bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of bi‐functional photorefractive hyperbranched polyisophthalesters
Authors: Kou Huiguang , Shi Wenfang 
Published: July 2004

AbstractA series of novel bi‐functional photorefractive (PR) hyperbranched polyisophthalesters (HPIPEs) with pendant end carbazolyl and azo groups, acting as photoconductors and electro‐optic (EO) chromophores, respectively, were synthesized by modifying the HPIPE with N‐hydroxyethyl carbazole and 4‐(p‐nitrophenylazo) (N‐ethoxyl‐N‐methyl)aniline. These obtained PR polymers were then characterized by UV‐vis and IR spectrum, 1H‐NMR, elemental analysis, gel permeation chromatography (GPC) measurements and thermal analysis. As expected, due to their three‐dimension molecular structures, the lower glass transition temperatures (21–49°C) were obtained in the absence of plasticizers, which provide a necessary free volume for the EO chromophores reorientation. The acceptable thermal stability, as well as the degradation temperatures of 205–260°C, was also determined by thermogravimetric analysis (TGA). The two‐beam coupling experiments of HPIPE‐25Azo theoretically containing 25% azo end groups showed that a high gain coefficient of 59 cm−1 was obtained at the applied electric field of 80 V μm−1. Copyright © 2004 John Wiley & Sons, Ltd.
Peripheral blood monocyte count as an aid in optimizing progenitor collection in children
Authors: Strahlendorf Caron , Chan Grace 
Published: July 2004

AbstractCD34 enumeration, although established as the gold standard for timing peripheral blood progenitor cell harvests, is not always available. We investigated whether the peripheral blood monocyte population could be used to assist in predicting the peak of circulating progenitors for harvesting autologous blood stem cells in children. A retrospective analysis was done on 140 harvests in 40 patients. Cross‐tabulation analysis of peripheral blood CD34 counts and monocyte counts showed a good correlation. We conclude that in the absence of CD34 results, the monocyte count gives a good indication of early marrow regeneration and helps in predicting optimal time for harvest. © 2004 Wiley‐Liss, Inc.
A new method for the extraction of specific interaction enthalpy from the enthalpy of solvation
Authors: Solomonov Boris N. , Novikov Vladimir B. , Varfolomeev Mikhail A. , Mileshko Natalia M. 
Published: July 2004

AbstractA new, simple method for the extraction of specific interaction enthalpy from the enthalpy of solvation is proposed. It is based on empirical but very general relationships describing the non‐specific solvation enthalpy. The specific interaction enthalpy is calculated from the solution enthalpies in the solvent under consideration, cyclohexane and tetrachloromethane. The solution enthalpy of at least one linear alkane in the solvent must also be available. The solution enthalpies of a ‘model compound’ or homomorph are not required. This method is applicable not only for proton‐donor solutes but also for acceptor solutes such as iodine. It can be used also for solvents associated by hydrogen bonding (e.g. alcohols). The enthalpies of specific interaction for 280 solute–solvent systems were calculated. Solution enthalpy data were mainly obtained from the literature and partially measured by the authors. The results were compared with literature data on complexation enthalpy. Copyright © 2004 John Wiley & Sons, Ltd.
Electron transfer reactivity of methyl‐substituted amine NHn(CH3)3−n/NHn(CH3) (n = 0–3) self‐exchange systems: a theoretical investigation
Authors: Sun Qiao , Bu Yuxiang , Sun Lixiang , Yan Shihai , Cheng Xueli 
Published: July 2004

AbstractThe geometries of NHn(CH3)3−n, NHn(CH3) (n = 0–3) and their corresponding coupling complexes [NHn(CH3)3−n···NHn(CH3) (n = 0–3)] were determined using density functional theory (DFT) and ab initio methods at the 6–311+G* basis set level, and the relative stability is predicted to decrease in the order H3N···NH > CH3H2N···NH2CH > (CH3)2HN···NH(CH3) > (CH3)3N···N(CH3) for the four stable encounter complexes. The inapplicability is also discussed for the DFT methods in predicting the dissociation energy curves especially with long contact distance in which the DFT methods give abnormal behavior for the dissociation of the complexes due to the ‘inverse symmetry breaking’ problem. The contact distance dependences of the activation energy, the coupling matrix element and the electron‐transfer (ET) rate were determined with the MP2/6–311+G* or MP2/6–31G* method. The results show that ET reactions occur chiefly only over a small range of contact distances where the favorable ones are 1.9 Å < RN—N < 4.0 Å for NH3···NH, 2.5 Å < RN—N < 5.0 Å for CH3H2N··· NH2CH, 2.1 Å < RN—N < 5.0 Å for (CH3)2HN···NH(CH3) and 3.2 Å < RN—N < 6.0 Å for (CH3)3N··· N(CH3) coupling systems. The most optimum contact distances for the above four coupling systems are 2.4, 3.0, 2.7 and 3.7 Å where the corresponding maximum ET rates are 2.53 × 105 s−1(H3N···NH), 1.16 × 103 s−1(CH3H2N···NH2CH), 7.55 × 10−3 s−1 [(CH3)2HN···NH(CH3)] and 2.25 × 10−4 s−1 [(CH3)3N··· N(CH3)], respectively, and the corresponding maximum ET rate order is H3N···NH > CH3H2N··· NH2CH > (CH3)2HN···NH(CH3) > (CH3)3N···N(CH3). Increasing substituents on the active N centers may significantly change the ET rate and other kinetic parameters. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of the particle size distribution on the low shear viscosity of high‐solid‐content latexes
Authors: Do Amaral Marcelo , Van Es Steven , Asua José M. 
Published: July 2004

AbstractThe production of high‐solid‐content, low‐viscosity latexes is an active field in both industry and academia. The viscosity of polymer dispersions has a clear dependence on the particle size distribution (PSD). An example is the rule of thumb that a bimodal PSD enables the reduction of the viscosity with respect to monomodal systems. Despite important progress in theoretical work, not much has been done to quantitatively predict the low shear viscosity of aqueous polymer dispersions as a function of the complex PSD. In this work, the capability of a low‐shear‐viscosity equation to quantitatively account for the influence of both the PSD and the physicochemical characteristics of the dispersions is experimentally assessed. An analysis, consistent with theoretical concepts, of the data with semiempirical correlations is proposed. Next, with values of the parameters of the viscosity equation obtained experimentally, the effect of a latex with a 70% solid content on the low shear viscosity is examined. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3936–3946, 2004
Tsp36, a tapeworm small heat‐shock protein with a duplicated α‐crystallin domain, forms dimers and tetramers with good chaperone‐like activity
Authors: Kappé Guido , Aquilina J. Andrew , Wunderink Lisa , Kamps Bram , Robinson Carol V. , Garate Teresa , Boelens Wilbert C. , de Jong Wilfried W. 
Published: July 2004

AbstractSmall heat shock proteins (sHSPs), which range in monomer size between 12 and 42 kDa, are characterized by a conserved C‐terminal α‐crystallin domain of 80–100 residues. They generally form large homo‐ or heteromeric complexes, and typically have in vitro chaperone‐like activity, keeping unfolding proteins in solution. A special type of sHSP, with a duplicated α‐crystallin domain, is present in parasitic flatworms (Platyhelminthes). Considering that an α‐crystallin domain is essential for the oligomerization and chaperone‐like properties of sHSPs, we characterized Tsp36 from the tapeworm Taenia saginata. Both wild‐type Tsp36 and a mutant (Tsp36C→R) in which the single cysteine has been replaced by arginine were expressed and purified. Far‐UV CD measurements of Tsp36 were in agreement with secondary structure predictions, which indicated α‐helical structure in the N‐terminal region and the expected β‐sandwich structure for the two α‐crystallin domains. Gel permeation chromatography and nano‐ESI‐MS showed that wild type Tsp36 forms dimers in a reducing environment, and tetramers in a non‐reducing environment. The tetramers are stabilized by disulfide bridges involving a large proportion of the Tsp36 monomers. Tsp36C→R exclusively occurs as dimers according to gel permeation chromatography, while the nondisulfide bonded fraction of wild type Tsp36 dissociates from tetramers into dimers under nonreducing conditions at increased temperature (43°C). The tetrameric form of Tsp36 has a greater chaperone‐like activity than the dimeric form. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Molecular modeling of the core of Aβ amyloid fibrils
Authors: Guo Jun‐tao , Wetzel Ronald , Xu Ying 
Published: July 2004

AbstractAmyloid fibrils, a key pathological feature of Alzheimer's disease (AD) and other amyloidosis implicated in neurodegeneration, have a characteristic cross‐β structure. Here we present a structural model for the core of amyloid fibrils formed by the Aβ peptide using computational approaches and experimental data. Aβ(15–36) was threaded against the parallel β‐helical proteins. Our multi‐layer model was constructed using the top scoring template 1lxa, a left‐handed parallel β‐helical protein. This six‐rung helical model has in‐register repeats of the Aβ(15–36) sequence. Each rung has three β‐strands separated by two turns. The model was tested using molecular dynamics simulations in explicit water, and is in good agreement with a number of experimental observations. In addition, a model based on right‐handed helical proteins is also described. The core structural model described here might serve as the building block of the Aβ(1–40) amyloid fibril as well as some other amyloid fibrils. Proteins 2004. © 2004 Wiley‐Liss, Inc.
Methods for electronic‐structure calculations: Overview from a reduced‐density‐matrix point of view
Authors: Ziesche P. , Tasnádi F. 
Published: July 2004

AbstractThe methods of quantum chemistry and solid state theory to solve the many‐body problem are reviewed. We start with the definitions of reduced density matrices, their properties (contraction sum rules, spectral resolutions, cumulant expansion, and N‐representability), and their determining equations (contracted Schrödinger equations), and we summarize recent extensions and generalizations of the traditional quantum chemical methods, of the density functional theory, and of the quasiparticle theory: from finite to extended systems (incremental method), from density‐to‐density matrix (density matrix functional theory), from weak to strong correlation (dynamical mean field theory), from homogeneous (Kimball–Overhauser approach) to inhomogeneous and finite systems. Measures of the correlation strength are discussed. The cumulant two‐body reduced density matrix proves to be a key quantity. Its spectral resolution contains geminals, possibly the solutions of an approximate effective two‐body equation, and we sketch the idea of how its contraction sum rule can be used for a variational treatment. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004
Virus‐induced neuronal apoptosis as pathological and protective responses of the host
Authors: Mori Isamu , Nishiyama Yukihiro , Yokochi Takashi , Kimura Yoshinobu 
Published: July 2004

AbstractExtensive efforts have been made to elucidate mechanisms by which viruses induce apoptosis in cultured neuronal cells. However, little is yet understood about the mechanisms of neuronal apoptosis in vivo as well as interpretations of this active host response. Here we review recent advances toward understanding these topics. The c‐Jun N‐terminal protein kinase cascade may be an important apoptotic mediator in virally infected neurons, which comes in focus as a therapeutic target for protecting neurons from death. A novel concept can be proposed that virus‐induced neuronal apoptosis in the central nervous system may represent a pathological host response, while that in the peripheral counterpart, especially olfactory receptor neurons, may mediate a protective host response. Copyright © 2004 John Wiley & Sons, Ltd.
Simian virus 40 (SV40) and human cancer: a review of the serological data
Authors: Shah Keerti V. , Galloway Denise A. , Knowles Wendy A. , Viscidi Raphael P. 
Published: July 2004

AbstractSerum antibodies are widely utilised as specific and sensitive markers of virus infections but they have been employed relatively infrequently in the investigation of simian virus 40 (SV40) as a human carcinogen. In the past few years, serological data have become available which allow an examination of whether SV40 is currently circulating in human communities and if SV40 infection is associated with human cancer. The development of EIA with virus‐like particles (VLPs) of SV40, BKV and JCV has facilitated serological studies. Sera from macaques naturally infected with SV40 cross‐react unambiguously with BKV and JCV VLPs. Tests of over 9000 human sera with different immunological assays reveal a common pattern of SV40 reactivity. A small proportion of sera react at low titers and this reactivity is unrelated to age or the geographic location of the donor, but correlates with the presence and titers of BKV and JCV antibodies. Absorption with BKV and JCV VLPs decreases or abolishes the SV40 reactivity of human sera. The SV40 reactivity of sera from patients with mesothelioma, osteosarcoma or lymphomas, cancers which are reported to be associated with SV40, was similar to that in their controls or other comparison groups. The SV40 reactivity of human sera appears to be almost entirely a result of cross‐reactivity with BKV and JCV antibodies. Serological data thus do not support the possibility that SV40 is circulating in human communities or that it is associated with human cancer. Copyright © 2004 John Wiley & Sons, Ltd.
Habitat survey and classification of urban rivers
Authors: Davenport Angela J. , Gurnell Angela M. , Armitage Patrick D. 
Published: July 2004

AbstractRiver surveys are undertaken for a variety of purposes including (i) to establish inventories of particular features and their changes, (ii) to collect data to underpin the classification of river types or to assess resources according to particular criteria, and (iii) to identify sites that have particular qualities or may require particular types of management. In this paper we describe a new reach‐scale survey technique, a range of synthetic indices, and a series of classifications specifically developed for application to urban rivers.The Urban River Survey (URS) is developed from the River Habitat Survey (RHS) which is applied routinely to UK rivers. A number of important differences between the URS and RHS allow the former to provide improved discrimination between urban river channels to support management decision‐making. Urban river stretches are identified for survey according to their engineering type (a combination of planform, cross‐sectional form and level of reinforcement). The URS is then applied to stretches of a single engineering type and incorporates recording of (i) additional variables to the RHS that are particularly relevant to urban channels (e.g. indicators of pollution); (ii) improved resolution in the recording of some variables in comparison with the RHS (e.g. habitat features); and (iii) separation of layers of information that relate to the engineered (e.g. artificially introduced materials) and more natural (e.g. bank materials and morphological features) channel properties so that the interaction between these properties can be identified.The URS is applied during two surveys of approximately 50 stretches of the River Tame, West Midlands, UK. The data are used to estimate a range of synthetic indices describing ‘Materials’, ‘Physical Habitat’ and ‘Vegetation’ attributes of urban river stretches. Cluster analysis is then applied to these indices to derive three classifications of urban river stretches. The similarity in classifications based on measurements from two different surveys indicates their robustness. Because the type of engineering applied to a stretch appears to have a significant influence on the class to which the stretch is allocated in each of the three classifications (with the strongest associations being apparent in the Materials classes and the weakest in the Vegetation classes), they can be used to explore the consequences of changed engineering, and the influence of scenarios of vegetation and water quality management can be additionally explored in relation to the Vegetation classification. Copyright © 2004 John Wiley & Sons, Ltd.
Modeling the effects of a log export ban in Indonesia
Authors: Dudley Richard G. 
Published: July 2004

AbstractBecause enforcement of forestry law has become extremely difﬁcult in Indonesia, a ban on export of logs has been suggested as a means of controlling over‐harvest and illegal logging. A model of a log export ban can help us visualize its effects on the forestry sector. The model consists of simpliﬁed overviews of: the wood processing sector, demand—price feedback loops, forest standing stock and log availability, log harvest capacity, and log exports. It examines important feedbacks that must be understood if the potential costs and beneﬁts of a log export ban are to be properly considered. Although some scenarios can help reduce log harvests to sustainable levels, others encourage expansion of small domestic milling capacity leading to increased log harvests. Excess domestic milling capacity added during a log export ban may continue to operate even after a log export ban is lifted. For a log export ban to be an effective tool in combating over‐harvest and illegal harvest, limits must also be placed on possible increases in domestic milling and logging capacity. Copyright © 2004 John Wiley & Sons, Ltd
Models for management of wildlife populations: lessons from spectacled bears in zoos and grizzly bears in Yellowstone
Authors: Faust Lisa J. , Jackson Rosemary , Ford Andrew , Earnhardt Joanne M. , Thompson Steven D. 
Published: July 2004

AbstractModels of population dynamics are frequently used in the management and conservation of wildlife populations. They provide a powerful method of quantitatively assessing a population's risk of decline and determining the potential to reverse the decline. Models from recent studies of managed populations are presented. The ﬁrst model simulates the spectacled bear populations maintained in American Zoo and Aquarium Association (AZA) zoos. The second model simulates the grizzly bear population in the Greater Yellowstone Ecosystem (GYE). The article concludes with a discussion of system dynamics modeling in the larger context of population dynamics modeling. Copyright © 2004 John Wiley & Sons, Ltd.
Activation of 5‐HT2 receptors enhances the release of acetylcholine in the prefrontal cortex and hippocampus of the rat
Authors: Nair Sunila G. , Gudelsky Gary A. 
Published: July 2004

AbstractThe role of 5‐HT2 receptors in the regulation of acetylcholine (ACh) release was examined in the medial prefrontal cortex and dorsal hippocampus using in vivo microdialysis. The 5‐HT2A/2C agonist ±1‐(2,5‐dimethoxy‐4‐iodophenyl) ‐2‐ aminopropane hydrochloride (DOI) (1 and 2 mg/kg, i.p.) significantly increased the extracellular concentration of ACh in both brain regions, and this response was attenuated in rats treated with the 5‐HT2A/2B/2C antagonist LY‐53,857 (3 mg/kg, i.p.). Treatment with LY‐53,857 alone did not significantly alter ACh release in either brain region The 5‐HT2C agonist 6‐chloro‐2‐(1‐piperazinyl)‐pyrazine) (MK‐212) (5 mg/kg, i.p.) significantly enhanced the release of ACh in both the prefrontal cortex and hippocampus, whereas the 5‐HT2 agonist mescaline (10 mg/kg, i.p.) produced a 2‐fold increase in ACh release only in the prefrontal cortex. Intracortical, but not intrahippocampal, infusion of DOI (100 μM) significantly enhanced the release of ACh, and intracortical infusion of LY‐53,857 (100 μM) significantly attenuated this response. These results suggest that the release of ACh in the prefrontal cortex and hippocampus is influenced by 5‐HT2 receptor mechanisms. The increase in release of ACh induced by DOI in the prefrontal cortex, but not in the hippocampus, appears to be due to 5‐HT2 receptor mechanisms localized within this brain region. Furthermore, it appears that the prefrontal cortex is more sensitive than the dorsal hippocampus to the stimulatory effect of 5‐HT2 agonists on ACh release. Synapse 53:202–207, 2004. © 2004 Wiley‐Liss, Inc.
Review of state‐of‐the‐art and output characteristics of table‐top soft x‐ray lasers
Authors: Janulewicz K. A. , Lucianetti A. , Priebe G. , Nickles P. V. 
Published: July 2004

AbstractX‐ray lasers (XRLs) belong to the brightest existing short‐wavelength sources. The development trends are discussed from the point of view their suitability for applications. A detailed analysis of the output parameters of the XRL with transient inversion proves that this type of laser has become sufficiently mature to be applied in practice. Copyright © 2004 John Wiley & Sons, Ltd.
Giotto in the Chapel of the Scrovegni: EDXRF analysis of the golden haloes with portable equipment
Authors: Cesareo Roberto , Castellano Alfredo , Buccolieri Giovanni , Quarta Stefano , Marabelli Maurizio 
Published: July 2004

AbstractEnergy‐dispersive x‐ray fluorescence (EDXRF) analysis is particularly suited to analyse paintings, because it does not significantly damage the sample and allows the measurement of several elements in a single measurement. The use of portable equipment allows a completely non‐destructive analysis, although the interpretation of the measured spectra requires a more accurate approach.EDXRF analysis of paintings generally gives the following information: identification of the elements, and therefore pigments, employed by the artist; possible presence of elements on the surface (sulphur, chlorine) due to pollution effects; identification of previous restoration areas, through the presence of ‘modern’ elements, such as titanium, zinc, cadmium and others.Recently, the famous Chapel of the Scrovegni, painted by Giotto in Padua in 1303–05, was analysed in detail to obtain the above information and, more specifically, to analyse the golden haloes. In this paper the measurement of sulphur on the surface of the frescoes is described, together with the composition of the golden haloes. Copyright © 2004 John Wiley & Sons, Ltd.
Experimental and numerical investigation of edge tones
Authors: Bamberger A. , Bänsch E. , Siebert K.G. 
Published: July 2004

AbstractWe study both, by experimental and numerical means the fluid dynamical phenomenon of edge tones. Of particular interest is the verification of scaling laws relating the frequency f to given quantities, namely d, the height of the jet, w, the stand–off distance and the velocity of the jet. We conclude that the Strouhal number Sd is related to the geometrical quantities through Sd = C ⋅ (d / w)n with n ≈ 1, in contrast to some analytical treatments of the problem. The constant C of the experiment agrees within 13–15% with the result of the numerical treatment. Only a weak dependence on the Reynolds number with respect to d is observed. In general, a very good agreement of the experimental and the numerical simulations is found.
Medical futility
Authors: Committee on Ethics  
Published: July 2004

AbstractIt is difficult to define medical futility prospectively and objectively. Nonetheless, as technology continues to advance and use more resources, it is important that physicians and their institutions develop a process for dealing with conflict surrounding the construct of medical futility.Prospective policies on medical futility are preferable to unilateral decision making by individual physicians. Such a medical futility policy should provide a systematic process for dealing with disagreements and for reaching a fair resolution, as outlined previously. When there is disagreement, patient and family values regarding treatment options and the default position of maintaining life ordinarily should take priority. However, situations may occur in which claims of reasonableness and equity in the distribution of resources are so powerful that the views of caregivers, the institution, and society will prevail.