bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of a Contaminated Site (The San Giuliano Landfill, Venice, Italy) on the Interaction between Water Bodies in a Coastal Aquifer System
Authors: Critto Andrea , Zuppi Giovanni Maria , Carlon Claudio , Marcomini Antonio 
Published: April 2004

AbstractA complex multiple aquifer system affected by a contaminated site and exposed to tidal effects was investigated to develop the hydrogeological conceptual model of the study case. Two water bodies were identified, from top to down: a surface aquifer unaffected by tidal events, and a semiconfined aquifer partly communicating with the brackish lagoon waters. By using the Cl‐/SO42‐ ratio and the DOC (Dissolved Organic Carbon) concentration, as well as by applying the kriking to the piezometric levels results, the groundwater flow directions and the hydraulic gradients within the investigated aquifers were also identified. Based on the overall results, a schematic of the conceptual model for the whole aquifer system was provided which allows to visualize the communication between the different water bodies.
Application of Voltammetric Methods for the Analysis of Gold and Other Transition Metals in Quartzite Rock
Authors: Tamrakar Praveen Kumar , Pitre Krishna Sadashiv 
Published: April 2004

AbstractSimple, rapid and accurate voltammetric methods viz. DCP, DPP and DPASV have been presented for the trace determination of gold and other transition metals in quartzite rock sample. The analysis has been performed using 0.1M(NH4)2 tartrate, 0.1M NaClO4 and 1M NaOH as supporting electrolyte with 0.001 % gelatin as maximum suppressor. The results show the presence of CuII(10.70), CoII(4.72), FeIII(66.96), AuIII(0.066), ZnII(1.68) and CdII(0.62) mg.g‐1 metal ions from the sample. Gold produced a well defined wave/peak with E1/2/EP = ‐0.61V/‐0.64V vs SCE, in 1M NaOH supporting electrolyte. The quantitative analysis of metal inos was carried out by the method of standard addition. Statistical treatment of the observed voltammetric data reveals high accuracy and good precision of determination. The observed voltammetric results are comparable with those obtained using AAS method.
Extraction of Electrolytes from Aqueous Solutions and Their Spectrophotometric Determination by Use of Acid‐Base Chromoionophores in Lipophylic Solvents
Authors: Barberi Paola , Giannetto Marco , Mori Giovanni 
Published: April 2004

AbstractThe formation of non‐absorbing complexes in an organic phase has been exploited for the spectrophotometric determination of ionic analytes in aqueous solutions. The method is based on liquid‐liquid extraction of aqueous solution with lipophylic organic phases containing an acid‐base chromoionophore, a neutral lypophilic ligand (neutral carrier) selective to the analyte and a cationic (or anionic) exchanger. The method avoids all difficulties of the preparation of the very thin membranes used in optodes, so that it can advantageously be used for the study of the role physical‐chemical parameters of the system in order to optimize them and to prepare, if necessary, an optimized optode. Two lipophylic derivatives of Nile Blue and 4', 5‐dibromofluorescein have been synthesized, in order to ensure their permanence within organic phase. Two different neutral carriers previously characterized by us as ionophores for liquid‐membrane Ion Selective Electrodes have been employed. Three different ionic exchangers have been tested. Furthermore, a model allowing the interpolation of experimental data and the determination of the thermodynamic constant of the ionic‐exchange equilibrium has been developed and applied.
Adjustments in the South Korean beef import market under beef import liberalization policies
Authors: Kim Renee B. , Kim Y.J. , Veeman Michele 
Published: April 2004

AbstractThis report analyzes the implications for exporters of the policy of gradual liberalization of beef importation that preceded the phasing out of state trader importation in the South Korean beef market. The process of beef trade liberalization involved successive increases in import quota, and the allocation of this, through a simultaneous buy‐sell system (SBS), to increasing numbers of licensed Korean importing firms, for several years prior to January 1, 2001. At that time, state trading was entirely replaced by private sector importation. During the period of policy adjustment of beef importation, licensed importing firms, known as “supergroups” (i.e., SBS firms), acted as designated SBS import beef traders for groups of end‐use businesses. The importation of beef is analyzed based on a model of the import behavior of the SBS firms for the period 1995 through 2000. The econometric model focuses on the source preferences of importers; the results suggest the importance of alliances of importers with various beef exporters. Model simulations suggest that with further import growth, the United States is likely to remain a major player in the Korean import beef market and that Australia may also gain from growth in this market. [EconLit citations: F14, L19, L66.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 201–216, 2004.
Primary agricultural product demand in post‐communist Russia
Authors: Shiptsova Rimma , Goodwin H.L. , Holcomb Rodney 
Published: April 2004

AbstractThis study examines food consumption patterns for households in Siberian Russia. The study is based on a survey conducted by the American Business Center in Vladivostok in February/March 1996. When incomes grow, households tend to include greater proportions of livestock products in their diets. That leads to a corresponding increase in indirect cereal consumption. Alternative measures of food consumption employed in the analysis are expenditures and calories. The results show that the expenditure income elasticity of cereal products is positive whereas income elasticities of cereal products are zero for calorie measures, implying demand for service from non‐agricultural sectors. The elasticities of total food and animal product consumption are positive for both measures. Stabilization of transition economies might lead to a substantial increase in indirect cereal consumption, which, in turn, would lead to a dramatic increase in demand for agricultural imports. [EconLit citations: L660, D120, Q180.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 129–141, 2004.
Advertising's effect on the market demand elasticity: A note
Authors: Kinnucan Henry W. , Zheng Yuqing 
Published: April 2004

AbstractUsing a simple market model and Frisch's duality relation, this report develops propositions about the relationship between advertising and the market demand elasticity that may prove useful in empirical research. In particular, we find that a parallel shift in a linear demand function always alters the market demand elasticity unless supply is unitary elastic. However, the elasticity change in most cases will be negligible. We also find that curve rotation does not imply that the demand elasticity has changed, and vice versa. Lastly, if the price level affects advertising's ability to shift the market demand curve, it must also be true that advertising affects the demand elasticity. The converse is also true, i.e., if advertising affects the demand elasticity, the price level must affect advertising's ability to shift the demand curve. [JEL citations: Q130, Q170, Q180.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 181–188, 2004.
Risk‐learning process in forming willingness‐to‐pay for egg safety
Authors: Maruyama Atsushi , Kikuchi Masao 
Published: April 2004

AbstractUsing data obtained from a mail survey on consumers' willingness‐to‐pay (WTP) and risk beliefs for reducing the risk of salmonella contamination of eggs, we have examined the risk‐learning process through which individuals form their WTP. The results of estimation of the WTP function support the hypothesis that respondents follow an adaptive learning process, in which they establish their posterior risk belief in a rational manner by adapting their prior risk belief as they are supplied with new risk information. We find that the weight of the prior risk belief is slightly smaller than that of new risk information in forming the posterior risk belief for three out of four estimation models. Knowledge of how consumers form their risk beliefs and who evaluates egg safety enables us to clearly specify targets for effective campaigns to enhance public awareness at a household level about health and food safety issues. [EconLit citations: D120, Q260.] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 167–179, 2004.
Mass‐transfer enhancement in a wavy‐walled tube by imposed fluid oscillation
Authors: Nishimura T. , Bian Y. N. , Kunitsugu K. 
Published: April 2004

AbstractThe present experimental study deals with mass‐transfer enhancement and fluid dynamic behavior in a wavy‐walled tube for pulsatile flow. Three flow parameters are considered here: the net flow Reynolds number, the oscillatory fraction of the flow rate, and the Strouhal number. Among them, we especially focused on the effect of Strouhal number on mass‐transfer enhancement under the condition of no reverse flow. Time‐averaged transport enhancement by means of imposed fluid oscillation is found to vary with the net flow Reynolds number and with the oscillatory fraction of the flow rate. The most effective mass‐transfer enhancement is registered when the net flow falls on just before the transitional flow regime for steady flow. Furthermore, there is an optimum Strouhal number, corresponding to the maximum transport enhancement, that depends on the oscillatory fraction of the flow rate. The results of time variation for flow behavior show that stable and unstable flow states exist during one oscillation cycle. The duration of the unstable flow state, corresponding to the optimum Strouhal number, is found to be the longest, and it leads to a remarkable fluid exchange between the mainstream and the recirculation zone, thus contributing to the mass transfer enhancement. These results indicate that the transport enhancement mechanism for the wavy‐walled tube is quite different from the resonant transport enhancement observed in the two‐dimensional (2‐D) wavy‐walled channel. © 2004 American Institute of Chemical Engineers AIChE J, 50: 762‐770, 2004
Crosslinking reaction of polyacrylate soap‐free hydrosol with zirconium chelate
Authors: Huang Zhihong , Xie Zhiming , Li Zhuomei 
Published: April 2004

AbstractThe crosslinking reaction mechanism of polyacrylate copolymer (monomer mass ratio of methyl methacrylate/butyl acrylate/acrylic acid = 48.77:46.69:4.54) hydrosol with triethanolamine chelate of zirconium isopropyloxide was studied with IR spectroscopy, NMR spectroscopy, differential scanning calorimetry, and ultraviolet spectroscopy. The instrumental analyses on the copolymer mixture heated at different temperatures were investigated, and we proved that the crosslinking adduct had amino groups that were provided by the chelate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3605–3609, 2004
Enzymatically degradable and pH‐sensitive hydrogels for colon‐targeted oral drug delivery. I. Synthesis and characterization
Authors: Bajpai S. K. , Saxena Sutanjay 
Published: April 2004

AbstractCylindrical hydrogels, composed of starch and poly(acrylic acid), were synthesized, and their swelling behavior was studied as a function of the pH of the medium. The gels underwent a sharp transition from Fickian swelling behavior (swelling exponent n = 0.30) to non‐Fickian swelling behavior (n = 0.96) as the pH of the swelling medium changed from 2.0 to 7.4. The hydrogels also underwent partial enzymatic degradation in an amylase‐containing medium of pH 7.4 at 37°C. The effects of the enzyme concentration in the swelling media, the amount of starch present in the gel, the initial water content, the degree of crosslinking, and the diameter of cylindrical hydrogels on the degradation behavior were studied. The degradation of the gels followed Michaelis–Menten kinetics, and the value of the Menten constant was 41.62 × 10−2. The gels exhibited minimum swelling in an acidic pH medium through the formation of a complex hydrogen‐bonded structure and underwent enzymatic degradation in a medium of pH 7.4 (i.e., simulating intestinal fluid) along with chain‐relaxation‐controlled swelling. Therefore, the gels have potential for colon‐targeted drug delivery. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3630–3643, 2004
Cellulose acetate–poly(ether sulfone) blend ultrafiltration membranes. II. Application studies
Authors: Mahendran R. , Malaisamy R. , Arthanareeswaran G. , Mohan D. 
Published: April 2004

AbstractUltrafiltration membranes are largely applied as macromolecular solutes and heavy‐metal‐ion separation from aqueous streams. Cellulose acetate and poly(ether sulfone) blend ultrafiltration membranes were prepared by the precipitation phase‐inversion technique in 100/0, 95/5, 85/15, and 75/25% polymer blend compositions in the absence and presence of a polymeric additive, poly(ethylene glycol) 600, at different additive concentrations and were used for the rejection of proteins trypsin, pepsin, egg albumin, and bovine serum albumin; a maximum of 94% rejection was achieved. The toxic heavy metal ions copper, nickel, and cadmium from dilute aqueous solutions were subjected to rejection by the blend membranes by complexation of the ions with the water‐soluble polymeric ligand, polyethyleneimine (PEI). Permeate flux studies of proteins and metal ions were performed simultaneously with the rejection experiments. The atomic absorption spectra results reveal maximum rejection for copper complex and a minimum rejection of about 60% for the cadmium complex. The rejection and permeate flux of the blend membranes were compared with those of pure cellulose acetate membranes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3659–3665, 2004
Superabsorbent polymeric materials. XI. Effect of nonionic monomers on the swelling behavior of crosslinked poly(sodium acrylate‐co‐nonionic monomers) in aqueous salt solutions
Authors: Lee Wen‐Fu , Yang Lin‐Gi 
Published: April 2004

AbstractA series of xerogels based on sodium acrylate, nonionic monomers such as 2‐hydroxyethyl methacrylate (HEMA) and poly(ethylene glycol) methacrylate (PEGMA), and N,N′‐methylene bisacrylamide were prepared by inverse suspension polymerization. The results indicate that the water absorbencies for these two gel series were effectively improved by the addition of a small amount of nonionic monomer (HEMA or PEGMA). The initial absorption rates in deionized water were faster for the PEGMA gels than for the HEMA gels. Scanning electron microscopy showed that the spherical particle size was smaller for the PEGMA gels than for the HEMA gels. In addition, the water absorbency of the gels in various salt solutions decreased with increasing ionic strength, especially for the multivalent salt solutions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3666–3674, 2004
Chromatographic performance of monodisperse macroporous particles produced by modified seeded polymerization. II. The effect of the diluent/seed‐latex ratio
Authors: Camli S. T. , Unsal E. , Senel S. , Tuncel A. 
Published: April 2004

AbstractPoly(styrene‐co‐divinylbenzene)‐based monodisperse macroporous particles were obtained by a modified seeded polymerization technique. The monodisperse polystyrene particles, obtained by dispersion polymerization in sufficiently large sizes and with suitable average molecular weights, were directly used as the seed latex in the production of macroporous particles. Therefore, the number of swelling and polymerization stages in the multistage production was reduced. In the first stage, the seed particles were swollen with a diluent, dibutyl phthalate (DBP), and then with a monomer phase including styrene, divinylbenzene, and, as an initiator, benzoyl peroxide. The monodisperse macroporous particles were obtained by the repolymerization of the monomer mixture in the seed particles. The particles, having different porosity characteristics, were synthesized through variations in the dibutyl phthalate/seed‐latex (DBP/SL) ratio. Selected macroporous particle samples were slurry‐packed into stainless steel high‐performance liquid chromatography columns (300 mm long × 7.8‐mm i.d.). The separation of the protein mixture by these columns in the reversed‐phase chromatography (RPC) mode was investigated. Liquid chromatograms with high resolutions were obtained under an acetonitrile/water gradient over a wide range of flow rates (i.e., 0.5–3 mL/min), especially for the particles produced with a monomer/seed‐latex (M/SL) ratio of 3.0 mL/g. In the RPC experiments, the particles produced with an M/SL ratio of 3.0 mL/g and DBP/SL ratios of 1.0 and 1.5 mL/g exhibited better chromatographic performance than the other samples. The maximum theoretical plate number was 3500 for the particles produced with the M/SL ratio of 3.0 mL/g and DBP/SL ratio of 1.5 mL/g with albumin as the analyte. The size exclusion chromatography (SEC) calibration curves and the back‐pressure/flow‐rate relationships of the produced columns were also determined. The particles obtained with an M/SL ratio of 3.0 mL/g and a DBP/SL ratio of 1.5 mL/g exhibited the best performance in SEC applications. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3685–3696, 2004
Surface modification of single‐walled carbon nanotubes with polyethylene via in situ Ziegler–Natta polymerization
Authors: Tong Xin , Liu Chang , Cheng Hui‐Ming , Zhao Haichao , Yang Feng , Zhang Xuequan 
Published: April 2004

AbstractSingle‐walled carbon nanotubes (SWNTs) were modified with polyethylene (PE) prepared by in situ Ziegler–Natta polymerization. Because of the catalyst pretreated on the surface of the SWNTs, the ethylene was expected to polymerize there. Scanning electron microscopy images and solubility measurements showed that the surface of the SWNTs was covered with a PE layer, and a crosslink may have formed between the SWNTs and PE. When the SWNTs covered with a PE layer were mixed with commercialized PE by melt blending, the resulting composite had better mechanical properties than the composite from the SWNTs without a PE layer. The yield strength, the tensile strength and modulus, the strain at break, and the fracture energy of the modified‐SWNT/PE composites were improved by 25, 15.2, 25.4, 21, and 38% in comparison with those of the raw‐SWNT/PE composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3697–3700, 2004
Bonding properties of epoxy resins containing two mesogenic groups
Authors: Ochi Mitsukazu , Hori Daisuke , Watanabe Yutaka , Takashima Hiroshige , Harada Miyuki 
Published: April 2004

AbstractLiquid‐crystalline epoxy resins, with introduced aliphatic chains between two mesogenic groups, were synthesized and their adhesive bonding properties were compared to those of the bisphenol‐A–type epoxy resin and the liquid‐crystalline epoxy resin, previously reported. The bonding strength of the former resin system was higher than that of the two later systems. We suggest that the high bonding strength of the twin mesogenic epoxy resins, cured with an aromatic amine, was attributable to the large plastic deformation of the adhesive layer in the fracturing process. We also investigated the effects of the aliphatic chain length in the twin mesogenic epoxy resin on their dynamic mechanical and bonding properties. The bonding strength of the cured twin mesogenic epoxy resins increased with an increase in the aliphatic chain length. We suggest that the high bonding strength of the system introduced by the long aliphatic chain was attributable to the large plastic deformation of the adhesive layer because of the higher network mobility. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3721–3729, 2004
New side‐chain nematic liquid crystalline elastomers containing smectic crosslinking units
Authors: Guan Yan , Yu Yan , Zhang Bao‐Yan , Zhang Li‐Feng 
Published: April 2004

AbstractA series of siloxane‐based liquid crystalline elastomers containing the smectic crosslinking agent M‐1 and nematic monomer M‐2 were synthesized by a one‐step hydrosilication reaction. The chemical structures of the monomers and polymers obtained were confirmed by FTIR spectroscopy. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X‐ray diffraction (XRD) measurements. The influence of the crosslinking unit on the phase behavior was discussed. The experimental results demonstrated that the glass transition temperatures of elastomers had no remarkable change, and isotropization temperatures decrease with increasing the content of the crosslinking agent M‐1. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3755–3760, 2004
Increased prevalence of semaphorin 3C, a repellent of sympathetic nerve fibers, in the synovial tissue of patients with rheumatoid arthritis
Authors: Miller Luitpold E. , Weidler Claudia , Falk Werner , Angele Peter , Schaumburger Jens , Schölmerich Jürgen , Straub Rainer H. 
Published: April 2004

AbstractObjectiveThe presence of selective sympathetic nerve repellents, i.e., semaphorins, may be responsible for the observed reduction of sympathetic innervation in the synovial tissue of patients with rheumatoid arthritis (RA). This study was undertaken to investigate the presence of different semaphorins in synovial tissue of patients with RA, patients with osteoarthritis (OA), and control subjects without inflammation.MethodsIn situ hybridizations with digoxigenin‐labeled RNA probes directed against different semaphorins were performed. The presence of semaphorin 3C (S3C) in the synovial tissue of 10 RA, 10 OA, and 5 control subjects was investigated using a polyclonal antiserum directed against S3C.ResultsAll in situ hybridizations revealed the presence of S3C messenger RNA, but no other investigated semaphorin (i.e., against primary afferent sensory nerve fibers), in the synovial tissue of RA and OA patients. Immunohistologic double staining demonstrated that macrophages and fibroblasts were positive for S3C protein. Quantitative analysis of S3C protein staining showed an increased density of S3C‐positive cells in the synovial tissue of RA patients (mean ± SEM 339 ± 65 cells/mm2) in comparison with OA patients (168 ± 27/mm2; P = 0.031 versus RA) and controls (126 ± 26/mm2; P = 0.027 versus RA). Studies of the relationship between sympathetic nerve fiber density and S3C‐positive cell density in the tissue of all patients showed that RA patients generally had lower densities of sympathetic nerve fibers and higher densities of S3C‐positive cells than OA patients and control subjects.ConclusionThese findings suggest that S3C from macrophages and fibroblasts, which is selectively directed against sympathetic nerve fibers, could be one element responsible for reduced sympathetic innervation in RA tissue. The inability of sympathetic nerve fibers to reinnervate synovial tissue could contribute to the chronic nature of RA.