bluuebunny/crossref_metadata_2025 huggingface dataset:
Lignin‐based polycondensation resins for wood adhesives
Authors: Mansouri N.‐E. El , Pizzi A. , Salvado J.
Published: November 2006

Lignin‐based wood adhesives are obtained that satisfy the requirements of relevant international standards for the manufacture of exterior‐grade wood particleboard. Formulations based on low molecular mass lignin and presenting an increase in the relative proportion of reactive points yield better results than the higher molecular mass lignin used in the past. These lignins allow a higher proportion of hydroxymethylation during preparation of methylolated lignins. These lignin‐based adhesives also yield acceptable results at particleboard pressing times that are sufficiently low to be of industrial significance. Lignin‐based wood adhesives, in which a nonvolatile nontoxic aldehyde (glyoxal) is substituted for formaldehyde in their preparation, are prepared and tested for application to wood panels such as particleboard. The adhesives yield good internal bond strength results for the panels, which are good enough to comfortably pass relevant international standard specifications for exterior‐grade panels. The adhesives also show sufficient reactivity to yield panels in press times comparable to that of formaldehyde‐based commercial adhesives. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1690–1699, 2007
Sorption and permeation behavior for CO2 in NH3‐plasma‐treated and untreated polystyrene membranes
Authors: Yang Y.‐S. , Kwak H. , Bae S.‐Y. , Kumazawa H.
Published: November 2006

In our preceding work, the simultaneous deviation from the conventional dual‐mode sorption and mobility model was observed in a case of CO2 in polystyrene (PS) membrane (glass transition temperature of pure polymer = 95°C) at 60 and 70°C. The plasticization effect of sorbed CO2 on both the sorption and diffusion processes tends to be brought about in glassy polymer membranes near the glass transition temperature. The behavior was simulated based on the concept that only one population of sorbed gas molecules of plasticizing ability to the polymer should exist. In the present work, the sorption and permeation behavior for CO2 in NH3‐plasma‐treated and untreated PS membranes at 40°C was investigated, where NH3‐plasma treatment was executed at plasma discharge powers of 40, 80, 120, and 160 W for an exposure time of 2 min. The sorption isotherm could be described by the sorption theory of Mi et al. (Macromolecules 1991, 24, 2361), where the glass transition temperature is depressed by a concentration of sorbed CO2 of plasticizing ability. NH3‐plasma treatment on PS membrane had little influence on the sorption behavior of CO2 at plasma discharge powers up to 160 W. The mean permeability coefficients were somewhat increased only at a discharge power of 160 W. At CO2 pressures below 0.9 MPa, the pressure dependencies of mean permeability coefficients for CO2 in both NH3‐plasma‐treated and untreated PS membranes at 40°C could also be simulated on the basis of the concept that only one population of sorbed gas molecules of plasticizing ability should exist. At CO2 pressures above 0.9 MPa, however, a plasticization action of sorbed CO2 had much more influence on the diffusion process rather than on the sorption one, and such a combined concept underestimated the mean permeability coefficient. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1798–1805, 2007
Optimization of elution conditions of chitosan gel and the study of its adsorbent mechanism
Authors: Tang Zhen‐Xing , Qian Jun‐Qing , Shi Lu‐E
Published: November 2006

Chitosan gel was prepared by crosslinking method. To make use of chitosan gel, the optimization of elution conditions and the adsorbent characteristics of chitosan gel were discussed in this article. The optimum elution conditions were c (NaCl) = 0.05 mol/L in Tris‐HCl (pH, 9.05) at the flow rate of 2.0–3.0 mL/min with chitosan gel (particle sizes, 120–140 μm). The effects of contact time, pH, initial BSA concentration, and temperature on adsorption were studied. The equilibrium data could be described well by Langmuir, Freundlich, and Redlich–Peterson models. Adsorption dynamics had been successfully studied by Langergren, intraparticle diffusion model and Avrami model. The thermodynamics parameters ΔG°, ΔH°, and ΔS° were calculated. The spectra studies indicated that the interaction between gel and protein was chiefly through electrostatic attraction in the shape of hydrogen bond. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1495–1506, 2007
Solid‐state polymerization of melt‐spun poly(ethylene terephthalate) fibers and their tensile properties
Authors: Nitta Sachiko , Yamaguchi Tomohiro , Ito Masayoshi
Published: November 2006

The production of high modulus and high strength poly(ethylene terephthalate) fibers was examined by using commercially available melt‐spun fibers with normal molecular weight (intrinsic viscosity = 0.6 dL/g). First, molecular weight of as‐spun fibers was increased up to 2.20 dL/g by a solid‐state polymerization, keeping the original shape of as‐spun fibers. Second, the polymerized as‐spun fibers were drawn by a conventional tensile drawing. The achieved tensile modulus and strength of as‐drawn fibers (without heat setting) were 20.0 and 1.1 GPa, respectively. A heat setting was carried out for the as‐drawn fibers. Tensile properties of the treated fibers were greatly affected by the condition of the heat setting. This was related to the increase of sample crystallinity and molecular degradation during the treatments. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1791–1797, 2007
Thermal and spectroscopic characterization of microbial poly(3‐hydroxybutyrate) submicrometer fibers prepared by electrospinning
Authors: Kim G.‐M. , Michler G. H. , Henning S. , Radusch H.‐J. , Wutzler A.
Published: November 2006

Submicrometer fibers based on the microbially synthesized ultra‐high‐molecular‐weight poly(3‐hydroxybutyrate) (PHB) were generated by an electrospinning (ES) process with chloroform as the solvent. To characterize the resulting electrospun fibers in comparison with the pure PHB before ES, differential scanning calorimetry, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy were performed. The diameters of the electrospun fibers characterized by SEM were in the range 400–1000 nm. Thermal analysis showed that the electrospun fibers contained both helical (α form) and trans‐zigzag (β form) crystals, whereas the solution‐cast PHB films mostly possessed the common helical structure. In addition, the crystallinity of the electrospun PHB fibers increased compared to that of the solution‐cast PHB films. Conformational changes occurred with the high extensional flow in the ES jets. Furthermore, the results from polarized FTIR measurements demonstrate that PHB molecules were oriented parallel to the fiber axis. As a result, the electrospun fibers exhibited strong birefringence under the polarized light. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1860–1867, 2007
Molecular weight and arm number of a star‐shaped styrene–butadiene block copolymer synthesized on a pilot‐vessel scale
Authors: Ma Rui , Zhang Lina
Published: November 2006

To improve the rheological properties and processability of industrial rubbers, star‐shaped styrene–butadiene–styrene (SBS) block copolymers were synthesized and characterized in this work. Through the variation of the ratio of divinylbenzene to the diblock anion, a series of SBS samples with three to six arms were prepared. Multi‐angle laser light scattering (MALLS) and size exclusion chromatography (SEC) combined with light scattering (LS) were used to determine the weight‐average molecular weight (Mw), radius of gyration (〈S2〉1/2), arm number, and chain conformation. The results from MALLS indicated that the Mw values of the star‐shaped SBS copolymers were 9.0, 13.0, 14.9, and 18.1 × 104, which corresponded to three, four, five, and six arms, respectively. There was a lot of Mw and 〈S2〉1/2 data for the many fractions in the SEC chromatograms of the SBS copolymers in tetrahydrofuran (THF) detected by LS, so the exponent of 〈S2〉1/2 = KMwα was determined to range from 0.59 to 0.30 for the samples having three to six arms. An analysis of the results revealed that the star SBS copolymers existed in a sphere conformation in THF, and their chain density increased with an increase in the arm number. The viscosity of the six‐arm SBS copolymer was reduced significantly, compared with that of the SBS samples having three to five arms, when their Mw values were similar. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1853–1859, 2007
Multiwall‐carbon‐nanotube‐reinforced poly(ethylene terephthalate) nanocomposites by melt compounding
Authors: Kim Jun Young , Park Hawe Soo , Kim Seong Hun
Published: November 2006

Poly(ethylene terephthalate) (PET) nanocomposites reinforced with multiwall carbon nanotubes (MWCNTs) were prepared through melt compounding in a twin‐screw extruder. The presence of MWCNTs, which acted as good nucleating agents, enhanced the crystallization of PET through heterogeneous nucleation. The incorporation of a small quantity of MWCNTs improved the thermal stability of the PET/MWCNT nanocomposites. The mechanical properties of the PET/MWCNT nanocomposites increased with even a small quantity of MWCNTs. There was a significant dependence of the rheological properties of the PET/MWCNT nanocomposites on the MWCNT content. The MWCNT loading increased the shear‐thinning nature of the polymer‐nanocomposite melt. The storage modulus and loss modulus of the PET/MWCNT nanocomposites increased with increasing frequency, and this increment effect was more pronounced at lower frequencies. At higher MWCNT contents, the dominant nanotube–nanotube interactions led to the formation of interconnected or networklike structures of MWCNTs in the PET/MWCNT nanocomposites. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1450–1457, 2007
New class of bioinspired lenses with a gradient refractive index
Authors: Jin Y. , Tai H. , Hiltner A. , Baer E. , Shirk James S.
Published: November 2006

The recognition that eye lenses in nature often employ a gradient refractive index to enhance the focusing power and to correct aberrations has motivated us to construct a synthetic lens using the layered concept encountered in biological lenses. The result is a highly flexible technology for the fabrication of gradient‐refractive index lenses that is based on a method of polymer forced assembly. Polymeric nanolayered films with incremental differences in the refractive index are assembled according to a prescribed design and molded into the desired shape. The exceptional flexibility of the process lies in the wide range of lens shapes and index profiles that can be realized. A lens with any refractive index distribution can be achieved within the refractive index range of available coextrudable optical materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1834–1841, 2007
Effect of the parent solution concentration on the flocculation performance of PAAm flocculants and the relation between the optimal parent solution concentration and critical concentrations
Authors: Zheng B. Q. , Qian J. W. , Li X. K. , Zhu Z. H.
Published: November 2006

Flocculation performance of three kinds of polyacrylamide (PAAm), linear‐PAAm, Al(OH)3–PAAm hybrid, and star–PAAm, in kaolin suspensions have been investigated by Spectrophotometer. It was found that the flocculation performance of the polymer flocculant is enhanced at the beginning and then impaired with increasing parent solution concentration (Cp) and an optimal parent solution concentration (Cop) exists, which is directly proportional to both critical concentrations of C* and Cs of the polymer in the dilute aqueous solution, and can be roughly expressed by an empirical formula, Cop = 3.1 × 10−3 + 643.1Cs. The findings suggests that flocculation performance of a given polymer is dependent on both of the interchain association and the chain contact of the polymer chains in the parent solution and in the kaolin suspension, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1585–1592, 2007
Bankruptcy prediction by generalized additive models
Authors: Berg Daniel
Published: November 2006

We compare several accounting‐based models for bankruptcy prediction. The models are developed and tested on large data sets containing annual financial statements for Norwegian limited liability firms. Out‐of‐sample and out‐of‐time validation shows that generalized additive models significantly outperform popular models like linear discriminant analysis, generalized linear models and neural networks at all levels of risk. Further, important issues like default horizon and performance depreciation are examined. We clearly see a performance depreciation as the default horizon is increased and as time goes by. Finally a multi‐year model, developed on all available data from three consecutive years, is compared with a one‐year model, developed on data from the most recent year only. The multi‐year model exhibits a desirable robustness to yearly fluctuations that is not present in the one‐year model. Copyright © 2006 John Wiley & Sons, Ltd.
Feasibility of using the national hospital discharge survey to estimate the prevalence of selected birth defects
Authors: Boulet Sheree L. , Correa‐Villaseñor Adolfo , Hsia Jason , Atrash Hani
Published: November 2006

BACKGROUND: Nationally representative data on the prevalence of certain birth defects are largely unavailable. We evaluated the feasibility of using data from the National Hospital Discharge Survey (NHDS) to describe the prevalence of selected birth defects. METHODS: All live births recorded in the NHDS during 1999–2001 were included. The prevalence for selected birth defects was calculated using weighted ratio estimators. Prevalence ratios comparing the NHDS estimates to published national estimates from the National Birth Defects Prevention Network (NBDPN) were calculated. RESULTS: With the exception of common truncus, the NHDS prevalence for the selected defects was consistently lower than the NBDPN estimates. The prevalence ratios ranged from 0.38 for trisomy 18 and anopthalmia/micropthalmia to 1.16 for common truncus. The NHDS prevalence estimates for spina bifida without anencephaly (PR 0.89, 95% CI: 0.57–1.22) and gastroschisis/omphalocele (PR 0.94, 95% CF: 0.48–1.40) most closely approximated the NBDPN estimates. CONCLUSIONS: NHDS data underestimate the prevalence of most birth defects. Additional research is needed to determine whether NHDS estimates may be useful for evaluating trends in certain conditions. Surveillance systems employing active case‐finding continue to provide more accurate estimates of birth defects prevalence. Birth Defects Research (Part A) 76:757–761, 2006. © 2006 Wiley‐Liss, Inc.
Role of geographic information systems in birth defects surveillance and research
Authors: Siffel Csaba , Strickland Matthew J. , Gardner Bennett R. , Kirby Russell S. , Correa Adolfo
Published: November 2006

BACKGROUND: With the significant advancement of geographic information systems (GIS), mapping and evaluating the spatial distribution of health events has become easier. We examine the role of GIS in birth defects surveillance and research. METHODS: We briefly describe the geocoding process and potential problems in accuracy of the obtained geocodes, and some of the capabilities and limitations of GIS. We illustrate how GIS has been applied using the Metropolitan Atlanta Congenital Defects Program geocoded dataset. We provide some comments on potential data quality and confidentiality issues with birth defects in relation to GIS. RESULTS: It is desirable to geocode addresses using a multistrategy approach to achieve a high‐quality and accurate GIS dataset. Beyond the basic but important function of mapping, sophisticated statistical approaches and software are available to analyze the spatial or spatial‐temporal occurrence of birth defects, alone or in association with environmental hazards, and to present this information without compromising the confidentiality of the subjects. CONCLUSIONS: We recommend a broad and systematic use of GIS in birth defects spatial surveillance and research. © Birth Defects Research (Part A) 76:825–833, 2006. © 2006 Wiley–Liss, Inc.
Evaluation of the Texas Birth Defects Registry: An active surveillance system
Authors: Miller Eric
Published: November 2006

BACKGROUND:Evaluations of surveillance systems are necessary to determine if the goals of the system are being met, how efficiently the surveillance is being implemented, and if resources are being used appropriately. An evaluation of the Texas Birth Defects Registry was conducted to assess the overall quality of data collection and to examine variations across regions of the state.METHODS:The registry was evaluated by using published guidelines for evaluating public health surveillance systems; the evaluation included staff interviews, process observation, and secondary data analysis.RESULTS:The registry monitors >370,000 births/year through active surveillance, with considerable disparities in workload across regions of the state. Because of the geographic size and substantial population of Texas, data collection is complex. However, the estimated sensitivity of the system appears sufficient, and rates for selected defects are highly comparable with other U.S. active birth‐defect surveillance systems. Registry staff continually monitor the quality of data collection and provide additional training. Amid unstable funding, the registry staff have demonstrated optimal foresight and flexibility to adapt and continue quality data collection. Timeliness needs to be improved and more consistent quality assurance is needed across regions of the state. Retaining staff and increasing visibility are essential to providing more stability.CONCLUSIONS:Active surveillance for birth defects is labor‐intensive but provides invaluable data for its stakeholders. The Texas Birth Defects Registry has proven to be a quality surveillance system and a beneficial resource for Texas. Birth Defects Research (Part A) 76:787–792, 2006. © 2006 Wiley‐Liss, Inc.
R‐stereopreference analysis of lipase Novozym®435 in kinetic resolution of flurbiprofen
Authors: Zhang Hua Yun , Wang Xin , Ching Chi Bun
Published: November 2006

Immobilized lipase from Candida antarctica (Novozym®435) was employed in the kinetic resolution of racemic flurbiprofen by enantioselective esterification with methanol. It was found that the lipase has the R‐stereopreference and the reaction matches Bi Bi Ping Pong mechanism with dead‐end inhibition of methanol. Furthermore, the R‐stereopreference was analyzed in details from the aspects of enzymatic kinetic mechanism and reaction activation energy of both enantiomers. The R‐enantiomer shows lower activation energy and higher maximum reaction rate than the S‐enantiomer, which implies the R‐stereopreference of the lipase and makes the kinetic resolution of flurbiprofen via enzymatic reaction feasible. Chirality 2006. © 2006 Wiley‐Liss, Inc.
A Theoretical Investigation of the Gas‐Phase Oxidation Reaction of the Saturated tert‐Butyl Radical
Authors: Choi Jong‐Ho , Nam Mi‐Ja , Youn Sung‐Eui
Published: November 2006

The radical‐radical reaction mechanisms and dynamics of ground‐state atomic oxygen [O(3P)] with the saturated tert‐butyl radical (t‐C4H9) are investigated using the density functional method and the complete basis set model. Two distinctive reaction pathways are predicted to be in competition: addition and abstraction. The barrierless addition of O(3P) to t‐C4H9 leads to the formation of an energy‐rich intermediate (OC4H9) on the lowest doublet potential energy surface, which undergoes subsequent direct elimination or isomerization–elimination leading to various products: C3H6O+CH3, iso‐C4H8O+H, C3H7O+CH2, and iso‐C4H8+OH. The respective microscopic reaction processes examined with the aid of statistical calculations, predict that the major addition pathway is the formation of acetone (C3H6O)+CH3 through a low‐barrier, single‐step cleavage. For the direct, barrierless H‐atom abstraction mechanism producing iso‐C4H8 (isobutene)+OH, which was recently reported in gas‐phase crossed‐beam investigations, the reaction is described in terms of both an abstraction process (major) and a short‐lived addition dynamic complex (minor).
Sensitivity of YBa2Cu3O7 thick films to gamma rays
Authors: Albiss B. A. , Al‐Akhras M. A.
Published: November 2006

Superconducting YBa2Cu3O7 (YBCO) thick films have been prepared using the screen printing method. Effects of gamma irradiation on their structure and transport properties have been investigated up to a gamma dose of 50 MR. A considerable decrease in the intensities of the major diffraction peaks of the XRD pattern was observed due to gamma irradiation. A gradual increase in the normal state resistance, with a gradual increase in the slope of the resistance‐temperature (R‐T) curves was observed with increasing gamma doses. However, slight decrease in the transition temperature has been observed. The Voltage‐current (V‐I) data were fitted to the power law V ∼ Iβ in which the power exponent β was found to increase gradually with gamma dose. The sensitivity of the R‐T and V‐I curves to gamma rays where precisely estimated and from which the regions of linear response were deduced. The possibility of using YBCO thick film as a candidate device for gamma rays sensing was presented. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhancement of solder properties of Sn‐9Zn lead‐free solder alloy
Authors: Kamal M. , Gouda E. S.
Published: November 2006

The eutectic alloy Sn‐9Zn was considered as a potential alternative to lead‐tin solder alloys when compared with other solders. In this paper, ternary, quaternary and penternary additions of the elements Bi, Cu and In were added to the eutectic alloy as a trial to improve its properties. The results showed that, the penternary alloy has properties superior to those of the binary, ternary and quaternary alloys. The alloy of composition Sn‐9Zn‐1Bi‐2Cu‐2In has the most suitable properties as a candidate alloy for lead‐free solder. It has a lower melting point, 186°C, which is very close to that of Sn‐37Pb solder, a lower value of electrical resistivity, 16.5 μΩ.cm, compared with that of Sn‐37Pb (17 μΩ.cm), higher value of the Young's modulus, 47 GPa, compared with 45 GPa of Sn‐37Pb and a higher value of the Vickers hardness, 191 MPa, compared with 129 MPa of Sn‐37Pb eutectic alloy. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystal and molecular structure of 1‐allyl‐5‐(4‐methylbenzoyl)‐4‐(4‐methylphenyl)pyrimidine‐2(1H)‐thione
Authors: Yıldırım İ. , Koca İ. , Dinçer M. , Özdemir N. , Andaç Ö.
Published: November 2006

The crystal structure of 1‐allyl‐5‐(4‐methylbenzoyl)‐4‐(4‐methylphenyl)pyrimidine‐2(1H)‐thione (C22H20N2OS) has been determined from three dimensional single crystal X‐ray diffraction data. The title compound crystallizes in the monoclinic space group P 21/c, with a = 10.6674(13), b = 10.1077(7), c = 17.9467(19) Å, β = 98.460(9)°, V = 1914.0(3) Å3, Dcalc = 1.251 g cm–3, Z = 4. In the title compound, the allyl group shows positional disorder. Molecules are linked by C‐H···O, C‐H···N and C‐H···S intermolecular interactions forming two‐dimensional network. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A General and Facile One‐Step Synthesis of Imido–Titanium(IV) Complexes: Application to the Synthesis of Compounds Containing Functionalized or Chiral Imido Ligands and Bimetallic Diimido Architectures (Eur. J. Inorg. Chem. 22/2006)
Authors: Lorber Christian , Choukroun Robert , Vendier Laure
Published: November 2006

The cover picture shows some various examples ofterminal imido–titanium complexes of the general formula Ti(=NR)Cl2(NHMe2)2 that are accessible through the reported one‐pot reaction of Ti(NMe2)4 with a primary amine RNH2 in the presence of excess chlorotrimethylsilane. This procedure appears to be general to the generation of a wide range of imido groups: alkyl‐, silyl‐, and arylimido groups, as well as functional organoimido, chiral imido, and diimido ligands. Ti(=NR)Cl2(NHMe2)2 complexes are of particular interest as organometallic synthons and for further applications in the field of homogeneous catalysis and materials science. The background photo of the famous palm tree vault of the Jacobins church (Toulouse, France, founded in the 13th–14th centuries) symbolizes the diversity of the compounds – arranged in arc around the palm tree vault – that can be prepared by using our promising synthetic strategy, and provides a solid foundation – the pillar – for attractive applications. Details are discussed in the article by C. Lorber et al. on p. 4503 ff. The authors acknowledge Christian Bergounhou (LCC Toulouse) for the Palm Tree photograph.
Aging of transformer insulating materials under selective conditions
Authors: Fofana I. , Borsi H. , Gockenbach E. , Farzaneh M.
Published: November 2006

In today's economic climate, it is important to know the condition, by means of suitable diagnostic tests, of the oil impregnated paper usable as primary insulation in equipment such as transformers, switchgear, bushings, cables, and their accessories. The aim of this paper is regarded as a main task to study the parameters that mostly influence the ageing process of oil/paper insulation used in transformers with preset moisture levels. A comparison is made between the performances of cellulose and Aramid papers. It is shown that Aramid paper is much less sensitive to water than cellulose paper. However, the addition of air (oxygen), via acid formation and oxidation in the oil, has a direct influence on the increase of the loss factor for both papers. The catalysts, that represent the metallic components in the transformer, accelerate the ageing process of the cellulose papers, while no influence on the ageing process of Aramid was observed. Oil ageing without a solid partner is insignificantly influenced by water, but accelerated by air‐oxygen, via the moisture and acid formation, and oxidation processes. A direct influence on the increase of the loss factor and the decrease of electric strength particularly at low temperatures is to be noted. Copyright © 2006 John Wiley & Sons, Ltd.
Analysis of load transfer on radial distribution systems with tie lines
Authors: Lee Chien‐Hsing , Huang Chi‐Ming
Published: November 2006

This paper analyzes four types of load transfer in the radial distribution system with tie lines of Taiwan power company (TPC). Type I is the two feeders tied and were fed by the same transformer located in the same secondary substation. Type II is the two feeders tied and were fed by two different transformers located in the same secondary substation. Type III is the two feeders tied and were fed by two different transformers located in different secondary substations. Type IV is the two feeders tied and were fed by two different transformers, one is located in a distribution substation and the other is located in a secondary substation. The test results are recorded and summarized to determine the effective scheme of load transfer without power interruptions. As a result, Type I is the most simple method to eliminate customers' interruption during load transfer. Copyright © 2006 John Wiley & Sons, Ltd.
Using vorticity to define conditions at multiple open boundaries for simulating flow in a simplified vortex settling basin
Authors: Ziaei A. N. , McDonough J. M. , Emdad H. , Keshavarzi A. R.
Published: November 2006

In this paper a method is developed to define multiple open boundary (OB) conditions in a simplified vortex settling basin (VSB). In this method, the normal component of the momentum equation is solved at the OBs, and tangential components of vorticity are calculated by solving vorticity transport equations only at the OBs. Then the tangential vorticity components are used to construct Neumann boundary conditions for tangential velocity components. Pressure is set to its ambient value, and the divergence‐free condition is satisfied at these boundaries by employing the divergence as the Neumann condition for the normal‐direction momentum equation. The 3‐D incompressible Navier–Stokes equations in a primitive‐variable form are solved using the SIMPLE algorithm. Grid‐function convergence tests are utilized to verify the numerical results. The complicated laminar flow structure in the VSB is investigated, and preliminary assessment of two popular turbulence models, k–ε and k–ω, is conducted. Copyright © 2006 John Wiley & Sons, Ltd.
Reducing vascular variability of fMRI data across aging populations using a breathholding task
Authors: Handwerker Daniel A. , Gazzaley Adam , Inglis Ben A. , D'Esposito Mark
Published: November 2006

The magnitude and shape of blood oxygen level‐dependent (BOLD) responses in functional MRI (fMRI) studies vary across brain regions, subjects, and populations. This variability may be secondary to neural activity or vasculature differences, thus complicating interpretations of BOLD signal changes in fMRI experiments. We compare the BOLD responses to neural activity and a vascular challenge and test a method to dissociate these influences in 26 younger subjects (ages 18–36) and 24 older subjects (ages 51–78). Each subject performed a visuomotor saccade task (a vascular response to neural activity) and a breathholding task (vascular dilation induced by hypercapnia) during separate runs in the same scanning session. For the saccade task, signal magnitude showed a significant decrease with aging in FEF, SEF, and V1, and a delayed time‐to‐peak with aging in V1. The signal magnitudes from the saccade and hypercapnia tasks showed significant linear regressions within subjects and across individuals and populations. These two tasks had weaker, but sometimes significant linear regressions for time‐to‐peak and coherence phase measures. The significant magnitude decrease with aging in V1 remained after dividing the saccade task magnitude by the hypercapnia task magnitude, implying that the signal decrease is neural in origin. These findings may lead to a method to identify vascular reactivity‐induced differences in the BOLD response across populations and the development of methods to account for the influence of these vasculature differences in a simple, noninvasive manner. Hum Brain Mapp 2006. © 2006 Wiley‐Liss, Inc.
Validity and power in hemodynamic response modeling: A comparison study and a new approach
Authors: Lindquist Martin A. , Wager Tor D.
Published: November 2006

One of the advantages of event‐related functional MRI (fMRI) is that it permits estimation of the shape of the hemodynamic response function (HRF) elicited by cognitive events. Although studies to date have focused almost exclusively on the magnitude of evoked HRFs across different tasks, there is growing interest in testing other statistics, such as the time‐to‐peak and duration of activation as well. Although there are many ways to estimate such parameters, we suggest three criteria for optimal estimation: 1) the relationship between parameter estimates and neural activity must be as transparent as possible; 2) parameter estimates should be independent of one another, so that true differences among conditions in one parameter (e.g., hemodynamic response delay) are not confused for apparent differences in other parameters (e.g., magnitude); and 3) statistical power should be maximized. In this work, we introduce a new modeling technique, based on the superposition of three inverse logit functions (IL), designed to achieve these criteria. In simulations based on real fMRI data, we compare the IL model with several other popular methods, including smooth finite impulse response (FIR) models, the canonical HRF with derivatives, nonlinear fits using a canonical HRF, and a standard canonical model. The IL model achieves the best overall balance between parameter interpretability and power. The FIR model was the next‐best choice, with gains in power at some cost to parameter independence. We provide software implementing the IL model. Hum Brain Mapp 2006. © 2006 Wiley‐Liss, Inc.
Effect of the number of response alternatives on brain activity in response selection
Authors: Woo Sung‐Ho , Lee Kyoung‐Min
Published: November 2006

It is well‐known in motor control literature that a response time (RT) increases as a logarithmic function of the number of response alternatives (NA) (Hick's law). In this study, we identified neural correlates for this relationship using event‐related functional MRI and a choice finger‐movement task. Behaviorally, average RTs of all subjects increased as a logarithmic function of the NA in accordance with the law. From a voxel‐wise search for brain areas where the activity was correlated with NA and thence the RT, a positive correlation was found at the posterior cingulate and left superior frontal gyri, whereas a negative correlation was observed at areas in bilateral inferior parietal lobules. This differential modulation by the task context, namely, the NA available for a choice response with identical stimulus and response, indicates that these regions are involved in various aspects of response selection, intentional retrieval of motor program, or spatial expectancy. Hum Brain Mapp 2006. © 2006 Wiley‐Liss, Inc.
Kinin B1 and B2 receptors are overexpressed in the hippocampus of humans with temporal lobe epilepsy
Authors: Perosa Sandra Regina , Argañaraz Gustavo Adolfo , Goto Eduardo Massatoshi , Costa Luciana Gilbert Pessoa , Konno Ana Carla , Varella Pedro Paulo Vasconcellos , Santiago Joselita Ferreira Carvalho , Pesquero João Bosco , Canzian Mauro , Amado Debora , Yacubian Elza Marcia , Carrete Henrique , Centeno Ricardo Silva , Cavalheiro Esper Abrão , Silva Jose Antonio , Mazzacoratti Maria da Graça Naffah
Published: November 2006

Molecular biology tools have been employed to investigate the participation of peptides in human temporal lobe epilepsy (TLE). Active polypeptides and their receptors have been related to several brain processes, such as inflammation, apoptosis, brain development, K+ and Ca2+ channels' activation, cellular growth, and induction of neuronal differentiation. Previous works have shown a neuroprotector effect for kinin B2 receptor and a deleterious, pro‐epileptogenic action for kinin B1 receptor in animal models of TLE. The present work was delineated to analyze the kinin B1 and B2 receptors expression in the hippocampus of patients presenting refractory mesial TLE. The hippocampi were removed during the patients surgery in a procedure used for seizure control and compared with tissues obtained after autopsy. Nissl staining was performed to study the tissue morphology and immunohistochemistry, and Western blot was used to compare the distribution and levels of both receptors in the hippocampus. In addition, real time PCR was employed to analyze the gene expression of these receptors. Nissl staining showed sclerotic hippocampi with hilar, granular, and pyramidal cell loss in TLE patients. Immunohistochemistry and Western blot analyses showed increased expression of kinin B1 and B2 receptors but the real‐time PCR data demonstrated increased mRNA level only for kinin B2 receptors, when compared with controls. These data show for the first time a relationship between human TLE and the kallikrein–kinin system, confirming ours previous results, obtained from experimental models of epilepsy. © 2006 Wiley‐Liss, Inc.
Transforming growth factor‐β2 modulates synaptic efficacy and plasticity and induces phosphorylation of CREB in hippocampal neurons
Authors: Fukushima Teruyuki , Liu Rong‐Yu , Byrne John H.
Published: November 2006

Transforming growth factor‐βs (TGF‐βs) are widely expressed and play roles as multifunctional growth factors and regulators of key events in development, disease, and repair. However, it is not known whether TGF‐βs affect the plasticity of hippocampal neurons. As a first step to address this issue, we examined whether TGF‐β2 modulated the electrophysiological and biochemical properties of cultured hippocampal neurons. We found that prolonged 24 h treatment with TGF‐β2 induced facilitation of evoked postsynaptic currents (ePSCs). This facilitation was associated with a decrease in short‐term synaptic depression of ePSCs and increases in both the amplitude and frequency of spontaneous miniature postsynaptic currents (mPSCs). The long‐term changes of ePSCs and mPSCs may be associated with cAMP response element‐binding protein (CREB), which has been previously implicated in long‐term potentiation. Immunofluorescence techniques and Western blot analysis both revealed that TGF‐β2 enhanced the phosphorylation of CREB. Together, these results suggest that TGF‐β2 may play a role in the cascade of events underlying long‐term synaptic facilitation in hippocampus, and that CREB may be an important mediator of these effects. © 2006 Wiley‐Liss, Inc.
Data mining: Going beyond traditional statistics
Authors: Zhao Chun‐Mei , Luan Jing
Published: November 2006

The authors provide an overview of data mining, giving special attention to the relationship between data mining and statistics to unravel some misunderstandings about the two techniques.
Applying data mining to predict college admissions yield: A case study
Authors: Chang Lin
Published: November 2006

Data‐mining technology's predictive modeling was applied to enhance the prediction of enrollment behaviors of admitted applicants at a large state university.
Using data mining to explore which students use advanced placement to reduce time to degree
Authors: Eykamp Paul W.
Published: November 2006

This chapter explores how multiple approaches including data mining can help examine how the lengths of student enrollment are associated with varying numbers of advanced placement units.
Practicing data mining for enrollment management and beyond
Authors: Luan Jing , Zhao Chun‐Mei
Published: November 2006

As a tour de force, data mining is likely to gain wider use in the next few years. To facilitate this transition, we make several recommendations addressed to both institutional research professionals and the Association of Institutional Research.
Functional divergence after gene duplication and sequence–structure relationship: a case study of G‐protein alpha subunits
Authors: Zheng Ying , Xu Dongping , Gu Xun
Published: November 2006

In this article, we use animal G‐protein alpha subunit family as an example to illustrate a comprehensive analytical pipeline for detecting different types of functional divergence of protein families, which is phylogeny‐dependent, combined with ancestral sequence inference and available protein structure information. In particular, we focus on (i) Type‐I functional divergence, or site‐specific rate shift, as typically exemplified by amino acid residue highly conserved in a subset of homologous genes but highly variable in a different subset of homologous genes, and (ii) Type‐II functional divergence, or the shift of cluster‐specific amino acid property, as exemplified by a radical shift of amino acid property between duplicate genes, which is otherwise evolutionally conserved. We utilized the software DIVERGE2 to carry out these analyses. In the case of G‐protein alpha subunit gene family, we have predicted amino acid residues that are related to either Type‐I or Type‐II functional divergence. The inferred ancestral sequences for these sites are helpful to explore the trends of functional divergence. Finally, these predicted residues are mapped to the protein structures to test whether these residues may have 3D structure or solvent accessibility preference. J. Exp. Zool. (Mol. Dev. Evol.) 306B, 2006. © 2006 Wiley‐Liss, Inc.
Cerebral vascular response to hypercapnia: Determination with perfusion MRI at 1.5 and 3.0 Tesla using a pulsed arterial spin labeling technique
Authors: Nöth Ulrike , Meadows Guy E. , Kotajima Futoshi , Deichmann Ralf , Corfield Douglas R. , Turner Robert
Published: November 2006

Purpose

To compare the quantification of cerebral blood flow (CBF) at 1.5 and 3.0 Tesla, under normo‐ and hypercapnia, and to determine the cerebral vascular response (CVR) of gray matter (GM) to hypercapnia, a pulsed arterial spin labeling technique was used. Additionally, to improve GM CBF quantification a high‐resolution GM‐mask was applied.

Materials and Methods

CBF was determined with the QUIPSS II with thin slice TI1 periodic saturation (Q2TIPS) sequence at 1.5 and 3.0 Tesla in the same group of eight subjects, both under normocapnia and hypercapnia. Absolute GM‐CBF maps were calculated using a GM‐mask obtained from a high‐resolution structural scan by segmentation. The CVR to hypercapnia was derived from the quantitative GM‐CBF maps.

Results

For both field strengths, the GM‐CBF was significantly higher under hypercapnia compared to normocapnia. For both conditions, there was no significant difference of GM‐CBF for 1.5 and 3.0 Tesla; the same applies to the CVR, which was 4.3 and 4.5%/mmHg at 1.5 and 3.0 Tesla, respectively.

Conclusion

The method presented allows for the quantification of CBF and CVR in GM at the common clinical field strengths of 1.5 and 3.0 Tesla and could therefore be a useful tool to study these parameters under physiological and pathophysiological conditions. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Multiple organizational identification levels and the impact of perceived external prestige and communication climate
Authors: Bartels Jos , Pruyn Ad , de Jong Menno , Joustra Inge
Published: November 2006

Earlier studies have shown that perceived external prestige and communication climate influence organizational identification. In this paper we present the results of a study of the influence of communication climate and perceived external prestige on organizational identification at various organizational levels of a regional police organization. In total, 314 respondents filled out a questionnaire on communication climate, perceived external prestige and organizational identification. The results of this study show that communication climate has the strongest link with employee identification when it concerns the identification with the daily work group and a weaker one with the organization as a whole. It also appears that perceived external prestige has a stronger influence on the identification with the organization as a whole than on the identification at the more concrete organizational levels (such as department or work group). This research offers reasons to presuppose that organizational identification and communication climate are multiple constructs. If management wishes to influence organizational identification through a bottom‐up process, it is wise to pay particular attention to the communication climate in the work groups. Influencing organizational identification with the organization as a whole is better conducted through perceived external prestige. Copyright © 2006 John Wiley & Sons, Ltd.
Functionally perturbed stochastic differential equations
Authors: Jovanović Miljana , Janković Svetlana
Published: November 2006

This paper is devoted to the large class of stochastic differential equations of the Ito type whose coefficients are functionally perturbed and depend on a small parameter. The solution of a such equation is compared with the solution of the corresponding unperturbed equation, in the (2m)‐th moment sense, on finite intervals or on intervals whose length tends to infinity as small parameter tends to zero. Some numerical estimations of these intervals with respect to the parameter are also given. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the absolutely continuous spectrum of the Laplace–Beltrami operator acting on p ‐forms for a class of warped product metrics
Authors: Antoci Francesca
Published: November 2006

We explicitely compute the absolutely continuous spectrum of the Laplace–Beltrami operator for p ‐forms for the class of warped product metrics dσ 2 = y 2a dy 2 + y 2b dθ 2, where y is a boundary defining function on the unit ball B (0, 1) in ℝN . (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Another characterization of the Hardy space with non doubling measures
Authors: Hu Guoen , Liang Shuang
Published: November 2006

Let μ be a Radon measure on ℝd which may be non doubling, and let H 1(μ) be the Hardy space associated with μ introduced by Tolsa. In this paper, a new atomic characterization of H 1(μ) is established. Some applications of this characterization are also given. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Valvular heart disease in Parkinson's disease patients treated with dopamine agonists: A reader‐blinded monocenter echocardiography study
Authors: Junghanns Susann , Fuhrmann Joerg T. , Simonis Gregor , Oelwein Christian , Koch Rainer , Strasser Ruth H. , Reichmann Heinz , Storch Alexander
Published: November 2006

Fibrotic valvular heart disease (VHD) has been reported in association with ergot dopamine agonists (DAs), but the current database is insufficient regarding clinical relevance and comparison to data on non‐ergot DAs. We evaluated the effects of four DAs (pergolide, cabergoline, ropinirole, pramipexole) on morphology and function of heart valves in patients with Parkinson's disease (PD) to determine the frequency and clinical relevance of DA‐induced VHD. A total of 85 patients treated with ergot or non‐ergot DAs and 38 age‐matched controls were evaluated by transthoracic echocardiography. Valvular pathology was assessed by established criteria of valvular regurgitation and a VHD scoring system. Both grading systems revealed increased frequency of VHD in ergot DA patients compared to both non‐ergot DA patients and controls with 22% of ergot DA patients having moderate VHD versus 3% of non‐ergot DA patients and none of controls (P = 0.001). We did not find correlations of echocardiographic findings with duration/cumulative dose of treatment, age, or vascular risk factors. Our data suggest that ergot DAs are associated with higher prevalence of VHD compared to non‐ergot DAs and controls. Standard echocardiography seems sufficient to detect VHD in PD patients treated with DAs. © 2006 Movement Disorder Society
Expression of insulin‐like growth factors systems in cloned cattle dead within hours after birth
Authors: Li Shijie , Li Yanxin , Yu Shuyang , Du Weihua , Zhang Lei , Dai Yunping , Liu Ying , Li Ning
Published: November 2006

Cloning by somatic nuclear transfer is an inefficient process in which many of the cloned animals die shortly after birth and display organ abnormalities. In an effort to determine the possible roles IGFs played in neonatal death and organ abnormalities, we have examined expression patterns of eight genes in insulin‐like growth factor (IGF) systems (IGF1, IGF2, IGF1R, IGF2R, IGFBP‐1, IGFBP‐2, IGFBP‐3, and IGFBP‐4) in six organs (heart, liver, spleen, lung, kidney, and brain) of both neonatal death cloned bovines (n = 9) and normal control calves (n = 3) produced by artificial insemination (AI) using real‐time quantitative RT‐PCR. The effect of the age of the fibroblast donor cell on the gene expression profiles was also investigated. Aberrant expressions of six genes (IGF2, IGF1R, IGF2R, IGFBP‐2, IGFBP‐3, and IGFBP‐4) were found in some studied tissues, but the expression of two genes (IGF1 and IGFBP‐1) had similar levels with the normal controls. For the studied genes, kidney was the organ that was most affected (five genes) by gene downregulation, whereas spleen was the organ that was not affected. The two upregulation genes were in brain, but both of downregulation and upregulation were found in the heart, liver, and lung. The expression of three genes (IGF2R, IGFBP‐4, and IGF2) in some tissues showed significant differences between AF cell‐derived and FF cell‐derived clones. Our results suggest that aberrations in gene expression within IGF systems were found in most cloned bovine tissues of neonatal death. Because IGF systems play an important role in embryo development and organogenesis, the aberrant transcription patterns detected in these clones may contribute to the defects of organs reported in neonatal death of clones. Mol. Reprod. Dev. 74: 397–402, 2007. © 2006 Wiley‐Liss, Inc.