bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multilevel governance and organizational performance: Investigating the political‐bureaucratic labyrinth
Authors: Meier Kenneth J. , O'Toole Laurence J. , Nicholson‐Crotty Sean 
Published: December 2003

AbstractResearch on governance has extensively explored the complex interactions of governmental, nongovernmental, and
for‐profit entities in the execution of public policy. It has consistently failed, however, to model
empirically the joint effects of political and bureaucratic actors in governance systems. To address this issue, a
theory of multilevel governance built upon the foundation of representative bureaucracy was developed and tested.
Results from an analysis of Texas school districts suggest that Latinos at all levels of the governance system,
political and managerial, influence representation at other levels. Findings also indicate that Latinos at each
level of governance have positive effects, directly and indirectly, on outcomes for Latino students. The influence
of both political and managerial actors at times extends beyond the immediately adjoining level; the effects
of such actors cascade through the governance system. The results show that a priority for systematic research
should be the identification of approaches and settings for examining the multilevel aspect of governance. ©
2004 by the Association for Public Policy Analysis and Management.
New insights into the roles of matrix metalloproteinases in colorectal cancer development and progression
Authors: Leeman Matthew F , Curran Stephanie , Murray Graeme I 
Published: December 2003

AbstractThis review outlines new concepts that are emerging for the functions of matrix metalloproteinases in colorectal cancer development and progression. The two main concepts that will be discussed are the role of matrix metalloproteinases in the early stages of colorectal tumour development and the functional mechanisms by which matrix metalloproteinases contribute to colorectal tumour invasion and metastasis. The matrix metalloproteinases are a group of enzymes, which have been best characterized for their ability to degrade extracellular matrix proteins and thus they have been extensively studied in tumour invasion. It is now becoming recognized that the matrix metalloproteinases have key roles in a variety of biological processes that are distinct from their well‐defined role in matrix degradation. This group of enzymes has been shown to interact with a broad range of non‐matrix proteins including growth factors and their receptors, mediators of apoptosis, and cell adhesion molecules. The elucidation of novel biological roles for the matrix metalloproteinases also challenges the current predominant concept of matrix metalloproteinases as enzymes only involved in matrix degradation. Recent studies have shown that several matrix metalloproteinases, especially matrilysin (MMP‐7), interact with the specific molecular genetic and signalling pathways involved in colorectal cancer development. In particular, matrilysin is activated at an early stage of colorectal tumourigenesis by the beta‐catenin signalling pathway. Furthermore, studies are now elucidating specific mechanisms by which individual matrix metalloproteinases, especially membrane‐type matrix metalloproteinases, interact with specific cell adhesion molecules and cytoskeletal proteins and thus contribute dynamically to colorectal tumour invasion. Copyright © 2003 John Wiley & Sons, Ltd.
CNS‐directed therapy in young children with T‐lineage acute lymphoblastic leukemia: High‐dose methotrexate versus cranial irradiation
Authors: Nathan Paul C. , Maze Ronnen , Spiegler Brenda , Greenberg Mark L. , Weitzman Sheila , Hitzler Johann K. 
Published: December 2003

AbstractBackgroundProphylactic use of cranial radiation therapy (CRT) in young children with acute lymphoblastic leukemia (ALL) is associated with significant long‐term morbidity. Therefore, current treatment protocols for pediatric B‐precursor ALL have abandoned prophylactic CRT in favor of intrathecal chemotherapy, combined with either high‐dose methotrexate infusions (HD‐MTX) or intensive systemic chemotherapy. In contrast, prophylactic CRT continues to be used in children with T‐lineage ALL (T‐ALL), who historically have had an inferior prognosis. We conducted a retrospective cohort study to determine the effect on survival of substituting HD‐MTX for CRT in young children with T‐ALL, a group that faces a high risk of long‐term sequelae from CRT.ProcedureTwenty‐six children, diagnosed with T‐ALL between the ages of 1 and 5 years, were treated on the same high‐risk leukemia protocol. Central nervous system (CNS) directed therapy consisted of either CRT (1,800 cGy) or HD‐MTX (three doses of 8 g/m2), depending on the treatment era in which patients were diagnosed.ResultsOf the 24 patients who entered remission, 12 received CRT and 12 received HD‐MTX. Five‐year event‐free survival (EFS) (±SE) was 92 ± 8% in the HD‐MTX group versus 75 ± 13% in the CRT group (P = 0.23). Five‐year overall survival (OS) was 100% in the HD‐MTX group versus 75 ± 13% in the CRT group (P = 0.07). There were no CNS recurrences in the HD‐MTX group. One patient treated with CRT developed a brain tumor.ConclusionsThe use of HD‐MTX instead of CRT as CNS‐directed therapy in very young children with T‐ALL does not compromise survival, while avoiding the adverse long‐term effects of cranial irradiation. © 2003 Wiley‐Liss, Inc.
Age is an independent prognostic factor in rhabdomyosarcoma: A report from the soft tissue sarcoma committee of the children's oncology group
Authors: Joshi D. , Anderson James R. , Paidas C. , Breneman J. , Parham D.M. , Crist W. 
Published: December 2003

AbstractBackgroundAlthough age <1 year at diagnosis has been associated with a worse prognosis in rhabdomyosarcoma (RMS), the relationship of age at diagnosis to clinical presentation and outcome has not been evaluated carefully. We reviewed data from recent Intergroup Rhabdomyosarcoma Study Committee (later called Group, IRSG) trials to examine this relationship in order to estimate prognosis more accurately and further refine treatment.ProcedureWe used data from IRS‐III, ‐IV Pilot, and ‐IV (1983–97, N = 2,343) to study the relationship of patient age with clinical features and prognosis in a large cohort of patients treated with contemporary therapy.ResultsWe showed that, after adjusting for important prognostic factors, age was an independent risk factor for treatment failure and patients could be classified into three failure‐risk categories based on age (i.e., <1 year; 1–9 years; >10 years). Infants and adolescents were more likely to have unfavorable features, including alveolar or undifferentiated tumors and advanced Group and Stage, and also had significantly poorer failure‐free survival (FFS) than did children aged 1–9 (53 and 51% vs. 72%,P < 0.001). Although there was a difference in FFS among age categories, there was no evidence that age influences outcome within the three categories.ConclusionsSince age relates independently to outcome after adjustment for known risk factors, it is likely that other factors, including perhaps patients' tolerance of protocol‐specified therapy, explain this relationship. © 2003 Wiley‐Liss, Inc.
Copolymers of 3,5‐dimethylphenyl acrylate and methyl methacrylate: synthesis, characterization and determination of monomer reactivity ratios
Authors: Vijayanand PS , Jone Selvamalar CS , Penlidis A , Nanjundan S 
Published: December 2003

AbstractCopolymers of 3,5‐dimethylphenyl acrylate (DMPA) and methyl methacrylate (MMA) having various compositions were synthesized using free radical solution polymerization in butane‐2‐one at 70 ± 1 °C with benzoyl peroxide as initiator. The structure of the copolymer was confirmed by FTIR, 1H NMR and 13C NMR spectroscopic techniques. The polydispersity indices of the copolymers determined using gel permeation chromatography suggest that the chain termination by disproportion was predominant when the mole fraction of MMA in the feed is high and radical recombination was predominant when the mole fraction of DMPA was high in the feed. The glass transition temperature of the copolymer increases with increase in MMA content. The thermal stability of the copolymers increases with increase in DMPA content. The copolymer compositions were determined using 1H NMR analysis. The monomer reactivity ratios were determined by application of conventional linearization methods such as the Fineman–Ross (r1 = 0.3942; r2 = 2.3250), the Kelen–Tüdös (r1 = 0.3848; r2 = 2.2584), an extended Kelen–Tüdös (r1 = 0.3608; r2 = 2.3384) and a non‐linear error‐in‐variables model method using a computer program, RREVM (r1 = 0.3879; r2 = 2.2642). These values suggest that MMA is more reactive than DMPA and the copolymer will be richer in MMA units. Copyright © 2003 Society of Chemical Industry
Phase transformations of some poly(vinyl alcohol)–NiCl2 composites
Authors: El‐Shahawy Magda A 
Published: December 2003

AbstractSamples of poly(vinyl alcohol)–NiCl2 composites containing up to 30 wt% NiCl2 were prepared by casting in order to study phase transformation–structural change relationships of these samples before and after heat treatment. Differential thermal analysis (DTA) thermograms were recorded at 10, 15, 20 and 30 °C min−1. For untreated samples four endotherms were assigned as: rotation of hydroxyl groups in the glassy state, glass transition, structural transition in the rubber‐like state, and melting transition. Ultrasonic attenuation measurements were carried out to confirm these transitions in the glassy and rubber‐like states. In the glassy state, the effect of NiCl2 addition is explained in terms of chain stiffness due to the creation of local crosslinked regions in amorphous parts of the polymer. Average values of activation energies for glass transition were calculated using both methods of Kissinger and Ozawa. However, addition of NiCl2 had an opposite effect on the heating rate independent crystallization melting temperature (Tm), relative to that on Tg. The DTA thermograms of heat‐treated samples indicated that square planar NiCl2 molecules were embedded in the polymer matrix with no local crosslinking role due to the formation of conjugated polyenes along the polymer chains by thermal treatment. Copyright © 2003 Society of Chemical Industry
Cross‐linking of polybutadiene: correlation between solid‐state 1H NMR spectroscopy, thermoporosimetry, densimetry and crystallinity measurements
Authors: Pilichowski Jean‐Francois , Liptaj Tibor , Morel Myriam , Terriac Emmanuel , Baba Mohamed 
Published: December 2003

AbstractT2 proton NMR relaxation times were used to follow the changes in the macromolecular chain mobility of a chemically (by dicumyl peroxide) cross‐linked polybutadiene matrix. The same phenomenon was also studied by an investigation of the ability of the polymer to crystallize using DSC measurements. The solubility of the elastomer depends on the size of its macromolecular chains. Cross‐linking, leading to an increase in the size of macromolecules, provokes an insolubility of the elastomer. By densimetry measurements, it was possible to follow the changes in the solubility of the polymer up to its gel‐point. Beyond the gel‐point, the swelling solvent, cyclohexane, was used as a textural probe. Using the shift of its solid‐solid thermal transition points, it was possible to calculate the distribution of the distances between the cross‐links as a function of the curing times by thermoporosimetry analysis. Copyright © 2003 Society of Chemical Industry
Phase transformation to β‐poly(vinylidene fluoride) by milling
Authors: Esterly Daniel M. , Love Brian J. 
Published: December 2003

AbstractCryogenic mechanical milling successfully converted α‐phase poly(vinylidene fluoride) (PVDF) powder into β‐phase PVDF, as measured by wide‐angle X‐ray diffraction. The presence of β‐phase PVDF became more pronounced with increased milling times over the limited time range evaluated. This was the first recorded instance of β‐phase powders forming from the α phase through milling. These β‐phase powders maintained their crystal structure during compression molding at 70 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 91–97, 2004
Curing of linear and crosslinked epoxy systems: A fluorescence study with dansyl derivatives
Authors: Mikeš František , González‐Benito Javier , Llidó Juan Baselga 
Published: December 2003

AbstractThe curing of diglycidyl ether of bisphenol A (DGEBA) with N,N′‐dimethylethylenediamine (N,N′‐DMEDA) or ethylenediamine (EDA) was monitored by fluorescence spectroscopy and Fourier transform infrared (in the near‐infrared region). 5‐Dimethylamino‐naphthalene‐1‐sulfonamide (DNS) derivatives were used as probes (fluorophores added to the reaction mixture) and labels (fluorophores attached by covalent bonds to diglycidyl reactants). The term containing the ratio of the reaction rate constants for the addition of the secondary and primary amine hydrogens to the epoxide was included in the reduced reaction rate term for the autocatalyzed and catalyzed epoxide curing reactions. The changes in the integrated fluorescence intensities of the labels during the epoxy group conversion indicated, in some cases, the most important changes in the chemical transformations of the reaction mixture: the epoxy group conversion, during which a rapid increase in the tertiary amino group concentration was first observed; the gel point (for EDA); and the entry of the system into the glassy state (for N,N′‐DMEDA and EDA). The fluorescence probes monitored neither the gel point nor the threshold of the glassy state. For the DGEBA–N,N′‐DMEDA system, a wavy dependence of the integrated fluorescence intensities of the DNS labels on the epoxy group conversion might reflect the molar concentrations of polymer homologues (referred to the initial number of moles in the system) in the reaction mixtures of the diepoxide and secondary diamine. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 64–78, 2004
The interaction between poly(N‐isopropylacrylamide) and salts in aqueous media: The “salting‐out” phenomenon as studied by attenuated total reflection/fourier transform infrared spectroscopy
Authors: Paz Yaron , Kesselman Ellina , Fahoum Lulu , Portnaya Irina , Ramon Ory 
Published: December 2003

AbstractThe effect of two strong salting‐out salts (Na2SO4 and K2SO4) on the temperature‐induced phase‐separation process in aqueous solutions of poly(N‐isopropylacrylamide) (PNIPA) was examined by attenuated total reflectance/Fourier transform infrared spectroscopy, differential scanning calorimetry, and viscosity measurements. On the basis of these measurements, a detailed scenario of the phase‐separation process was deduced. The phase‐separation scenario of solutions containing PNIPA and water was altered in the presence of sulfate ions. Here, the sulfate ions induced partial intrachain collapse, manifested by a relatively compact structure well below the lower critical solution temperature. This led to a more gradual, smooth phase transition, with temperature‐resolved intrachain collapse and interchain aggregation and a lesser extent of hysteresis. Although at the macrolevel one may not be able to differentiate among various scenarios altering the solvent into a poor solvent, the aforementioned microlevel measurements provided a way to expose the difference between raising the temperature and adding cosolutes. Follow‐up studies on the effect of salting‐in salts will be presented. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 33–46, 2004
Biopolymer mimicry with polymeric wormlike micelles: Molecular weight scaled flexibility, locked‐in curvature, and coexisting microphases
Authors: Dalhaimer Paul , Bermudez Harry , Discher Dennis E. 
Published: December 2003

AbstractGiant and stable wormlike micelles formed in water from a series of poly(ethylene oxide) (PEO)‐based diblock copolymer amphiphiles mimicked the flexibility of various cytoskeletal filaments. The worm diameter (d) was found by cryo‐transmission electron microscopy to scale with the length of the hydrophobic chain (Nh) of the copolymer as d ∼ Nh0.61. By fluorescence video imaging of worm dynamics, we also showed that the persistence length (lP) of wormlike micelles scaled as lP ∼ d2.8, consistent with a fluid aggregate (∼d3) rather than a solid rod (∼d4). By polymerizing the unsaturated bonds of assembled copolymers, fluid worms were converted to solid‐core worms, extending the bending rigidity from that of intermediate filament biopolymers to actin filaments and, in principle, microtubules. Through partial crosslinking, polymerized worms further locked in spontaneous curvature at a novel fluid‐to‐solid percolation point. The dynamics of distinct, branched conformations were also imaged for recently discovered Y‐junctioned wormlike micelles composed of diblocks of high molecular weight (>10–15 kg/mol). Finally, block copolymers of hydrophilic weight fraction close to the transition between a vesicle‐ and worm‐former assembled into both structures, allowing encapsulation of wormlike micelles in giant vesicles reminiscent of cytoskeletal filaments enclosed within cells. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 168–176, 2004
The potential use of continuous‐flow isotope‐ratio mass spectrometry as a tool in forensic soil analysis: a preliminary report
Authors: Croft Debra J. , Pye Kenneth 
Published: December 2003

AbstractThe use of continuous‐flow isotope‐ratio mass spectrometry (CF‐IRMS) as a tool in soil analysis has been assessed as part of a larger study using a number of geological techniques applied in a forensic context. Carbon and nitrogen isotopic ratios, δ13C and δ15N, have been analysed to investigate situations which have arisen from crime casework. Three questions have been addressed: the role of spatial variation found over the short‐scale (less than 20 m), temporal variation over a period of almost 2 years, and the variation found between source soils and soil transferred to footwear soles during a simple one‐stage transfer process. Results are presented for the three experiments. The use of carbon and nitrogen isotopes has been shown to be useful in discriminating between soil types and sample locations, even when sampling occurs at a different time (as might be the case with a crime scene). In cases of primary transfer (from a source soil by a one‐stage transfer to another surface, in this case, shoes and boots), the combination of carbon and nitrogen isotope ratios is a valuable tool in discriminating between sites and in showing the relationship of the transferred samples to the relevant source soils. Used in combination with other analytical techniques, isotopic analysis may prove to be a useful tool in a forensic context. Copyright © 2003 John Wiley & Sons, Ltd.
Use of compound‐specific δ13C and δD stable isotope measurements as an aid in the source apportionment of polyaromatic hydrocarbons
Authors: Sun Chenggong , Cooper Mick , Snape Colin E. 
Published: December 2003

AbstractThe potential of using compound‐specific stable carbon isotopic analysis for the source apportionment of environmental polycyclic aromatic hydrocarbons (PAHs) has already been demonstrated by the authors, and other researchers. PAHs arising from wood burning and vehicle emissions have been shown to exhibit different isotopic signatures, and the isotopic compositions of n‐alkanes and PAHs produced from combustion of C3 and C4 plant species have been reported. 13C/12C isotopic ratios for PAHs derived from coal and wood pyrolysis and from diesel particulates have been noted to vary over a range by ca. 8‰, which may provide a basis for source apportionment. In order to further improve the ability of stable isotope measurements to source apportion environmental PAHs, hydrogen stable isotopes (δD) of PAHs from a number of processes have been measured. The wide range of δD values, in conjunction with the δ13C values obtained, provide a much greater degree of differentiation between petrol and jet fuel derived PAHs, and between PAHs from different coal conversion processes, than the δ13C values alone. Copyright © 2003 John Wiley & Sons, Ltd.
Performance evaluation of a reservation TDMA protocol for voice/data transmissions in a LEO satellite communication system
Authors: Fantacci Romano , Nannicini Saverio , Pecorella Tommaso 
Published: December 2003

AbstractIn this paper, the capability is investigated of a reservation TDMA‐based protocol to support constant bit rate and best‐effort traffics in Low Earth Orbit (LEO) satellite communication systems under typical propagation conditions. Differently from several previous papers on the same subject, we focus here on a communication channel affected by multipath fading and characterized by a high round trip delay. In our protocol, a higher priority is given to constant bit rate terminals with respect to best‐effort data terminals. The performance for constant bit rate and best‐effort terminals was derived by means of a suitable analytical approach and computer simulations. The results shown herein permits to evaluate the influence of the channel propagation conditions on the system performance. Moreover, they highlight that the reservation TDMA protocol exhibits a good behaviour for the communication channel under consideration and in comparison with a recent protocol based on the classical PRMA scheme. Copyright © 2003 John Wiley & Sons, Ltd.
Sensitivity studies for quantitative assays: use of censored data analysis
Authors: Weusten Jos J. A. M. , Wouters Pieter A. W. M. , van Zuijlen Martien C. A. 
Published: December 2003

AbstractProbit regression analysis is frequently used to study the relation between the concentration of an analyte in a sample and the probability that the assay used yields a positive test result. For these analyses only the qualitative classification ‘positive’ or ‘negative’ is used, whereas, particularly in the case where the assay is quantitative in nature, the results contain more information. In the current paper, we propose an alternative method, in which the negative test results are treated as being (left) censored. As such, more efficient use is made of the information in the data. The procedures are illustrated using two generations of NucliSens assays (BioMérieux), which are designed to quantify the viral load of HIV‐1 in blood samples. Computer simulations are used to illustrate some properties of the estimated parameters. Copyright © 2003 John Wiley & Sons, Ltd.
Bayesian approaches to multiple sources of evidence and uncertainty in complex cost‐effectiveness modelling
Authors: Spiegelhalter David J , Best Nicola G 
Published: December 2003

AbstractIncreasingly complex models are being used to evaluate the cost‐effectiveness of medical interventions. We describe the multiple sources of uncertainty that are relevant to such models, and their relation to either probabilistic or deterministic sensitivity analysis. A Bayesian approach appears natural in this context. We explore how sensitivity analysis to patient heterogeneity and parameter uncertainty can be simultaneously investigated, and illustrate the necessary computation when expected costs and benefits can be calculated in closed form, such as in discrete‐time discrete‐state Markov models. Information about parameters can either be expressed as a prior distribution, or derived as a posterior distribution given a generalized synthesis of available data in which multiple sources of evidence can be differentially weighted according to their assumed quality. The resulting joint posterior distributions on costs and benefits can then provide inferences on incremental cost‐effectiveness, best presented as posterior distributions over net‐benefit and cost‐effectiveness acceptability curves. These ideas are illustrated with a detailed running example concerning the cost‐effectiveness of hip prostheses in different age–sex subgroups. All computations are carried out using freely available software for conducting Markov chain Monte Carlo analysis. Copyright 2003 John Wiley & Sons, Ltd.