bluuebunny/crossref_metadata_2025 huggingface dataset:
Using the Impact of Event Scale to Evaluate Distress in the Context of Genetic Testing for Breast Cancer Susceptibility
Authors: Dorval Michel , Drolet Mélanie , LeBlanc Mélanie , Maunsell Elizabeth , Dugas Michel J. , Simard Jacques
Published: July 2007

The data obtained with two forms of the Impact of Event Scale were compared, one referring to a BRCA1/2 test result (IES-T) and another to cancer (IES-C). The sample consisted of 272 women with a family history suggestive of a BRCA1/2 mutation who underwent genetic testing and received results: noncarrier, carrier, or inconclusive. Globally, mean scores on the IES-C form were higher than those obtained on the IES-T form. Among carriers of a BRCA1/2 mutation, mean scores on the two forms were similar and agreement was good, as measured by the in-traclass correlation coefficient (.83; 95% 95% CI = .72, .91). Agreement between the forms was poor to fair among noncarriers (ICC = .38; CI = .15, .57) and women with an inconclusive result (ICC = .40; 95% CI = .26, 52). Having had cancer increased total scores but had little influence on agreement between scores on forms. These findings highlight the importance of carefully selecting the form of the Impact of Event Scale in the context of genetic testing for breast cancer susceptibility.
Relations among Self-Efficacy, Goal Setting, and Metacognitive Experiences in Problem-Solving
Authors: Akama Kenichi
Published: July 2007

This study examined the roles of metacognitive experiences in the self-regulation process before problem-solving. 260 Japanese undergraduate students participated. To investigate the role of metacognitive experiences, a structural equation model was constructed to examine the relations among Self-efficacy, Goal Setting, Metacognitive Experiences, and Performance. Analysis showed that Metacognitive Experiences mediated the influence of Self-efficacy on Goal Setting and Performance. In addition, these experiences were related to Performance to some extent. Finally, these results are discussed in relation to those obtained in previous studies.
Synergies between Bio‐ and Oil Refineries for the Production of Fuels from Biomass
Authors: Huber George W. , Corma Avelino
Published: July 2007

As petroleum prices continue to increase, it is likely that biofuels will play an ever‐increasing role in our energy future. The processing of biomass‐derived feedstocks (including cellulosic, starch‐ and sugar‐derived biomass, and vegetable fats) by catalytic cracking and hydrotreating is a promising alternative for the future to produce biofuels, and the existing infrastructure of petroleum refineries is well‐suited for the production of biofuels, allowing us to rapidly transition to a more sustainable economy without large capital investments for new reaction equipment. This Review discusses the chemistry, catalysts, and challenges involved in the production of biofuels.
Assessing indices of happiness and unhappiness in individuals with developmental disabilities: a review
Authors: Dillon Courtney M. , Carr James E.
Published: July 2007

The behavioral deficits of individuals with profound multiple disabilities (PMD) make it difficult to assess their satisfaction and quality of life. To address this problem, researchers have recently evaluated affective behavior (i.e., indices of happiness and unhappiness) to document the effects of therapeutic interventions and to assist with clinically relevant decisions. We review the recent literature on indices of happiness and unhappiness and discuss its major themes. In addition, potential concerns with this technology are discussed and clinical recommendations are provided. Copyright © 2007 John Wiley & Sons, Ltd.
Assessment of preference for behavioral treatment versus baseline conditions
Authors: Dozier Claudia L. , Vollmer Timothy R. , Borrero John C. , Borrero Carrie S. , Rapp John T. , Bourret Jason , Gutierrez Anibal
Published: July 2007

This study was designed to determine whether behavioral treatments would be preferred over no treatment (baseline) conditions. Functional analyses and descriptive observations were conducted to determine the variables that maintained each participant's problem behavior. Next, treatments were implemented based on assessment results. Finally, participants were provided a choice between baseline and treatment conditions to determine whether they preferred to participate in treatment. Baseline conditions were in place on one side of a room and treatment conditions were in place on the other side of the room. Assessment results suggested that problem behavior was automatically reinforced for one participant and multiply controlled for another participant. The treatment results showed that differential reinforcement and extinction (extinction was not implemented for automatically reinforced behavior) were effective in reducing problem behavior for each participant. Results of the choice between baseline and treatment phase showed that both participants chose treatment over baseline conditions. Copyright © 2007 John Wiley & Sons, Ltd.
Single molecule studies of molecular diffusion in cellular membranes: Determining membrane structure
Authors: Ritchie Ken , Spector Jeff
Published: July 2007

Since the advent of single particle/molecule microscopies, researchers have applied these techniques to understanding the fluid membranes of cells. By observing diffusion of membrane proteins and lipids in live cell membranes of eukaryotic cells, it has been found that membranes contain a mosaic of fluid compartments. Such structure may be instrumental in understanding key characteristics of the membrane. Recent single molecule observations on prokaryotic cell membranes will also be discussed. © 2007 Wiley Periodicals, Inc. Biopolymers 87: 95–101, 2007.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Students' preferred teaching techniques for biochemistry in biomedicine and medicine courses
Authors: Novelli Ethel L. B. , Fernandes Ana Angélica H.
Published: July 2007

The aim of this study was to investigate the students' preferred teaching techniques, such as traditional blackboard, power‐point, or slide‐projection, for biochemistry discipline in biomedicine and medicine courses from São Paulo State University, UNESP, Botucatu, São Paulo, Brazil. Preferences for specific topic and teaching techniques were determined from questionnaires on a Liquert scale from 1 to 5 (strongly disagree; disagree; neither agree, nor disagree; agree; strongly agree) distributed at the end of biochemistry discipline to 180 biomedical students (30 students/year) and 540 medical students (90 students/year), during the years 2000–2005. Despite of the different number of hours applied to the course topics for the two groups of students, the majority of undergraduates from biomedicine and medicine preferred metabolic topics. Although the perception of a medical student is expected to be different than that of a biomedical student, as the aims of the two programs are different, 92.4% of students from each course agreed or strongly agreed with the biochemistry topics, and 92.1% thought highly on this subject. The majority of students, a number of 139 undergraduates from biomedicine and 419 from medicine course, preferred traditional blackboard teaching than slide‐projection, or power‐point class. In conclusion, it is imperative that the health courses reflect on sophisticated technology and data presentation with high density of information in biochemistry discipline. The traditional classes with blackboard presentation were most favored by students from biomedicine and medicine courses. The use of students' preferred teaching techniques might turn biochemistry more easily understood for biomedical and medical students.
Lactate dehydrogenase kinetics and inhibition using a microplate reader
Authors: Powers Jennifer L. , Kiesman Natalie E. , Tran Connie M. , Brown John H. , Bevilacqua Vicky L. H.
Published: July 2007

A lactate dehydrogenase (LDH) enzyme kinetics laboratory experiment has been developed in which students obtain kinetic data using a microplate spectrophotometer (reader). These instruments have the capability of reading absorbances of many samples in a very short time frame. In this experiment 12 samples are prepared at a time and the absorbances read in less than 1 min. In a 3‐hr laboratory period, students collect data at five different substrate concentrations without inhibitor and also in the presence of two different concentrations of inhibitor. Students have enough time to repeat each part if they obtain too much scatter in their data. The enzyme examined, LDH, correlates with the study of metabolism and has particular relevance for students who are interested in medical careers. The LDH assay itself is not new, but the microplate format and the use of urea as a quench reagent are novel features. Students plot Michaelis–Menten and Lineweaver–Burk plots and calculate values for Vmax, apparent Vmax (Vmaxapp), Km, apparent Km (Kmapp), kcat, and KI. Students typically obtain results correctly showing that oxalic acid is a competitive inhibitor and oxamic acid is a noncompetitive inhibitor when lactate is the substrate of the reaction.
Hexahydro‐closo‐hexaborane as a Ligand in Coordination Compounds: Syntheses and Crystal Structures of [M2(μ‐bis‐η3‐B6H6)(PPh3)2] )M = Cu, Au)
Authors: Schaper Tanja , Preets Wilhelm
Published: July 2007

By reaction of (PPh3)3 CuCl and PPh3AuCl with [B6H6]2− in organic media, dinuclear complexes are formed containing the hexaborate as a bridging ligand coordinated to the metal centers by opposite B3 facets of the B6 cluster in a trihapto mode. This is verified by single‐crystal X‐ray structural analysis of the isotypical (Paā) compounds [Cu2μ‐bis‐η3‐B6H6)(PPh3)2] (1) and [Au2(μ‐bis‐η3‐B6H6)(PPh3)2)] (2) which showed the metal centers to be very close to the B3 plane [1.92 (1), 2.10 (2) Å. The 11B NMR spectra of the two compounds feature doublets, at δ= −15.32 in 1 and at −11.51 in 2, which are significantly shifted downfield in comparison to [B6H6]2‐ (δ= −17.2).
Recent Developments in the Chemistry of Covalent Azides
Authors: Klapötke Thomas M.
Published: July 2007

The experimental and theoretical chemistry of covalently bound azides is an area that has seen considerable renaissance over the past 10 years. This review is not exhaustive in scope but rather focuses on and highlights certain aspects in this field. In particular, the stability and dissociation of HN3is discussed at a very high level of theory (CASSCF and MCSCF‐CI) and compared and contrasted with experimental data and results from „medium”︁‐level ab initio computations (MP2, B‐LYP). From these results credence is given to those values calculated for larger systems and heavy elements for which very high level computations are not possible. The experimentally well‐characterized covalent halogen azides (XN3, where X = F, Cl, Br, I) as well as the heavy‐element group‐15 compound Sb(N3)3are discussed. The review also includes discussion of the bond properties of the highly unstable N‐bound azides ON–N3and (FSO2)2N–N3. In the final chapter attention is drawn to the recently predicted and eventually experimentally verified elusive species OCN–NCO, which is isoelectronic to the hitherto unknown diazide N6.
Molybdenum‐Catalysed and ‐Mediated Cycloaddition Reactions: Efficient Synthesis of Complex Products from 1‐Oxa‐1,3‐dienes and Cyclotrienes or ‐tetraenes
Authors: Schmidt Thomas
Published: July 2007

Molybdenum‐mediated [6 + 2]‐cycloaddition reactions of unsaturated ketones to cyclotri‐ or ‐tetraenes, e.g. cyclohepta‐1,3,5‐triene or cyclooctatetraene, proceed under very mild conditions, in high yields and with excellent stereoselectivity starting from the appropriate dicarbonylbis[π4‐(1‐oxa‐1,3‐diene)]molybdenum complexes. The stereochemistry of the product arising from the reaction of dicarbonylbis[π4‐(5‐methylhex‐3‐en‐2‐one)]molybdenum with cyclohepta‐1,3,5‐triene allows one to deduce a stepwise mechanism for this addition. The reactants are fused, as would be expected from an exo‐type approach, thus indicating an intermolecular attack of the cycloheptatriene. Tungsten oxadiene complexes are effective in analogous reactions at somewhat reduced reaction rates. Catalytic cycloadditions are observed in several cases when 1–5 mol% of the highly reactive dicarbonylbis[π4‐(R‐(+)‐pinocarvone)]molybdenum is employed as the catalyst. Cycloadducts are formed diastereospecifically in most cases. When cyclooctatrienes are employed as reactants, a sequence of electrocyclization of the triene and subsequent [4 + 2]‐cycloadditon occurs with high selectivity and efficiency, leading to a pentacyclic ketone. The product structure reveals an endo‐type approach of the polyene in this case.
Transition Metal Complexes with Sulfur Ligands, 123[[ Synthesis and Reactivity of New Complexes Containing the [Ru(“S4”)] Fragment [S42‐ = 1,2‐Bis(2‐mercaptophenylthio)ethane(2‐)]
Authors: Sellmann Dieter , Gottschalk‐Gaudig Torsten , Heinemann Frank W. , Knoch Falk
Published: July 2007

In order to synthesize labile and well‐soluble [Ru(L)(L')(“S4”)] complexes, [Ru(CI)2(DMSO)4] was treated With “S4”‐Na2 (S42‐ = 1,2‐bis(2‐mercaptophenylthio)‐ethane(2–1)] yielding [Ru(DMSO)2(“S4”)] (1 which contains two labile DMSO ligands. An X‐ray structural analysis of 1, verifies that both DMSO ligands are coordinated via their S atoms. The reaction of 1 with small ligands such as PR3 (R = Et, nPr, nBu) or tetrahydrothiophene (THT) leads to substitution of both DMSO ligands yielding [Ru(PR3)2(“S4”)] (R = Et 3a, nPr 3b, nBu 3c) and [Ru(THT)2(“S4”] 2, respectively, while bulky phosphane ligands such as PCy3 and PiPr3 substitute one DMSO ligand to yield [Ru(DMSO)(PR3])(“S4”] (R = iPr 4a, Cy 4b). X‐ray structural analyses of [Ru(PnPr3)2(“S4”)] · 0.5 MeOH (3b · 0.5 MeOH), [Ru(PnBu3)2(S4)} (3c), and [Ru(Pme3)2(“S4”)] (3d) confirm the pseudo‐octahedral coordination of the Ru centers by four Sdonors and two cis P‐donors and reveal close similarities bet ween the three complexes. Comparision of the structural parameters of 3b · 0.5 MeOH, 3c and 3d with those of [Ru(PPh3)2(“MeS, 4”)] [MeS4“2” = 1,2‐bis(2‐mercaptophenylthio)propane(2–1)] indicates that the inertness towards substitution of 3b · 0.5 MeOH, 3c and 3d as opposed to the substitution lability of [Ru(PPh3)2(,MeS4“)] is caused by the small cone angles of the alkyl phosphanes. In the DMSO/PCy3 complex 4b both coligands are labile, and which one is substituted depends on the size of the entering ligand. The reactions of 4b with PnR3 yield [Ru(DMSO)(PR3)('S4”)] (R = nPr 4c, nBu 4d) in contrast to the reaction with CO. PMe3, and SMe2 which give [Ru(CO)(Pcy3)(“S4”)] (5b), [Ru(P‐Me3)(PCy3)(“S4”)] (6, and [Ru(SMe2)(PCy3)(“S4”)] (7, respectively. In an analogous manner, the CO complexes [Ru(CO(PR3)(“S4”)] (R = iPr 5a, nBu 5c) have been obtained by treatement of 4a and 4d with CO. The reactions of 4a and 4b with S8 yielded the readily soluble μ‐S2 complexes [μ‐S2[Ru(PR3)(“S4”)]2] (R ‐ iPr 8a, Cy 8b). The spectroscopi9c data of complex 8b and its cyclic voltammogram, which exhibits four quasi‐reversible redox waves, indicate a strong electronic coupling of the two [Ru(PCy3)(“S4”)] fragments via the μ‐S2 bridge.
(EIZ)‐Equilibria, 19 Dimeric α‐Lithio‐2,6‐dimethylstyrene
Authors: Knorr Rudolf , Behringer Claudia , Lattke Ernst , Räpple Edith , Nöth Heinrich , Schmidt Martin
Published: July 2007

Improved preparations of 2,6‐dimethylstyrene (5) and its α‐bromo derivative (10) are described. The Br/Li exchange reaction of 10 provides single crystals of the title compounds 11 or 12, which were characterized as disolvated dimers by X‐ray analyses. A similar dimer persists in diethyl ether, tert‐butyl methyl ether, and toluene at all accessible temperatures, with significant lithiation NMR shifts (relative to 5) partially due to charge delocalization from the sp2‐carbanionic center. Some NMR coupling constants are typical of the dimeric aggregate. The configurational (E,Z) lability is quantified in toluene solution.
Reactions of Pt3Ru6(CO)2(μ3‐H)(μ‐H)3 with Phos[phanes — The Synthesis and Structural Characterizations of [Pt(PMe3)3H][Pt3Ru6(CO)21(μ3‐H)(μ‐H)2] and [Pt3Ru6(CO)20(PPh3)(μ‐H)3(μ3H)]
Authors: Adams Richard D. , Barnard Thomas S. , Li Zhaoyang , Zhang Lijuan
Published: July 2007

The reactions of [Pt3Ru6(CO)21(μ‐H)3(μ3‐H)] (1) with PMe3 and PPh3 have produced the salts [Pt(PR3)3H]‐[Pt3Ru6(CO)21(μ3‐H)(μ‐H)2], 5a and 5d, R = Me and Ph in the yields 9% and 22%, respectively. By contrast the reaction of 1 with PPh3 in the presence of Me3NO has yielded the phosphane‐substituted derivative [Pt3Ru6(CO)20(PPh3)μ‐H)3(μ3‐H)] }(6) in 22% yield. Compounds 5a and 6 were characterized by single crystal X‐ray diffraction analysis. Compounds 5a and 5d are salts of the anion [Pt3Ru6(CO)21(μ3‐H)(μ‐H)2]−. The anion contains a layer segregated Ru3Pt3Ru3 structure similar to that of 1 with two bridging hydride ligands on one Ru3 triangle and one semi‐triply bridging hydride ligand on the other. The cation [Pt(PR3)3H]+ was evidently formed by the abstraction of platinum from other molecules of 1. Compound 6 is a PPh3 derivative of the parent 1 that also contains the layer segregated stacking of Ru3 and Pt3 triangles. The PPh3 ligand is coordinated to one of the ruthenium atoms in an axial position.
2‐Phosphanylphosphinines as Bridging Ligands for Dinuclear Transition Metal Carbonyls
Authors: Waschbüch Klaus , Le Floch Pascal , Ricard Louis , Mathey François
Published: July 2007

The 2‐phosphanyl‐4,5‐dimethylphosphinines1‐5are powerful bridging ligands able to stabilize metal‐metal single and triple bonds between low‐valent transition metal centres. Their reaction with Mn2(CO)10in refluxing xylene yields the corresponding Mn2(CO)8complexes6and7. Reaction with [Fe2Cp2(CO)4] under UV irradiation similarly yields the Fe‐Fe‐bridged Fe2Cp2(CO)2complexes8and9. An additional observation is that the 2‐phosphininyl‐3,4‐dimethylphosphaferrocene10is formed upon reaction of the 2‐phospholylphosphinine5with [Fe2Cp2(CO)4] at high temperature under CO pressure. A clean addition occurs at the Mo≡Mo triple bond of [Mo2Cp2(CO)4] to give the Mo‐Mo single‐bonded complexes11‐15. The thermolysis of these complexes succeeds when the phosphanyl group is a phosphonite P(OEt)2(13) or P(OAr)2(14), affording cleanly the Mo2Cp2(CO)4triple‐bonded complexes16and17, respectively. The metal‐metal triple bonds of these complexes readily add two molecules of CO to reform13and14, or one molecule oftBu‐N≡C to give18and19. The X‐ray crystal structure analysis of the MO2C2(CO)4complex13a, with the 2‐P(OEt)2‐ phosphinine, shows agaucheorientation of the two Cp rings and very short P‐Mo bonds of 2.3565(4) and 2.406(2) Å to the phosphinine and P(OEt)2groups, respectively.
Synthesis, Structure, and Dynamic Behavior of (μ‐Aldimido)(μ‐η1: η2‐alkyne)‐ biszirconocene Cation Complexes That Contain Planar‐Tetracoordinate Carbon
Authors: Aglers Wikfgabg , Erker Gerhard , Fröblich Roland , Peuchert Ulrich
Published: July 2007

The benzonitrile hydrozirconation product Cp2ZrCl(NCHPh) 8 was treated with propynyl lithium to yield the (propynyl)(benzaldimido)ZrCp; complex 9. Subsequent treatment with trityl tetraphenylborate generated [Cp2Zr(CCCH3)−BPh−4] that instantaneously added to 9 to eventually form the (μ‐aldimido)(μ‐η1:η2‐hexadiyne)ZrCp2 cation 11. The X‐ray crystal structure analysis showed that 11 contains a planar‐tetracoordinate carbon atom that is stabilized by forming a three‐center‐two‐electron bond with the two adjacent metal atoms. Similarly, complex 9 reacted with [Cp2Zr(CH3)+CH3B(C6F5)3 1 to yield the planar‐tetracoordinate carbon containing (μ‐aldimido)(μ‐η1:η2‐2‐butyne) Cp; cation 12. Both complexes 11 and 12 exhibit dynamic NMR spectra due to their rapid reorganization of the dimetallabicyclic frameworks (ΔG* = 10 kcal mol−1) in addition to an anchimerically assisted CN bond rotation (ΔG* =15 kcal mol−1).
Subsite‐Specific Reactions of a Cyclotriveratrylene [4Fe‐4S] Cluster Complex
Authors: Van Strijdonck Gino P. F. , Ten Have Petrus T. J. H. , Peiters Martinus C. , Van Der Lindenm Johannes G. M. , Steggerda Jan J. , Nolte Roeland J. M.
Published: July 2007

Ligand exchange reactions are carried out exclusively at the unique iron site of a subsite‐differentiated cyclotriveratrylene [4Fe‐4S] cluster complex. The effect of a variety of thiolate, phenolate, bidentate, and bridging ligands on the redox potential of the subsite‐differentiated [4Fe‐4S] cluster complex is studied and compared with the effects of such ligands on an [Fe4S4C14]2‐ cluster. The redox potential can be modulated within the range of −1.60 to −1.80 V (vs. Fc0/+) by varying the ligand. The introduction of an electron releasing substituent shifts the redox potential to more negative values, whereas an electron withdrawing substituent has the opposite effect. A linear relationship exists between the number of substituted sites and the reduction potential of the cluster.
The Equilibrium Between 2‐Lithium‐Oxazole(‐Thiazole, ‐Imidazole) Derivatives and Their Acyclic Isomers – A Structural Investigation
Authors: Hilf Christoff , Bosold Ferdinand , Harms Klaus , Marsch Michael , Boche Gernot
Published: July 2007

2‐Metallated oxazoles, thiazoles and imidazoles are of interest for the preparation of derivatives of the respective heterocycles, and – especially in the case of metallated thiazoles – as acyllithium equivalents in organic syntheses. Metallation at C2 of these compounds, however, often leads (more so with Li‐oxazoles than with Li‐thiazoles and Li‐imidazoles) to products derived from the acyclic isomers of the metallated heterocycles. In order to obtain more information on the positions of the relevant equilibria, we have carried out a 13C‐NMR study of substituted li‐ and ZnCl‐oxazoles, Li‐thiazoles and Li‐imidazoles. In the case of Li‐oxazoles, the equilibrium is completely on the side of the acyclic isomers. Addition of ZnCl2, however, leads to ring‐closure, and, even in the case of 2‐ZnCl‐substituted benzoxazole, only the ring‐closed isomer is observed. This demonstrates a dramatic gegenion effect on the equilibrium between two isomeric anions. In the case of Li‐thiazoles, depending on the substitution pattern, either solely the ring‐closed or an equilibrium with the ringopened isomer is observed. In the series of Li‐imidazoles, only the 2‐lithiated benzimidazole is in equilibrium with its ring‐opened isomer. The tendency of these compounds to undergo ring‐opening parallels the leaving group properties of the various subunits [OLi > SLi > R2NLi, and phenyl‐O(S, NR)Li > vinyl‐O(S, NR)Li]. The difference between the effects of Li+ vs. ZnCl+ in the (benz)oxazole series is in agreement with results of solid‐state structure investigations of 2‐lithiated and a 2‐zincated thiazole: in the Li compound the C–S bond is 2.9 pm longer than in the ZnCl species, indicating a more facile C–S bond cleavage with Li+ as the gegenion.
[CR(CO)5PCl3] — A Starting Material for Phosphorus‐Rich Px Ligand Complexes
Authors: Scheer Manfred , Schuster Kay , Krug André , Hartung Helmut
Published: July 2007

[Cr(CO)5PCl3] reacts with different metallates K[CpxMo(CO)3] [Cpx = ·5‐C5H4tBu (Cp]), ·5‐C5H3tBu2‐1,3 (Cp))], K[CpFe(CO)2], K[Cp]Cr(CO)3], K[C}*Ni(CO)] and Na2[Cr2(CO)10] at –78°C in THF to yiel various P2, cyclo‐ P3 and cyclo‐P5 ligand complexes of the formulae [Cp] Mo(CO)2 (.2‐P3)] (1a), [Cp]Mo(CO)2(.3‐P3)] (1b), [{CP'Mo‐(CO)2}2(μ,.2‐P2)] (2a), [{Cp]Mo(CO)2}2(μ, ·2‐P2)] (2b), [Cp]Fe).5‐P5)] (3), [(Cp'Cr)2(μ,.5‐P5)] (4), [{Cp]Cr(CO)2}2‐(μ,.2‐P2)] (5), [(Cp*Ni)2(μ,.2‐P2){Cr(CO)5}2] (6). [{(CO)5Cr}Cl2PPCl2{Cr(CO)5}] (7) and [{Cr(CO)5}2PCl (8). Comprehensive studies of the reaction pathway leading to formation of the cyclo‐P3 product 1a give strong indications that a sequence involving metal‐halogen exchange and stepwise P–P bond formation takes place, proceeding via [{CO}5Cr}Cl2PPCl2{Cr(CO)5}] (7) and the cyclo‐P3 precursor compond [{Cp]Mo(CO)3}{Cp'Mo(CO)2}2{Cr(CO)5}(μ,.3:1:1−P3)] (9). The latter two complexes have been isolated and structurally characterized.
Artificial DNAs Based on Alkynyl C‐Nucleosides as a Superior Scaffold for Homo‐ and Heteroexcimer Emissions
Authors: Chiba Junya , Takeshima Sakiko , Mishima Kikyo , Maeda Hajime , Nanai Yasuaki , Mizuno Kazuhiko , Inouye Masahiko
Published: July 2007

DNA‐like fluorescent oligomers composed of alkynyl β‐D‐ribofuranosides bearing pyrene, perylene, and anthracene as a fluorophore were synthesized by solid‐phase DNA synthesis. The fluorescent oligomers possess the defined number and order of the fluorophores. In these oligomers, the adjacent fluorophores efficiently interact with each other by hydrophobic interactions in their electronic ground states in a face‐to‐face fashion. The predominant excimer emissions were observed from not only the homooligomers (pyrene–pyrene and perylene–perylene systems) but also the heterooligomers (pyrene–perylene, pyrene–anthracene, and perylene–anthracene systems) in aqueous media.
Improved Cyclodextrin‐Based Receptors for Camptothecin by Inverse Virtual Screening
Authors: Steffen Andreas , Thiele Carolin , Tietze Simon , Strassnig Christian , Kämper Andreas , Lengauer Thomas , Wenz Gerhard , Apostolakis Joannis
Published: July 2007

We report the computer‐aided optimization of a synthetic receptor for a given guest molecule, based on inverse virtual screening of receptor libraries. As an example, a virtual set of β‐cyclodextrin (β‐CD) derivatives was generated as receptor candidates for the anticancer drug camptothecin. We applied the two docking tools AutoDock and GlamDock to generate camptothecin complexes of every candidate receptor. Scoring functions were used to rank all generated complexes. From the 10 % top‐ranking candidates nine were selected for experimental validation. They were synthesized by reaction of heptakis‐[6‐deoxy‐6‐iodo]‐β‐CD with a thiol compound to form the hepta‐substituted β‐CDs. The stabilities of the camptothecin complexes obtained from solubility measurements of five of the nine CD derivatives were significantly higher than for any other CD derivative known from literature. The remaining four CD derivatives were insoluble in water. In addition, corresponding mono‐substituted CD derivatives were synthesized that also showed improved binding constants. Among them the 9‐H‐purine derivative was the best, being comparable to the investigated hepta‐substituted β‐CDs. Since the measured binding free energies correlated satisfactorily with the calculated scores, the applied scoring functions appeared to be appropriate for the selection of promising candidates for receptor synthesis.
Online end‐to‐end quality of service monitoring for service level agreement management
Authors: Ta Xiaoyuan , Mao Guoqiang
Published: July 2007

A major challenge in network and service level agreement (SLA) management is to provide Quality of Service (QoS) demanded by heterogeneous network applications. Online QoS monitoring plays an important role in the process by providing objective measurements that can be used for improving network design, troubleshooting and management. Online QoS monitoring becomes increasingly difficult and complex due to the rapid expansion of the Internet and the dramatic increase in the speed of network. Sampling techniques have been explored as a means to reduce the difficulty and complexity of measurement. In this paper, we investigate several major sampling techniques, i.e. systematic sampling, simple random sampling and stratified sampling. Performance analysis is conducted on these techniques. It is shown that stratified sampling with optimum allocation has the best performance. However, stratified sampling with optimum allocation requires additional statistics usually not available for real‐time applications. An adaptive stratified sampling algorithm is proposed to solve the problem. Both theoretical analysis and simulation show that the proposed adaptive stratified sampling algorithm outperforms other sampling techniques and achieves a performance comparable to stratified sampling with optimum allocation. A QoS monitoring software using the aforementioned sampling techniques is designed and tested in various real networks. Copyright © 2007 John Wiley & Sons, Ltd.
Optimal SIR for an hybrid cellular DS/SFH CDMA system
Authors: Varzakas P.
Published: July 2007

A hybrid direct‐sequence/slow frequency hopping code‐division multiple‐access (DS/SFH CDMA) system operating in a Rayleigh fading environment is described and its spectral efficiency is estimated in terms of the theoretically achievable average channel capacity (in the sense of information theory) per user. The analysis covers the operation over a broadcast cellular time‐varying link and leads to a simple novel closed‐form expression for the optimal average spread signal‐to‐interference power ratio (SIR) received by each user based on the maximization of the achieved spectral efficiency. Copyright © 2007 John Wiley & Sons, Ltd.
Menarche, puberty, and first sexual activities in eating‐disordered patients as compared with a psychiatric and a nonpsychiatric control group
Authors: Mangweth‐Matzek Barbara , Rupp Claudia Ines , Hausmann Armand , Kemmler Georg , Biebl Wilfried
Published: July 2007

Objective:

To examine chronology and experience of menarche, puberty, and first sexual activities in eating‐disordered patients as compared with a psychiatric and a nonpsychiatric control group.

Method:

We interviewed 150 females, namely 50 patients with anorexia or bulimia nervosa (ED), 50 patients with polysubstance dependence (PSD‐CO), and 50 healthy controls (HE‐CO) (defined by DSM‐IV) on chronology and their experience of menarche, puberty, and first sexual activities adjusted for childhood sexual abuse.

Results:

ED women were similar to HE‐CO in age at menarche and most sexual milestones, but differed significantly from PSD‐CO women, who were “early starters.” Regarding their experience of menarche, pubertal body changes, and first sexual activities, however, ED women rated these variables significantly more negatively than did either of the comparison groups. These significant differences remained after adjusting for sexual abuse.

Conclusion:

These findings suggest a negative body attitude in ED patients already at pubertal age, namely years before onset of the disorder. Prospective data are needed. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2007
Synthetic Routes to Three Novel Scaffolds for Potential Glycosidase Inhibitors
Authors: Rommel Michael , Ernst Alexander , Koert Ulrich
Published: July 2007

Efficient syntheses of three novel scaffolds for potential β‐glycosidase inhibitors were developed: The first consists of a 2,7‐dioxabicyclo[2.2.1]heptane derivative, which was prepared by an intramolecular ketalisation. The second scaffold consists of a hydroxylated cyclopentylamine, which could be synthesised stereoselectively from 2‐azabicyclo[2.2.1]hept‐5‐en‐3‐one. The third scaffold, a 4,5‐dihydroxynicotinic acid, was accessible through a sequence of substituent directed ortho‐lithiations. Selected compounds were tested as inhibitors for a number of glycosidases. Three nicotinic acid derivatives were found to be selective β‐glucosidase inhibitors.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Impacts of river restoration on small‐wood dynamics in a low‐gradient headwater stream
Authors: Millington C. E. , Sear D. A.
Published: July 2007

Wood is an important element in many river systems, interacting with channel and floodplain geomorphology, hydrology and ecology. Restoration practices are increasingly re‐introducing wood into streams and researchers have started to study the geomorphic and ecological effects of re‐introducing wood into rivers. However, little research has attempted to quantify the impacts of river restoration (including the addition of wood jams) on wood retention. Based on tracing dowels to simulate small wood (ranging in length from 0·184 to 1·06 m and diameter from 0·006 to 0·035 m) in three study reaches before and after restoration, this study provides a detailed representation of the influence of restoration on small‐wood transport and the relative importance of different trapping sites within a low‐order meandering stream in the New Forest, UK. The research specifically addresses the following questions. (i) Does restoration reduce transport of small wood? (ii) Does restoration increase the frequency and type of small‐wood trapping sites? (iii) Do wood jams trap more small wood than other trapping sites? (iv) Do shorter pieces of wood travel further than long pieces? The study has demonstrated that (i) different types of restoration have different effects on the frequency and type of small‐wood trapping mechanisms, and hence also on small‐wood transport; (ii) wood jams were the most effective structures for trapping small wood in this environment; (iii) shorter pieces of wood travelled further than long pieces. Channel–floodplain interactions were also found to be important, allowing the floodplain to function as a trapping site. Copyright © 2007 John Wiley & Sons, Ltd.
Validation of a biotelemetric technique, using ambulatory miniature black globe thermometers, to quantify thermoregulatory behaviour in ungulates
Authors: Hetem Robyn S. , Maloney Shane K. , Fuller Andrea , Meyer Leith C.R. , Mitchell Duncan
Published: July 2007

Behavioural thermoregulation is an animal's primary defence against changes in the thermal environment. We aimed to validate a remote technique to quantify the thermal environment behaviourally selected by free‐ranging ungulates. First, we demonstrated that the temperature of miniature, 30 mm diameter, black globes (miniglobes) could be converted to standard, 150 mm diameter, black globe temperatures. Miniglobe temperature sensors subsequently were fitted to collars on three free‐ranging ungulates, namely blue wildebeest (Connochaetes taurinus), impala (Aepyceros melampus) and horse (Equus caballus). Behavioural observations were reflected in animal miniglobe temperatures which differed from those recorded by an identical miniglobe on a nearby exposed weather station. The wildebeest often selected sites protected from the wind, whereas the impala and the horse sheltered from the sun. Nested analysis of variances revealed that the impala and horse selected significantly less variable environments than those recorded at the weather station (P<0.001) over a 20‐min time interval, whereas, the microclimates selected by wildebeest tended to be more variable (P=0.08). Correlation of animal miniglobe against weather station miniglobe temperature resulted in regression slopes significantly less than one (P<0.001) for all species studied, implying that, overall, the animals selected cooler microclimates at high environmental heat loads and/or warmer microclimates at low environmental heat loads. We, therefore, have developed an ambulatory device, which can be attached to free‐ranging animals, to remotely quantify thermoregulatory behaviour and selected microclimates. J. Exp. Zool. 307A:342–356, 2007. © 2007 Wiley‐Liss, Inc.
Reactive desorption electrospray ionization for selective detection of the hydrolysis products of phosphonate esters
Authors: Song Yishu , Cooks R. Graham
Published: July 2007

Reactive desorption electrospray ionization (reactive DESI) is demonstrated to be a rapid and sensitive method for the direct detection of alkyl methylphosphonic acids, the hydrolysis products and metabolites of the chemical warfare (CW) agents VX (S‐2‐diisopropylaminoethyl‐O‐ethyl methylphosphonothiolate) and GB (sarin, isopropylmethyl phosphonofluoridate). Rapid and sensitive detection of these compounds is readily achieved by performing DESI from a solid surface; detection specificity is enhanced by implementation of a heterogeneous ion/molecule reaction using boric acid in the spray solvent. The reagent ion H2BO3− generated in the spray readily reacts with condensed‐phase alkyl MPA to form anionic adducts. The specificity of this chemical reaction, together with the characteristic fragmentation patterns of the reaction products, supplies a highly discriminatory detection method for methylphosphonic acid (MPA), ethylphosphonic acid (EMPA) and isopropyl methylphosphonic acid (IMPA) in complex matrices. Copyright © 2007 John Wiley & Sons, Ltd.
Establishment and characterization of an in vivo model for Epstein–Barr virus positive gastric carcinoma
Authors: Oh Sang Taek , Cha Jung‐Ho , Shin Dong‐Jik , Yoon Sungjoo Kim , Lee Suk Kyeong
Published: July 2007

Research regarding the role of the Epstein–Barr virus (EBV) in gastric carcinogenesis has been hampered by the absence of a suitable model system. SNU‐719 is a gastric carcinoma cell line naturally infected with EBV. This cell line developed tumors in nude mice approximately 40–56 days after inoculation. SNU‐719 also showed low serum dependency and anchorage independent growth in vitro. The developed tumors expressed EBERs, EBNA1, and LMP2A but not other EBV latent genes. Additionally, Qp was active and either mono‐ or bi‐clonal EBV genome was observed in the tumor tissues. Because the developed tumors retained characteristics of EBV‐associated gastric cancer, this cell line could serve as a useful in vivo system to investigate the tumorigenesis mechanism and treatment methods for this type of tumor. J. Med. Virol. 79:1343–1348, 2007. © Wiley‐Liss, Inc.
Amine‐Functionalized Polyacrylamide for Labeling and Crosslinking Purposes
Authors: Seiffert Sebastian , Oppermann Wilhelm
Published: July 2007

Free radical copolymerization of acrylamide with N‐(3‐aminopropyl)‐methacrylamide yields water‐soluble polymers with randomly distributed pendent nucleophilic amine moieties. The copolymerization parameters were determined to be r1 = 0.49 and r2 = 0.85. A procedure which allows controlling the degree of functionalization and the molecular weight is described in detail. Copolymers with low amounts of functional groups were used to synthesize polymers with fluoresceine or rhodamine side groups as fluorescence labels. Furthermore, reaction of the amine moieties of the copolymers with glutaraldehyde under suitable conditions provides a way to generate polymer networks via random crosslinking of existent chains in a semi‐dilute solution.

magnified image
Free Energy of Deformation of the Radius of Gyration in Semiflexible Chains
Authors: Cifra Peter , Bleha Tomáš
Published: July 2007

The distribution function P(S) of the radius of gyration S, the corresponding elastic free energy A(S) and the mean force $\left\langle f \right\rangle (S)$ were computed from simulations based on the wormlike chain (WLC) model. The relation of the S‐conjugated elastic functions to the analogous functions based on the chain vector R and their connection to the statistical‐mechanics ensembles was elucidated. Simulation data revealed that available analytical functions for P(S) fail to predict the behavior of semiflexible chains. When the power‐law function P(S) was used instead, the exponents sizeably raised with stiffness at chain expansion. The exponents deduced from elastic compression of a chain agreed fairly with the scaling exponents for chain confinement into a sphere.

magnified image
Qualitative methodologies I: asking research questions with reflexive insight
Authors: Hale Elizabeth D. , Treharne Gareth J. , Kitas George D.
Published: July 2007

The purpose of this paper, the first of a series of two discussion pieces, is to introduce some of the issues in the debate surrounding qualitative research to the readers of Musculoskeletal Care. Recent issues of the Journal have seen an informative focus on quantitative methods and statistical analysis, and here we provide an equivalent introduction to semi‐structured interviewing and qualitative analysis in this series. In the qualitative tradition, we have tried to keep our discussion reflexive, transparent and contextualized within the history of the approach and the theoretical considerations that underlie it, including the origins, nature, methods and limits of the approach. We provide information that we hope is useful for readers with all levels of familiarity with qualitative research, building from an introduction to some basic assumptions and ethical issues. We also introduce one specific qualitative approach, interpretative phenomenological analysis, which researchers might wish to apply. In the accompanying paper in a subsequent issue of Musculoskeletal Care, we will describe the potential application of this approach. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of laterally loaded piles with rectangular cross sections embedded in layered soil
Authors: Basu D. , Salgado R.
Published: July 2007

An analysis is developed to determine the response of laterally loaded rectangular piles in layered elastic media. The differential equations governing the displacements of the pile–soil system are derived using variational principles. Closed‐form solutions of pile deflection, the slope of the deflected curve, the bending moment and the shear force profiles can be obtained by this method for the entire pile length. The input parameters needed for the analysis are the pile geometry and the elastic constants of the soil and pile. The new analysis allows insights into the lateral load response of square, rectangular and circular piles and how they compare. Copyright © 2007 John Wiley & Sons,
Ltd.
Association between prenatal pesticide exposures and the generation of leukemia‐associated T(8;21)
Authors: LaFiura Katherine M. , Bielawski Dawn M. , Posecion Norberto C. , Ostrea Enrique M. , Matherly Larry H. , Taub Jeffrey W. , Ge Yubin
Published: July 2007

Background

This study was designed to investigate the relationship between prenatal pesticide exposures and the generation of leukemia‐associated t(8;21)(q22;q22), one of the most common cytogenetic abnormalities in childhood acute myeloid leukemia (AML).

Procedure

Gas chromatography/mass spectrometry (GC/MS) was used to quantitatively detect different pesticides (propoxur and cypermethrin) in meconium from 49 newborn babies from the Philippines. The generation of t(8;21) was determined in the corresponding umbilical cord blood samples by detection of the AML1‐ETO fusion transcripts derived from t(8;21) using nested RT‐PCR. Levels for the AML1‐ETO fusion transcripts were quantitated by real‐time RT‐PCR in the t(8;21) positive cord blood samples. AML1‐ETO fusion transcript forms were characterized by RT‐PCR amplification and DNA sequencing.

Results

In the present study using umbilical cord blood samples obtained from infants whose prenatal exposure to the pesticide, propoxur, was determined by meconium analysis, we showed that (i) incidence of t(8;21) in the exposed group was two‐fold higher than that in the unexposed group; and (ii) the levels for AML1‐ETO fusion transcripts resulting from t(8;21) positively correlated with propoxur concentrations in meconium. Similar heterogeneity in the fusion transcripts was detected in the t(8;21) positive cord blood samples as in our previous study with t(8;21) AML patients.

Conclusion

These results further confirm the prenatal origin of t(8;21) and establish a significant correlation between prenatal pesticide exposures and the generation of t(8;21). They suggest that prenatal pesticide exposures may be causal factors for the generation of leukemia‐associated chromosomal translocations. Pediatr Blood Cancer 2007;49:624–628. © 2007 Wiley‐Liss, Inc.
Microstructural characterization of polymeric materials by small angle neutron scattering
Authors: Rogante Massimo , Lebedev Vassili T.
Published: July 2007

Small angle neutron scattering (SANS) is considered as a nondestructive technique adoptable for the microstructural characterization of polymeric materials. The possibility to substitute hydrogen for deuterium makes SANS an exclusive technique for investigating macromolecular structures in synthetic and biological polymers. The same method allows a visualization of polymer chains, because of a local contrast between small size ordered domains and amorphous matrix around. In this article, some theoretical bases are reported, and industrial applications of SANS in the polymers field are shown. In particular, SANS investigations of either monoethylene glycol‐based polyurethanes, or heat cured and laser machined organic resin microturbines as used for airflow sensing are described. Other examples are mentioned, moreover, showing the usefulness of SANS in characterizing polymers and confirming the improvement of this tool to a level of industrial applicability. POLYM. ENG. SCI., 47:1213–1219, 2007. © 2007 Society of Plastics Engineers
Capability of cationic water‐soluble polymers in conjunction with ultrafiltration membranes to remove arsenate ions
Authors: Rivas Bernabé L. , Carmen Aguirre María del , Pereira Eduardo , Moutet Jean‐Claude , Aman Eric S.
Published: July 2007

Arsenic is one of the most hazardous pollutants, and is present in water, mainly, as As(V) and As(III), and in its inorganic hydrolysis species. Great efforts have been made to develop effective removal techniques. One alternative is the use of water‐soluble polymers containing functional groups to remove these toxic species. This paper presents the synthesis and characterization (FT‐IR and 1H NMR spectroscopy, as well as thermogravimetry TG‐DSC) of two cationic water‐soluble polymers containing tetra alkylammonium groups, poly[2‐(acryloyloxy)ethyl]trimethylammonium chloride, and poly[2‐acryloyloxy)ethyl]trimethylammonium methyl sulfate (P(SAETA)). The arsenate retention properties were investigated using the liquid‐phase polymer‐based retention technique. The polymer structure and the exchangeable anions' nature have been shown to be two important variables in the removal efficiency of arsenate anions from aqueous solutions. Both investigated polymers were found to efficiently remove HAsO42− species from an aqueous media, with pH ranging from 6 to 8. The exchange of methyl sulfate for the chloride anion on P(SAETA) improved arsenate ion retention ability. The modification of ionic strength by Na2SO4 addition induced a significant decrease in the cationic polymer's arsenate retention properties. The polymers' retention properties were not studied using real samples. POLYM. ENG. SCI., 47:1256–1261, 2007. © 2007 Society of Plastics Engineers
Controlled free radical photopolymerization of styrene initiated by trithiocarbonate
Authors: Ran Rong , Wan Tao , Gao Tao , Gao Jian , Chen Zhi
Published: July 2007

Density functional theory calculations are reported for prediction of the trends in CS bond dissociation energies and atomic spin densities for radicals using S,S′‐bis(α,α′‐dimethyl‐α‐acetic acid) trithiocarbonate (TTCA) and bis(2‐oxo‐2‐phenylethyl) trithiocarbonate (TTCB) as reversible addition fragmentation chain transfer (RAFT) reagents. The calculations predict that the value of the CS bond length (1.865 Å) of TTCA is longer than that (1.826 Å) of TTCB, and TTCA is more effective for the polymerization of styrene (St) compared to TTCB as predicted by density functional theory. In photopolymerizations, pseudo‐first‐order kinetics were confirmed for TTCB‐mediated photopolymerization of St due to the linear increase of ln([M]0/[M]) up to about 28% conversion, suggesting the living characteristics behavior of the photopolymerization of St in the presence of TTCB. For both TTCA and TTCB the polydispersities change with increasing conversion in the range 1.10–1.45, typical for RAFT‐prepared (co)polymers and well below the theoretical lower limit of 1.50 for a normal free radical polymerization. In addition, the triblock copolymer polystyrene‐block‐poly(butyl acrylate)‐block‐polystyrene (PSPBAPS) was successfully prepared, with very good control over molecular weight and narrow polydispersity (Mw/Mn = 1.45), using PSSC(S)SPS as macro‐photoinitiator under UV irradiation at room temperature. This indicated that this reversible and valid strategy led to a better controlled block copolymer with defined structures. Copyright © 2007 Society of Chemical Industry