bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Half‐Sandwich Tungsten Chlorogermyl and Chlorostannyl Complexes
Authors: Braunschweig Holger , Bera Holger , Geibel Barbara , Dörfler Rainer , Götz Daniel , Seeler Fabian , Kupfer Thomas , Radacki Krzysztof
Published: June 2007

The reaction of the dichlorogermane Me2GeCl2 and stannanes R2SnCl2 (R = Me, Bu) with the alkali tungsten salts M[(η5‐C5R′5)L(OC)2W] (L = CO, PPh3; M = Li, Na; R′ = H, Me) yields via alkali salt elimination a range of novel chlorostannyl‐ and chlorogermyl‐functionalized tungsten complexes of the general formula [(η5‐C5R′5)L(OC)2W(ER2Cl)] (R′ = H, Me; L = CO, PPh3; E = Ge, Sn; R = Me, Bu) (3a–e). The use of the phosphane‐substituted tungsten anion Na[(η5‐C5Me5)(Ph3P)(OC)2W] (1c) and Me2SnCl2 leads to a mixture consisting of the mono‐ (3e) as well as the di‐substituted stannyl compound [{(η5‐C5H5)(Ph3P)(OC)2W}2(SnMe2)] (4). Access to 3a is also given by reaction of ClMe2Sn–C5H5 (5) with [(MeCN)3W(CO)3] which includes chemoselective tin shift from the cyclopentadiene to the tungsten atom. In addition, a successive chlorination of [(η5‐C5H5)(OC)3W(SnMe3)] (6) via [(η5‐C5H5)(OC)3W(SnMe2Cl)] (3a) and [(η5‐C5H5)(OC)3W(SnMeCl2)] (7) to [(η5‐C5H5)(OC)3W(SnCl3)] (8) is presented. All new compounds have been fully characterized by elemental analyses and in solution by IR and multinuclear NMR spectroscopy. The crystal structures of complexes 3b–d and 8 were presented and discussed, showing bond lengths of 2.6272(4) Å for Ge–W, 2.7959(5) (3b), 2.7866(3) (3d) and 2.7244(3) (8) Å for the Sn–W bonds.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
On the use of high‐order finite‐difference discretization for LES with double decomposition of the subgrid‐scale stresses
Authors: Meyers J. , Lacor C. , Baelmans M.
Published: June 2007

Large eddy simulation (LES) with additional filtering of the non‐linear term, also coined LES with double decomposition of the subgrid‐scale stress, is considered. In the literature, this approach is mainly encountered in combination with pseudo‐spectral discretization methods. In this case, the additional filter is a sharp cut‐off filter, which appears in the eventual computational algorithm as the 2/3‐dealiasing procedure. In the present paper, the LES approach with additional filtering of the non‐linear term is evaluated in a spatial, finite‐difference discretization approach. The sharp cut‐off filter used in pseudo‐spectral methods is then replaced by a ‘spectral‐like’ filter, which is formulated and discretized in physical space.
As suggested in the literature, the filter width Δ of this spectral‐like filter corresponds at least to 3/2 times the grid spacing h to avoid aliasing. Furthermore, spectral‐like discretization of the derivatives are constructed such that derivative‐discretization errors are low in the wavenumber range resolved by the filter, i.e. 0⩽kh⩽2π/3. The resulting method in combination with a Smagorinsky model is tested for decaying homogeneous isotropic turbulence and compared to standard lower‐order discretization methods. Further, an analysis is elaborated of the Galilean‐invariance problem, which arises when LES in double decomposition approach is combined with filters, which do not correspond to an orthogonal projection. The effects of a Galilean coordinate transformation on LES results, are identified in simulations, and we demonstrate that a Galilean transformation leads to wavenumber‐dependent shifts of the energy spectra. Copyright © 2007 John Wiley & Sons, Ltd.
Community social and place predictors of sense of community: A multilevel and longitudinal analysis
Authors: Long D. Adam , Perkins Douglas D.
Published: June 2007

Sense of community (SOC) is empirically “unpacked” as a multilevel construct with place and social elements. SOC has been studied primarily at the individual level despite researchers acknowledging its effects at the community level. Little attention has been given to the roles of place and place attitudes in SOC. We argue that place and social are inextricably bound, and studying the impact of the social alone on community‐oriented constructs like SOC constrains our ability to adequately understand such multilevel, multifaceted phenomena. The present, cross‐sectional and longitudinal analyses demonstrate that SOC is intimately related to social capital (neighboring, citizen participation, collective efficacy, informal social control), communitarianism, place attachment, community confidence, and community satisfaction. Implications for community and environmental psychology theory are discussed. © 2007 Wiley Periodicals, Inc. J Comm Psychol 35: 563–581, 2007.
Perceptions about services and dropout from a substance abuse case management program
Authors: Sosin Michael R. , Durkin Elizabeth
Published: June 2007

This article uses event history analysis to examine certain determinants of dropout from a case management program that serves homeless adults with substance abuse problems. The examined determinants are perceptions of conventional treatment services: (a) client perceptions concerning the value of the conventional services that case managers help them to obtain, (b) the views of use services held by social contacts, and (c) client perceptions of the legitimacy of conventional services. The findings, some of which involve statistical interactions, suggest that clients drop out of case management services more slowly (a) when they favor pursuit of particularly efficacious conventional programs; (b) when they find conventional programs to be of low legitimacy; (c) when, under special conditions, they perceive that conventional services are less caring; or (d) when social contracts do not pressure them. These findings generally imply that clients look to case management services when they are more skeptical about conventional services. The variables predicting dropout from case management poorly predict continuation in conventional substance abuse services, indicating that dropout is linked to perceptions of services in context‐specific ways. © 2007 Wiley Periodicals, Inc. J Comm Psychol 35: 583–602, 2007.
What factors predict women's disclosure of sexual assault to mental health professionals?
Authors: Starzynski Laura L. , Ullman Sarah E. , Townsend Stephanie M. , Long LaDonna M. , Long Susan M.
Published: June 2007

Although many sexual assault survivors seek support from mental health sources for adverse psychological symptoms due to sexual assault, many do not. A diverse sample of adult sexual assault survivors was surveyed about their sexual assault experiences, social reactions received when disclosing assault, attributions of blame, coping strategies, and psychological symptomatology. Statistical analyses were run to identify demographic, assault, and postassault factors differentiating women who disclosed from those who did not disclose sexual assault to mental health sources. Both demographic (race, sexual orientation, and age) and postassault factors (posttraumatic stress disorder [PTSD] symptom severity, number of informal support sources told, receipt of tangible aid/information support) significantly predicted assault disclosure. Implications of the results are discussed. © 2007 Wiley Periodicals, Inc. J Comm Psychol 35: 619–638, 2007.
Erratum: Adjuvant therapy for pancreatic cancer: A time that has not yet come
Authors: Neifeld James P.
Published: June 2007

The original article to which this Erratum refers was published in J. Surg. Oncol. 2007;95:530–531
Dynamic Viscoelastic Characterization of Bitumen/Polymer Roofing Membranes
Authors: Goikoetxeaundia Goretti , González Oscar , Muñoz María Eugenia , Peña Juan José , Santamaría Anton
Published: June 2007

Dynamic viscoelastic functions of bitumen/polymer waterproofing membranes are investigated. Analyses of the effect of polymer concentration on the height of the loss tangent peak observed around 20 °C reveals the existence of a continuous polymer phase. The variation of the elastic modulus and the loss modulus with frequency leads to define a Relaxation Spectrum Index which is used to determine the polymer concentration for the phase inversion. This is related to the Spanish UNE 104281 technical norm on bitumen/polymer blends for roofing. The results of the elastic modulus as a function of temperature and frequency were employed to evaluate the bonding capacity of the membranes to the roof surface. New perspectives on the characterization of bitumen/polymer membranes, similar to the Strategic Highway Research Program (SHRP) used in road pavement, are open.

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Effect of Organoclay on the Morphology and Properties of Poly(propylene)/Poly[(butylene succinate)‐co‐adipate] Blends
Authors: Sinha Ray Suprakas , Bandyopadhyay Jayita , Bousmina Mosto
Published: June 2007

The effect of organically modified clay on the morphology and properties of poly(propylene) (PP) and poly[(butylene succinate)‐co‐adipate] (PBSA) blends is studied. Virgin and organoclay modified blends were prepared by melt‐mixing of PP, PBSA and organoclay in a batch‐mixer at 190 °C. Scanning electron microscopy studies revealed a significant change in morphology of PP/PBSA blend in the presence of organoclay. The state of dispersion of silicate layers in the blend matrix was characterized by X‐ray diffraction and transmission electron microscopic observations. Dynamic mechanical analysis showed substantial improvement in flexural storage modulus of organoclay‐modified blends with respect to the neat polymer matrices or unmodified blends. Tensile properties of virgin blends also improved in the presence of organoclay. Thermal stability of virgin blends in air atmosphere dramatically improved after modification with organoclay. The effect of organoclay on the melt‐state liner viscoelastic properties of virgin blends was also studied. The non‐isothermal crystallization behavior of homopolymers, virgin, and organoclay‐modified blends were studied by differential scanning calorimeter. The effect of incorporation of organoclay on the cold crystallization behavior of PP/PBSA blends is also reported.

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Template‐Assisted Synthesis of Self‐Doped Polyaniline: Morphological Effects of Templates on the Conductivity
Authors: Kim Seong‐Cheol , Kim Dongwook , Lee Joonsuk , Wang Yanping , Yang Ke , Kumar Jayant , Bruno Ferdinando F. , Samuelson Lynne A.
Published: June 2007

Self‐doped sulfonated polyaniline (PSA) has been synthesized on the surface of micellar nanoparticles made from positively charged surfactants by biocatalysis. The conformation forced by the electrostatic charge interactions between the positively charged micelle and the negatively charged PSA increases the conductivity of the PSA by three orders of magnitude. The pure PSA recovered from ion exchange, however, shows quite similar electrical properties compared with sulfonated polyanilines reported earlier. The increased conductivity of PSA complexes is as a result of the increased charge carrier concentration caused by a certain conformational locking.

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Electropolymerizable Terthiophene S,S‐Dioxide‐Fullerene Diels‐Alder Adduct for Donor/Acceptor Double‐Cable Polymers
Authors: Vida Yolanda , Suau Rafael , Casado Juan , Berlin Anna , Navarrete Juan T. López , Pérez‐Inestrosa Ezequiel
Published: June 2007

The preparation of a novel fullerene‐thiophene derivative by Diels‐Alder addition of terthiophene S,S‐dioxide was demonstrated. Extrusion of SO2 from the adduct is an effective process that yields a stable cyclohexadiene‐1,4‐bisthiophene–C60 adduct in good isolable yield. The product has been accurately characterized and opens the way to synthesize new C60 derivatives “via” Diels‐Alder methodology without the possibility of cycloreversion. Electrochemical and spectroscopic properties of this macromolecule were studied and supported by theoretical calculations to interpret its electronic structure. The first approach to the electropolymerization of this macromonomer produces donor‐acceptor molecular wires providing a new and versatile way to fullerene‐based double cable polymers.

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Deficiency in recapitulation of stage‐specific embryonic gene transcription in two‐cell stage cloned mouse embryos
Authors: Vassena Rita , Han Zhiming , Gao Shaorong , Latham Keith E.
Published: June 2007

One possible explanation to account for the ability to clone animals by somatic cell nuclear transfer is that the donor genome is reprogrammed by the oocyte to recapitulate a normal embryonic pattern of gene expression. Mouse embryos display transient transcriptional induction of a group of genes (TIGs) at the mid two‐cell stage, the first major transcriptional output of the embryonic genome, uniquely suited for evaluating whether the oocyte directs correct and efficient recapitulation of an embryo stage‐specific gene expression program before any in vitro selection occurs. We analyzed the expression of eight TIGs in two‐cell stage clones prepared with cumulus cell nuclei. One failed to be transcribed, and seven others were transcribed, but supported significantly reduced mRNA expression. The reduction ranged from 1.6‐ to 17‐fold at the mid two‐cell stage, and 1.5‐ to 13‐fold for the late two‐cell stage. Five genes were not expressed in the donor cells, and these displayed the most pronounced deficiencies in expression. Two genes were expressed in cumulus cell donors, and supported progressive accumulation of their mRNAs in clones during this period, albeit at reduced rates. One other gene expressed in cumulus cells was not activated in clones. Although a significant proportion of these genes is reactivated in two‐cell stage clones, this recapitulation is grossly imperfect, occurs at a substantially reduced level, and even fails entirely to occur for some genes. Thus, the oocyte is incapable of efficiently directing the recapitulation of early embryonic stage‐specific gene expression. Mol. Reprod. Dev. 74: 1548–1556, 2007. © 2007 Wiley‐Liss, Inc.
Relationship between muscle stress and intramuscular pressure during dynamic muscle contractions
Authors: Ward Samuel R. , Davis Jennifer , Kaufman Kenton R. , Lieber Richard L.
Published: June 2007

Intramuscular pressure (IMP) has been used to estimate muscle stress indirectly. However, the ability of this technique to estimate muscle stress under dynamic conditions is poorly characterized. Therefore, the purpose of this study was to determine the extent to which IMP is a valid surrogate for muscle stress during dynamic contractions. IMP and muscle stress were compared under steady‐state isotonic conditions and during complex dynamic length changes. During concentric contractions the shape of the IMP–velocity curve mimicked the basic shape of the force–velocity curve but with much higher variability. For eccentric contractions, a precipitous drop in IMP was observed despite increased muscle stress. The dissociation between muscle stress and IMP during dynamic contractions was partially explained by sensor movement. When the muscle was not moving, IMP explained 89% ± 5% of the variance in muscle force. However, when transducer movement occurred the linear relationship between IMP and stress was no longer observed. These findings demonstrate the difficulty in interpreting IMP under dynamic conditions when sensor movement occurs. They also illustrate the need to control transducer movement if muscle stress is to be inferred from IMP measurements such as might be desired during clinical gait testing. Muscle Nerve, 2007
Managing electronic documents and work flows: Enterprise content management at work in nonprofit organizations
Authors: Iverson Joel , Burkart Patrick
Published: June 2007

Web management and knowledge management systems have made significant technological advances, culminating in large information management systems such as enterprise content management (ECM). ECM is a Web‐based publishing system that manages large numbers of electronic documents and other Web assets intended for publication to Web portals and other complex Web sites. Work in nonprofit organizations can benefit from adopting new communication technologies that promote collaboration and enterprisewide knowledge management. The unique characteristics of ECM are enumerated and analyzed from a knowledge management perspective. We identify three stages of document life cycles in ECM implementations—content, reification, and commodification/process—as the content management model. We present the model as a mechanism for decision makers and scholars to use in evaluating the organizational impacts of systems such as ECM. We also argue that decision makers in nonprofit organizations should take care to avoid overly commodifying business processes in the final stage, where participation may be more beneficial than efficiency.
Fractals of strategic coherence in a successful nonprofit organization
Authors: Black Janice A. , Hinrichs Kim T. , Fabian Frances H.
Published: June 2007

We theorize that organizations that are able to use stories and examples to explain their strategy and offer a flexible guide to discretionary employee behaviors use them in what can be termed a fractal fashion. The thesis is based on the idea of how strategic logic can be communicated and how it can be reiterated to lead to strategic coherence across different levels of analysis in organizations. The parallels of a nonlinear, reinforcing process that is based on iteration inspired us to draw on complexity theory and fractal processes to understand the generation of strategic coherence. We present the case of a successful nonprofit organization where it appears that such a fractal use of stories occurred.
Catholic NGOs following the 1995 referendum on divorce in the Republic of Ireland
Authors: Besel Karl , Brown Joe H.
Published: June 2007

This article examines patterns of political, social, and economic change within the Republic of Ireland that led to passage of the 1995 Referendum of Divorce. It also looks at this policy's impact on public and nongovernmental organizations (NGOs) that provide court‐related services. Because the passing of the referendum is in many ways a reflection of the changing role of the Catholic church in public life, considerable attention is granted to the evolving nature of this institution, from policymaker to service provider. Implications include how Catholic NGOs partner with public institutions in providing services to families experiencing divorce.
A value‐driven approach to health care
Authors: Seicean Andreea , Neuhauser Duncan
Published: June 2007

Redefining Healthcare: Creating Value‐Based Competition on Results, by Michael E. Porter and Elizabeth O. Teisberg. Boston: Harvard Business School Press, 2006. 506 pp., $35.00 cloth.
The power spectrum of partnering
Authors: Garvey David G.
Published: June 2007

Unequal Partnerships: Beyond the Rhetoric of Philanthropic Collaboration, by Ira Silver. New York: Routledge, 2006. 160 pp., $70.00 cloth.
Silver (I) antimicrobial cotton nonwovens and printcloth
Authors: Sachinvala Navzer , Parikh D. V. , Sawhney Paul , Chang SeChin , Mirzawa Jerzey , Jarrett William , Joiner Beth
Published: June 2007

In this paper we discuss the preparation and comparative evaluation of silver (I) [Ag(I)] nonwoven and woven antimicrobial barrier fabrics generated from commercial calcium‐sodium alginates and laboratory prepared sodium carboxymethyl (CM) cotton nonwovens and CM‐cotton printcloth for potential use as wound dressings. Degrees of CM substitution (DS) in cotton nonwoven and printcloth samples by titrimetry were 0.38 and 0.10, respectively. Coordination of Ag(I) with carboxylates on fabrics was effected by ion exchange and nitrates were removed by washing to mitigate nitrate ion toxicity issues. Durability of silver coordinated fabrics was tested by soaking them in deionized water with slight agitation at 50°C. Ag(I) alginates and nonwoven Ag(I)‐CM‐cottons lost structural integrity in water. Ag‐CM‐cotton printcloth samples retained structural integrity even after four soak‐and‐dry cycles, were smooth to the touch when dry, and were smoother when moistened. They could be easily peeled from wound surfaces without inducing trauma. Solid‐state carbon‐13 (13C) nuclear magnetic resonance (NMR) spectrometry was used to observe changes in carbonyl resonances in Ag(I) alginates and Ag(I)‐CM‐printcloth, and the chemical shift positions of carbonyl resonances of uncoordinated and Ag(I) coordinated fabrics did not change. Inductively coupled plasma‐mass spectrometry (ICP‐MS) was used following fabric digestion to determine the total Ag(I) ion content in fabrics. Ag(I) alginates were found to hold about 10–50 mg Ag(I) per gram fabric; and Ag(I) cotton woven and nonwoven fabrics held about 5–10 mg Ag(I) ions per gram fabric. Kinetic release of Ag(I) after soaking once in physiological saline was studied with ICP‐MS to estimate the availability of Ag(I) upon a single exchange with Na(I) ions on wound surfaces. Alginates released between ∼13 and 28% of coordinated Ag(I), and CM‐cotton nonwovens and CM‐cotton printcloth released ∼14 and 3% of coordinated Ag(I) ions, respectively. Finally, Ag(I) alginates and Ag(I)‐CM‐cotton printcloth samples were evaluated against Gram‐positiveStaphylococcus aureusand Gram‐negativeKlebsiella pneumoniae. Ag(I) alginates suppressed 99.95% of bacterial growthin vitro. Even after four soak‐and‐dry cycles in deionized water Ag(I)‐CM‐cotton printcloth suppressed 99.99% of bacterial growthin vitro. Published in 2007 by John Wiley & Sons, Ltd.
The effect of moderate pressure on the crystalline structure of oriented polypropylene tapes using in situ X‐ray diffraction
Authors: Shavit‐Hadar Liron , Rein Dmitry M. , Khalfin Rafail L. , Terry Ann E. , Cohen Yachin
Published: June 2007

Highly oriented isotactic polypropylene tapes were examined under moderate pressure by heating and cooling during in situ X‐ray diffraction (XRD) measurements using synchrotron radiation. The formation of γ‐isotatic polypropylene (iPP) is observed upon recrystallization under pressure from the melt. The amount of γ‐iPP formed, as a function of pressure, exhibits a minimum at about 100 MPa. Upon applying moderate pressure (up to 60 MPa) significant changes are observed in the unit cell parameters, compared to their values at atmospheric pressure. At pressures above 60 MPa only a small decrease in the b unit cell parameter is observed. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis, characterization, and electroluminescence of new conjugated PPV derivatives bearing triphenylamine side‐chain through a vinylene bridge
Authors: Tan Zhan'ao , Tang Rupei , Xi Fu , Li Yongfang
Published: June 2007

Three new conjugated poly(p‐phenylene vinylene) (PPV) derivatives bearing triphenylamine side‐chain through a vinylene bridge, poly(2‐(4′‐(diphenylamino)phenylenevinyl)‐1,4‐phenylene‐vinylene) (DP‐PPV), poly(2‐(3′‐(3″,7″‐dimethyloctyloxy)phenyl)‐1,4‐phenylenevinylene‐alt‐2‐(4′‐ (diphenylamino)phenylenevinyl)‐1,4‐phenylenevinylene) (DODP‐PPV), and poly(2‐(4′‐(diphenylamino)phenylenevinyl)‐1,4‐phenylenevinylene‐co‐2‐(3′,5′‐bis(3″,7″‐dimethyloctyloxy)‐1,4‐phenylenevinylene) (DP‐co‐BD‐PPV), were synthesized according to the Gilch or Wittig method. Among the three polymers, the copolymer DP‐co‐BD‐PPV is soluble in common solvents with good thermal stability with 5% weight loss at temperatures higher than 386°C. The weight‐average molecular weight (Mw) and polydispersity index (PDI) of DP‐co‐BD‐PPV were 1.83 × 105 and 2.33, respectively. The single‐layer polymer light‐emitting diodes (PLEDs) with the configuration of Indium tin oxide (ITO)/poly (3,4‐ethylenedioxythiophene): poly(4‐styrene sulfonate)(PEDOT:PSS)/DP‐co‐BD‐PPV/Ca/Al were fabricated. The PLED emitted yellow‐green light with the turn‐on voltage of ca. 4.9 V, the maximum luminance of ca. 990 cd/m2 at 15.8 V, and the maximum electroluminescence (EL) efficiency of 0.22 cd/A. Copyright © 2007 John Wiley & Sons, Ltd.
Bismaleimide/carbon nanotube hybrids for potential aerospace application: I. Static and dynamic mechanical properties
Authors: Gu Aijuan , Liang Guozheng , Liang Dan , Ni Miao
Published: June 2007

Two kinds of hybrids based on diallyl bisphenol A modified bismaleimide (BMI‐BA) and carbon nanotubes (CNTs) or aminated carbon nanotubes (A‐CNTs) were prepared, their static and dynamic mechanical properties were investigated in detail by using impact and flexural measurements as well as dynamic mechanical analysis (DMA). Results show that these mechanical properties of hybrids greatly depended on the nature (or the functional groups on CNTs) and loading in BMI‐BA matrix of hybrids. For example, the BMI‐BA/A‐CNT hybrid with a desirable amount of A‐CNTs has a higher impact strength than the original BMI‐BA resin, while all BMI‐BA/CNT hybrids have lower impact strength than the original BMI‐BA resin. DMA test shows that all hybrids have somewhat lower storage modulus and glass transition temperature than a pure polymer, which maybe attributed to the fact that both CNTs and A‐CNTs shift the curing peak to a higher temperature range and thus decrease the crosslinking density of networks. Copyright © 2007 John Wiley & Sons, Ltd.
Dialing in color with rare earth metals: facile photoluminescent production of true white light
Authors: Shunmugam Raja , Tew Gregory N.
Published: June 2007

Combining polymeric architectures with metal ions produces hybrid materials with extremely rich properties. We are studying polymers containing terpyridine in the side chain. In this report, the chelation of lanthanide ions, Eu3+, Tb3+, and Dy3+ resulted in metal functionalized copolymers that exhibited excellent emission of red, green, and blue light respectively. The polymer architecture easily allows incorporation of all three colors into the material, which leads to the facile production of true white light in solution or the solid state. Quantum efficiencies for the polymer systems were determined. The white light system had an efficiency of 5%. Various combinations of colors were achieved from the basic RBG colors by simply varying the metal ion ratios in the polymer backbone. This easy tuning of the color makes these systems attractive. Copyright © 2007 John Wiley & Sons, Ltd.
Initial testing of cisplatin by the pediatric preclinical testing program
Authors: Tajbakhsh Mimi , Houghton Peter J. , Morton Christopher L. , Kolb E. Anders , Gorlick Richard , Maris John M. , Keir Stephen T. , Wu Jianrong , Reynolds C. Patrick , Smith Malcolm A. , Lock Richard B.
Published: June 2007

Background

Cisplatin is one of the most widely used drugs for the treatment of solid tumors in adults and children. Here, we report the activity of cisplatin against the PPTP panels of childhood cancer xenografts.

Procedures

Cisplatin was evaluated against 23 cell lines, and 40 xenografts representing brain tumors, neuroblastoma, rhabdoid tumors, sarcoma, Wilms tumor, and acute lymphoblastic leukemia (ALL). The IC50 concentration in vitro was determined for 96 hr exposure. Solid tumors were grown subcutaneously in immune‐deficient mice, and tumor dimensions measured weekly. ALL xenografts were inoculated intravenously and the percent human CD45+ cells in the peripheral blood determined weekly. The antitumor activity of cisplatin (7 mg/kg administered intraperitoneally on Days 0 and 21) was evaluated using time to event (EFS T/C), tumor growth delay (tumor volume T/C), and objective response measures.

Results

The median IC50 concentration in vitro was 0.87 µM (0.24–4.29 µM), and cisplatin exhibited broad range activity. Cisplatin induced significant differences in EFS distributions compared to controls in 20/28 solid tumors and 4/8 ALL models. Objective responses were observed in 7/28 solid tumor models (25%): partial responses in three rhabdomyosarcomas and one Ewing's sarcoma; complete responses in one rhabdoid tumor and the medulloblastoma; and a maintained complete response in one Wilms tumor. No objective responses were observed in the ALL panel.

Conclusions

Cisplatin exhibits significant antitumor activity against a broad range of solid tumor xenograft models and limited activity against ALL xenografts. This preclinical pattern of activity is generally consistent with cisplatin's clinical activity. Pediatr Blood Cancer 2008;50:992–1000. © 2007 Wiley‐Liss, Inc.
Preservation of spleen and brain function in children with sickle cell anemia treated with hydroxyurea
Authors: Hankins Jane S. , Helton Kathleen J. , McCarville M. Beth , Li Chin‐Shang , Wang Winfred C. , Ware Russell E.
Published: June 2007

Introduction

Chronic organ damage is an insidious process in patients with sickle cell anemia (SCA). Although hydroxyurea prevents acute vaso‐occlusive events, its effects on the preservation of organ function remain undefined.

Patients and Methods

We retrospectively reviewed our single institution experience with children with SCA treated with hydroxyurea for clinical disease severity, who had optional radionuclide liver‐spleen (LS) and brain magnetic resonance imaging (MRI)/with angiography (MRA) performed before and during therapy. Studies were reviewed by pediatric radiologists blinded to treatment status. Demographic and laboratory predictors were modeled using logistic regression.

Results

A total of 43 children had spleen function measured both at baseline and on therapy. After a median of 2.6 years (range, 0.2–8.6 years) of hydroxyurea at maximum tolerated dose (MTD), six patients (14%) completely recovered splenic function and two (5%) had preserved splenic function. These eight children had a greater hemoglobin (Hb) concentration on hydroxyurea therapy than those without splenic function (9.1 vs. 8.6 gm/dl, P = 0.01). Of 25 children with brain MRI/MRA studies performed before initiating hydroxyurea and on therapy, 24 (96%) had no change in brain ischemic lesions compared with pre‐treatment studies, after a median of 2.9 years of treatment.

Conclusion

These retrospective data suggest that hydroxyurea at MTD possibly preserves spleen and brain function in children with SCA, and can even result in recovery of splenic function. Higher final Hb concentration during therapy is a significant laboratory predictor of improved splenic function. Pediatr Blood Cancer 2008;50:293–297. © 2007 Wiley‐Liss, Inc.
The European sertindole safety and exposure survey: a follow‐up study of 8600 patients
Authors: Peuskens Joseph , Moore Nicholas , Azorin Jean‐Michel , Toumi Mondher , Cochran John
Published: June 2007

Background

A regulatory signal suggested that sertindole was associated with a 10‐fold increased risk of death. This observational study aimed to identify deaths and their causes in patients treated with sertindole.

Methods

Sertindole‐treated patients in Germany, Austria, Belgium, Hungary, The Netherlands and the United Kingdom were identified and their vital status ascertained. Eventual cause of death and patient and treatment characteristics were ascertained. A nested case‐control study compared on‐treatment cardiac or unexplained deaths with randomly selected survivors matched on age and gender for potential risk factors.

Results

Eight thousand six hundred eight patients were identified as having initiated treatment with sertindole, for a total 3819 person‐years exposure. Thirty‐five had died since (all‐cause mortality rate 0.92 per 100 person‐years exposed). Of these, 15 (43%) had been previously reported to the regulatory authorities. Eight deaths were suicides, of which 2 (25%) had been previously reported; 11 were cardiac deaths, of which 8 (73%) had been reported.

On average, patients who died because of cardiac disorders were older, and patients who committed suicide were younger than the other patients who died. The nested case‐control study revealed that patients receiving sertindole were at a higher risk of premature cardiac or unexplained death if they had hypertension or other cardiovascular disorders associated with diabetes or metabolic disorder.

Conclusion

Overall and cardiovascular death rates were similar or lower than those observed in premarketing clinical trials. There was a very high reporting rate of all‐cause and cardiovascular deaths that could have contributed to the regulatory alert. Copyright © 2007 John Wiley & Sons, Ltd.
The impact of pharmaceuticals on the decline of cardiovascular mortality in Germany
Authors: Häussler Bertram , Schiffhorst Guido , Gothe Holger , Hempel Elke
Published: June 2007

Purpose

The effect of innovative medicines and surgical interventions on the decline of (cardiovascular) mortality is often called into question. The increase in general economic prosperity is often seen as the main reason for the continuous increase in life expectancy. The purpose of this study is to investigate the extent to which mortality from cardiovascular diseases has been affected by pharmaceuticals and other medical interventions over the last 30 years in Germany.

Methods

Main outcome measures were the time series of direct method death rates (DMDR) of cardiovascular and non‐cardiovascular mortalities. To control for socioeconomic and secular trends the difference between both time series was calculated. The impact of interventions on mortality was analysed by developing two linear regression models: The onset model analyses whether the introduction of interventions influences mortality or not. The consumption model estimates the quantitative impact of interventions in two phases.

Results

Cardiovascular mortality as a percentage of total mortality fell from 40 to 38% over the study period. All investigated interventions had statistically significant effects on the decline of cardiovascular diseases, which is expressed by the standardised regression coefficient: onset model: preventive behaviour index (PBI) −8.3, angioplasty/CABG −0.6, antithrombotic agents −1.5, diuretics −0.9, beta‐blockers −1.0, calcium channel blockers −0.8 and ACE inhibitors −1.1 (all interventions p < 0.01); consumption model: innovative drugs phase I −7.5 (p = 0.017), innovative drugs phase II −6.9 (p < 0.01), PBI −13.1 (p < 0.01) and angioplasty/CABG −9.9 (p < 0.01).

Conclusions

All innovative drug classes and surgical interventions had a positive effect on the decline of cardiovascular mortality. Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis of fluorene‐based high performance polymers. I. Poly(arylene thioether)s with excellent solubility and high refractive index
Authors: Seesukphronrarak Surasak , Kawasaki Shinichi , Kobori Kana , Takata Toshikazu
Published: June 2007

Several poly(arylene thioether)s (PTEs) containing a fluorene moiety were synthesized by the polycondensation of masked dithiols such as 9,9‐bis(4‐(N,N‐dimethyl‐S‐carbamoyl)phenyl)fluorene and various difluoroarenes. All PTEs were obtained in quantitative yields. The PTEs showed good thermal stability: the 10% weight loss temperature was over 480 °C under both nitrogen and air atmosphere by TGA, and glass temperature was within a range of 204–275 °C by DSC. Most PTEs exhibited remarkably high refractive index values in a range of 1.66–1.72 at 589 nm, whereas they had a very low degree of birefringence properties. Furthermore, the PTEs showed high solubility in ordinary organic solvents such as chloroform, N‐methylpyrrolidone, and tetrahydrofuran. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3073–3082, 2007
Preparation of polymers having hole and electron transport units by Friedel–Crafts reaction
Authors: Washizu Takashi , Pei Yuanfu , Ha Jaekook , Vacha Martin , Tani Kuniko , Ogino Kenji , Sato Hisaya
Published: June 2007

Polymers having 2,5‐diphenyl‐1,3,4‐oxadiazole (BCO) or anthracene (BCA) as an electron transport unit and N,N′‐diphenyl‐N,N′‐bis(4‐butylphenyl)‐benzidine (BTPD) as a hole transport unit were prepared by condensation polymerization using Friedel–Crafts reaction. It was found that BCO was less reactive than BCA. The low reactivity of the BCO monomer can be explained by the oxygen atom in the oxadiazole unit, which acts as a Lewis base and reduces the activity of the catalyst. The redox behavior measured by cyclic voltammetry showed for both BTPD‐BCO and BTPD‐BCA almost the same oxidation potential. In addition, the BTPD‐BCO also exhibited a reduction peak. Hole and electron drifts mobility of the polymers were measured by the time‐of‐flight method. The hole drift mobility of both BTPD‐BCO and BTPD‐BCA was 7.4 × 10−5 cm2 V−1 s−1. The electron drift mobilities of BTPD‐BCO and BTPD‐BCA were 6.5 × 10−5 cm2 V−1 s−1 and 5.2 × 10−6 cm2 V−1 s−1, respectively. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3083–3089, 2007
Kinetics of methyl methacrylate and n‐butyl acrylate copolymerization mediated by 2‐cyanoprop‐2‐yl dithiobenzoate as a RAFT agent
Authors: Gao Jing , Luo Yingwu , Wang Rui , Li Bogeng , Zhu Shiping
Published: June 2007

The RAFT (co)polymerization kinetics of methyl methacrylate (MMA) and n‐butyl acrylate (BA) mediated by 2‐cyanoprop‐2‐yl dithiobenzoate was studied with various RAFT concentrations and monomer compositions. The homopolymerization of MMA gave the highest rate. Increasing the BA fraction fBA dramatically decreased the copolymerization rate. The rate reached the lowest point at fMMA ∼ 0.2. This observation is in sharp contrast to the conventional RAFT‐free copolymerization, where BA homopolymerization gave the highest rate and the copolymerization rate decreased monotonously with increasing fMMA. This peculiar phenomenon can be explained by the RAFT retardation effect. The RAFT copolymerization rate can be described by 〈Rp〉/〈Rp〉0 = (1 + 2(〈kc〉/〈kt〉)〈K〉)[RAFT]0)−0.5, where 〈Rp〉0 is the RAFT‐free copolymerization rate and 〈K〉 is the apparent addition–fragmentation equilibrium coefficient. A theoretical expression of 〈K〉 based on a terminal model of addition and fragmentation reactions was derived and successfully applied to predict the RAFT copolymerization kinetics with the rate parameters obtained from the homopolymerization systems. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3098–3111, 2007
Renewable chain transfer agents for metallocene polymerizations: The effects of chiral monoterpenes on the polyolefin molecular weight and isotacticity
Authors: Mathers Robert T. , Damodaran Krishnan
Published: June 2007

Monoterpenes were used as renewable chain transfer agents and polymerization solvents for metallocene/methylaluminoxane (MAO) catalysis. The polymerization of 1‐hexene, ethylene, and propylene in d‐limonene, hydrogenated d‐limonene and α‐pinene is reported. As detected by 1H NMR analysis of the alkene region, chain transfer to d‐limonene yielded a higher percentage of trisubstituted alkenes. Size exclusion chromatography detected a decrease in molecular weight values resulting from chain transfer to d‐limonene. The [mmmm] pentads for isotactic polypropylene were characterized by 13C NMR and FTIR spectroscopy. Propylene polymerizations with the Et(Ind)2ZrCl2/MAO and Me2Si(Ind)2ZrCl2/MAO catalyst systems in d‐limonene gave [mmmm] pentad values as high as 0.97. For the Et(Ind)2ZrCl2/MAO catalyst system at 0 °C, the mol fraction of [mmmm] pentads increased from 0.86 to 0.94 upon switching the solvent from toluene to d‐limonene. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3150–3165, 2007
Linear and branched fluoroazo‐benzene chromophores with increased compatibility in semifluorinated polymers
Authors: Campbell Victoria E. , Paoprasert Peerasak , Mykietyn Justin D. , In Insik , McGee David J. , Gopalan Padma
Published: June 2007

A family of fluorinated azobenzene‐based push‐pull chromophores with one, two, and three trifluorovinyl ether (TFV) groups in linear and branched architecture was synthesized and utilized as active materials in the low optical loss electro‐optic (EO) composites. The fluorinated azobenzene chromophores exhibited increased solubility (30–50 wt %) in semifluorinated polymer host, such as perfluorocyclobutane (PFCB) aromatic ether resin after crosslinking, compared with the commercially available nonfluorinated azobenzene chromophore Disperse Red 1 (1–2 wt %). The impact of this approach on the optical properties on the polymer blends is assessed through optical propagation loss measurements and EO characterization. The resulting fluorinated EO composites showed excellent optical clarity, low birefringence, and low optical loss less than 0.5 dB/cm, while giving EO coefficients of about 3–7 pm/V at 1550 nm. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3166–3177, 2007
Effects of carbon nanotubes on crystallization and melting behavior of poly(L‐lactide) via DSC and TMDSC studies
Authors: Shieh Yeong‐Tarng , Liu Gin‐Lung
Published: June 2007

In this work, multiwalled carbon nanotubes (MWNTs) were surface‐modified and grafted with poly(L‐lactide) to obtain poly(L‐lactide)‐grafted MWNTs (i.e. MWNTs‐g‐PLLA). Films of the PLLA/MWNTs‐g‐PLLA nanocomposites were then prepared by a solution casting method to investigate the effects of the MWNTs‐g‐PLLA on nonisothermal and isothermal melt‐crystallizations of the PLLA matrix using DSC and TMDSC. DSC data found that MWNTs significantly enhanced the nonisothermal melt‐crystallization from the melt and the cold‐crystallization rates of PLLA on the subsequent heating. Temperature‐modulated differential scanning calorimetry (TMDSC) analysis on the quenched PLLA nanocomposites found that, in addition to an exothermic cold‐crystallization peak in the range of 80–120 °C, an exothermic peak in the range of 150–165 °C, attributed to recrystallization, appeared before the main melting peak in the total and nonreversing heat flow curves. The presence of the recrystallization peak signified the ongoing process of crystal perfection and, if any, the formation of secondary crystals during the heating scan. Double melting endotherms appeared for the isothermally melt‐crystallized PLLA samples at 110 °C. TMDSC analysis found that the double lamellar thickness model, other than the melting‐recrystallization model, was responsible for the double melting peaks in PLLA nanocomposites. Polarized optical microscopy images found that the nucleation rate of PLLA was enhanced by MWNTs. TMDSC analysis found that the incorporation of MWNTs caused PLLA to decrease the heat‐capacity increase (namely, ΔCp) and the Cp at glass transition temperature. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1870–1881, 2007
Analysis of recombinant human erythropoietin and darbepoietin in spiked plasma
Authors: Singh Ashok K. , Gupta Shveta
Published: June 2007

Darbepoietin (DAR) and recombinant human erythropoietin (rhEPO) stimulate erythropoiesis, leading to an increase in red blood cells. Along with their legitimate clinical use, rhEPO and DAR are also misused in racing horses for performance enhancement. To control the illegal use of DAR and rhEPO, it is important to develop analytical methods for the detection and confirmation of these proteins in plasma. Analysis of rhEPO and DAR in plasma is challenging due to the presence of a number of high abundance proteins including albumin that interferes with their extraction. The present study showed that the extraction of rhEPO or DAR from plasma using anti‐EPO–antibody coupled immunoaffinity (IA) extraction yielded low (25–40%) recovery. Albumin‐depletion using antialbumin–antibody coupled IA columns also depleted the target proteins and further reduced their recovery. Pre‐extraction of spiked plasma using hydroxyapatite (HTP)‐ProGel or ConA columns followed by the IA column yielded 65 to 70% recovery. The extracted samples were (i) analyzed directly with or without SDS‐PAGE for intact proteins and (ii) analyzed after trypsin hydrolysis, with or without SDS‐PAGE, for peptide fingerprinting using MALDI‐TOF. Trypsin and enolase were used as internal calibrators for intact protein analysis and a peptide EYEATLEECCAK was used as internal calibrator for fragment analysis. Analysis of extracted sample without SDS‐PAGE yielded, along with the target proteins (rhEPO and DAR), albumin and other related proteins. SDS‐PAGE separated the target proteins with albumin and yielded clean samples. Inclusion of internal calibrators resulted in a linear dose–response relationship for both intact protein and digested fragments and allowed quantification of the target peptides. Thus, extraction of plasma using a combination of ConA and IA extractions yielded approximately 70% recovery of target proteins with a small amount of albumin and other proteins. SDS‐PAGE improved the quality of the MALDI‐TOF results. Minimum detection limits for digested fragments were lower than those for intact proteins.
Estimation of the marginal survival time in the presence of dependent competing risks using inverse probability of censoring weighted (IPCW) methods
Authors: Matsuyama Yutaka , Yamaguchi Takuhiro
Published: June 2007

In medical studies, there is interest in inferring the marginal distribution of a survival time subject to competing risks. The Kyushu Lipid Intervention Study (KLIS) was a clinical study for hypercholesterolemia, where pravastatin treatment was compared with conventional treatment. The primary endpoint was time to events of coronary heart disease (CHD). In this study, however, some subjects died from causes other than CHD or were censored due to loss to follow‐up. Because the treatments were targeted to reduce CHD events, the investigators were interested in the effect of the treatment on CHD events in the absence of causes of death or events other than CHD. In this paper, we present a method for estimating treatment group‐specific marginal survival curves of time‐to‐event data in the presence of dependent competing risks. The proposed method is a straightforward extension of the Inverse Probability of Censoring Weighted (IPCW) method to settings with more than one reason for censoring. The results of our analysis showed that the IPCW marginal incidence for CHD was almost the same as the lower bound for which subjects with competing events were assumed to be censored at the end of all follow‐up. This result provided reassurance that the results in KLIS were robust to competing risks. Copyright © 2007 John Wiley & Sons, Ltd.
The Unsteady Boundary Layer on a Spherical Gas Bubble
Authors: Slavchev S. G. , Simeonov G.
Published: June 2007

The boundary layer on a spherical gas bubble started from rest in a viscous incompressible fluid with unsteady velocity is investigated. The velocity is assumed to depend on the time as a power function. As initial motion of the bubble is studied, the Strouhal number is large. The Strouhal number and the Reynolds number are assumed to be of the same order. The Navier‐Stokes equations expressed in spherical polar co‐ordinates are solved by the method of inner and outer expansions. The stream function is analytically obtained up to the fourth approximation. The solution is uniformly valid in the whole flow field and takes into account the interaction between the boundary layer on the bubble surface and the coming external flow. The drag force experienced by the bubble is calculated. The impulsive and uniformly accelerated motions of of the bubble are considered.
On a Nonholonomic System Serving as a Model of a Four‐Wheeled Vehicle
Authors: Lobas L. G.
Published: June 2007

The nonholonomic system considered in this study consists of absolutey solid bodies. Their configuration is described by eight generalized coordinates, their motion obeys to six equations of nonholonomic constraints. The differential equations have two first integrals. The free, steered and programmed motion was investigated. The effects of the longitudinal distribution of the masses of the system are described, recommendations are given for an effective choise of a design scheme of the vehicle.
On the Construction of Operators and Bounding Functionals for Dual Extremum Principles
Authors: Smith P.
Published: June 2007

A method is given for the decomposition of certain boundary‐value problems which contain Laplacian and non‐symmetric operators. For Hamiltonian systems this allows the application of upper and lower bounding functionals of dual extremum principles. The method is illustrated in the context of magnetohydrodynamic duct flow.