bluuebunny/crossref_metadata_2025 huggingface dataset:
Economic reform versus food security: Kerala's Gordian knot
Authors: Suryanarayana M. H.
Published: September 2002

With high levels of poverty and inadequate domestic food grain production, Kerala has been one of the most food insecure states in India. Its adverse implications, however, have been mitigated through active state government intervention and highly subsidized public distribution system operated under public vigil. As a result, per capita cereal consumption has increased in spite of a decline in domestic cereal production. Yet, about 80 per cent of the population suffer from inadequate calorie intake. The scale of the public distribution system is substantial; but its effective utilization is less than 50 per cent of the potential due to inadequate economic access and poor quality of food grains. Still the system is not sustainable for fiscal reasons. The ongoing adjustment programme has sought to streamline the food distribution programme by reforming its pricing rule and by targeting it only to the poor. The present article examines its implications for food security and social development in Kerala. Copyright © 2001 John Wiley & Sons, Ltd.
Occurrence of hepatitis E virus IgM, low avidity IgG serum antibodies, and viremia in sporadic cases of non‐A, ‐B, and ‐C acute hepatitis
Authors: Zhang J.‐Z. , Im Stanley W.K. , Lau S.H. , Chau T.N. , Lai S.T. , Ng S.P. , Peiris Malik , Tse Cindy , Ng T.K. , Ng M.H.
Published: September 2002

Serum samples were taken from 57 patients with sporadic non‐A, ‐B, and ‐C (Non A, B, C) acute hepatitis at different times after onset of the disease and tested for the presence of the hepatitis E virus (HEV) RNA, IgM, and low avidity IgG antibodies. The viral antibodies were detected using two ELISA. One assay (GL) was produced using a mixture of recombinant peptides specified by ORF2 and ORF3 of the viral genome. The other was produced with an ORF2 specified peptide, pE2. The latter occurs naturally as homodimer, it is recognized strongly in its dimeric form by human sera and, in the primate model, it confers protection against experimental HEV infection. Nineteen samples were positive for one or more of these acute markers of HEV infection, 14 of which were acute sera with elevated ALT levels and 5 were convalescent sera with normal ALT level. The results showed that icteric phase of sporadic hepatitis lasts for about 17 days and it coincides with a period when viremia is subsiding as HEV antibodies are developing. Viremia was intermittent and all but one of the 5 instances were confined to the icteric phase with elevated ALT levels. On two of these occasions, viremia preceded detection of HEV antibody, on another 2 occasions it was concurrent with the detection of pE2 specific IgM and/or low avidity IgG and only in one case of protracted viremia was the viral genome detected concurrently with avid pE2 IgG antibody. Ten (71%) of the 14 acute sera were reactive for pE2 IgM, eight (57%) were reactive for low avidity pE2 IgG, and six (43%) for the GL IgM. The sensitivity for the diagnosis of acute hepatitis E may be increased to 87% by combining pE2 IgM and viremia. GL IgM was detected later, but persisted for a longer period of time than the pE2 antibodies, and it was the only acute antibody detected in the convalescent sera. J. Med. Virol. 66:40–48, 2002. © 2002 Wiley‐Liss, Inc.
High prevalence of hepatitis E antibodies among Danish prisoners and drug users
Authors: Christensen Peer B. , Engle Ronald E. , Jacobsen Svend Erik H. , Krarup Henrik B. , Georgsen Jørgen , Purcell Robert H.
Published: September 2002

Injecting drug users and prisoners have high prevalences of antibodies to hepatitis A–C. The aim of this study was to determine the prevalence of antibodies to hepatitis E virus (anti‐HEV) in two Danish high‐risk populations and correlate anti‐HEV with risk factors for transmission. Three hundred thirty male prisoners and 137 patients at a drug treatment center were tested for anti‐HEV with an in‐house enzyme‐linked immunoassay (EIA) utilizing antigens derived from open reading frame 2 (ORF2). This was compared with a commercial test with antigens derived from ORF2 and ORF3 (Abbott HEV EIA). In addition the samples were tested for antibodies against hepatitis A–C viruses, human immunodeficiency virus (HIV) 1 and 2, human T lymphotropic virus (HTLV) I and II and herpes simplex virus type 2 (HSV2). The participants were interviewed about risk factors for transmission. The anti‐HEV prevalence was 16.9% (95% CI 14–21) for the in‐house assay compared to 4.1% (95% CI 2.5–6.3) with the commercial assay. The correlation between the two assays was low (87% overall agreement; κ value 0.32). One sample was strongly anti‐HEV IgM positive, suggesting recent HEV infection inside Denmark. The presence of anti‐HEV was associated significantly with anti‐HAV among prisoners and increased with age in both groups. In contrast, associations were not found with injecting drug use or sexual risk factors. With the commercial assay an increased prevalence of anti‐HEV was found among participants who had spent more than 5 years outside Northern Europe. In conclusion, anti‐HEV was highly prevalent among Danish prisoners and drug users but not related to risk factors for blood‐borne or sexual transmission. J. Med. Virol. 66:49–55, 2002. © 2002 Wiley‐Liss, Inc.
Late‐glacial and Holocene high‐altitude environmental changes in Vallée des Merveilles (Alpes–Maritimes, France): insect evidence
Authors: Ponel Philippe , Andrieu‐Ponel Valérie , Parchoux Franck , Juhasz Imola , de Beaulieu Jacques‐Louis
Published: September 2002

A series of sedimentary profiles derived from the Lac Long Inférieur peat‐bog (2090 m altitude, southern Alps) enabled the tracing of the evolution of successive fossil insect assemblages (Coleoptera, Hymenoptera Formicidae, Diptera Bibionidae, Trichoptera, Megaloptera and Nevroptera) from the Würm deglaciation to the present in this part of Vallée des Merveilles. This evolution reflects the climatic changes and hence the vegetation changes, as well as the human impact on the environment since neolithic times. During deglaciation, an episode marked by very poor fossil insect assemblages was followed by one with abundant boreo‐alpine Coleoptera dependent on melting snow and steppe Coleoptera. This episode corresponds to the Younger Dryas climatic deterioration (10 970 ± 210yr BP; 10 430 ± 210yr BP) during which a steppe vegetation prevailed. The sudden fall in the number of insects belonging to cold environments marks the beginning of the Holocene warming. During the Preboreal and the Boreal period (8801 ± 54 yr BP; 8692 ± 53 yr BP) these insects disappear almost totally. On the other hand, Coleoptera mostly living at the tree‐line and at forest margins increase and reach a maximum at the end of the Boreal. Thereafter (Atlantic, 8087 ± 58yr BP; 5678 ± 50yr BP) they decrease to the benefit of forest insects. This development corresponds to an elevation of the tree‐line during the Atlantic and the Sub‐boreal (4770 ± 300yr BP; 3740 ± 160yr BP) and to a thicker forest cover. Coleoptera dependent on Abies and Larix appear at this time. The final entomological event occurs at the end of the Sub‐boreal and in the Subatlantic (2660 ± 190yr BP): it is characterised by a regular decrease of tree‐dependent taxa. This development is attributed to human action. Copyright © 2001 John Wiley & Sons, Ltd.
Options for increasing carbon sequestration in West African soils: an exploratory study with special focus on Senegal
Authors: Batjes N. H.
Published: September 2002

The organic matter content of many soils in West Africa has been depleted due to overgrazing, agricultural mismanagement, deforestation and overexploitation of the natural resources. Degraded agro(eco)systems can be managed to increase carbon sinks in vegetation and soil, and to reduce carbon emissions to the atmosphere. The capacity for sequestering carbon will increase as annual precipitation increases, and generally as mean temperature decreases, provided the soil and terrain conditions are not limiting for crop (biomass) growth. The agroecological suitability of three pilot sites, proposed for soil carbon sequestration projects in Senegal, is assessed and the feasibility of various management options to increase organic carbon levels in the soil is discussed. For the future, a Land Resources Information System should be developed to consider detailed data on climate, soil and terrain conditions, status of soil degradation, and land‐use systems for West Africa. Upon its linkage to a dynamic soil carbon model and a socio‐economic module, such an integrated system can be used to assess the ecotechnological and socio‐economic potential for carbon sequestration projects in the context of the Clean Development Mechanism (CDM) proposed under article 12 of the Kyoto Protocol to the United Nations Framework Convention on Climate Change. If adopted, this mechanism could confer funds to West African countries for the sustainable use and conservation of their natural resources, thereby providing economic, environmental and societal benefits for local populations, while simultaneously contributing to climate change mitigation. Copyright © 2001 John Wiley & Sons, Ltd.
Cytoplasmic changes in relation to nuclear maturation and early embryo developmental potential of porcine oocytes: Effects of gonadotropins, cumulus cells, follicular size, and protein synthesis inhibition*
Authors: Sun Qing‐Yuan , Lai Liangxue , Bonk Aaron , Prather Randall S. , Schatten Heide
Published: September 2002

Morphological and biochemical changes indicative of cytoplasmic maturation in relation to nuclear maturation progression and early embryo developmental potential was studied. Fluorescently labeled microfilaments and cortical granules were visualized by using laser scanning confocal microscopy. The mitogen‐activated protein (MAP) kinase phosphorylation and cyclin B1 levels were revealed by Western blot. With the maturation of oocytes, cortical granules and microfilaments were localized at the cell cortex. A cortical granule‐free domain (CGFD) and an actin‐thickening area were observed over both the MII spindle of a mature oocyte and chromosomes of a nocodazole‐treated oocyte, suggesting that chromosomes, but not the spindle, determined the localization of CGFD and actin‐thickening area. In oocytes that are incompetent to resume meiosis, as indicated by the failure of germinal vesicle breakdown (GVBD), peripheral localization of cortical granules and microfilaments, phosphorylation of MAP kinase and synthesis of cyclin B1 did not occur after 44 hr in vitro. These cytoplasmic changes were also blocked when GVBD of meiotically competent oocytes was inhibited by cycloheximide. Culture of oocytes in a chemically defined medium showed that biological factors such as gonadotropins, cumulus cells and follicle size affected both nuclear and cytoplasmic maturation as well as embryo developmental potential. Absence of gonadotropins or removal of cumulus cells alone did not significantly influence GVBD or cyclin B1 levels, but decreased the final maturation and developmental ability of oocytes. A combination of gonadotropin absence and cumulus removal decreased GVBD, MAP kinase phosphorylation and embryo development. A high proportion of oocytes derived from small follicles were able to resume meiosis, synthesize cyclin B1, phosphorylate MAP kinase and translocate CGs, but their maturation and embryo developmental ability were limited. Removal of cumulus cells from small follicle‐derived oocytes severely affected their ability to undergo cytoplasmic and nuclear maturation. Mol. Reprod. Dev. 59:192–198, 2001. © 2001 Wiley‐Liss, Inc.
Improved lumen visualization in metallic vascular implants by reducing RF artifacts
Authors: Bartels Lambertus W. , Bakker Chris J.G. , Viergever Max A.
Published: September 2002

In this study, a method is proposed for MRI of the lumen of metallic vascular implants, like stents or vena cava filters. The method is based on the reduction of artifacts caused by flow, susceptibility, and RF eddy currents. Whereas both flow artifacts and susceptibility artifacts are well understood and documented, RF artifacts are not. Therefore, the present study comprises an in‐depth theoretical explanation of the factors governing the severity of these RF artifacts. It is explained that the RF caging inside cage‐like implants is caused by disturbances of the send and receive sensitivities due to coupling between the loops in the implant and the MR scanner's send and receive coils. A scaled excitation angle model describing the behavior of the signal intensity inside the implants as a function of the applied nominal excitation angle is introduced. This theoretical model was validated in phantom experiments. Reduced signal from within implants due to the caging problem could be restored by increasing the applied RF power in the excitation pulse, without exceeding the generally accepted SAR safety limits. The method was tested in vitro and in vivo in a pig model and allowed adequate depiction of the interior of a nitinol stent and that of a vena cava filter in contrast‐enhanced MR angiograms. Magn Reson Med 47:171–180, 2002. © 2002 Wiley‐Liss, Inc.
Detection of sodium ions in anisotropic environments through spin‐lock NMR
Authors: Hancu Ileana , van der Maarel Johan R.C. , Boada Fernando E.
Published: September 2002

A new method for selectively detecting sodium ions in anisotropic environments is presented. A spin‐lock (SL) sequence, followed by a coherence transfer pulse, generates rank‐two zero‐quantum coherences, and converts them into observable transverse magnetization. The quadrupolar polarization is only generated when there are residual quadrupolar couplings in the sample, and provided the SL field strength is comparable to these couplings. This filter has proved to be more efficient than a double‐quantum magic‐angle (DQ‐MA) filter in generating observable signal from ions in anisotropic media in both a nasal bovine cartilage sample and a liquid crystalline DNA sample. Finally, the SL filtering technique does not rely on a flip angle effect for the selection of the desired signal component, as does a DQ‐MA filter, and may therefore prove desirable in an imaging experiment, due to its better tolerance to phase and flip angle imperfections. Magn Reson Med 47:68–74, 2002. © 2002 Wiley‐Liss, Inc.
Aging of the human neuromuscular system
Authors: Vandervoort Anthony A.
Published: September 2002

Loss of cells from the motor system occurs during the normal aging process, leading to reduction in the complement of motor neurons and muscle fibers. The latter age‐related decrease in muscle mass has been termed “sarcopenia” and is often combined with the detrimental effects of a sedentary lifestyle in older adults, leading to a significant reduction in reserve capacity of the neuromuscular system, which is the primary subject of this review. Clear evidence of this aging effect is seen when voluntary or stimulated muscle strength is compared across the adult lifespan, with a steady decline of ∼1–2% per year occurring after the sixth decade. Interestingly, when compared with isometric contractions, the effect of aging is more pronounced for concentric movements and less for eccentric movements (i.e., muscle shortening versus lengthening). This phenomenon appears to be linked to the stiffer muscle structures and prolonged myosin crossbridge cycles of aged muscles. It is encouraging that the capability of physiological adaptations in the motor pathways remains into very old age — when an appropriate exercise stimulus is given — and long‐term prevention strategies are advocated to avoid excessive physical impairments and activity restrictions in this age group. © 2002 John Wiley & Sons, Inc. Muscle Nerve 25: 17–25, 2002
Near optimization of stochastic dynamic systems by decomposition and aggregation
Authors: Sethi S.P. , Zhang Q.
Published: September 2002

The paper is concerned with the reduction of a class of stochastic optimal control problems to simpler problems by using decomposition and aggregation. Decomposition is shown to provide a good approximation when the system dynamics involve nearly decomposable matrices or variables with strong and weak interactions. Aggregation provides a good approximation if each decomposed matrix has one or more dominant eigenvalues. It is shown how one can construct nearly optimal controls for the given system from the optimal solutions of the simpler reduced problems. The results extend the corresponding results obtained (Sethi and Zhang, Journal of optimization theory and applications 1998; 99:1–22) in a deterministic environment. The results hold a significant promise in dealing with large dynamic stochastic macroeconomic problems. Copyright © 2001 John Wiley & Sons, Ltd.
Triisobutylaluminum as cocatalyst for zirconocenes. I. Sterically opened zirconocene/triisobutylaluminum/perfluorophenylborate as highly effective ternary catalytic system for synthesis of low molecular weight polyethylenes
Authors: Panin A. N. , Sukhova T. A. , Bravaya N. M.
Published: September 2002

Ethylene polymerizations with catalytic systems Me2SiCp*NtBuZrX2 (1) [Cp* = C5(CH3)4; X = Cl (1Cl), Me (1Me)], triisobutylaluminum (TIBA), perfluorophenylborate CatB(C6F5)4 [Cat = CPh3 (3), Me2NHPh (4)], or Me2SiCp2ZrX2 [X = Cl (2Cl), Me (2Me)]/TIBA/3 (4) were performed within a wide range of ethylene pressures of different Al/Zr ratios, and Zr/B = 1. Catalytic systems 1Cl(2Cl)/TIBA/3 led to the formation of very high linear molecular weight polyethylene (PE) of Mη ∼2,000,000 with low activity. The replacement of both chlorine ligands in the precatalyst for the methyl ones led to the formation of active species producing low molecular weight PE with high activity. Chain transfer to ethylene was shown to be the main reaction controlling PE chain propagation: kp/ktr ∼20–30 for 1Me/TIBA/3 and kp/ktr ∼350–500 for 2Me/TIBA/3. It was suggested that TIBA was present in the active center first in the form of a neutral heterobimetallic Zr–Al bridged complex followed by the formation of a partially polarized Zr–Al(Cl)R2 (R = iBu) or an unreactive Zr–AlR3 cationic complex by abstraction of the alkyl ligand under the action of borate. It was concluded that AlR3 from the latter cationic complex may be easily reversibly replaced under the specific coordination of ethylene or accumulated α‐olefin, giving rise to highly labile and sterically accessible cationic species. Experiments on ethylene polymerization with the catalytic systems 1Cl(1Me)/TIBA/3/Ph2NH, 1Cl(1Me)/TIBA/4, 2Cl(2Me)/TIBA/3/Ph2NH, and 2Cl(2Me)/TIBA/4 were performed to confirm the suggestion. Catalytic systems derived from dichloride complexes in the presence of a σ‐donor substrate also produced low molecular weight PEs with molecular weight characteristics similar to those of products obtained with the dimethylated precatalysts. The specific feature of active species derived from 2Me complexes to isomerize coordinated α‐olefin into trans‐vinylene polymer chains was also revealed. The catalytic behavior of the ternary catalytic system based on 2Me relative to 2Me or 2Cl precatalysts activated with polymethylaluminoxane at different Al/Zr ratios was compared. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1901–1914, 2001
Mechanical properties of emulsion polymer blends
Authors: Robeson Lloyd. M. , Berner Robert. A.
Published: September 2002

Polymer blend technology has been one of the most investigated areas in polymer science in the past 3 decades. The one area of polymer blends that has been virtually ignored involves simple emulsion blends, although several articles have recently appeared that address film formation and mechanical characteristics. In this study, we investigated the mechanical property behavior of emulsion blends composed of low/high‐glass‐transition‐temperature polymers (where low and high mean below and above the test temperature, respectively). The emulsions chosen for this study had similar particle sizes, and the mixtures were rheologically stable. Two conditions were chosen, a binary combination of polymers that were thermodynamically immiscible and another system that was thermodynamically miscible. The mechanical property results over the entire composition range were compared with the predictions of the equivalent box model (EBM) with the universal parameters predicted by percolation theory. An array of randomly mixed and equal‐size particles of differing moduli was expected to show excellent agreement with theory, and the emulsion blends provided an excellent experimental basis for testing the theory. For the immiscible blend, the EBM prediction for the modulus showed excellent agreement with experimental results. With tensile strength, the agreement between the modulus and theory was good if the yield strength for the higher glass‐transition‐temperature polymer was employed in comparison with the actual tensile strength. The phase inversion point (where both phases were equally continuous) was at a 0.50 volume fraction of each component (based on an analysis employing Kerner's equation), just as expected for a random mixture of equal‐size particles. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 1093–1106, 2001
Molecular orbital interpretation of thymine/graphite nc‐AFM images
Authors: Komiyama Masaharu , Uchihashi Takayuki , Sugawara Yasuhiro , Morita Seizo
Published: September 2002

Recent non‐contact atomic force microscopy (nc‐AFM) images of a deoxyribonucleic acid (DNA) base thymine (2,4‐dioxy‐5‐methylpyrimidine) vacuum‐deposited on a highly oriented pyrolytic graphite (HOPG) surface are interpreted by means of theoretical adsorption simulations, and the molecular geometry and the energetics of the adsorption system are estimated. The lowest‐energy dimer configuration was found to be the one in which the respective hydrogen on N1 and the oxygen on C6 of two thymine molecules hydrogen bond to each other. A surface unit cell structure was reproduced. Adsorption energy for the thymine pair on HOPG is rather small, amounting to only ∼1 kcal mol−1, with small variations depending on the molecular orientation with respect to the substrate surface. The possibility of having a mirrored adsorption configuration in adjacent domains also is suggested. Copyright © 2001 John Wiley & Sons, Ltd.
Surface morphology of asymmetric latex film prepared from blends of natural rubber and poly(methyl methacrylate) latexes
Authors: Ho C. C. , Khew M. C. , Liew Y. F.
Published: September 2002

Colloidally stable latex blends of natural rubber (NR) and poly(methyl methacrylate) (PMMA) latexes containing up to 50 wt.% PMMA can be prepared by mixing commercial NR ammoniated latex concentrate and monodisperse PMMA latex dispersion. The clarity and tackiness of the films obtained depend on the PMMA content; films become opaque and non‐tacky at >30 wt.% PMMA content. The morphology of these films shows asymmetric distribution of the PMMA particles across the thickness of the film. There is preferential enrichment of PMMA particles at both the air/polymer and glass/polymer interfaces and a predominating NR interior. More PMMA particles are accumulated preferentially at the glass/polymer interface than at the air/polymer interface. The accumulation of the PMMA particles at the interface is strongly dependent on the size and concentration of the PMMA particles. The formation of these asymmetric latex films is explained in terms of the surface energetics, compatibility, Tg and density of the polymers, stability of the component latex, surface chemistry and particle size of the latex particles used. Copyright © 2001 John Wiley & Sons, Ltd.
Interfacial microstructure evolution in aluminium matrix composites reinforced with unoxidized and oxidized SiC particles
Authors: Shi Zhongliang , Ochiai Shijiro , Gu Mingyuan , Hojo Masaki , Lee Jae‐chul
Published: September 2002

Interfacial microstructure evolution of Al matrix composites with non‐oxidized and oxidized SiC particles as reinforcement was investigated using x‐ray diffraction, field emission scanning electron microscopy (FE‐SEM) and transmission electron microscopy (TEM). Hexagonal platelet‐shaped Al4C3 and Si are the two major interfacial reaction products in the non‐oxidized SiC‐particle‐reinforced Al matrix composites (SiCp/Al). In addition, the eutectic θ‐CuAl2 and Si phases precipitate at the SiCp/matrix interface during the last solidification stage. Observation of the interfacial reaction between the oxidized SiC particles and Al alloy containing Mg shows that the SiO2 layer has good bonding with both SiC and Al matrix and that nanoparticles of MgO have formed initially. The MgO particles will change into octahedral MgAl2O4 crystals when there is a low Mg content in the matrix (≤2 wt.%) and will remain as MgO when there is a high Mg content (≥4 wt.%). Copyright © 2001 John Wiley & Sons, Ltd.
From cofactor to enzymes. The molecular evolution of pyridoxal‐5′‐phosphate‐dependent enzymes
Authors: Christen Philipp , Mehta Perdeep K.
Published: September 2002

The pyridoxal‐5′‐phosphate (vitamin B6)‐dependent enzymes that act on amino acid substrates have multiple evolutionary origins. Thus, the common mechanistic features of B6 enzymes are not accidental historical traits but reflect evolutionary or chemical necessities. The B6 enzymes belong to four independent evolutionary lineages of paralogous proteins, of which the α family (with aspartate aminotransferase as the prototype enzyme) is by far the largest and most diverse. The considerably smaller β family (tryptophan synthase β as the prototype enzyme) is structurally and functionally more homogenous. Both the D‐alanine aminotransferase family and the alanine racemase family consist of only a few enzymes. The primordial pyridoxal‐5′‐phosphate‐dependent protein catalysts apparently first diverged into reaction‐specific protoenzymes, which then diverged further by specializing for substrate specificity. Aminotransferases as well as amino acid decarboxylases are found in two different evolutionary lineages, providing examples of convergent enzyme evolution. The functional specialization of most B6 enzymes seems to have already occurred in the universal ancestor cell before the divergence of eukaryotes, archebacteria, and eubacteria 1500 million years ago. Pyridoxal‐5′‐phosphate must have emerged very early in biological evolution; conceivably, metal ions and organic cofactors were the first biological catalysts. To simulate particular steps of molecular evolution, both the substrate and reaction specificity of existent B6 enzymes were changed by substitution of active‐site residues, and monoclonal pyridoxal‐5′‐phosphate‐dependent catalytic antibodies were produced with selection criteria that might have been operative in the evolution of protein‐assisted pyridoxal catalysis. © 2001 John Wiley & Sons, Inc. and The Japan Chemical Journal Forum Chem Rec 1:436–447, 2001
Patterson oriented automatic structure determination: superposition pseudosymmetry
Authors: Pavelčík F. , Pivovarcikova O.
Published: September 2002

An automatic structure determination method based on an interpretation of the Patterson function has been improved by utilizing information on superposition pseudosymmetry. This pseudosymmetry can be detected using MIF (multiple implication function) groups. A new method of structure determination based on an enantioselective cross-vector function and on a sum atomic minimum superposition is introduced. This new method seems to be suitable for equal-atom structures. The reliability and speed of the structure determination has been increased.
Experimental error caused by sample displacement in time-of-flight neutron diffractometry
Authors: Wang X.-L. , Wang Y. D. , Richardson J. W.
Published: September 2002

A significant error may occur in the measured lattice parameters when the sample is displaced from the diffractometer center. For time-of-flight neutron diffractometers, this error gives rise to different lattice parameters, not only for detectors at different 2θ but also for detectors at the same 2θ but on opposite sides of the incident beam. Tests made on GPPD at IPNS, Argonne National Laboratory, show that this error largely arises from a change in the diffraction constant, 1/Lsinθ, whereLis the total flight path. Modeling of the experimental data indicates that in order to achieve a precision of 10−4, a typical requirement for strain measurements, for a wide angular range of detectors, the sample should be positioned to within ∼0.1 mm of the diffractometer center. Equations are given to relate the errors measured at different diffraction angles. For small sample displacement, the error may be corrected by introducing the displacements along and normal to the incident beam as refinable parameters in least-squares-based analysis programs.
X-ray structure determination of the rare earth oxides (Er1−uGdu)2O3applying the Rietveld method
Authors: Heiba Zein , Okuyucu Hasan , Hascicek Y. S.
Published: September 2002

Nanosized polycrystalline samples of (Er1−uGdu)2O3(0 ≤u≤ 1.0) were synthesized by a sol–gel technique. X-ray diffraction data were collected and the crystal structures were refined by the Rietveld method. All samples are found to have the same crystal system and formed solid solutions over the whole range ofu. The Er3+and Gd3+ions were randomly distributed over two cationic sites, 8band 24d, in the space groupIa\bar{3} (206) in all refined structures. The lattice parameter was found to vary non-linearly with the composition (u). The average microstrain and average crystallite size have been calculated from the Williamson–Hall plots for each sample. The average size ranges from 50 to 70 nm, and the microstrain from 0.4 to 1.7%.
OMNIBUS: a program for reduction, modelling and viewing X-ray single-crystal data from various four-circle diffractometers
Authors: Gałdecka E.
Published: September 2002

OMNIBUSis a new, revised, extended and refined version of theDATPROC9program [Gałdecka (1999).J. Appl. Cryst.32, 827–832]. The basic aim of the program is to process the step-scan-measured Bragg reflections recorded on a single-crystal diffractometer to obtain aname.hkl collection of intensities for crystal structure determination. The task may be realised byOMNIBUSwith various methods, from simple ones to more sophisticated ones, based on the learnt-profile idea. Another aim that may be realised with the program is the inspection of intensity plots of the measured profiles and, for the data modelling methods, their models. The novelty of the program, in relation to its former version, lies in a new `symmetric' profile modelling method, the use of a common background model, the possibility of optimization of the width of the profile range, a wider selection of options for the calculations [available to the user in the program menu(s)] and the compatibility of the program with data from various single-crystal diffractometers (KM4-Kuma Diffraction, P3 of Siemens, CAD, Nicolet and Stoe). Special attention is paid to the data modelling, which may be observed on the screen during the calculations and analysed afterwards, based on special report files, which can for some users be treated as a task in itself.
Analysis of asymmetric broadening of X-ray diffraction peak profiles caused by randomly distributed polarized dislocation dipoles and dislocation walls
Authors: Groma I. , Monnet G.
Published: September 2002

The problem of asymmetric X-ray diffraction peak broadening caused by dislocations is investigated. The leading term responsible for the asymmetry of the intensity distribution is calculated for randomly distributed polarized dipoles and dipole walls. It is found that the polarization structure of a dislocation ensemble can be determined from the diffraction order dependence of the profile asymmetry.
A high-resolution X-ray diffractometer for the study of imperfect materials
Authors: Boulle A. , Masson O. , Guinebretière R. , Lecomte A. , Dauger A.
Published: September 2002

A high-resolution X-ray diffractometer devoted to the study of imperfect materials (mainly oxides and ceramics) is presented. It is based on a rotating anode generator, a four-bounce monochromator, a five-movement sample holder and a curved position-sensitive detector (PSD). This setup allows rapid acquisition of a reciprocal-space map (in less than 10 h) even for very poorly diffracting materials. The two-dimensional instrumental profile is calculated taking into account each optical element in the beam path. The one-dimensional instrumental profiles corresponding to widely used scans (ω scan, θ–2θ scan, rocking curve and powder scan) are also calculated. In the three former cases, the setup exhibits an excellent angular resolution (0.003°), whereas in the latter case the resolution is lowered by one order of magnitude at the benefit of a strong increase in the collected intensity. The possibilities of this diffractometer are illustrated with three examples: an epitaxic layer, a microstructured single crystal and a powder.
Resolution of neutron three-axis spectrometers using acceptance diagrams
Authors: Cussen L. D.
Published: September 2002

Two-dimensional `acceptance diagrams' are used to discuss the transmission function and the resolution of neutron three-axis spectrometers. The discussion is simplified by assuming rectangular rather than the usual Gaussian transmission profiles for the beam elements,i.e.collimators and crystal mosaic spreads, but the results can be applied to the Gaussian profile approximation. The formalism clearly shows the effects of beam elements on the instrument transmission to the detector. Suitable choices of beam elements are determined to match the transmission functions of the primary and secondary spectrometers and hence optimize measurements. The effect of sample mosaic is addressed. The `focusing angle' for inelastic scattering is determined and discussed.
Proprietary market research: are online panels appropriate?
Authors: McDevitt Paul K. , Small Michael H.
Published: September 2002

This study assesses the efficacy of using an online panel to represent the views of participants in an annual proprietary multi‐sports event. A mixed mode (online and mail survey) research design was used in an attempt to collect data from the entire client‐base. While there were some demographic similarities between the online and mail respondent groups, there were also some significant demographic and behavioral differences and important product preference differences. Our survey findings are presented and discussed. In addition, we discuss the implications of our findings for panel selection in proprietary marketing research settings.
The self‐concept and image congruence hypothesis
Authors: Heath Adam P. , Scott Don
Published: September 2002

Evaluates the applicability of self‐concept and product image congruity theory within the new motor vehicle market. By utilising competitive product offerings, and by employing the perceptions of actual owners, the paper provides a true market assessment of the applicability of the theory. Respondents were examined using self‐concept and product value constructs and their responses were used to test a number of hypotheses. Among others, the results of analysis of variance indicated that when different brands of motor vehicles were physically similar, owners perceived no difference between their own self‐concepts and the self‐concepts they attributed to owners of competing product brands. This finding differs from previous research conducted on other products and suggests a different orientation by owners of similar motor vehicles to that suggested by self‐concept theory.
Towards an ecological collaborative relationship management A “co‐opetive” perspective
Authors: Amin Zineldin Mosad
Published: September 2002

Attempts to address how organizations are responding to the growing complexities of global business, technology, and virtual organizations. Argues that organizations can co‐operate and compete at the same time in order to be more effective in the marketplace utilizing a relationship perspective. This is why we have integrated the concepts cooperation and effectiveness, to create the new “co‐opetive” terminology. An ecological collaborative value system (CVS) has been developed. The behaviour of the system is affected by the condition of its components, and the system components are affected by environmental conditions. CVS suggests that customers, suppliers, distributors, competitors, and other organizations are equal partners in the system. Argues that it is imperative for a successful alliance and relationship between the collaborators to communicate and cooperate in an atmosphere of frank debate, trust, interdependence, and mutual positive expectation so that the mutual benefits and interests may be achieved. This mechanism may enable each component of the system to monitor its performance and to adjust its operation to ensure uniform quality of its input‐output. In short, it may allow the system to learn, adapt and evolve.
A NEW AND SIMPLE CHAOS TOY
Authors: BOLLT ERIK M. , KLEBANOFF AARON
Published: September 2002

We present two new, and perhaps the simplest yet, mechanical chaos demonstrations. They are both designed based on a recipe of competing nonlinear oscillations. One of these devices is simple enough that using the provided description, it can be built using a bicycle wheel, a piece of wood routed with an elliptical track, and a ball bearing. We provide a thorough Lagrangian mechanics based derivation of equations of motion, and a proof of chaos based on showing the existence of an embedded Smale horseshoe using Melnikov's method. We conclude with discussion of a future application.
"MIDDLE" PERIODIC ORBIT AND ITS APPLICATION TO CHAOS CONTROL
Authors: YANG LING , LIU ZENGRONG , ZHENG YONGAI
Published: September 2002

In this paper, a new method, by which any point in a chaotic attractor can be guided to any target periodic orbit, is proposed. The "Middle" periodic orbit is used to lead an initial point in a chaotic attractor to a neighborhood of the target orbit, and then controlling chaos can be achieved by the improved OGY method. The time needed in the method using "Middle" periodic orbit is less than that of the OGY method, and is inversely proportional to the square of the topological entropy of the given map. An example is used to illustrate the results.
ROBUST METHOD FOR EXPERIMENTAL BIFURCATION ANALYSIS
Authors: LANGER GERRIT , PARLITZ ULRICH
Published: September 2002

We present a robust method to locate and continue period-doubling, saddle-node and symmetry-breaking bifurcations of periodically driven experimental systems. The method is illustrated from results obtained for an electronic implementation of a Duffing oscillator.
THE SUBHARMONIC MELNIKOV THEORY FOR DAMPED AND DRIVEN OSCILLATORS REVISITED
Authors: YAMGOUÉ SERGE BRUNO , KOFANÉ TIMOLÉON CRÉPIN
Published: September 2002

The Melnikov theory for detecting subharmonic responses in periodically forced oscillators, the so-called subharmonic Melnikov theory, is a well-known technique within the dynamical system fields. The method succeeds in establishing the existence and stability of subharmonics in perturbed Hamiltonian systems as well as in discussing their bifurcations. But the parameter values estimated for the bifurcations are often found to be in poor agreement with those determined numerically. For damped and periodically driven oscillators, an approach which may substantially improve the agreement between analytical predictions and numerical investigations is proposed. The suggested technique consists in analyzing the forced regime of the oscillations by variational procedure, starting from the (approximate) solution for the free but damped oscillations. Applying this approach to the weakly nonlinear Duffing oscillator, it has been possible to detect analytically some subharmonics that the standard Melnikov theory fails to detect, thus demonstrating the ability of the proposed technique to capture much more of the dynamics.
THE CALCULATION OF THE HOPF/HOPF MODE INTERACTION POINT IN PROBLEMS WITH Z2-SYMMETRY
Authors: AMDJADI FARIDON
Published: September 2002

A direct method for finding the mode interaction point of a symmetry breaking Hopf bifurcation and a symmetry preserving Hopf bifurcation in problems with ℤ2-symmetry is developed. It has been shown that the mode interaction point corresponds to an isolated solution of an extended system. The existence of this solution relies on the occurrence of the mode interaction point and this is interpreted in the context of the mode interaction, using centre manifold reduction. A numerical example with the symmetry group O(2), which has a branch of ℤ2-symmetric nontrivial steady state solutions, is considered to provide clarification of the method.
Detection of Experimental Autoimmune Myocarditis in Rats by
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In Monoclonal Antibody Specific for Tenascin-C
Authors: Sato Mikio , Toyozaki Tetsuya , Odaka Kenichi , Uehara Tomoya , Arano Yasushi , Hasegawa Hiroshi , Yoshida Katsuya , Imanaka-Yoshida Kyoko , Yoshida Toshimichi , Hiroe Michiaki , Tadokoro Hiroyuki , Irie Toshiaki , Tanada Shuji , Komuro Issei
Published: September 2002

Background—

Although the identification of inflammatory infiltrates in endomyocardial biopsy specimens is necessary for the definite diagnosis of myocarditis, the biopsy test is invasive and is not sensitive. Therefore, a new diagnostic technique for the early and noninvasive evaluation of myocarditis has been awaited. Expression of tenascin-C (TNC), one of the oligometric extracellular glycoproteins, is induced in various pathological states, including inflammation, suggesting that TNC can be a molecular marker of myocarditis.

Methods and Results—

An
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In anti-TNC monoclonal antibody Fab′ fragment was injected intravenously into rats with experimental autoimmune myocarditis (EAM), and the biodistribution of this radiotracer was measured. Rapid clearance of radioactivity from the blood was observed in both EAM and control rats (<1% at 6 hours after injection). Myocardial uptake of the tracer was much higher in EAM rats than in control rats (7.54-, 4.39-, and 3.51-fold at 6, 24, and 48 hours after injection, respectively). By autoradiography, high radioactivities were clearly observed in the regions indicative of inflammation in EAM rats. Single-photon emission CT imaging demonstrated the focal myocardial uptake of
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In anti-TNC Fab′ in vivo.

Conclusions—

Radiolabeled anti-TNC Fab′ may be useful for the noninvasive diagnosis of myocarditis.
The Disambiguation of Nominalizations
Authors: Lapata Maria
Published: September 2002

This article addresses the interpretation of nominalizations, a particular class of compound nouns whose head noun is derived from a verb and whose modifier is interpreted as an argument of this verb. Any attempt to automatically interpret nominalizations needs to take into account: (a) the selectional constraints imposed by the nominalized compound head, (b) the fact that the relation of the modifier and the head noun can be ambiguous, and (c) the fact that these constraints can be easily overridden by contextual or pragmatic factors. The interpretation of nominalizations poses a further challenge for probabilistic approaches since the argument relations between a head and its modifier are not readily available in the corpus. Even an approximation that maps the compound head to its underlying verb provides insufficient evidence. We present an approach that treats the interpretation task as a disambiguation problem and show how we can “re-create” the missing distributional evidence by exploiting partial parsing, smoothing techniques, and contextual information. We combine these distinct information sources using Ripper, a system that learns sets of rules from data, and achieve an accuracy of 86.1% (over a baseline of 61.5%) on the British National Corpus.
Catalytic Oxidation of 2-Mercaptoethanol by Cationic Water-soluble Phthalocyaninatocobalt(II) Complexes
Authors: KIMURA MUTSUMI , YAMAGUCHI YUJI , KOYAMA TOSHIKI , HANABUSA KENJI , SHIRAI HIROFUSA
Published: September 2002

The cationic amphiphilic cobalt(II) phthalocyanines have been prepared, and are characterized by UV-absorption spectra in water and organic solvents and in their mixtures. The monomer–dimer transformation equilibrium was affected by solvent polarity and the length of the alkyl chains in the amphiphilic parts. All complexes are efficient catalysts for the oxidation of 2-mercaptoethanol in the presence of dioxygen. The positive charge around the complex increases the acceleration of the dissociation of 2-mercaptoethanol under neutral pH. The catalytic activity is affected by the length of the alkyl chain; consequently the stability of aggregation between cobalt(II) phthalocyanines, as catalysts for the oxidation of 2-mercaptoethanol, can be changed.
A Convenient Procedure for Moderate-scale Rothemund Synthesis of Lipophilic Porphyrins: an Alternative to the Adler–Longo and Lindsey Methodologies
Authors: CROSSLEY MAXWELL J. , THORDARSON PALL , BANNERMAN J. PATRICK , MAYNARD PHILIP J.
Published: September 2002

Rothemund synthesis of porphyrins is conveniently achieved using p-toluenesulfonic acid-catalysed reaction between pyrrole and aldehyde with azeotropic removal of the water formed in the reaction. These conditions are suitable for moderate-scale reactions and involve an easy work-up. In this way, 5,10,15,20-tetraheptylporphyrin (2), 5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrin (3), 5,10,15,20-tetra-tert-butylporphyrin (4) and 5,10,15,20-[pyromellitoyl(tetrakis-o-oxyethoxyphenyl)]por-phyrin (5) were prepared in moderate to good yields.
Facile Synthesis of 131-Oxo-porphyrins Possessing Reactive 3-Vinyl or 3-Formyl Group, Protochlorophyll-a/dDerivatives by 17,18-Dehydrogenation of Chlorins
Authors: TAMIAKI HITOSHI , WATANABE TAKUYA , MIYATAKE TOMOHIRO
Published: September 2002

Methyl protopyropheophorbides-a/d were prepared by modification of readily available chlorophyll-a. The key step was oxidation of 131-oxo-chlorin to the corresponding porphyrin, and 2,3-dichloro-5,6-dicyano-p-benzoquinone was effective for 17,18-dehydrogenation. A reduction in oxidation potential of the chlorin was necessary for the oxidation. Facile oxidation was achieved by insertion of zinc as the central metal, reduction of the 13-carbonyl group and/or aggregation by high concentration. The synthetic 131-oxo-porphyrins had vinyl and formyl groups at the 3-position. These groups were very reactive in the molecule and selectively converted to other functional groups.
Porphyrin Dimers Linked by Conjugated Butadiyne Bridges: Preparations, Spectra, Voltammetry and Reductive Spectroelectrochemistry of {[M(OEP)](μ-C4)[M(OEP)]}(M2≡H4, Co2, Ni2, Cu2, Zn2, Pd2, Pt2, Co/Ni, Ni/Cu, Ni/Zn)
Authors: ARNOLD DENNIS P. , HEATH GRAHAM A. , JAMES DAVID A.
Published: September 2002

A series of derivatives M 2 P 2 ( M 2 ≡ H 4, Co 2, Ni 2, Cu 2, Zn 2, Pd 2, Pt 2, Co / Ni , Ni / Cu , Ni / Zn ) of the ligand meso,meso′-bis(octaethylporphyrinyl)butadiyne has been prepared and characterized by 1 H NMR, FT Raman and visible absorption spectroscopies as well as by cyclic and a.c. voltammetry in CH 2 Cl 2 solution at 20 and −40 °C. The electronic spectra exhibit multiple Soret bands and the voltammetry reveals successive one-electron reductions indicating the accessibility of ‘mixed valence’ π-radical anions and π-dianions. Using in situ thin layer spectroelectrochemistry, the UV to near-IR spectra of [ M 2 P 2]1− and [ M 2 P 2]2− ( M as above) were recorded at ≤ −40 °C. Apart from the Co complexes (reduced at the metal ion), the bis(porphyrin) anions have spectra which include sharp, intense near-IR bands (ε = 50 000–200 000 M−1cm−1) at c. 4500 and 11 500 cm−1([ M 2 P 2]1−) and 9500 cm−1([ M 2 P 2]2−). An empirically constructed semiquantitative frontier orbital model explains the observed electronic absorption bands. Inter-porphyrin conjugation, mediated by the butadiyne bridge, is responsible for the Soret band multiplicity. The near-IR bands of the anions are assigned to long-axis polarized π → π* transitions within the newly occupied upper manifold of the two-porphyrin eight-orbital framework. The small comproportionation constants found for the diporphyrin monoanions contradict the usual assumption that electronically coupled dimers should have a large voltammetric separation between the first and second redox steps.