Procedure), which assigns secondary structures of a polypeptide chain using the list of α‐carbon coordinates. This program uses three‐dimensional Voronoï tessellation. This geometrical tool associates with each amino acid a Voronoï polyhedron, the faces of which unambiguously define contacts between residues. Thanks to the face area, for the contacts close together along the primary structure (low‐order contacts) a distinction is made between strong and normal ones. This new definition yields new contact matrices, which are analyzed and used to assign secondary structures. This assignment is performed in two stages. The first one uses contacts between residues close together along the primary structure and is based on data collected on a bank of 282 well‐refined nonredundant structures. In this bank, associations were made between the prints defined by these low‐order contacts and the assignments performed by different automatic methods. The second step focuses on the strand assignment and uses contacts between distant residues. Comparison with several other automatic assignment methods are presented, and the influence of resolution on the assignment is investigated. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Crystal structure of a putative aspartate aminotransferase belonging to subgroup IV
Authors: Katsura Yasuhiro , Shirouzu Mikako , Yamaguchi Hiroto , Ishitani Ryuichiro , Nureki Osamu , Kuramitsu Seiki , Hayashi Hideyuki , Yokoyama Shigeyuki 
Published: April 2004

AbstractProtein TT0402 from Thermus thermophilus HB8 exhibits about 30–35% sequence identity with proteins belonging to subgroup IV in the aminotransferase family of the fold‐type I pyridoxal 5′‐phosphate (PLP)‐dependent enzymes. In this study, we determined the crystal structure of TT0402 at 2.3 Å resolution (Rfactor = 19.9%, Rfree = 23.6%). The overall structure of TT0402 exhibits the fold conserved in aminotransferases, and is most similar to that of the Escherichia coli phosphoserine aminotransferase, which belongs to subgroup IV but shares as little as 13% sequence identity with TT0402. Kinetic assays confirmed that TT0402 has higher transamination activities with the amino group donor, L‐glutamate, and somewhat lower activities with L‐aspartate. These results indicate that TT0402 is a subgroup IV aminotransferase for the synthesis/degradation of either L‐aspartate or a similar compound. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Unfolded state of polyalanine is a segmented polyproline II helix
Authors: Kentsis Alex , Mezei Mihaly , Gindin Tatyana , Osman Roman 
Published: April 2004

AbstractDefinition of the unfolded state of proteins is essential for understanding their stability and folding on biological timescales. Here, we find that under near physiological conditions the configurational ensemble of the unfolded state of the simplest protein structure, polyalanine α‐helix, cannot be described by the commonly used Flory random coil model, in which configurational probabilities are derived from conformational preferences of individual residues. We utilize novel effectively ergodic sampling algorithms in the presence of explicit aqueous solvation, and observe water‐mediated formation of polyproline II helical (PII) structure in the natively unfolded state of polyalanine, and its facilitation of α‐helix formation in longer peptides. The segmented PII helical coil preorganizes the unfolded state ensemble for folding pathway entry by reducing the conformational space available to the diffusive search. Thus, as much as half of the folding search in polyalanine is accomplished by preorganization of the unfolded state. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Folding of β/α‐unit scrambled forms of S. cerevisiae triosephosphate isomerase: Evidence for autonomy of substructure formation and plasticity of hydrophobic and hydrogen bonding interactions in core of (β/α)8‐barrel
Authors: Shukla Anshuman , Guptasarma Purnananda 
Published: April 2004

AbstractThe (β/α)8‐barrel domain consists of eight topologically equivalent supersecondary structural motifs known as β/α‐units. Each unit consists of a single β‐strand, an α‐helix, and two loops. Evidence collected in recent years indicates that the (β/α)8‐barrel motif may not be a single, autonomously‐folding domain, as was previously assumed. Segments of some (β/α)8‐barrels appear to fold autonomously. However, the extent to which this is true of various (β/α)8‐barrel domains remains to be explored. In this study, we have scrambled (reshuffled) the native order of β/α‐units (1‐2‐3‐4‐5‐6‐7‐8) comprising the polypeptide chain of a model (β/α)8‐barrel from S. cerevisiae, triosephosphate isomerase (TIM). Total scrambling was effected in order to examine whether folding can still occur to yield β/α‐structures in spite of a global ‘destruction’ of native hydrophobic and hydrogen bonding interactions among β/α‐units, while still allowing the occurrence of native interactions within individual units. Our results demonstrate that scrambled full‐barrel forms (2‐4‐6‐8‐1‐3‐5‐7 and 1‐3‐5‐7‐2‐4‐6‐8), as well as half‐barrel (2‐4‐6‐8) and quarter‐barrel (1‐3) forms of TIM fold into β/α‐structures that sustain tertiary and quaternary structural interactions. In particular, one variant (2‐4‐6‐8‐1‐3‐5‐7) was found to fold and form a stable dimer with native‐like structural content and other characteristics. Our results demonstrate that (β/α)8‐barrels can tolerate profound alterations of both strand–strand interactions responsible for the creation of the β‐barrel and the geometry of presentation of nonpolar sidechains into the hydrophobic core of the β‐barrel by individual β‐strands. These findings lend support to our recent proposal1 that a hierarchy of interactions probably regulates structure formation and stability in (β/α)8‐barrels, where folding proceeds successively through three stages: (i) the tentative formation of individual β/α‐units which associate through ‘near‐neighbor’ diffusion‐collision interactions into (ii) curved assemblies of multiple β/α‐units through sequence‐independent hydrogen bonding of strands of neighboring units, leading finally to (iii) the association of curved (quarter/half‐barrel) assemblies around a common hydrophobic core through packing interactions that remain plastic and amenable to change. Proteins 2004. © 2004 Wiley‐Liss, Inc.
CHOP proteins into structural domain‐like fragments
Authors: Liu Jinfeng , Rost Burkhard 
Published: April 2004

AbstractWe developed a method CHOP dissecting proteins into domain‐like fragments. The basic idea was to cut proteins beginning from very reliable experimental information (PDB), proceeding to expert annotations of domain‐like regions (Pfam‐A), and completing through cuts based on termini of known proteins. In this way, CHOP dissected more than two thirds of all proteins from 62 proteomes. Analysis of our structural domain‐like fragments revealed four surprising results. First, >70% of all dissected proteins contained more than one fragment. Second, most domains spanned on average over ∼100 residues. This average was similar for eukaryotic and prokaryotic proteins, and it is also valid—although previously not described—for all proteins in the PDB. Third, single‐domain proteins were significant longer than most domains in multidomain proteins. Fourth, three fourths of all domains appeared shorter than 210 residues. We believe that our CHOP fragments constituted an important resource for functional and structural genomics. Nevertheless, our main motivation to develop CHOP was that the single‐linkage clustering method failed to adequately group full‐length proteins. In contrast, CLUP—the simple clustering scheme CLUP introduced here—succeeded largely to group the CHOP fragments from 62 proteomes such that all members of one cluster shared a basic structural core. CLUP found >63,000 multi‐ and >118,000 single‐member clusters. Although most fragments were restricted to a particular cluster, ∼24% of the fragments were duplicated in at least two clusters. Our thresholds for grouping two fragments into the same cluster were rather conservative. Nevertheless, our results suggested that structural genomics initiatives have to target >30,000 fragments to at least cover the multimember clusters in 62 proteomes. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Discovery and characterization of novel oxide anodes for solid oxide fuel cells
Authors: Tao Shanwen , Irvine John T.S. 
Published: April 2004

AbstractThe search for alternative anode materials for solid oxide fuel cells (SOFCs) has been reviewed in the light of structure, stability, conductivity, chemical and thermal compatibility with electrolyte YSZ. In this review, we have presented the advantages and disadvantages of the traditional Ni‐YSZ anode for SOFCs. The development of alternative anode for SOFCs with fluorite, rutile, tungsten bronze, pyrochlore, perovskite and spinel structures has been reviewed and discussed in detail. Among the reported materials systems, materials with perovskite structure are promising particularly where two ions with complimentary function are present on the B‐site at high concentration. We have recently found a good redox stable anode (La0.75Sr0.25)1−xCr0.5Mn0.5O3 (0 ≤ x ≤ 0.1) using this approach. These materials exhibit comparable performance to the traditional Ni‐YSZ anode. Therefore, we can use nickel‐free redox stable anode for SOFCs. With further optimisation of the composition and microstructure, the performance of these materials may be further improved and hopefully replace the traditional Ni‐YSZ anode in the future. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 83–95; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20003
Tunable haptotropic metal migration in fused arenes: towards organometallic switches
Authors: Dötz Karl Heinz , Jahr Holger C. 
Published: April 2004

AbstractTricarbonyl chromium complexes of naphthalene derivatives are synthesized by chromium‐templated [3 + 2 + 1]‐benzannulation and subjected to thermally induced haptotropic rearrangement experiments. Thermodynamic and kinetic parameters for the metal shift demonstrate the influence of the arene substitution pattern. In turn, the chromium template may be tuned as well by phosphorus coligands which allow to accelerate or slow down the isomerization process; this effect quantitatively reflects the steric and electronic properties of the coligand sphere. Proper adjustment of the template allows for a photo‐induced reverse migration of the chromium moiety which results in a switchable organometallic device. Experiments with enantiopure arene chromium complexes indicate a stereospecific metal migration. The rearrangement proceeds by an intramolecular mechanism in both directions. Haptotropic isomerization reactions are not limited to bicyclic arenes and can be extended from naphthalenes to phenanthrene or tetra‐ and pentacyclic heteroarene systems. © 2004 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 61–71; 2004: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20007
Gaseinlasssystem zur massenspektrometrischen Analyse kleiner Gasproben. Gas Inlet System to Analyse Small Gas Samples by a Mass Spectrometer
Authors: Bux R. , Juhnke Ch. , Klein H. H. 
Published: April 2004

AbstractFür die quantitative Analyse kleiner Gasproben (< 1 cm3), die menschlichen Leichen mit einer Injektionsspritze entnommen werden, wurde für ein Quadrupol‐Massenspektrometer ein Gaseinlasssystem entwickelt und gebaut. Mit dem entwickelten Gaseinlasssystem können die Gasproben unverfälscht in Zusammensetzung und Größe in einen Probenraum überführt werden, von wo das Gas durch ein UHV‐Nadelventil direkt in die Ionenquelle des Massenspektrometers einströmt. Nach einer sorgfältigen Kalibrierung des Massenspektrometers bezüglich der interessierenden Probenbestandteile können diese quantitativ mit einer Ungenauigkeit von < 1 % bestimmt werden.