bluuebunny/crossref_metadata_2025 huggingface dataset:
Macrocyclic effect of auxiliary ligand on the gas‐phase dissociation of ternary copper(II)–GGX complexes
Authors: Lam Cory N. W. , Siu S. O. , Orlova Galina , Chu Ivan K.
Published: February 2006

Previous studies into the dissociation of [CuII(dien)peptide].2+ ions (dien = diethylenetriamine) have shown that NH‐containing auxiliary ligands do not favor the formation of [peptide].+ species; instead, they promote proton‐transfer reactions, especially for peptides containing basic amino residues. Formation of radical cationic tripeptides of the form GGX.+ [GGX = glycylglycyl(residue X)] becomes feasible upon substituting the open‐chain tridentate ligand dien with its analogous cyclic ligand, 1,4,7‐triazacyclononane (9‐aneN3); i.e., from [CuII(9‐aneN3)GGX].2+ ions. Similar enhancements occur when using 1,4,7,10‐tetraoxacyclododecane (12‐crown‐4) in place of its open‐chain analog, 2,5,8,11‐tetraoxadecane (triglyme). We have demonstrated that a sterically encumbered auxiliary macrocyclic ligand within [CuII(L)GGX].2+ complex ions [where L = 9‐aneN3 or 12‐crown‐4] facilitates the formation of radical cationic peptides through gas‐phase fragmentation. We verified our experimental observations by examining the reactivities of a series of 19 tripeptides of the type GGX that differ only in the identity of their C‐terminal residue. The energy of the electron‐transfer reaction correlates well with the bond‐dissociation energy of the peptide–Cu(II) interaction; the presence of a constrained macrocyclic ligand weakens metal–peptide chelation through steric repulsion between the ligand and the peptide, and this situation may lead to more favorable radical cationic peptide formation. Copyright © 2006 John Wiley & Sons, Ltd.
A novel 14C‐postlabeling assay using accelerator mass spectrometry for the detection of O6‐methyldeoxy‐guanosine adducts
Authors: Tompkins Elaine M. , Farmer Peter B. , Lamb John H. , Jukes Rebekah , Dingley Karen , Ubick Esther , Turteltaub Kenneth W. , Martin Elizabeth A. , Brown Karen
Published: February 2006

Accelerator mass spectrometry (AMS) is currently one of the most sensitive methods available for the trace detection of DNA adducts and is particularly valuable for measuring adducts in humans or animal models. However, the standard approach requires administration of a radiolabeled compound. As an alternative, we have developed a preliminary 14C‐postlabeling assay for detection of the highly mutagenic O6‐methyldeoxyguanosine (O6‐MedG), by AMS. Procedures were developed for derivatising O6‐MedG using unlabeled acetic anhydride. Using conventional liquid chromatography/mass spectrometry (LC/MS) analysis, the limit of detection (LOD) for the major product, triacetylated O6‐MedG, was 10 fmol. On reaction of O6‐MedG with 14C‐acetic anhydride, using a specially designed enclosed system, the predominant product was 14C‐di‐acetyl O6‐MedG. This change in reaction profile was due to a modification of the reaction procedure, introduced as a necessary safety precaution. The LOD for 14C‐di‐acetyl O6‐MedG by AMS was determined as 79 amol, ∼18 000‐fold lower than that achievable by liquid scintillation counting (LSC). Although the assay has so far only been carried out with labeled standards, the degree of sensitivity obtained illustrates the potential of this assay for measuring O6‐MedG levels in humans. Copyright © 2006 John Wiley & Sons, Ltd.
Development of a liquid chromatography/tandem mass spectrometry method for the simultaneous determination of 16 mycotoxins on cellulose filters and in fungal cultures
Authors: Delmulle B. , De Saeger S. , Adams A. , De Kimpe N. , Van Peteghem C.
Published: February 2006

The development of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the simultaneous determination of 16 mycotoxins possibly related to the ‘Sick Building Syndrome’ on filters and in fungal cultures is described. Fungi‐surface sampling as regards the ‘Sick Building Syndrome’ preferably happens by scraping off fungal material and vacuuming onto cellulose filters. Therefore, these two media were used as samples. They were spiked with nivalenol, deoxynivalenol, zearalenone, diacetoxyscirpenol, T‐2 toxin, verrucarol, verrucarin A, neosolaniol, sterigmatocystin, roridin A, ochratoxin A, aflatoxin B1, aflatoxin B2, aflatoxin G1 and aflatoxin G2, which can be produced by isolates from fungi‐damaged buildings. Deepoxy‐deoxynivalenol was used as internal standard. Samples were extracted with organic solvents and the different mycotoxins were separated by high‐performance liquid chromatography (HPLC) using a C18 reversed‐phase SunFire analytical column and a mobile phase of variable mixtures of ammonium acetate (10 mM) and sodium acetate (20 µM) in water (solvent A) and in methanol (solvent B). The samples were run on‐line with a Micromass Quattro Micro triple quadrupole mass spectrometer in positive electrospray ionisation mode using multiple reaction monitoring (MRM). The detection limits of the procedure varied from 50 to 0.009 pg/µL for filter samples and from 75 to 0.04 pg/µL for fungal culture samples. As the method includes few and non‐labourious sample treatment steps, it should allow for a high throughput of samples. Copyright © 2006 John Wiley & Sons, Ltd.
Fragmentation of the deprotonated ions of peptides containing cysteine, cysteine sulfinic acid, cysteine sulfonic acid, aspartic acid, and glutamic acid
Authors: Men Lijie , Wang Yinsheng
Published: February 2006

We examined the fragmentation of the electrospray‐produced [M–H]− and [M–2H]2− ions of a number of peptides containing two acidic amino acid residues, one being aspartic acid (Asp) or glutamic acid (Glu), and the other being cysteine sulfinic acid [C(SO2H)] or cysteine sulfonic acid [C(SO3H)], on an ion‐trap mass spectrometer. We observed facile neutral losses of H2S and H2SO2 from the side chains of cysteine and C(SO2H), respectively, whereas the corresponding elimination of H2SO3 from the side chain of C(SO3H) was undetectable for most peptides that we investigated. In addition, the collisional activation of the [M–H]− ions of the C(SO2H)‐containing peptides resulted in the cleavage of the amide bond on the C‐terminal side of the C(SO2H) residue. Moreover, collisional activation of the [M–2H]2− ions of the above Asp‐containing peptides led to the cleavage of the backbone N‐Cα bond of the Asp residue to give cn and/or its complementary [zn–H2O] ions. Similar cleavage also occurred for the singly deprotonated ions of the otherwise identical peptides with a C‐terminal amide functionality, but not for the [M–H]− ions of same peptides with a free C‐terminal carboxylic acid. Furthermore, ab initio calculation results for model cleavage reactions are consistent with the selective cleavage of the backbone N–Cα bond in the Asp residue. Copyright © 2006 John Wiley & Sons, Ltd.
H2O‐δD‐FeIII relations of dehydrogenation and dehydration processes in magmatic amphiboles
Authors: Demény Attila , Vennemann Torsten W. , Harangi Szabolcs , Homonnay Zoltán , Fórizs István
Published: February 2006

Stable isotope compositions of a suite of magmatic amphiboles from alkaline basalts and andesitic rocks were examined to constrain the effects of degassing processes on the hydrogen isotope compositions. The Fe3+ (as Fe3+/Fetotal) and H2O contents, as well as the H isotope compositions of the amphiboles, differ markedly (27–58%, 0.5–2.2 wt%, −107 to −15‰, respectively) but indicate systematic variations. The observed trends can be explained either as dehydrogenation or dehydration processes, both of which are coupled to oxidation processes, the latter most probably related to O2− substitution within amphiboles. The dehydrogenation‐dehydration models can be used to assess the primary compositions of the magmas. As an important example, δD values of amphiboles of Martian meteorites are discussed in a similar context. Copyright © 2006 John Wiley & Sons, Ltd.
Electrospray mass spectrometric studies of the complexational behavior of maleonitrile thiacrown ethers with various metals
Authors: Starke Ines , Fürstenberg Sylvia , Müller Holger , Holdt Hans‐Jürgen , Kleinpeter Erich
Published: February 2006

Electrospray ionization was employed to study the mass spectrometric behavior of the maleonitrile tetrathiacrown ethers mn12S4 (1) and mn13S4 (2) and maleonitrile pentathiacrown ether mn15S5 (3) and of their complexes with various metal salts (MX2, M = Pd, Pt, Ni, Co, Fe; X = Cl, CrCl3, Ni(BF4)2, TlPF6 or Cd(NO3)2) and Cu(SO3CF3)2. Both singly charged, [MXL]+ and [MXL2]+, and doubly charged complexes, [MLn]2+ (n = 2–5), were observed. The formation of the different complexes consisting of the transition metal ion, the counterion and the various crown ethers and their subsequent dissociation was also studied by collision‐induced dissociation measurements which were also used to evaluate the relative stabilities of the complexes. It was found that the collisional voltages for the dissociation of the complexes were generally greater in the [MXL]+ complexes than in the corresponding [MXL2]+ complexes. Copyright © 2006 John Wiley & Sons, Ltd.
Stability studies of testosterone and epitestosterone glucuronides in urine
Authors: Jiménez C. , Torre R. de la , Segura J. , Ventura R.
Published: February 2006

The stability of testosterone glucuronide (TG), epitestosterone glucuronide (EG) and the T/E ratio in urine has been studied. Samples were analyzed by gas chromatography coupled to mass spectrometry (GC/MS). Urine samples were submitted to a solid‐liquid cleanup followed by extraction of unconjugated testosterone (T) and epitestosterone (E) with tert‐butyl methyl ether (free fraction). The remaining aqueous phase was hydrolyzed with β‐glucuronidase and extracted at alkaline pH with n‐pentane. Analytes were analyzed by GC/MS as their enol‐trimethylsilyl (TMS) derivatives. The urine for stability testing was obtained from an excretion study after the administration of T to healthy volunteers. The homogeneity of the sample was verified before starting the stability study. The stability of TG and EG was evaluated at different storage conditions. For long‐term stability testing, analyte concentration in urine stored at 4°C and −20°C was determined at different time intervals for 22 months. For short‐term stability testing, analyte concentration was evaluated in urine stored at 37°C for 3 and 7 days. The effect of repeated freezing (at −20°C) and thawing (at room temperature) was studied for up to three cycles. Data obtained in this work demonstrated the stability of TG, EG and the T/E ratio in sterilized urine samples stored at 4 and −20°C for 22 months and after going through repeated freeze/thaw cycles. Decreases in concentration were observed after 7 days of storage at 37°C due to the partial cleavage of the glucuronide conjugates; however, the T/E ratio was not affected. These results show the feasibility of preparing reference materials containing TG and EG to be used for quality control purposes. Copyright © 2006 John Wiley & Sons, Ltd.
Rapid characterization of edible oils by direct matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry analysis using triacylglycerols
Authors: Lay Jackson O. , Liyanage Rohana , Durham Bill , Brooks John
Published: February 2006

Direct matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometric (MALDI‐TOFMS) analysis of solutions of edible fats/oils yielded spectra useful for their rapid differentiation and classification. Results also reflected the individual fatty acid components and their degree of unsaturation. After dissolution in hexane, MALDI‐MS analysis revealed spectra showing characteristic triacylglycerols (TAGs), the main fat/oil components, as sodium adduct ions. The Euclidean distances calculated using the mass and intensity values for 20 TAGs were used to evaluate and compare spectra. With cluster analysis, animal fats grouped together differently than vegetable oils and the individual oils grouped together by type. The ion abundances for the individual TAGs and their presumed compositions were used to approximate the overall fatty acid composition of canola, soybean, corn, olive and peanut oil, as well as lard. Using this approach the calculated fatty acid compositions and degree of unsaturation generally fell within about 4% of literature values. When the degree of saturation was compared with values calculated from the package labeling the differences were about 7%. Copyright © 2006 John Wiley & Sons, Ltd.
A novel discharge source of hydronium ions for proton transfer reaction ionization: design, characterization, and performance
Authors: Inomata Satoshi , Tanimoto Hiroshi , Aoki Nobuyuki , Hirokawa Jun , Sadanaga Yasuhiro
Published: February 2006

A novel ion source based on direct current (d.c.) discharge has been developed for proton transfer reaction ionization operated at relatively high ion drift tube pressure. The shape and geometry of the ion source are designed to maximize overall ion intensity and to minimize interference from sample air. The initial performance of the technique, including speciation and intensity of reagent ions, their stability, and the impact of artifact signals, is evaluated by means of a proton transfer reaction time‐of‐flight mass spectrometer (PTR‐TOFMS) newly built in our laboratory. Intensities of the hydronium (H3O+) ions are typically (5–7) × 105 counts for a 1‐min integration time with a duty cycle of ∼1%. The fluctuations of the ion signals over a period of hours are within 4%. Although the formation of artifact ions from sample air (NO+ and O), which react with volatile organic compounds (VOCs) and subsequently cause fragmentation, is observed as background signals in addition to hydronium and mono‐ and di‐hydrate H3O+ ions, intensities of both NO+ and O ions are only ∼0.5% of those of H3O+ ions. Using our PTR‐TOFMS system at a drift tube pressure of ∼5 Torr, the detection sensitivities are significantly improved and the detection limits for propene, acetaldehyde, acetone, isoprene, benzene, toluene, and p‐xylene are estimated to be at the sub‐ppbv level for 1‐min integration. Copyright © 2006 John Wiley & Sons, Ltd.
Determination of aerobic‐anaerobic metabolism‐related compounds in a Chaoborus flavicans population by infusion ion trap mass spectrometry of extracts of individual larvae
Authors: da Graça Gama Melão Maria , Simó‐Alfonso Ernesto , Ramis‐Ramos Guillermo , Vicente Eduardo
Published: February 2006

In a daily migration, the aquatic larvae of Chaoborus flavicans (a phantom midge) alternate oxygen‐saturated and anoxic lake strata. To investigate this cycle, larvae were collected at a natural environment, and acetate, propionate, pyruvate, lactate, glycerol, phosphate, maleate, succinate, glucose and citrate were determined. Each larva was homogenized with 200 µL water and deproteinized with a spin‐filter; 50 µL aliquots were mixed with 50 µL of a buffer containing 80 mM propylamine, 20 mM HCl and 0.06 mM 2,4‐dihydroxybenzoic acid (internal standard) in methanol. The extracts were infused in an electrospray ionization ion‐trap mass spectrometer. The limits of detection for the [M–H]− peaks ranged from 2 µM for pyruvate and lactate to 200 µM for acetate and glycerol. The MS2 ion‐trap spectra obtained at pH 7 (ammonium acetate buffer) were used to distinguish maleate (cis‐2‐butenedioic), which gave [M–CO2–H]− (m/z 71), from fumarate (trans‐2‐butenedioic), which showed first a loss of water yielding an instable peak at m/z 97. The compounds involved in the aerobic‐anaerobic adjustment of the metabolism were revealed by linear discriminant analysis. Acetate, citrate, glucose, maleate (which decreased during the daytime), and particularly succinate (which increased), showed the maximal discrimination power between the day‐ and night‐time samples. Copyright © 2006 John Wiley & Sons, Ltd.
Science students' critical examination of scientific information related to socioscientific issues
Authors: Kolstø Stein Dankert , Bungum Berit , Arnesen Erik , Isnes Anders , Kristensen Terje , Mathiassen Ketil , Mestad Idar , Quale Andreas , Tonning Anne Sissel Vedvik , Ulvik Marit
Published: February 2006

It is widely accepted that to be scientifically literate one needs to have the ability to make thoughtful decisions about socioscientific issues (SSI). This includes critical assessment of scientific claims and arguments involved. In this study we asked 89 science education students with substantial academic qualifications in science, working in groups of two and three, to assess the reliability of scientific claims in an article of their own choice, but related to a socioscientific issue, and to present their evaluation in a short text. In analyzing the students' texts, we focused on the criteria they had explicitly and implicitly used in their evaluations. Through a qualitative analysis, we identified 13 different criteria focusing on empirical and theoretical adequacy, completeness of presented information, social aspects, and manipulative strategies. An inspection of the students' evaluations revealed that they drew upon knowledge of possible institutional interests, different signs of competence and an appreciation of concurrent expert views, but also methodological norms in science, specialized content knowledge, and an appreciation of evidence and disclosure of sources. The number of criteria used and the quality of their application varied, indicating that critical examination of texts with a science dimension needs to be emphasized in science teacher education. © 2006 Wiley Periodicals, Inc. Sci Ed 90:632–655, 2006
Metal enolates of α‐CF3 ketones: theoretical guideline, direct generation, and synthetic use
Authors: Mikami Koichi , Itoh Yoshimitsu
Published: February 2006

The difficulty as well as the significance of the direct generation of metal enolates of α‐CF3 ketones cannot be easily understood by chemists unfamiliar with F. In sharp contrast to the sunny side of non‐F, hydrocarbon chemistry, F chemistry has long been overshadowed. Metal enolates of carbonyl compounds are synthetically important in CC bond‐forming reactions. However, the metal enolates of fluorinated carbonyl compounds have been severely limited to α‐F metal enolates. α‐CF3 metal enolates have generally been recognized as unstable and difficult to prepare because of the facile β‐M–F elimination. However, we have developed a direct generation and synthetic application of α‐CF3 metal enolates. Therefore, the present results regarding the direct generation and synthetic use of metal enolates of α‐CF3 ketones might be recognized as a real breakthrough for the general use of metal enolates in F chemistry. © 2006 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 6: 1–11; 2006: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20066
Controlling the regiochemistry of radical cyclizations
Authors: Ishibashi Hiroyuki
Published: February 2006

This review describes the results of our recent studies on the control of the regiochemistry of radical cyclizations. N‐vinylic α‐chloroacetamides generally cyclized in a 5‐endo‐trig manner to give five‐membered lactams, whereas 4‐exo‐trig cyclization occurred when the cyclized radical intermediates were highly stabilized by an adjacent phenyl or phenylthio group to afford β‐lactams. The 5‐exo or 6‐exo cyclization of aryl radicals onto the alkenic bond of enamides could be shifted to the corresponding 6‐endo or 7‐endo mode of cyclization by a positional change of the carbonyl group of enamides. The 6‐endo‐ and 7‐endo‐selective aryl radical cyclizations were applied to radical cascades for the synthesis of alkaloids such as phenanthroindolizidine, cephalotaxine skeleton, and lennoxamine. The 5‐exo‐trig cyclization of an alkyl radical onto the alkenyl bond of enamides could also be shifted to the 6‐endo mode by a positional change of the carbonyl group of enamides. The 6‐endo‐ selective cyclization was applied to the radical cascade to afford a cylindricine skeleton. Other examples of controlling the regiochemistry of radical cyclizations and their applications to the synthesis of natural products are also discussed. © 2006 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 6: 23–31; 2006: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20069
Organic–inorganic hybrid mesoporous silicas: functionalization, pore size, and morphology control
Authors: Park Sung Soo , Ha Chang‐Sik
Published: February 2006

Topological design of mesoporous silica materials, pore architecture, pore size, and morphology are currently major issues in areas such as catalytic conversion of bulky molecules, adsorption, host–guest chemistry, etc. In this sense, we discuss the pore size‐controlled mesostructure, framework functionalization, and morphology control of organic–inorganic hybrid mesoporous silicas by which we can improve the applicability of mesoporous materials. First, we explain that the sizes of hexagonal‐ and cubic‐type pores in organic–inorganic hybrid mesoporous silicas are well controlled from 24.3 to 98.0 Å by the direct micelle‐control method using an organosilica precursor and surfactants with different alkyl chain lengths or triblock copolymers as templates and swelling agents incorporated in the formed micelles. Second, we describe that organic–inorganic hybrid mesoporous materials with various functional groups form various external morphologies such as rod, cauliflower, film, rope, spheroid, monolith, and fiber shapes. Third, we discuss that transition metals (Ti and Ru) and rare‐earth ions (Eu3+ and Tb3+) are used to modify organic–inorganic hybrid mesoporous silica materials. Such hybrid mesoporous silica materials are expected to be applied as excellent catalysts for organic reactions, photocatalysis, optical devices, etc. © 2006 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 6: 32–42; 2006: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20070
The impacts of network relationships on SMEs' internationalization process
Authors: Zain Mohamed , Ng Siew Imm
Published: February 2006

In today's globalization era, more and more firms are striving to have an international presence, even though they face many challenges. Based on a multisite case study method, this article examines how indigenous Malaysian small and medium‐sized enterprises (SMEs) use their network relationships to facilitate their internationalization process. The evidence from the case of three software firms and one control firm in this study support the firms' internationalization process in the ways that network relationships trigger and motivate them to internationalize, influence their marketselection decision and mode‐of‐entry decision, help them gain initial credibility, allow access to additional relationships and established channels, help in lowering cost and reducing risk, and influence their internationalization pace and pattern. © 2006 Wiley Periodicals, Inc.
Auslegung und Gestaltung von hochtourigen Kleinstverdichtern
Authors: Surek D. , Stempin S. , Goldner A.
Published: February 2006

In der Medizintechnik und im Bereich der physikalischen Technik werden oft sehr geringe Luft‐ und Gasvolumenströme bei geringen Drücken von Δp = 10 kPa bis 20 kPa z. B. für die Luftversorgung, für Heiz‐ oder Kühlgeräte benötigt. Dafür eignen sich Seitenkanalverdichter in besonderer Weise, da sie für kleine Volumenströme und große Druckzahlen, d. h. für kleine Durchmesserzahlen und geringe Schnelllaufzahlen geeignet sind. Bei Kleinstverdichtern werden auch strenge Anforderungen an die Größe der Abmessungen, die Masse und die abgestrahlte Lautstärke gestellt. Diese Forderungen führen zu hohen Drehzahlen und zu hohen Schaufeldrehfrequenzen bei den üblichen Umfangsgeschwindigkeiten des Laufrades von ua= 70 m/s bis 80 m/s. Bei diesen mäßigen Umfangsgeschwindigkeiten entstehen auch keine nennenswert hohen Schalldruckpegel, aber höhere Schaufeldrehfrequenzen als bei großen Seitenkanalverdichtern. Da sich die hochfrequenten Geräusche durch sekundäre Schallschutzmaßnahmen leichter eindämmen lassen als niederfrequente Geräusche, sind damit Vorteile verbunden.
Druckmessung im 10–3 mbar Bereich mit Wärmeleitungs‐ und Membran‐Vakuummeter
Authors: Jitschin Wolfgang
Published: February 2006

Zur zuverlässigen und einfachen Druckmessung im 10–3 mbar Bereich bieten sich das Wärmeleitungs‐ und das kapazitive Membran‐Vakuummeter an. Geräte beider Typen wurden eingesetzt, um an einem Kolbenmanometer den Glockendruck zu erfassen. Die Messeigenschaften der Geräte wurden durch regelmäßige Kalibrierungen überwacht und erwiesen sich als stabil. Wie sich aus den Kalibrierdaten ergibt, scheint das Wärmeleitungsvakuummeter wegen seiner besseren Nullpunktstabilität vorteilhaft zu sein. Im praktischen Einsatz treten jedoch erhebliche Unterschiede der Druckanzeigen der beiden Geräte auf. In der vorliegenden Arbeit werden daher ihre Messeigenschaften beim Einsatz untersucht, bei dem der Druck eines unbekannten Gases innerhalb kurzer Zeit zuverlässig gemessen werden soll. Die Untersuchungen zeigen, dass das Wärmeleitungs‐Vakuummeter wegen seiner langsamen Reaktion bei kleinen Drücken und seiner Abhängigkeit von der Gasart unzuverlässige Werte liefert. Bei der vorliegenden praktischen Anwendung erweist sich das Membran‐Vakuummeter sehr deutlich als überlegenes Messgerät.
Permanente plasmapolymere Trennschichten
Authors: Vissing Klaus‐D. , Klyszcz‐Nasko Holger
Published: February 2006

Beschichtungen mit Trennaktivität zeichnen sich dadurch aus, dass das O/Si‐Verhältnis ca. 1:1 und das Kohlenstoff‐Siliziumverhältnis ca. 2:1 beträgt. Hieraus lässt sich folgern, dass für die Trennwirkung eine Struktur verantwortlich ist, die dem PDMS ähnlich ist und für die dreidimensionale Vernetzung ein erhöhter Anteil an Si‐O‐Bindungen notwendig ist.

Das entwickelte Trennschichtsystem (EP 1 301 286 B1) wird derzeit vielfältig eingesetzt und getestet, um seine Leistungsfähigkeit zu beweisen. In Einzelfällen sind bis zu 1250 Entformungen ohne Verschlechterung der Trennwirkung durchgeführt worden. In anderen Fällen erfolgt bereits eine Qualifizierung.
Kontrollierte Abscheidung und Alterung von Plasmapolymerschichten
Authors: Unger Wolfgang
Published: February 2006

Es wird gezeigt, dass mit einer Kombination der Oberflächenanalyseverfahren ESCA, ToF‐ SIMS und XAS eine erfolgreiche chemische Charakterisierung von Plasmapolymerfilmen erreicht werden kann. Es werden Elemente und Bindungstypen identifiziert und (semi‐)quantitativ bestimmt. Eine Korrelation zwischen Abscheidebedingungen und chemischen Eigenschaften der Plasmapolymerschichten kann hergestellt werden; eine kontrollierte Abscheidung wird damit möglich. Alterungsprozesse, die als Folge einer Atmosphärenexposition auftreten, können beobachtet werden. Die direkte Verbindung der Analysetechniken mit einem Plasmareaktor ermöglicht es, die Alterungsphänomene der Schichten systematisch mit Bezug auf eine frisch abgeschiedene und keinerlei Atomsphäre ausgesetzte Plasmapolymerschicht zu studieren.

Die Verfahrensweise wird exemplarisch am Beispiel von Ethylen‐, Allylamin‐ und Allylalkohol‐Plasmapolymerschichten demonstriert.
Der Natur auf der Spur: einzigartige Farbanmutungen auf Basis Photonischer Kristalle mit Opalstruktur
Authors: Winkler Holger , Bauer Josef , Schneider René , Heckmeier Michael
Published: February 2006

Seit ihrer theoretischen Beschreibung Ende der Achtziger Jahre sind Photonische Kristalle im Fokus von Wissenschaft und Technik: Diese dem Edelstein Opal ähnlichen Beugungsgitterstrukturen ermöglichen neuartige Farbeffekte und eine Vielzahl interessanter optischer Anwendungen. Im vorliegenden Artikel wird ein Prozess beschrieben, der es erstmals ermöglicht, großflächig Photonische Kristalle herzustellen.
The Greatest Lower Bound to the Reliability of a Test and the Hypothesis of Unidimensionality
Authors: Ten Berge Jos M. F. , Sočan Gregor
Published: February 2006

To assess the reliability of congeneric tests, specifically designed reliability measures have been proposed. This paper emphasizes that such measures rely on a unidimensionality hypothesis, which can neither be confirmed nor rejected when there are only three test parts, and will invariably be rejected when there are more than three test parts. Jackson and Agunwamba's (1977) greatest lower bound to reliability is proposed instead. Although this bound has a reputation for overestimating the population value when the sample size is small, this is no reason to prefer the unidimensionality-based reliability. Firstly, the sampling bias problem of the glb does not play a role when the number of test parts is small, as is often the case with congeneric measures. Secondly, glb and unidimensionality based reliability are often equal when there are three test parts, and when there are more test parts, their numerical values are still very similar. To the extent that the bias problem of the greatest lower bound does play a role, unidimensionality-based reliability is equally affected. Although unidimensionality and reliability are often thought of as unrelated, this paper shows that, from at least two perspectives, they act as antagonistic concepts. A measure, based on the same framework that led to the greatest lower bound, is discussed for assessing how close is a set of variables to unidimensionality. It is the percentage of common variance that can be explained by a single factor. An empirical example is given to demonstrate the main points of the paper.
Estimating Latent Distributions
Authors: Mislevy Robert J.
Published: February 2006

Consider vectors of item responses obtained from a sample of subjects from a population in which ability θ is distributed with density g (θ‖α), where the α are unknown parameters. Assuming the responses depend on θ through a fully specified item response model, this paper presents maximum likelihood equations for the estimation of the population parameters directly from the observed responses; i.e., without estimating an ability parameter for each subject. Also provided are asymptotic standard errors and tests of fit, computing approximations, and details of four special cases: a non-parametric approximation, a normal solution, a resolution of normal components, and a beta-binomial solution.
Matrix Correlation
Authors: Ramsay J. O. , ten Berge Jos , Styan G. P. H.
Published: February 2006

A correlational measure for an n by p matrix X and an n by q matrix Y assesses their relation without specifying either as a fixed target. This paper discusses a number of useful measures of correlation, with emphasis on measures which are invariant with respect to rotations or changes in singular values of either matrix. The maximization of matrix correlation with respect to transformations XL and YM is discussed where one or both transformations are constrained to be orthogonal. Special attention is focussed on transformations which cause XL and YM to be n by s, where s may be any number between 1 and min (p, q). An efficient algorithm is described for maximizing the correlation between XL and YM where analytic solutions do not exist. A factor analytic example is presented illustrating the advantages of various coefficients and of varying the number of columns of the transformed matrices.
A General Rotation Criterion and Its Use in Orthogonal Rotation
Authors: Crawford Charles B. , Ferguson George A.
Published: February 2006

Measures of test parsimony and factor parsimony are defined. Minimizing their weighted sum produces a general rotation criterion for either oblique or orthogonal rotation. The quartimax, varimax and equamax criteria are special cases of the expression. Two new criteria are developed. One of these, the parsimax criterion, apparently gives excellent results. It is argued that one of the most important factors bearing on the choice of a rotation criterion for a particular problem is the amount of information available on the number of factors that should be rotated.
Maximizing the Validity of a Unit-Weight Composite as a Function of Relative Component Lengths with a Fixed Total Testing Time
Authors: Jackson Paul H. , Novick Melvin R.
Published: February 2006

An explicit solution is given to the problem of assigning relative lengths to the subtests of a test so as to maximize the correlation of the unit weight composite with a specified criterion when the total testing time is fixed. This solution is valid and unique whenever it specifies nonnegative times for all variables. A step-down procedure is suggested for cases in which some of the testing times are zero. This procedure does not necessarily provide an optimal allocation. However in examples studied it is found to provide near optimum results. Algorithms are also developed for the determination of the least total testing time required to attain specified multiple and composite correlations. A numerical example is given illustrating the use of the unit weight procedure in combination with the regression weight algorithm.
Studies on the pathway from ornithine to proline in cultured skin fibroblasts with reference to the defect in hyperornithinaemia with hyperammonaemia and homocitrullinuria
Authors: Gray R. G. F. , Hill S. E. , Pollitt R. J.
Published: February 2006

The reduction in the conversion of ornithine to proline by fibroblasts from a patient with hyperornithinaemia with hyperammonaemia and homocitrullinuria cannot be explained by a reduced uptake of exogenous ornithine, an altered total intracellular ornithine content, or reduced conversion of γ‐glutamate semialdehyde to proline. However, neither could the postulated defect in mitochondrial ornithine uptake be demonstrated using the digitonin method. Increasing the ornithine concentration in the medium increased the incorporation of14C label from ornithine into protein in both the patient's and control cells. In the patient's cells the apparentKm for ornithine was ten times that of the controls although theVmax values were comparable. this result parallels the clinical response to ornithine supplementation.
Biochemical variability of arylsulphatases‐A,‐B and‐C in cultured fibroblasts from patients with multiple sulphatase deficiency
Authors: Chang P. L. , Rosa N. E. , Ballantyne S. R. , Davidson R. G.
Published: February 2006

Multiple sulphatase deficiency (MSD) in man is inherited as an autosomal recessive trait and associated with deficient activities of various sulphohydrolases. Cultured fibroblasts from seven different patients were assayed for arylsulphatases‐A,‐B and‐C activities. On the basis of the results, they may be classified into three groups: I, deficient in all three arylsulphatases: II, deficient only in arylsulphatases‐A and‐C with half or near‐normal arylsulphatase‐B; electrophoretically, arylsulphatase‐A activity bands are undetectable as in metachromatic leukodystrophy; III, same as in II except electrophoretically, the residual arylsulphatase‐A is detectable as faint activity bands similar to those in pseudo arylsulphatase‐A deficiency. In addition to the variability among different strains, within the same strain of MSD or normal cells, each enzyme activity increased several fold with increasing time in culture. These sources of biochemical variability among and within different cell strains have not been recognized before in the study of this apparently monogenic trait with multiple enzyme deficiencies. They may account for some of the discrepancies reported in the literature on arylsulphatase activities among cultured cells from different multiple sulphatase deficient patients.
Chemical studies on postmortem tissues from an infant with a sphingomyelin storage disorder
Authors: Donaghey S. F. O'B. , Raine D. Noel , Crossley J. E.
Published: February 2006

Investigations of formalin‐stored tissues from a female child 3 weeks old showed that the concentrations of sphingomyelin, cholesterol and other lipids were increased in spleen and other tissues. Although the disorder could not be confirmed enzymatically, the findings are most consistent with the patient having a sphingomyelin storage disorder. Tissue lipid data for a series of subjects without storage disorders are presented and may provide useful information for interpretation of results from autopsy samples.
Ascorbic acid: An unstable ninhydrin‐positive urinary constituent running with valine in a commonly used screening system
Authors: Pollitt R. J. , Sandhu B.
Published: February 2006

Large amounts of ascorbic acid occur occasionally in the urine of children being investigated for possible inherited metabolic disease and may give a positive ninhydrin reaction after thin‐layer chromatography. As this compound is unstable in urine and runs with valine in a solvent system commonly used for preliminary screening, it is a possible source of confusion.
Excretion pattern of branched‐chain amino acid metabolites during the course of acute infections in a patient with methylmalonic acidaemia
Authors: KØlvraa S. , Gregersen N. , Christensen E. , Rasmussen K.
Published: February 2006

A 1‐year‐old boy with a typical B12‐responsive form of methylmalonic acidaemia was hospitalized twice due to acute bacterial infections. On both occasions, the child was lethargic with a severe ketoacidosis on admission. Intensive therapy with protein restriction, intravenous administration of electrolytes and antibiotics was effective within 4 days on both occasions. The urinary excretion of organic acids showed the same pattern on both occasions. There were rising excretion concentrations, reaching a peak value within the first 24‐hour period, for the following compounds: 3‐hydroxybutyric acid, 3‐hydroxypropionic acid, 3‐hydroxyisobutyric acid and 3‐hydroxyisovaleric acid. Excretion concentrations of the following rose for 48 h: isobutyric acid, 2‐methylbutyric acid, isovaleric acid, lactic acid and the 2‐oxo‐acids.

There was no increase until 12–24 h after the onset of severe illness in the excretion of propionic acid and methylmalonic acid. Propionic acid excretion was maximal at about 48 h, while peak excretion of methylmalonic acid was delayed until about 72 h after the onset of severe illness; at this time there was clinical improvement. The biochemical implications of this excretion pattern are discussed.
Defective adenosylcobalamin synthesis in a case of transcobalamin II deficiency
Authors: Linnell J. C. , Quadros E. V. , Elliott P. G. , Malleson P.
Published: February 2006

Cobalamin metabolism has been investigated in a new case of transcobalamin II (TC II) deficiency. Using the chromatobioautographic technique, an abnormal distribution of cobalamins was detected in the child's erythrocytes and reduced synthesis of adenosylcobalamin but not of methylcobalamin in cultured fibroblasts. These results suggest that there may be a close link between TC II‐mediated cobalamin transport and intracellular synthesis of adenosylcobalamin (Ado‐Cbl).
Variation of urinary excretion of aspartylglucosamine and associated clinical findings in aspartylglucosaminuria
Authors: Aula P. , Raivio K. O. , Maury P.
Published: February 2006

The urinary excretion of aspartylglucosamine (AADG), the main accumulating glycoprotein degradation product in aspartylglucosaminuria (AGU), was studied in 40 patients at various stages of the disease. Only slight variation was found when the amount of AADG excreted by ten AGU patients under 10 years of age was compared with AADG excretion of older patients at a clinically advanced stage of the disease. The 24 h AADG excretion of the younger patients was 354 mg compared with 441 mg in the group often patients over 20 years of age. Clinical symptoms were unrelated to AADG excretion.
Some Improved Diagnostics for Failure of the Rasch Model
Authors: Molenaar Ivo W.
Published: February 2006

Although several goodness of fit tests have been developed for the Rasch model for dichotomous items, most of them are of a global, asymptotic, and confirmatory type. This paper, based on ideas from a recent thesis by Van den Wollenberg, offers some suggestions for local, small sample, and exploratory techniques: difficulty plots for person groups scoring right and wrong on a specific item, a slope test per item based on a binomial distribution per score group, and a unidimensionality check based on an extended hypergeometric distribution per score group.
Characterizing the Manifest Probabilities of Latent Trait Models
Authors: Cressie Noel , Holland Paul W.
Published: February 2006

The problem of characterizing the manifest probabilities of a latent trait model is considered. The item characteristic curve is transformed to the item passing-odds curve and a corresponding transformation is made on the distribution of ability. This results in a useful expression for the manifest probabilities of any latent trait model. The result is then applied to give a characterization of the Rasch model as a log-linear model for a 2J- contingency table. Partial results are also obtained for other models. The question of the identifiability of “guessing” parameters is also discussed.
A formal approach to property testing in causally consistent distributed traces
Authors: Hallal H. H. , Boroday S. , Petrenko A. , Ulrich A.
Published: February 2006

A formal framework for the analysis of execution traces collected from distributed systems at run-time is presented. We introduce the notions of event and message traces to capture the consistency of causal dependencies between the elements of a trace. We formulate an approach to property testing where a partially ordered execution trace is modeled by a collection of communicating automata. We prove that the model exactly characterizes the causality relation between the events/messages in the observed trace and discuss the implementation of this approach in SDL, where ObjectGEODE is used to verify properties using model-checking techniques. Finally, we illustrate the approach with industrial case studies.
Sensitivity and Utility of Parathyroid Scintigraphy in Patients with Primary Versus Secondary and Tertiary Hyperparathyroidism
Authors: Pham Tuan H. , Sterioff Sylvester , Mullan Brian P. , Wiseman Gregory A. , Sebo Thomas J. , Grant Clive S.
Published: February 2006

Introduction

Parathyroid scintigraphy (PS) may be used to localize hyperactive parathyroid glands preoperatively. Performance of PS in the setting of secondary and tertiary hyperparathyroidism (HPT) is not well quantified. The performance of PS in secondary/tertiary HPT versus primary HPT may reflect physiologic as well as radiopharmaceutical kinetic differences between multigland hyperplasia versus adenoma. The aim of this study was to review the performance of PS in secondary/tertiary HPT with a comparison to that for primary HPT. Moreover, we evaluated (1) the sensitivity of PS in detecting enlarged glands, and (2) PS detectability as a function of gland weight.

Methods

We performed a retrospective review of the Mayo Clinic database from 2000 to 2004. We identified 40 patients with secondary or tertiary HPT as well as a matched control group of 40 patients with primary HPT who had had preoperative PS and underwent parathyroid surgery.

Results

Parathyroid scintigraphy correctly localized all enlarged glands in 88% of patients in the primary HPT group. PS correctly identified both the number and locations of all hyperplastic glands in only 28% of the secondary/tertiary HPT patients. PS failed to identify one enlarged gland in 23% of the patients and two or more enlarged glands in 40% of the patients. PS correctly detects the largest gland in 88% of the patients with secondary and tertiary HPT. The mean gland weight detectable by PS was 612 ± 120 mg for primary HPT. In secondary/tertiary HPT, glands detected by PS had a mean weight of 950 ± 109 mg, whereas the mean weight was 276 ± 34 mg for undetected glands (P < 0.002).

Conclusions

Parathyroid scintigraphy is a sensitive study for localizing parathyroid glands preoperatively in primary HPT patients. Its sensitivity is low in secondary and tertiary HPT patients. Thus PS has limited value as a preoperative localization study in secondary/tertiary HPT patients.
Structural study of TiO2 thin films by micro-Raman spectroscopy
Authors: Niilisk Ahti , Moppel Mart , Pärs Martti , Sildos Ilmo , Jantson Taavi , Avarmaa Tea , Jaaniso Raivo , Aarik Jaan
Published: February 2006

The Raman spectroscopy method was used for structural characterization of TiO2 thin films prepared by atomic layer deposition (ALD) and pulsed laser deposition (PLD) on fused silica and single-crystal silicon and sapphire substrates. Using ALD, anatase thin films were grown on silica and silicon substrates at temperatures 125–425 °C. At higher deposition temperatures, mixed anatase and rutile phases grew on these substrates. Post-growth annealing resulted in anatase-to-rutile phase transitions at 750 °C in the case of pure anatase films. The films that contained chlorine residues and were amorphous in their as-grown stage transformed into anatase phase at 400 °C and retained this phase even after annealing at 900 °C. On single crystal sapphire substrates, phase-pure rutile films were obtained by ALD at 425 °C and higher temperatures without additional annealing. Thin films that predominantly contained brookite phase were grown by PLD on silica substrates using rutile as a starting material.
Human intentionality in the functionalist theory of social change: the role of French provincial intendants in state-society differentiation
Authors: Clark Samuel
Published: February 2006

This paper seeks to assess the validity, in a particular historical case, of two ways of thinking in functionalist literature about the role of human intentionality in social change. It does so by means of an analysis of the contribution of French provincial intendants of the seventeenth and eighteenth centuries to the differentiation of state and society. It is argued that if functionalists are to build a theory of social change it is necessary that they deal more directly with the question of human intentionality. Four historical views, each positing a different relationship between intentionality and the evolution of the state in Early Modern France, are outlined as different approaches to understanding the establishment of the institution of intendants and the part they played in state-society differentiation. The historical evolution of French intendants is traced and 1066 actions by intendants and the French crown during the seventeenth and eighteenth centuries are analysed to determine the extent to which intendants contributed to state-society differentiation and whether they and the crown did so intentionally.
On the enchantment of the state: Indian thought on the role of the state in the narrative of modernity
Authors: Kaviraj Sudipta
Published: February 2006

One of the fundamental ideational changes brought by modernity into Indian intellectual culture was the transformation in the idea of the state. From an institution that was traditionally seen as a necessarily limited and distinctly unpleasant part of the basic furniture of any society, the idea of the state has been transformed into that of a central moral force, producing an immense enchantment in India’s intellectual life. Indeed, in the Indian context, as distinct from the European one, it has been the primary source of modernity. This paper seeks to present an absurdly short history of the curious adventures of this idea. It also seeks to explain why, despite the global dominance of ideas of liberalisation, and a reduction of the state’s interference in social and economic life, in India this enchantment is still undiminished.
Synchronous bilateral tonsillar carcinoma: role of fluoro-deoxyglucose positron emission tomography scanning in detecting occult primary tumours in metastatic nodal disease of the head and neck
Authors: Price T , Pickles J
Published: February 2006

We present the second case of primary synchronous bilateral tonsillar squamous cell carcinoma reported in the English literature and evaluate the role of fluoro-deoxyglucose positron emission tomography scanning in the search for the occult primary tumour in a patient presenting with metastatic nodal disease in the head and neck.