bluuebunny/crossref_metadata_2025 huggingface dataset:
Polymerized high internal‐phase emulsions: Properties and interaction with water
Authors: Sergienko Anatoly Y. , Tai Huiwen , Narkis Moshe , Silverstein Michael S.
Published: August 2002

The synthesis and characterization of novel polymerized high internal‐phase emulsions (polyHIPE) materials are described. Homogeneous, highly porous, low‐density, open‐cell crosslinked copolymers were prepared by polymerizing the continuous phase of HIPE containing styrene and varying amounts of 2‐ethylhexyl methacrylate. The glass transition temperatures (Tgs) of the homopolymers were similar to the literature values, but the copolymer Tgs were lower than expected. These results indicate that the copolymer composition is richer in 2‐ethylhexyl methacrylate than the feed composition. The homopolymer moduli, calculated from the foam moduli, were similar to the literature values. The influence of composition and surface treatment on the water absorbed by the foams was investigated. For example, washing a polyHIPE based on poly(ethylhexyl acrylate) in water at 70°C increased water absorption because of the removal of the residual salt. Adding a fluorinated comonomer to the HIPE reduced hydrophilicity and, thus, water absorption. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2018–2027, 2002; DOI 10.1002/app.10555
Toughness enhancement of high‐impact polystyrene based on γ‐radiation vulcanized natural rubber latex by using block copolymer
Authors: Sangribsub S. , Tangboriboonrat P.
Published: August 2002

Polyisoprene‐block‐polystyrene‐block‐polyisoprene (ISI) was synthesized by the iniferter route and its use, as compared to a commercial polystyrene‐block‐polyisoprene‐block‐polystyrene (SIS), in the enhancement of the toughness of high‐impact polystyrene (HIPS), prepared by the γ‐radiation vulcanized natural rubber (RVNR) latex/phase transfer/bulk polymerization technique, was investigated. Addition of 5% SIS was adequate as an interfacial agent, which effectively increased the unnotched Izod impact energy of HIPS, whereas use of 10% of ISI was required. A long polyisoprene block with two polystyrene segments of SIS was favorable for compatibilization of HIPS. Transmission electron micrographs revealed the uniform distribution of the block copolymer at the shell region of the rubber particle. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1307–1316, 2002
Function mechanisms of polyamines in rosin sizing under neutral papermaking conditions
Authors: Wu Zonghua , Chen Shaoping , Tanaka Hiroo
Published: August 2002

The surface analyses of the papers sized with a rosin emulsion (RE) and five typical polyamines, polyallylamine (PAAm), polyvinylamine (PVAm), polyethyleneimine (PEI), poly(diallyldimethylammonium chloride (PDADMAC), and poly(dimethylamino ethyl methacrylate) (PDMAEMA), were performed using a X‐ray photoelectron spectrometer. The results show that the chemical states of the polyamines on the outermost surfaces of the papers changed significantly during the neutral rosin sizing. The five polyamines could react with carboxyl groups of the fibers to form urethane linkages at 400.0 ± 0.1 eV, which resulted in absorption of the polyamines onto the fibers. Only PAAm and PVAm could combine with RE to form urethane linkages at 400.7–0.1 eV, which were related deeply to sizing effectiveness. The polyamines distributed mainly on the surfaces of the fibers. The concentrations of PAAm and PVAm on the surfaces of the sized papers were much larger than those of PEI, PDMAEMA, and PDADMAC. A larger sizing degree was related to a larger C1 component at 285.0 eV (CC) in the C1s XPS spectra of the sized papers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2185–2190, 2001
Structural, mechanical, and electrical properties of electropolymerized polypyrrole composite films
Authors: Bhat N. V. , Gadre A. P. , Bambole V. A.
Published: August 2002

Electrochemical polymerization of pyrrole in a solution containing dissolved poly(vinyl alcohol) (PVA) produces a homogeneous, free‐standing, flexible, and conductive polymer film. The films were characterized using infrared spectroscopy, wide‐angle X‐ray diffraction analysis, and scanning electron microscopy. The appearance of standard and some new absorption bands for polypyrrole (PPy) and PVA confirms the composite formation. The mechanical properties of conducting PVA + PPy films were studied and found to be improved with respect to the control PPy films. The electrical conductivity of the PVA + PPy films was measured by using standard four‐ and two‐probe methods. The conductivity of the films was found to depend on the pyrrole content. These conducting composites were further used as gas sensors by observing the change in current with respect to ammonia gas. It was observed that the current decreases when these composites were exposed to ammonia gas. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2511–2517, 2001
Thermal characterization of three‐component blends for hot‐melt adhesives
Authors: Fernandes E. G. , Lombardi A. , Solaro R. , Chiellini E.
Published: August 2002

Traditional solvent‐based adhesives used in the footwear industry have been demonstrated as harmful to the workers' health and environment. Solvent‐free three‐component adhesives (hot‐melt adhesives or HMAs) for various applications including the leather and footwear industry are becoming more and more attractive. Thus, the formulation of a three‐component HMA was realized in this study. Thermogravimetry, differential scanning calorimetry, and the apparent strength of the adhesive bond were used to investigate the relationship between their properties and the polymer/wax/resin compositions. The thermal stability of HMA formulations was determined and compared with thermal traces based on an additive weight computation of the single components' thermal profiles. All HMA formulations showed a direct relationship between the glass‐transition temperature and the apparent adhesive shear strength at the leather–rubber interface. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2889–2901, 2001
Preparation of poly(acrylic acid)/poly(vinyl alcohol) membrane for the facilitated transport of CO2
Authors: Matsuyama Hideto , Teramoto Masaaki , Matsui Kenji , Kitamura Yoshiro
Published: August 2002

Poly(acrylic acid) (PAA)/poly(vinyl alcohol) (PVA) membrane was prepared for the facilitated transport of CO2. The carrier of CO2 was monoprotonated ethylenediamine and was introduced in the membrane by ion exchange. The ion‐exchange capacity of the membrane was 4.5 meq/g, which was much higher than that of the Nafion 117 membrane. The membrane was highly swollen by the aqueous solution. Much higher selectivity of CO2 over N2 and higher CO2 permeability were obtained in the PAA/PVA membrane than in the Nafion membrane because of the higher ion‐exchange capacity and solvent content. The highest selectivity was more than 1900 when the CO2 partial pressure in the feed gas was 0.061 atm. Effects of ion‐exchange capacity, membrane thickness, and annealing temperature in conditions of membrane preparation on membrane performance were investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 936–942, 2001
Supercritical carbon dioxide dewaxing of old corrugated containers
Authors: Stauffer Thad C. , Venditti Richard A. , Gilbert Richard D. , Kadla John F. , Chernyak Yury , Montero Gerardo A.
Published: August 2002

Wax‐coated old corrugated containers (OCC) are not part of the paper recycling stream because a process to remove the wax coating is not presently available. Residual waxes influence fiber–fiber bonding, reducing the paper properties of recycled OCC as well as the paper machine operating efficiency. A procedure to dewax OCC is a major objective of the paper industry. Here we describe a novel process to quantitatively dewax OCC by using supercritical carbon dioxide to remove the wax. The results obtained for the extraction of both saturated and curtain‐coated waxed containers are reported and compared with Soxhlet extraction with hexane. Quantitative removal of the waxes was obtained under a variety of operating conditions. Gas chromatographic analysis of the extracted paraffin wax shows that supercritical fluid extraction does not chemically alter the paraffin wax, indicating the recovered wax may be recycled. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1107–1114, 2001
Effect of the composition profile of 2‐ethyl hexyl acrylate/methyl methacrylate latex particles on adhesion
Authors: Laureau C. , Vicente M. , Barandiaran M. J. , Leiza J. R. , Asua J. M.
Published: August 2002

The adhesive properties (tack, shear, and peel) of 2‐ethyl hexyl acrylate/methyl methacrylate copolymer latex particles of different composition profiles (constant, positive, and negative gradients) but similar molecular weight distributions were studied. The composition profile had a strong effect on tack in the region of low molecular weights (weight‐average molecular weight ≤ 100,000 g/mol), but this effect was less important for higher molecular weights. No effect of the composition profile on shear or peel was observed for low‐molecular‐weight latices; nevertheless, for higher molecular weights (400,000 g/mol), resistance to shear strongly increased as heterogeneity increased, and resistance to peel was higher for gradient profiles. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1258–1265, 2001
Polymerization of pyrrole and processing of the resulting polypyrrole as blends with plasticised PVC
Authors: Abraham D. , Jyotsna T. S. , Subramanyam S. V.
Published: August 2002

Polypyrrole was synthesized by chemical oxidation of pyrrole in water containing various sulphonic acids like toluene sulphonic acid (TSA), sulphosalicylic acid (SSA), and camphor sulphonic acid (CSA), as well as a combination of each sulphonic acid with sodium dodecyl benzene sulphonate (NaDBS) to investigate the effect of doping on conductivity, yield, and processability of the conducting polymer. Free‐standing blend films of polypyrrole and plasticized polyvinyl chloride (PVC) were obtained by casting an homogeneous suspension of the two polymers in tetrahydrofuran. The maximum conductivity of the blend film is ∼ 0.3 S/cm, corresponding to a weight fraction of 0.16 w/w polypyrrole. The blend film is semiconducting in the range 300–10 K. A TG‐DTA scan indicates the blend film to be amorphous with a stepwise decomposition process similar to pristine PVC. The choice of a dual dopant system during synthesis and the plasticised polymer during subsequent processing were keys to obtaining homogeneous high‐quality films. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1544–1548, 2001
Mooney scorch time and cure index of epoxidized natural rubber in presence of sodium carbonate
Authors: Poh B. T. , Tan E. K.
Published: August 2002

The effect of sodium carbonate on the Mooney scorch time and cure index of epoxidized natural rubber (ENR 50) was studied with concentrations of 0–2 phr and 100–160°C temperatures. A conventional vulcanization system based on an ASTM formulation was used throughout the investigation on the gum and carbon black filled rubber compound. The results indicated that the scorch time and cure index for the gum and filled compounds increased to a maximum value at 0.15 phr of sodium carbonate, and further loading of sodium carbonate caused it to decrease. This observation was attributed to the neutralization of the residual acid in ENR 50 in the initial stage, thus reducing the formation of ether crosslinks via an acid‐catalyzed ring‐opening reaction with the epoxide group in ENR 50. However, as the sodium carbonate was increased beyond 0.15 phr, the excess sodium carbonate enhanced the vulcanization rate as shown by the drop of the scorch time and cure index. The peak maximum was more evident at lower temperature and its peak height decreased with increasing temperature, suggesting that the neutralization effect by sodium carbonate was overshadowed by the faster cure rate resulting from the availability of thermal energy to overcome the activation energy of vulcanization as the temperature was elevated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1352–1355, 2001
Epoxy–urethane copolymers: Relation between morphology and properties
Authors: Stefani P. M. , Moschiar S. M. , Aranguren M. I.
Published: August 2002

The modification of an amine‐cured epoxy resin by the addition of polyurethanes (PU) was investigated, and their mechanical and impact properties were related to their microstructure and morphology. For the study, two different PU were selected: a commercial sample, D12, with a NCO : OH ratio equal to 2 and end blocked by reaction with an alkylphenol; and a synthesized sample, with NCO : OH ratio equal to 1 and equally end blocked in our laboratory. The usual trend of improved toughening and reduced modulus, EF, and compression yield stress, σYC, was observed in all samples. However, the toughening of the D12‐modified samples was larger for the same initial rubber content. This result correlates with a finer rubber particle separation, but also the ductilization effect that this rubber has on the epoxy‐rich phase. D12 co‐reacts with the epoxy–amine, leading to a lower glass transition temperature (Tg) of the modified system and incomplete phase separation, as observed by scanning electron microscopy. The practically unreactive PU1 rubber leads to the usual spherical inclusion morphology observed in modified epoxies, except at 20% rubber content. The particular morphology generated in this case, co‐continuous epoxy‐rich and rubber‐rich regions, leads to a material with the largest toughening in this study, but also with an impressive reduction in mechanical properties. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2544–2552, 2001
Effect of the ethylene content of poly(ethylene‐co‐vinyl alcohol) on the formation of microporous membranes via thermally induced phase separation
Authors: Matsuyama Hideto , Kobayashi Kiyotaka , Maki Taisuke , Tearamoto Masaaki , Tsuruta Hitoshi
Published: August 2002

Porous poly(ethylene‐co‐vinyl alcohol) (EVOH) membranes were prepared via thermally induced phase separation. The effect of the EVOH ethylene content on the membrane morphology and solute rejection property was investigated. For EVOHs with ethylene contents of 27–44 mol %, polymer crystallization (solid–liquid phase separation) occurred, and the membrane morphology was the particulate structure. However, the liquid–liquid phase separation occurred before crystallization for EVOH with a 60 mol % ethylene content. Cellular pores were formed in this membrane. For the particulate membranes, higher solute rejection and lower water permeance were obtained for EVOH with a lower ethylene content. The membrane formed by the liquid–liquid phase separation showed a sharper solute rejection change with a change in the solute radius than the particulate membranes did. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2583–2589, 2001
Fluorescence method for monitoring isothermal curing and shelf life of an epoxy–anhydride system
Authors: Vatanparast Ramin , Li Shuyan , Lemmetyinen Helge
Published: August 2002

A fluorescence technique with seven fluorescent probes was applied to monitor the curing and shelf life of an epoxy resin. As isothermal curing proceeded, the fluorescence emission bands of the probes exhibited blue shifts because of microviscosity and micropolarity changes. An intensity ratio method was applied in which ratios of the lowest and highest intensity changes in the emission bands were used to determine the degree of isothermal curing. A smooth and, in some cases, a linear correlation was found between the fluorescence intensity ratio and the degree of cure. This method enables the degree of cure to be monitored and allows comparable results from different types of probes to be monitored during the same curing process. The fluorescence technique and the ratio method offer the possibility of monitoring the precuring and the shelf life of the epoxy polymer. The method can be used to compare the kinetics of various monomers and resin formulations under constant curing conditions. Thus, the method would be useful for developing new resin formulations and technologies and could be applied to a variety of commercial and industrial uses of epoxy resins. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2607–2615, 2001
Adsorption of heavy metal ions from aqueous solutions by porous polyacrylonitrile beads
Authors: Godjevargova T. , Simeonova A. , Dimov A.
Published: August 2002

The adsorption of Cu(II), Ni(II), Zn(II), and Pb(II) from aqueous solutions on acrylonitrile copolymer sorbents was studied. We prepared five types of sorbents from polyacrylonitrile by varying its concentration in the initial polymer solution and the composition of the coagulation bath, aiming to achieve a different porous structure. The specific area, pore volume, and pore radius of the sorbents were determined on a porosimeter. The porous structure was studied by scanning electron microscopy. Modification of sorbents with sodium hydroxide and hydroxylamine was carried out to form amidooxyme and carboxylic groups with proven complex‐forming properties toward heavy metal ions. The optimal pH of the sorption of metal ions was found. The adsorption kinetics were investigated. The order of polymer sorbents toward the sorption of Pb(II), Cu(II), Ni(II), and Zn(II) ions, and the order of heavy metal uptake were determined for all types of sorbents. The effectiveness of heavy metal desorption and the coefficient of recovery of sorption ability were determined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3036–3044, 2002; DOI 10.1002/app.2334
Community‐based management of the environment: lessons from the past and options for the future
Authors: Evans S.M. , Birchenough A.C.
Published: August 2002

1. Traditional community‐based systems of managing coastal fisheries were (or in some cases are) successful in managing resources at sustainable levels. These systems are used as models in the present study.

2. They were (or are) under‐pinned by a sense of ownership and intimate knowledge of the environment in local people.

3. Such features have been largely lost, as subsistence economies have been replaced by capitalist ones, and environmental management responsibilities have shifted from local communities to national or international government.

4. There are, nevertheless, some examples of community‐based management systems that still operate successfully and we believe that modern management practices, in general, would benefit from increased community involvement. This will require renewed emphases on feelings of ownership and increased knowledge of the environment in the general public.

5. Environmental education will have a fundamental role to play in achieving this goal. However, its impact in schools and universities has been disappointingly ineffective so far in promoting a population that is sufficiently knowledgeable and well‐motivated to partake meaningfully in environmental management processes.

6. It is argued that educational initiatives, which involve all ages and sections of society, are required. Five promising possibilities are: (i) the participation of community groups in scientific projects; (ii) increased emphasis on life‐long learning; (iii) educational campaigns; (iv) citizens' juries; and (v) the involvement of community groups in environmental planning and management processes.

7. Wide‐scale adoption of innovations of these kinds will require funding and this will be achieved only by national re‐assessments of educational needs and priorities. Copyright © 2001 John Wiley & Sons, Ltd.
Changes and recovery of macrozoobenthic communities after restoration measures of the Orbetello Lagoon (Tyrrhenian coast, Italy)
Authors: Lardicci Claudio , Como Serena , Corti Serena , Rossi Francesca
Published: August 2002

1. This paper describes the long‐term dynamics of the macrozoobenthic communities in the Orbetello Lagoon, one of the largest Western Mediterranean lagoons, which was affected by eutrophication processes that began in the 1980s and peaked with two severe anoxic crises in 1992 and 1993.

2. The aim of the present research was first to establish the characteristics of this basin prior to the anoxic crises, and second to assess the recovery of the lagoon after various restoration measures were completed in 1996. Investigations were carried out by studying macrozoobenthic communities in 4 years (1976, 1988, 1994, 1999) that were representative of the different (eu)trophic status in the lagoon.

3. Results of multivariate analyses indicated that each year was significantly different from the others. The years 1976 and 1999 exhibited the highest number of species as compared with 1988 and 1994. The majority of species characterizing the 1976 communities were marine taxa whereas 1988 and 1994 showed a lower percentage of marine species and a higher percentage of opportunistic organisms in comparison with 1976. The species assemblage in 1999 showed an intermediate composition between 1976 and 1988–1994.

4. Eutrophication processes caused a clear impoverishment of the macrobenthic communities in 1988 and 1994. The increase in overall number of species during 1999 may have been due to improved environmental conditions of the lagoon. However, the composition of the community suggested that still there were signs of disturbance in the lagoon in 1999, 6 years after the last intense anoxic crises and even after completion of the environmental restoration measures.

5. It was hypothesized that secondary disturbance events, sustained by high seasonal release of nutrients from the sediments, could cause the deviations from the expected improvement in benthic conditions. Copyright © 2001 John Wiley & Sons, Ltd.
Predictive mapping for management and conservation of seagrass beds in North Carolina
Authors: Kelly Nina M. , Fonseca Mark , Whitfield Paula
Published: August 2002

An Erratum has been published for this article in Aquatic Conservation: Marine and Freshwater Ecosystems 12(2), 2002 577

This research extends techniques of predictive mapping from their application in terrestrial environments to marine landscapes by investigating the relationship between seagrass and hydrodynamics in Core Sound, North Carolina, USA.

An empirically derived logistic multiple regression model and a Boolean logic suitability model were used to produce several predictive map products, including: susceptibility of seagrasses to storms, probability of seagrass cover, and suitability of areas for restoration of seagrasses. A visual comparison between these maps and conventional seagrass polygon maps allows for a discussion of ‘field’ versus ‘object’ mapping, and the ramifications for management based on different cartographic techniques.

The predictive method used here showed that only a small portion (19%) of the seagrass bed in the study area would be expected to have a high probability of seagrass coverage. The majority of the seagrass habitat in the study area was predicted to have less than 50% probability of seagrass cover. In addition, 16% of the nearly 2000 ha of seagrass within the study area were predicted to be highly susceptible to acute storm events. Moreover, using a conservative set of site selection criteria, only 7% of the study area encompassed by seagrass habitat was predicted to have a high probability of successful restoration if injured.

This method provides for an inexpensive way to scale‐up from high‐resolution data to a coarser scale that is often required for conservation and management.

Copyright © 2001 John Wiley & Sons, Ltd.
Indirect‐collective referencing (ICR) in the elite journal literature of physics. II. A literature science study on the level of communications
Authors: Száva‐Kováts Endre
Published: August 2002

In the author's three previous articles dealing with the ICR phenomenon (JASIS, 49, 1998, 477–481; 50, 1999, 1284–1294; JASIST, 52, 2001, 201–211) the nature, life course, and importance of this phenomenon of scientific literature was demonstrated. It was shown that the quantity of nonindexed indirect‐collective references in The Physical Review now alone exceeds many times over the quantity of formal references listed in the Science Citation Index as “citations.” It was shown that the ICR phenomenon is present in all the 44 elite physics journals of a representative sample of this literature. The bibliometrically very heterogeneous sample is very homogeneous regarding the presence and frequency of the ICR phenomenon. However, no real connection could be found between the simple degree of documentedness and the presence and frequency of the ICR phenomenon on the journal level of the sample. The present article reports the findings of the latest ICR investigation carried out on the level of communications of the representative sample. Correlation calculations were carried out in the stock of all 458 communications containing the ICR phenomenon as a statistical population, and within this population also in the groups of communications of the “normal” and the “letter” journals, and the “short communications.” The correlation analysis did not find notable statistical correlation between the simple and specific degree of documentedness of a communication and the number of works cited in it by ICR act(s) either in the total population or in the selected groups. There is no correlation either statistical or real (i.e., cause‐and‐effect) between the documentedness of scientific communications made by their authors and the presence and intensity of the ICR method used by their authors. However, in reality there exists a very strong connection between these two statistically independent variables: both depend on the referencing author, on his/her subjectivity and barely limited subjective free will. This subjective free will shapes the stock of the formal‐direct references of scientific communications, thereby placing the achievements cited in this way and their creators into the (indexed) showcase of present Big Science. The same free will decides on the use or nonuse of the ICR method, and in the case of use also on the intensity with which the method is used.
An algorithm for term conflation based on tree structures
Authors: Diaz Irene , Morato Jorge , Lloréns Juan
Published: August 2002

This work presents a new stemming algorithm. This algorithm stores the stemming information in tree structures. This storage allows us to enhance the performance of the algorithm due to the reduction of the search space and the overall complexity. The final result of that stemming algorithm is a normalized concept, understanding this process as the automatic extraction of the generic form (or a lexeme) for a selected term.
Collaborative relevance judgment: A group consensus method for evaluating user search performance
Authors: Zhang Xiangmin
Published: August 2002

Relevance judgment has traditionally been considered a personal and subjective matter. A user's search and the search result are treated as an isolated event. To consider the collaborative nature of information retrieval (IR) in a group/organization or even societal context, this article proposes a method that measures relevance based on group/peer consensus. The method can be used in IR experiments. In this method, the relevance of a document is decided by group consensus, or more specifically, by the number of users (or experiment participants) who retrieve it for the same search question. The more users who retrieve it, the more relevant the document will be considered. A user's search performance can be measured by a relevance score based on this notion. The article reports the results of an experiment using this method to compare the search performance of different types of users. Related issues with the method and future directions are also discussed.
CYP3A inductive potential of the rifamycins, rifabutin and rifampin, in the rabbit
Authors: Weber Allan , Kaplan Mindy , Chughtai Shazia A. , Cohn Leah A. , Smith Arnold L. , Unadkat Jashvant D.
Published: August 2002

Rifabutin is effective in the treatment and prevention of Mycobacterium avium infection in people with HIV infection. Rifabutin is structurally related to another rifamycin, rifampin, a well‐known inducer of the human P‐450 isoform 3A. The rabbit isoform CYP3A6 and the human isoform CYP3A4 have similar P‐450 predominance and substrate specificity and are both induced by rifampin. Our goal was to predict the CYP3A induction capacity of rifabutin and to determine if ex vivo CYP3A induction potential of rifamycins is predictive of that obtained in vivo. We determined the in vivo and ex vivo CYP3A6 induction by 4 days of treatment with rifabutin (100 mg/kg), rifampin (100 mg/kg), or vehicle (DMSO) in the rabbit. The ex vivo measures were CYP3A6 activity (N‐demethylation of erythromycin and hydroxylation of triazolam) and CYP3A content in rabbit hepatic microsomes preparations. The in vivo measures were oral clearance of triazolam and its formation clearance to its hydroxylated metabolites, α‐hydroxytriazolam and 4‐hydroxytriazolam. Rifampin increased CYP3A6 activity by 2‐ to 3‐fold in hepatic microsomes compared to vehicle. Rifabutin increased CYP3A content 1.7‐fold, but did not significantly increase microsomal CYP3A6 activity. Oral triazolam clearance and formation clearances to the two hydroxylated metabolites were 2‐ to 3‐fold greater in rabbits treated with rifampin. These clearances were unaffected by rifabutin administration. Ex vivo enzyme activities correlated with in vivo changes in clearance of triazolam and the formation clearance to its hydroxylated metabolites. Rifabutin is a weaker inducer of CYP3A6 than rifampin. These data suggest that ex vivo enzyme activity is a viable approach to predict in vivo inductive potential of CYP3A inducers. Copyright © 2001 John Wiley & Sons, Ltd.
Temporal trends and misclassification in residential 60 Hz magnetic field measurements
Authors: Banks Robert S. , Thomas William , Mandel Jack S. , Kaune William T. , Wacholder Sholom , Tarone Robert E. , Linet Martha S.
Published: August 2002

This research addressed the question of how well measurement data collected during a single visit, made at an arbitrary hour of day, day of week, and season, estimate longer term residential 60 Hz magnetic field levels. We made repeat spot and 24 h measurements in 51 children's home, located in the Detroit, MI, and the Minneapolis‐St. Paul, MN metropolitan areas, on a regular bimonthly schedule over a 1 year period, as well as a single 2 week measurement, for total of eight visits, producing 21 days of data for each residence. We defined the long term estimate (LTE) as the geometric mean of all available 24 h geometric means from the first six bimonthly visits. The LTE served as the reference level for assessing seasonal, day of week, and diurnal effects, as well as the potential for misclassification. We found a small, but statistically significant (P < .05), seasonal effect, with levels approximately 3% lower than the LTE in the spring and about 4% greater during the summer. No effect was found for day of week. However, we did find a systematic and appreciable diurnal effect, suggesting that, for example, an evening spot measurement may overestimate the LTE by 20% or more. We also assessed how well the 24 h measurement from the last visit, which was not used in calculation of the LTE, estimated the LTE. We found a high degree of correlation (r = .92) and fair to good agreement using four exposure categories (κ = .53). Thus, the 24 h measurement appears to be a satisfactory LTE estimator. However, this finding must be interpreted with caution since considerable unexplained variability was present among the repeat 24 h measurements in about one‐third of the homes. While the 2 week measurement does somewhat decrease exposure misclassification, its added intrusiveness and cost are likely to outweigh the improved precision. Bioelectromagnetics 23:196–205, 2002. © 2002 Wiley‐Liss, Inc.
Individual molecules of thermostable alkaline phosphatase support different catalytic rates at room temperature
Authors: Dyck Ashley C. , Craig Douglas B.
Published: August 2002

Thermus thermophilus cells were grown at 70°C, lysed and the lysate subjected to single molecule alkaline phosphatase assays, using a capillary electrophoresis laser‐induced fluorescence detection‐based method. The enzyme was found to be heterogeneous with respect to catalytic rate when assayed at room temperature. Turnover numbers ranged 12‐fold, with an average of 400 ± 200 reactions/min for the 80 molecules assayed. Copyright © 2002 John Wiley & Sons, Ltd.
Application of a chaperone‐based refolding method to two‐ and three‐dimensional off‐lattice protein models
Authors: Gorse Denise
Published: August 2002

A model of protein–chaperone interaction as a two‐phase (unfolding/refolding) iterative annealing mechanism able to promote structural segregation of hydrophobic and hydrophilic monomers and thereby facilitate access to nativelike states has recently been applied successfully to two 22‐mers of the Honeycutt and Thirumalai BLN (hydrophobic, hydrophilic, neutral) heteropolymer model. This technique is here applied to a much wider data set: 94 8‐mers of the off‐lattice protein model originally presented in two dimensions by Stillinger and Head‐Gordon, and later extended into three dimensions by Irbäck and Potthast; the model chaperone is shown to be equally successful, and by progressive elaboration of the chaperone model as in the earlier BLN model work, to be utilizing very similar underlying mechanisms. It is demonstrated that on average, contacts with the model chaperone give rise to a consistent movement in structure space in the direction of more nativelike structures; this method of global minimization does not therefore rely fundamentally on random search. Insofar as the responses to the chaperone of the two‐ and three‐dimensional forms of the substrate model do differ, this can be interpreted as reflecting the different handling of hydrophilic monomers in the models—in particular, whether there is active repulsion between these and monomers of hydrophobic character. The chaperone‐induced refolding method is also tested on a set of 220 9‐mer chains of each version of the substrate model, where it is seen that the two‐dimensional model, with its more clearly distinguished roles for the hydrophobic and hydrophilic monomers, shows a more favorable scaling behavior. © 2002 Wiley Periodicals, Inc. Biopolymers 64: 146–160, 2002
Toward an enzyme‐based oxygen scavenging laminate. Influence of industrial lamination conditions on the performance of glucose oxidase
Authors: Andersson Mats , Andersson Thorbjörn , Adlercreutz Patrick , Nielsen Tim , Hörnsten Erik Gunnar
Published: August 2002

The laminate consisted of several polymer layers, aluminium, and one cellulose‐based layer containing the active enzymatic system (e.g., glucose oxidase, catalase, glucose, and CaCO3). During the industrial lamination process, the enzyme layer was exposed to three temperature spikes up to 325°C without significant enzyme inactivation. Ninety‐seven percent of the glucose oxidase activity still remained after the lamination process. The best laminate had an oxygen absorbing capacity of 7.6 ± 1.0 L/m2. A reference that was not laminated expressed a corresponding oxygen absorbing capacity of 7.1 ± 0.8 L/m2. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 79: 37–42, 2002.
Effect of temperature, medium composition, and cell passage on production of herpes‐based viral vectors
Authors: Wechuck James B. , Ozuer Ali , Goins William F. , Wolfe Darren , Oligino Thomas , Glorioso Joseph C. , Ataai Mohammad M.
Published: August 2002

Our work uses replication‐defective genomic herpes simplex virus type‐1 (HSV‐1)‐based vectors to transfer therapeutic genes into cells of the central nervous system and other tissues. Obtaining highly purified high‐titer vector stocks is one of the major obstacles remaining in the use of these vectors in gene therapy applications. We have examined the effects of temperature and media conditions on the half‐life of HSV‐1 vectors. The results reveal that HSV stability is 2.5‐fold greater at 33°C than at 37°C and is further stabilized at 4°C. Additionally, a significantly higher half‐life was measured for the vector in infection culture conditioned serum medium compared to fresh medium with or without serum. Synchronous infections incubated at 33°C produced 2‐fold higher amounts of vector than infected cells incubated at 37°C, but with a lag of 16–24 h. Vector production yielded 3‐fold higher titers and remained stable at peak levels for a longer period of time in cultures incubated at 33°C than 37°C. A pronounced negative effect of increased cell passage number on vector yield was observed. Vector production at 33°C yielded similar levels regardless of passage number but was reduced at 37°C as passage number increased. Together, these results contribute to improved methods for high‐titer HSV vector production. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 79: 112–119, 2002.
Kinetics of the lipase‐catalyzed synthesis of glucose esters in acetone
Authors: Arcos Jose A. , Hill Charles G. , Otero Cristina
Published: August 2002

A simple kinetic model derived from a ping‐pong bi‐bi mechanism is proposed to describe the lipase‐catalyzed esterification of glucose with fatty acids. The mathematical expressions derived from this model have been tested using several sets of data obtained from reactions carried out under different reaction conditions. The predicted values provide very good fits of the experimental data for temperatures from 30 to 60°C, enzyme loadings from 90 to 180 mg, and fatty acid concentrations from 0.33M to 1M. Experiments conducted at different temperatures permit one to estimate an activation energy of ∼12 kcal/mol for the rate‐limiting step of the reaction (formation of the acyl‐enzyme complex). The model also considers the kinetics of inactivation of the biocatalyst during the reaction. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 73: 104–110, 2001.
Influence of temperature and pH on xylitol production from xylose by Debaryomyces hansenii
Authors: Converti Attilio , Domínguez José Manuel
Published: August 2002

The production of xylitol from concentrated synthetic xylose solutions (So = 130‐135 g/L) by Debaryomyces hansenii was investigated at different pH and temperature values. At optimum starting pH (pHo = 5.5), T = 24°C, and relatively low starting biomass levels (0.5–0.6 gx/L), 88% of xylose was utilized for xylitol production, the rest being preferentially fermented to ethanol (10%). Under these conditions, nearly 70% of initial carbon was recovered as xylitol, corresponding to final xylitol concentration of 91.9 gP/L, product yield on substrate of 0.81 gP/gS, and maximum volumetric and specific productivities of 1.86 gP/L · h and 1.43 gP/gx · h, respectively. At higher and lower pHo values, respiration also became important, consuming up to 32% of xylose, while negligible amounts were utilized for cell growth (0.8–1.8%). The same approach extended to the effect of temperature on the metabolism of this yeast at pHo = 5.5 and higher biomass levels (1.4–3.0 gx/L) revealed that, at temperatures ranging from 32–37°C, xylose was nearly completely consumed to produce xylitol, reaching a maximum volumetric productivity of 4.67 gP/L · h at 35°C. Similarly, both respiration and ethanol fermentation became significant either at higher or at lower temperatures. Finally, to elucidate the kinetic mechanisms of both xylitol production and thermal inactivation of the system, the related thermodynamic parameters were estimated from the experimental data with the Arrhenius model: activation enthalpy and entropy were 57.7 kJ/mol and −0.152 kJ/mol · K for xylitol production and 187.3 kJ/mol and 0.054 kJ/mol · K for thermal inactivation, respectively. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 39–45, 2001.
Discrete particle simulations predicting mixing behavior of solid substrate particles in a rotating drum fermenter
Authors: Schutyser M. A. I. , Padding J. T. , Weber F. J. , Briels W. J. , Rinzema A. , Boom R.
Published: August 2002

A soft‐sphere discrete particle model was used to simulate mixing behavior of solid substrate particles in a slow rotating drum for solid‐state fermentation. In this approach, forces acting on and subsequent motion of individual particles can be predicted. The (2D) simulations were qualitatively and quantitatively validated by mixing experiments using video and image analysis techniques. It was found that the simulations successfully predicted the mixing progress as a function of the degree of filling and size of the drum. It is shown that only relatively large, straight baffles perpendicular to the drum wall (67% of the drum radius) increase the mixing performance of the rotating drum. Considering the different aspects of mixing dealt with in this work, it is concluded that the soft sphere discrete particle model can serve as a valuable tool for investigating mixing of solid substrate particles. Finally, it is expected that this model may evolve into a potential tool for design and scale‐up of mixed solid‐state fermenters. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 666–675, 2001.
Race, youth violence, and the changing jurisprudence of waiver
Authors: Feld Barry C.
Published: August 2002

This article analyzes the legal history and jurisprudential theory of legislative offense‐exclusion and prosecutorial waiver laws over the past quarter‐century. Initially concerns about racial discrimination and civil rights motivated the Supreme Court in Kent v. United States to require due process in judicial waiver hearings. Offense‐exclusion and “direct file” laws evolved and expanded in direct reaction to Kent as lawmakers sought simple and expedient alternatives to judicial waiver hearings. The “just deserts” sentencing movement of the 1970s, which advocated determinate and presumptive offense‐based sentences, provided a conceptual alternative to judicial discretion and a jurisprudential rationale for offense exclusion laws. Research on delinquent and criminal careers in the 1970s, which initially promised empirically grounded selective incapacitation sentencing strategies, provided another conceptual foundation for offense‐based waiver laws that focused on youths' prior records. Finally, offense exclusion provided a politically attractive strategy for “get tough” public officials who proposed to “crack down” on “baby boom” increases in youth crime. The jurisprudential shift in sentencing emphases from considerations of the offender to characteristics of the offense relocated waiver and sentencing discretion from judges to prosecutors. By the early 1990s, as a result of political “crack‐downs” on youth crime, the scope of excluded offense legislation increased substantially, became overly inclusive and excessively rigid, and exhibited many of the negative features associated with mandatory sentencing laws. Copyright © 2001 John Wiley & Sons, Ltd.
Self–other representations and relational and overt aggression in adolescent girls and boys*
Authors: Moretti Marlene M. , Holland Roy , McKay Sue
Published: August 2002

Aggressive behavior in girls has received far less attention than similar problems in boys. This study examined self‐representation, and others' representation of self, as predictors of relational aggression, overt aggression, and assaultive behavior in 32 girls and 52 boys, 10 to 17 years of age, referred for assessment due to significant aggressive and delinquent behavior problems. As predicted, negativity of self‐representation predicted relational aggression in girls but not boys. Negativity of self‐representation also predicted overt aggression and assaultive behavior in both girls and boys. Parental representations of self were not predictive in this sample; however, negativity of peer representations of self, was associated with increased relational aggression in girls and decreased relational aggression in boys. Negativity of peer representations of self also predicted overt aggression and assaultive behavior in both girls and boys. Results suggest that the evaluation of self–other representations may be valuable in the assessment of risk for gender specific patterns of aggression. Copyright © 2001 John Wiley & Sons, Ltd.
Pulley anatomy for the radial side of the wrist
Authors: Simovitch R. , Abel M. , Arslan O. , Frank C.
Published: August 2002

This is the first presentation in the literature of a radial tendon flexor pulley in the distal forearm adjacent to the flexor carpi radialis. The clinical significance is that in performing wrist tendon arthroplasty, this structure and, in close proximity, the sensory branch of the median nerve may be encountered. Whether cutting the pulley of the flexor carpi radialis is clinically significant in changing wrist biomechanics is unknown. Clin. Anat. 14:246–247, 2001. © 2001 Wiley‐Liss, Inc.
Community psychology, millennium volunteers and UK higher education: a disruptive triptych?
Authors: Duckett Paul S.
Published: August 2002

In this paper I critically explore the ideological underpinnings of pedagogical and political practices in UK Higher Education (HE). I first map out the political and pedagogical features of community psychology and then describe the Millennium Volunteers project at the University of Northumbria—a scheme that integrates voluntary placements into undergraduate degree programmes, reflecting on the political and pedagogical premises upon which it is based. I consider the political context and recent social policy trends in UK HE. Through exploring the ideological underbellies of community psychology and Millennium Volunteers I describe the tensions created once both are situated within a HE student's learning and a lecturer's teaching portfolio. I reflect on how each appears to share similar wish lists but conclude that a surface comparison of the pedagogical practices of each can leave unrecognized serious ideological, ethical and political differences that can cause disruption at the interfaces of staff, students and HE institutions. I recommend making the political and ideological assumptions behind pedagogical practices and education policy initiatives more transparent to both students and lecturers alike and outline the reasons for doing so. I conclude by reflecting on implications for the widening access agenda in the present political climate from the standpoint of a community psychologist. Copyright © 2002 John Wiley & Sons, Ltd.
Safety and clinical benefits of transsubxiphoidal left ventricular puncture
Authors: Zuguchi Masayuki , Shindoh Chiyohiko , Chida Koichi , Saito Haruo , Takai Yosihiro , Yamada Shogo , Iguchi Atsushi , Endo Masato , Akimoto Hiroji , Tabayashi Koichi
Published: August 2002

We performed a transsubxiphoidal LV puncture (TSLVP) to evaluate left ventricular function in 21 patients with both mechanical prosthetic aortic and mitral valves and successfully obtained hemodynamic information on each patient. Analyzing cardiac hemodynamic information and ventriculographic findings obtained with TSLVP, we concluded that seven of the patients required repair of their prosthetic valves. Five of these seven patients agreed to replacement of their valves, whereas two did not. TSLVP was performed adequately and safely without severe complications, suggesting that this maneuver is easier than that of transapical LV puncture and should be recommended for the assessment of left ventricular hemodynamic functions instead of the transapical LV puncture, especially in patients requiring replacement of two valves. Cathet Cardiovasc Intervent 2002;55:58–65. © 2002 Wiley‐Liss, Inc.
Interview with Michael Bevan: The Arabidopsis genome is sequenced, what next?
Authors: Bevan Michael
Published: August 2002

Professor Michael Bevan is at the John Innes Centre, Norwich, UK, where he is Head of the Cell and Developmental Biology Department. He was the co‐ordinator of the European Union Arabidopsis Genome Sequencing Consortium, which contributed to the sequence and analysis of the complete Arabidopsis genome that was published late last year. He is the co‐ordinator of the EC funded EXOTIC program and is also a member of GARNet and UK CropNet. (For more background detail on these projects, please see our Featured Organism: Arabidopsis thaliana piece, also in this issue of CFG, or visit the websites listed below).