bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact behavior of sawdust/recycled–PP composites
Authors: Li T. Q. , Ng C. N. , Li R. K. Y.
Published: August 2002

The instrumented Izod and Charpy tests were performed on the sawdust–polypropylene (PP) composites to study the nature of impact resistance in the thermoplastic wood composites. The notched Izod strength was found to increase with filler content in composites containing the Maleic–anhydride–grafted PP (MAPP) additive. The Izod strength even exceeds that of the neat matrix resin at higher filler contents, indicating a methodology for applying the recycled PP and also for reinforcing the thermoplastics with wood powders. While the static tensile results show evidences for the reinforcing role of the wood filler, a fracture mechanics characterization through the Charpy impact tests effects of MAPP under the impact loading rates. The choice of MAPP as the additive was discussed accordingly for application of the sort of materials. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1420–1428, 2001
Application of isothermal and model‐free isoconversional modes in DSC measurement for the curing process of the PU system
Authors: Li Shuyan , Vuorimaa Elina , Lemmetyinen Helge
Published: August 2002

The dynamic, isothermal, and model‐free isoconversional modes of differential scanning calorimetry measurement were used to monitor the curing process of the polyurethane system. Conversions obtained from these three methods were in good agreement with one another, indicating that isothermal and model‐free isoconversional modes can successfully be used for monitoring the curing process. For the isothermal mode, the highest reaction rate occurred at time zero, and autoacceleration was not observed for this system. From the model‐free isoconversional mode, it was possible to calculate the activation energy changes during the curing process. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1474–1480, 2001
Modeling and simulation of urethane acrylates synthesis. II. Kinetics of uncatalyzed reaction of toluene diisocyanate with a polyether diol
Authors: Grepinet B. , Pla F. , Hobbes Ph. , Monge Th. , Swaels Ph.
Published: August 2002

Toluene diisocyanate reacts with poly(propylene glycol) during the synthesis of some urethane acrylate oligomers. The present work deals with kinetic studies and molecular characterization of the uncatalyzed bulk reaction of these two difunctional monomers. Back titration and H1‐NMR are used to follow the reaction of the different isocyanate groups with an alcohol group belonging to poly(propylene glycol) and to allow a good description of the urethane groups evolution. The global reaction rate as well as that of each individual isocyanate group are well described by a second‐order equation. Kinetic constants were calculated by using the software SIMULBATCH®. The reaction of two difunctional monomers leads to the formation of oligomers of different polymerization degrees, opposite to the reaction of TDI with a monoalcohol. Thus, another approach was developed to characterize the oligomers by size exclusion chromatography and to calculate the molecular weight distribution by using a combination of kinetic and probabilistic arguments. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3149–3160, 2001
Sorption of dye wastes by poly(vinyl alcohol)/poly(carboxymethyl cellulose) blend grafted through a radiation method
Authors: El‐Salmawi K. M. , Zaid M. M. Abu , Ibraheim S. M. , El‐Naggar A. M. , Zahran A. H.
Published: August 2002

The instability in water of poly(vinyl alcohol) (PVA)/poly(carboxymethyl cellulose) (CMC) was improved through radiation‐induced grafting with a styrene monomer. The PVA/CMC blend graft copolymer was used as a sorbent for dye wastes normally released from textile factories. The factors that may affect the sorption process such as time, temperature, weight of the blend graft copolymer, and volume of the dye waste were investigated. The sorption of dyestuffs by the blend graft copolymer was determined by a method based on spectroscopic analysis. The results showed that the blend graft copolymer has a high affinity for basic, acid, and reactive dyes. Meanwhile, it was observed that the sorption of dyes is more effective at the high temperature of 70oC. Moreover, it was found that the sorption of dyes depends on the weight of the blend graft copolymer and does not depend on the volume of the waste solution. The sorption of the dyestuffs by a PVA/CMC graft copolymer may be considered to be a practical method to remove organic pollutants. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 136–142, 2001
Absolute online monitoring of a stepwise polymerization reaction: Polyurethane synthesis
Authors: Çatalgil‐Giz Huceste , Giz Ahmet , Alb Alina , Reed Wayne F.
Published: August 2002

The feasibility of using a recently introduced method for continuous, absolute online monitoring for step‐growth polymerization was demonstrated, and polyurethane synthesis was chosen for the demonstration. The previously reported use of this method was for monitoring free‐radical initiated chain‐growth polymerization. The technique involves continuously withdrawing a small stream of reaction liquid from the polymerization reactor and pumping it through a series of light scattering and viscosity detectors. This permits the absolute weight‐average molecular weight and reduced viscosity to be simultaneously monitored as the reaction proceeds. The final weight‐average molecular weights of the polyurethane samples were compared to the separate light scattering measurements of the final products. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2070–2077, 2001
Studies on preparation and swelling properties of the N‐isopropylacrylamide/chitosan semi‐IPN and IPN hydrogels
Authors: Lee Wen‐Fu , Chen Ying‐Jou
Published: August 2002

Semi‐interpenetrating network (semi‐IPN) polymer gels and interpenetrating network (IPN) polymer gels with thermosensitivity were prepared by introducing a biodegradable polymer, chitosan, into the N‐isopropyacrylamide (PNIPAAm) gel system. The swelling behavior, temperature sensitivity, pH sensitivity, gel strength, and drug‐release behavior of PNIPAAm/chitosan semi‐IPN and IPN hydrogels were investigated. The results indicated that the NIPAAm/chitosan semi‐IPN and IPN hydrogels exhibited pH and temperature‐sensitivity behavior and could slow drug release and diffusion from the gels. From the stress–strain curves of the hydrogels, the compression moduli of IPN gels containing crosslinked chitosan were higher than those of semi‐IPN gels. This is because IPN gels have a more compact structure. The morphology of PNIPAAm/chitosan hydrogels was also investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2487–2496, 2001
Polymerization of β‐pinene with ethylaluminum dichloride (C2H5AlCl2)
Authors: Guiné Raquel P. F. , Castro José A. A. M.
Published: August 2002

The main goal of this work is to study the cationic polymerization of terpenes, particularly of β‐pinene, with alkylaluminum catalysts. Some experiments at different polymerization temperatures (10, 20, and 50°C) were carried out with ethylaluminum dichloride catalyst, C2H5AlCl2. From the results, it is possible to draw some general conclusions about the evolution of chain growth during polymerization. This work also includes the influence of reaction temperature on some properties of the final resin, particularly the molecular weight distribution, the softening point, and the Gardner color index. The role of reducing agents, such as iodine, during the distillation of the final resin is also evaluated with respect to color and softening point. As a result of this investigation, the Mark–Howink constants for terpene resins in toluene and dicloromethane as solvents have also been experimentally determined, thus allowing a more precise use of size exclusion chromatography in the characterization of such natural based products. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2558–2565, 2001
Application of styrene‐acrylonitrile random copolymer–polyarylate block copolymer as reactive compatibilizer for polyamide and acrylonitrile‐butadiene‐styrene blends
Authors: Ohishi Hiroshi , Nishi Toshio
Published: August 2002

Styrene‐acrylonitrile random copolymer (SAN) and polyarylate (PAr) block copolymer were applied as a reactive compatibilizer for polyamide‐6 (PA‐6)/acrylonitrile‐butadiene‐styrene (ABS) copolymer blends. The SAN–PAr block copolymer was found to be effective for compatibilization of PA‐6/ABS blends. With the addition of 3.0–5.0 wt % SAN–PAr block copolymer, the ABS‐rich phase could be reduced to a smaller size than 1.0 μm in the 70/30 and 50/50 PA‐6/ABS blends, although it was several microns in the uncompatibilized blends. As a result, for the blends compatibilized with 3–5 wt % block copolymer the impact energy absorption reached the super toughness region in the 70/30 and 50/50 PA‐6/ABS compositions. The compatibilization mechanism of PA‐6/ABS by the SAN–PAr block copolymer was investigated by tetrahydrofuran extraction of the SAN–PAr block copolymer/PA‐6 blends and the model reactions between the block copolymer and low molecular weight compounds. The results of these experiments indicated that the SAN–PAr block copolymer reacted with the PA‐6 during the melt mixing process via an in situ transreaction between the ester units in the PAr chain and the terminal amine in the PA‐6. As a result, SAN–PAr/PA‐6 block copolymers were generated during the melt mixing process. The SAN–PAr block copolymer was supposed to compatibilize the PA‐6 and ABS blend by anchoring the PAr/PA‐6 and SAN chains to the PA‐6 and ABS phases, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2300–2313, 2002
A review of marine protected areas in the northwestern Mediterranean region: siting, usage, zonation and management
Authors: Francour Patrice , Harmelin Jean‐Georges , Pollard David , Sartoretto Stéphane
Published: August 2002

1. We present in this review a general description of marine protected areas (MPAs) in the northwestern Mediterranean and some general principles for the establishment of protected areas, including their size, location, biotope composition, regulation, and management.

2. Many Mediterranean MPAs are located around or adjacent to islands, but the placement of a marine reserve close to a large urban area is not necessarily a handicap, as has been demonstrated by some examples. It is not, therefore, necessary to restrict future MPAs solely to regions of low human density.

3. The conceptual question of MPA size (single large or several small — SLOSS debate) has never been explicitly considered in the selection of Mediterranenan MPAs. However, studies of fish recruitment in MPAs, and the development of a network of small MPAs between Spain and France have highlighted the importance and value of small sized MPAs (200–2000 ha).

4. Whatever the location of a future MPA, its success as measured in terms of stock restoration will depend on whether (i) sufficient suitable habitat is available, (ii) the variety and abundance of prey species are adequate and (iii) the possibilities for recruitment of the biota are reasonable.

5. The initial choices of zonation and legislation regulating the management of any future MPA are of primary importance. The zonation plan should be as simple as possible (gradation of 2 or 3 levels) and it should be acknowledged that the significance of management conflicts within a MPA will be inversely proportional to the extent of preliminary consultations with all of the users, both professional and amateur.

6. The examples of semi‐protected areas where professional fishing is still allowed demonstrate without ambiguity the negative impact of spear‐fishing, and the limited impacts from regulated professional activities on fish assemblages. The means of regulating consist essentially of (i) a prohibition of certain type of fishing methods (trawling); and (ii) a limitation of the numbers of fishermen by a system of restriction or authorization.

7. In the MPAs examined, there is a great diversity of situations in relation to the size of and distribution of duties between staff assigned to their management. However, the single most important factor underlying whether or not a MPA will be successful and beneficial is the presence of a dedicated staff. Copyright © 2001 John Wiley & Sons, Ltd.
Red coral: conservation and management of an over‐exploited Mediterranean species
Authors: Santangelo Giovanni , Abbiati Marco
Published: August 2002

1. Corallium rubrum is a precious circum‐Mediterranean octocoral, which occurs on rocky reefs between 10 and over 250 m in depth.

2. This species has been harvested for a long time and most commercial populations have been over‐exploited. The Mediterranean overall yield was reduced by 66% over the last 15 years.

3. Two type populations may be identified: (a) dense shallow‐water populations consisting of small, slow‐growing, short‐lived colonies and (b) deep‐dwelling populations, composed of large, sparse, long‐lived colonies. The former populations have little economic value, but should ensure a reproductive stock for the species.

4. While the structure and demography of shallow‐water populations have been studied, the demographic parameters of deep‐dwelling populations are largely unknown.

5. Recent genetic studies quantified levels of genetic divergence among coastal populations. Estimated numbers of migrants among populations suggested that the planulae of C. rubrum have short‐range dispersal. Geographic distances greater than 100 km can be considered as the threshold for genetic divergence between populations.

6. Development of a regime for the sustainable exploitation of this species requires a better knowledge of population dynamics, life‐history traits and quantitative genetics, especially concerning commercial populations. Copyright © 2001 John Wiley & Sons, Ltd.
Gross anatomy in the surgical curriculum in Switzerland: Improved cadaver preservation, anatomical models, and course development
Authors: Groscurth P. , Eggli P. , Kapfhammer J. , Rager G. , Hornung J.‐P. , Fasel J.D.H.
Published: August 2002

The invention of new techniques for surgery and interventional radiology demand improved training for ongoing specialists. The Anatomical Institutes in Switzerland support these requirements by establishing hands‐on practical training courses by using new procedures for cadaver embalming and model construction. Improvements allow courses to provide students with more realistic simulations of both established and experimental surgical methods. Through these changes, the value of in‐depth gross anatomy is enhanced as a topic of fundamental importance for the postgraduate medical and surgical curriculum. The web site http://www.unifr.ch/sgahe/snga.html contains information on courses using the Thiel embalming solution. Details about training courses in Switzerland using anatomical models are available at http://www.heartlab.org, http://www.vascular‐international.org, and http://www.elastrat.com. Anat Rec (New Anat) 265:254–256, 2001. © 2001 Wiley‐Liss, Inc.
TrkA and TrkB neurotrophin receptor immunoreactivity in the teleost (Scorpaena porcus) endocrine pancreas
Authors: Lucini Carla , Maruccio Lucianna , De Girolamo Paolo , Vega Josè A. , Castaldo Luciana
Published: August 2002

Mammalian‐like and specific neurotrophins, as well as their cognate tyrosine kinase Trk‐like receptors have been identified in teleosts. They are mainly distributed in neuronal tissues, but evidence suggests that some non‐neuronal tissues also express Trks. In this study we used immunohistochemistry to investigate the occurrence and cell distribution of Trks in the pancreas of teleosts (Scorpaena porcus). Immunoreactivity for TrkA and TrkB, but not for TrkC receptors, was found in the scorpionfish pancreas. TrkA‐like positive cells were exclusively observed within pancreatic islets, among insulin‐ and glucagon‐containing cells, but apparently did not co‐localize with these hormones. TrkB immunostaining was found in islet cells, presumably colocalized with glucagon, as well as in some cells of the exocrine portion. These data provide a morphological basis for a role of the TrkA and TrkB ligands in the endocrine pancreas of teleosts. Anat Rec 263:113–117, 2001. © 2001 Wiley‐Liss, Inc.
Immunogenicity of recombinant type IX collagen in murine collagen‐induced arthritis
Authors: Myers L. K. , Pihlajamaa T. , Brand D. D. , Cremer M. A. , Bodo M. , Ala‐Kokko L. , Kang A. H.
Published: August 2002

Objective

Past attempts to isolate type IX collagen (CIX) from cartilage using limited proteolysis yielded partially degraded material. Recent application of recombinant technology, however, has allowed the preparation of intact native CIX. We used the murine collagen‐induced arthritis model to characterize the immunologic properties of recombinant human CIX (rCIX) produced using a baculovirus expression system.

Methods

A panel of B10 congenic mice was immunized with rCIX emulsified with Freund's complete adjuvant (CFA). The ability of the rCIX to induce tolerance and suppress arthritis was determined by administration intravenously or orally before challenge with CII/CFA.

Results

None of the mice immunized with rCIX developed overt arthritis, although 2 of 5 HLA–DR1 transgenic mice developed limited digital erythema and swelling. Recombinant CIX administered by either route effectively induced suppression of arthritis, although the suppression was less pronounced than that induced with CII. Immune responses to CIX and CII were specific, suggesting that bystander suppression, rather than cross‐reactivity with CII, was instrumental in suppressing arthritis.

Conclusion

These data show that CIX down‐regulates arthritis in mice while having no associated risk of inducing arthritis.
Exchange rate uncertainty and employment: an algorithm describing ‘play’
Authors: Belke Ansgar , Göcke Matthias
Published: August 2002

The paper deals with the impacts of exchange rate uncertainty on the relationship between macroeconomic labour market variables. Under uncertainty, areas of weak reactions—so‐called ‘play’ areas—have to be considered at the macrolevel. The width of the play area is a positive function of the degree of uncertainty. When changes go beyond the play‐area suddenly strong reactions (‘spurts’) occur. These non‐linear dynamics are captured in a simplified linearized way. An algorithm describing linear play hysteresis is developed and implemented into a regression framework. As an empirical application, the exchange rate impacts on German employment are analysed considering play effects. Copyright © 2001 John Wiley & Sons, Ltd.
Electrochemical treatment of mouse Ehrlich tumor with direct electric current
Authors: Cabrales Luis Bergues , Ciria Héctor Camué , Bruzón Rodolfo Pérez , Quevedo Magalys Suárez , Aldana Richard Hinojosa , De Oca Libán Montes , Salas Miriam Fariñas , Peña Odalis de la Guardia
Published: August 2002

Electrochemical treatment of cancer utilizes direct electric current (DEC) to produce direct alterations and chemical changes in tumors. However, the DEC treatment is not established and mechanisms are not well understood. In vivo studies were conducted to evaluate the effectiveness of DEC on animal tumor models. Ehrlich tumors were implanted subcutaneously in sixty male BALB/c mice. When the tumor volumes reached 850 mm3, four platinum electrodes were inserted into the tumors. DEC of 4 mA was applied for 21 min to the treated group; the total charge was 5 C. The healthy and sick control groups were subjected to the same conditions but without DEC. Hematological and chemical parameters as well as histopathological and peritumoral findings were studied. After the electrochemical therapy it was observed that both tumor volume decrease and necrosis percentage increase were significant in the treated group. Moreover, 24 h after treatment an acute inflammatory response, as well as sodium ion decrease, and potassium ion and spleen weight increase were observed in this group. It was concluded that both electrochemical reactions (fundamentally those in which reactive oxygen species are involved), and immune system stimulation induced by cytotoxic action of the DEC could constitute the most important antitumor mechanisms. Bioelectromagnetics 22:316–322, 2001. © 2001 Wiley‐Liss, Inc.
Health and safety implications of exposure to electromagnetic fields in the frequency range 300 Hz to 10 MHz
Authors: Litvak E. , Foster K.R. , Repacholi M.H.
Published: August 2002

An international seminar on health effects of exposure to electromagnetic fields (EMF) in the frequency range from 300 Hz to 10 MHz (referred to as the Intermediate Frequency (IF) range) was held in Maastricht, Netherlands, on 7–8 June 1999. The seminar, organized under the International EMF Project, was sponsored jointly by the World Health Organization (WHO), the International Commission on Non‐Ionizing Radiation Protection (ICNIRP), and the Government of the Netherlands. This report does not attempt to summarize all of the material presented at the conference, but focuses on sources of exposure, biophysical and dosimetric considerations pertinent to extrapolating biological data from other frequency ranges to IF and identifies potential health concerns and needs for developing exposure guidelines. This paper is based on presentations at the conference and reports of working groups consisting of the speakers and other experts. It concludes with recommendations for further research aimed at improving health risk assessments in this frequency range. Bioelectromagnetics 23:68–82, 2002. © 2002 Wiley‐Liss, Inc.
Novel adipocyte lines from brown fat: A model system for the study of differentiation, energy metabolism, and insulin action
Authors: Klein Johannes , Fasshauer Mathias , Klein Harald H. , Benito Manuel , Kahn C. Ronald
Published: August 2002

Adipose tissue has emerged as an important endocrine regulator of glucose metabolism and energy homeostasis. By virtue of the mitochondrial protein uncoupling protein‐1 (UCP‐1), brown fat additionally plays a unique role in thermoregulation. Interest has focused on this tissue not only as a target for pharmacotherapy of obesity and insulin resistance but also as an endocrine tissue with leptin secretion and high insulin sensitivity. Most studies of adipocytes have been limited either to primary cell culture or to a small number of established cell lines. Recently, we have generated immortalized brown adipocyte cell lines from single newborn mice of different knockout mouse models. These cell lines retain the main characteristics of primary cells including UCP‐1 expression. They display sensitive and diverse metabolic responses to insulin and adrenergic stimulation and have proven to be useful in the characterization of UCP regulation and the role of key insulin signaling elements for insulin action. Here, we outline common approaches to the generation of adipose tissue cell lines. Furthermore, we propose that the novel technique of generating brown adipocyte lines from a single newborn mouse will be instrumental in gaining further insight into the role of a broad range of signaling molecules in adipose tissue biology and in the pathogenesis of insulin resistance. BioEssays 24:382–388, 2002. ©2002 Wiley Periodicals, Inc.
O6‐alkylguanine‐DNA alkyltransferase: Role in carcinogenesis and chemotherapy
Authors: Margison Geoffrey P. , Santibáñez‐Koref Mauro F.
Published: August 2002

The DNA in human cells is continuously undergoing damage as consequences of both endogenous processes and exposure to exogenous agents. The resulting structural changes can be repaired by a number of systems that function to preserve genome integrity. Most pathways are multicomponent, involving incision in the damaged DNA strand and resynthesis using the undamaged strand as a template. In contrast, O6‐alkylguanine‐DNA alkyltransferase is able to act as a single protein that reverses specific types of alkylation damage simply by removing the offending alkyl group, which becomes covalently attached to the protein and inactivates it. The types of damage that ATase repairs are potentially toxic, mutagenic, recombinogenic and clastogenic. They are generated by certain classes of carcinogenic and chemotherapeutic alkylating agents. There is consequently a great deal of interest in this repair system in relation to both carcinogenesis and cancer chemotherapy. BioEssays 24:255–266, 2002. © 2002 Wiley Periodicals, Inc.; DOI 10.1002/bies.10063
Innexins get into the gap
Authors: Phelan Pauline , Starich Todd A.
Published: August 2002

Connexins were first identified in the 1970s as the molecular components of vertebrate gap junctions. Since then a large literature has accumulated on the cell and molecular biology of this multi‐gene family culminating recently in the findings that connexin mutations are implicated in a variety of human diseases. Over two decades, the terms “connexin” and “gap junction” had become almost synonymous. In the last few years a second family of gap‐junction genes, the innexins, has emerged. These have been shown to form intercellular channels in genetically tractable invertebrate organisms such as Drosophila melanogaster and Caenorhabditis elegans. The completed genomic sequences for the fly and worm allow identification of the full complement of innexin genes in these two organisms and provide valuable resources for genetic analyses of gap junction function. BioEssays 23:388–396, 2001. © 2001 John Wiley & Sons, Inc.
The role of chemoattraction in cancer metastases
Authors: Moore Malcolm A.S.
Published: August 2002

It has long been unclear as to why particular cancers preferentially metastasize to certain sites. The possibilities usually discussed involve differential survival and proliferation at these sites, or selective trapping with or without preferential homing. A recent report by Muller et al.(1) provides evidence for preferential homing of breast cancer to metastatic sites. The findings indicate that the chemokine receptors CXCR4 and CCR7 are found on breast cancer cells and their ligands are highly expressed at sites associated with breast cancer metastases. This results in chemotaxis, or directed migration of tumor cells from their primary site via the circulation to the preferential sites of metastases. The evidence for this model and its significance are reviewed here. BioEssays 23:674–676, 2001. © 2001 John Wiley & Sons, Inc.
Generalized concentration dependence of globular protein self‐diffusion coefficients in aqueous solutions
Authors: Nesmelova Irina V. , Skirda Vladimir D. , Fedotov Vladimir D.
Published: August 2002

The self‐diffusion coefficients of globular proteins (myoglobin, bovine serum albumin, barstar, lysozyme) in aqueous solutions at different temperatures and pH values are obtained by pulsed‐gradient spin‐echo NMR, and their concentration dependence is analyzed. The generalized concentration dependence of globular protein self‐diffusion coefficients is empirically established, and compared to the concentration dependence of diffusion coefficients of flexible polymers and rigid Brownian particles. © 2002 John Wiley & Sons, Inc. Biopolymers 63: 132–140, 2002
Receptor‐dependent G‐protein activation in lipidic cubic phase
Authors: Navarro Javier , Landau Ehud M. , Fahmy Karim
Published: August 2002

The primary step in cellular signaling by G‐protein‐coupled receptors (GPCRs) is the interaction of the agonist‐activated transmembrane receptor with an intracellular G‐protein. Understanding the underlying molecular mechanisms requires the structural determination of receptor G‐protein complexes that are not yet achieved. The crystal structure of the bovine photoreceptor rhodopsin, a prototypical GPCR, was solved recently and the structures of different states of engineered G‐proteins were reported. Posttranslational hydrophobic modifications of G‐proteins are in most cases removed for crystallization but play functional roles for interactions among G‐protein subunits with receptors, as well as membranes. Bovine rhodopsin is reconstituted into lipidic cubic phases to assess their potential for crystallization of receptor G‐protein complexes under conditions that may preserve the structural and functional roles of hydrophobic protein modifications. Three‐dimensional bilayers of a bicontinuous lipidic cubic phase are successfully employed for crystallization of membrane and soluble proteins. UV–visible absorption and attenuated total reflection Fourier transform IR difference spectroscopy reveal that light activation of cubic phase reconstituted rhodopsin results in the generation of a metarhodopsin II‐like state. Via diffusion along aqueous channels, transducin couples efficiently to this photoproduct as evidenced by the nucleotide‐dependent increase of transducin fluorescence. Thus, rhodopsin transducin interactions do not crucially depend on the presence of sn1 and sn2 acyl chains, phospholipid head groups, or membrane planarity. Because lipidic cubic phases preserve the essential functional and structural properties of native rhodopsin and transducin, they appear suitable for the detergent‐free crystallization of receptor G‐protein complexes carrying a normal pattern of hydrophobic modifications. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 167–177, 2002
Influence of Ca2+ cations on low pH‐induced DNA structural transitions
Authors: Muntean C. M. , Puppels G. J. , Greve J. , Segers‐Nolten G. M. J.
Published: August 2002

A confocal Raman microspectrometer was used to investigate the influence of Ca2+ cations on low pH‐induced DNA structural changes. The effects of Ca2+ cations on the protonation mechanism of opening AT and changing the protonation of GC base pairs in DNA are discussed. Based on the observation that the midpoint of the transition of Watson–Crick GC base pairs to protonated GC base pairs lies at around pH 3 (analyzing the 681 cm−1 line), measurements were carried out on calf thymus DNA at neutral pH and pH 3 in the presence of low and high concentrations of Ca2+ cations. Raman spectra show that low concentrations of Ca2+ cations partially protect DNA against protonation of cytosine (characteristic line at 1262 cm−1) and do not protect adenine (characteristic line at 1304 cm−1) and the N(7) of guanine (line at 1488 cm−1) against binding of H+. High Ca2+ concentrations can prevent protonation of cytosine and protonation of adenine (little disruption of AT pairs). Analyzing the line at 1488 cm−1, which obtains most of its intensity from a guanine vibration, high salt was also found to protect the N(7) of guanine against protonation. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 282–284, 2002
A novel reactor for making uniform capsules
Authors: Anilkumar A. V. , Lacik I. , Wang T. G.
Published: August 2002

A novel chemical reactor was designed and developed for the continuous high‐rate production of uniform capsules. This reactor helps to control precisely the reaction time between the reacting liquids (anion drops and the cation bath, or vice versa), thereby leading to the formation of uniform capsules with walls of identical thickness. In addition, mild tumbling of the capsules during transit through the reactor ensures that every capsule wall is uniformly thick all around. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 581–589, 2001.
Effect of copy number and mRNA processing and stabilization on transcript and protein levels from an engineered dual‐gene operon
Authors: Smolke Christina D. , Keasling Jay D.
Published: August 2002

To study the effect of mRNA stability and DNA copy number on protein production from a dual‐gene operon, a synthetic operon containing the reporter genes gfp and lacZ under the control of the araBAD promoter was placed in pMB1‐based (approximately 100 copies/cell) and F plasmid‐based (approximately 1 copy/cell) vectors. DNA cassettes encoding secondary structures were placed at the 5' and 3' ends of the genes and a putative RNase E site was placed between the two genes. Although the copy number of the pMB1‐based vectors was approximately 100‐fold greater than the copy number of the F plasmid‐based vectors, transcript and protein levels from the pMB1‐based vector were not 100‐fold greater than from the F plasmid‐based vectors. In identical plasmid backbones, different combinations of mRNA control elements were used to alter steady‐state levels of transcripts. Control elements that amplified the stability of one coding region relative to another amplified the ratio of protein produced from those transcripts. The effects of mRNA stability control elements were greater at low inducer concentrations, where mRNA levels limit protein production, than at high inducer concentrations. Although we can alter mRNA and protein levels through copy number, induction level, and mRNA stability control elements, some aspect of gene expression remains dependent on inherent characteristics of the coding region. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 412–424, 2002.
Determination of the maximum specific uptake capacities for glucose and oxygen in glucose‐limited fed‐batch cultivations of Escherichia coli
Authors: Lin H. Y. , Mathiszik B. , Xu B. , Enfors S.‐O. , Neubauer P.
Published: August 2002

A simple pulse‐based method for the determination of the maximum uptake capacities for glucose and oxygen in glucose limited cultivations of E. coli is presented. The method does not depend on the time‐consuming analysis of glucose or acetate, and therefore can be used to control the feed rate in glucose limited cultivations, such as fed‐batch processes. The application of this method in fed‐batch processes of E. coli showed that the uptake capacity for neither glucose nor oxygen is a constant parameter, as often is assumed in fed‐batch models. The glucose uptake capacity decreased significantly when the specific growth rate decreased below 0.15 h−1 and fell to about 0.6 mmol g−1 h−1 (mmol per g cell dry weight and hour) at the end of fed‐batch fermentations, where μ was approximately 0.02 h−1. The oxygen uptake capacity started to decrease somewhat earlier when μ declined below 0.25 h−1 and was 5 mmol g−1 h−1 at the end of the fermentations. The behavior of both uptake systems is integrated in a dynamic model which allows a better fitting of experimental values for glucose in fed‐batch processes in comparison to generally used unstructured kinetic models. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 73: 347–357, 2001.
Efficient preparation of (R)‐α‐monobenzoyl glycerol by lipase catalyzed asymmetric esterification: Optimization and operation in packed bed reactor
Authors: Xu Jian‐He , Kato Yasuo , Asano Yasuhisa
Published: August 2002

Optically active (R)‐α‐monobenzoyl glycerol (MBG) was synthesized by Candida antarctica lipase B (CHIRAZYME® L‐2) catalyzed asymmetric esterification of glycerol with benzoic anhydride in organic solvents. Various conditions, such as the type and composition of the organic solvent, water content of the system, reaction temperature, and concentrations of the substrates were systematically examined and optimized in screw‐capped test tubes with respect to both the reaction rate and the enzyme selectivity. 1,4‐Dioxane was found to be the best solvent and no additional water was needed for the system. The optimum temperature was around 30°C, while the most suitable substrate concentrations were 100 mM each for glycerol and benzoic anhydride, respectively. However, when excessive anhydride (e.g., 200 mM) was used, the produced MBG could be further transformed into 1,3‐dibenzoyl glycerol (DBG) by the same enzyme with a priority to (S)‐MBG, resulting in a significant improvement of the product optical purity from ca. 50–70% e.e. Under optimal conditions (100 mM glycerol, 100–200 mM benzoic anhydride, dioxane, 25–30°C), the enzymatic synthesis of (R)‐MBG was successfully operated in a packed‐bed reactor for about 1 week, with an average productivity of 0.79 g MBG/day/g biocatalyst in the case of continuous operation and 0.94 g MBG/day/g biocatalyst in the case of semicontinuous operation. After refinement and preferential crystallization of the crude product, (R)‐MBG could be obtained in an almost optically pure form (>98% e.e.). © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 73: 493–499, 2001.
Photosynthetic productivity of conical helical tubular photobioreactors incorporating Chlorella sp. under various culture medium flow conditions
Authors: Morita Masahiko , Watanabe Yoshitomo , Okawa Tomio , Saiki Hiroshi
Published: August 2002

The characteristics of the flow of culture medium significantly affects the photosynthetic productivity of bioreactors incorporating microalgae. Therefore, in order to optimize the performance of a conical helical tubular photobioreactor (CHTP) designed to be useful in practical applications, we characterized the flow pattern of the culture medium through the reactor. The effects of medium flow conditions on the photosynthetic productivity of Chlorella sp. were investigated using several different CHTP units with 0.50‐m2 installation areas which were designed to vary the direction and rate of flow driven by airlift. In addition, the performance of two‐ and four‐unit systems constructed by combining individual CHTP units was evaluated. We found that when medium flowed from the bottom to the top of the photostage, it exhibited smoother flow of culture medium than when flowing from top to bottom, which led to higher photosynthetic productivity by the former. Consistent with theoretical calculations, varying the lengths of vertical flow passages caused flow rates to vary, and higher flow rates meant smoother circulation of medium and better photosynthetic performance. Flow of medium through a four‐unit CHTP system was similar to that in single units, enabling a photosynthetic productivity of 31.0 g‐dry biomass per m2‐installation area per day to be achieved, which corresponded to a photosynthetic efficiency of 7.50% (photosynthetically active radiation (PAR; 400–700 nm)). This high photosynthetic performance was possible because smoother medium flow attained in single units was also attained in the four‐unit system. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 136–144, 2001.
Expression of the transcription factor GADD153 is an indicator of apoptosis for recombinant chinese hamster ovary (CHO) cells
Authors: Murphy Tracy C. , Woods Nigel R. , Dickson Alan J.
Published: August 2002

Loss of cell viability, through engagement of apoptotic cell death, represents a limitation to maintenance of high levels of productivity of recombinant animal cells in culture. The ability to monitor the status of recombinant cells, and to define indicators of their “well‐being,” would present a valuable approach to permit a rational intervention at appropriate times during culture. Growth arrest and DNA damage gene 153 (GADD153) is a member of the CCAAT/enhancer‐binding protein (C/EBP) family of transcription factors and has been associated with apoptosis. We have examined the expression of GADD153 in conditions associated with apoptosis of recombinant CHO cells in batch culture. GADD153 expression is very low in CHO cells growing in the exponential phase of batch culture but is activated as cells enter the decline phase. Depletion of nutrients (glucose or glutamine) causes activation of GADD153 expression as does the imposition of endoplasmic reticulum stress. In all cases, there is a good relationship between the extent of apoptosis that occurs in response to each stress and the degree of GADD153 expression. In addition, nutrient refeeding or reversal of stress produces a concomitant decrease in expression of GADD153 and the susceptibility to apoptosis. Thus, GADD153 appears to offer a valid indicator of apoptosis and illustrates the potential for definition of monitors of cellular status related to the likelihood of apoptosis of cell populations. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 621–629, 2001.
Preadolescent adjudicative competence: methodological considerations and recommendations for practice standards
Authors: Oberlander Lois B. , Goldstein Naomi E. , Ho Caleb N.
Published: August 2002

This article examines developmental and legal issues directed toward a downward age extension of forensic evaluation practice standards for preadolescent defendants whose competence is questioned. Existing research and practice standards were developed for cases involving adolescents and adults, but they lack sufficient application to evaluations of young children because of the ways in which legal parameters affect young children. We review practice implications of the legal role of “immaturity” for adjudicative competence, alterations of Dusky in some juvenile courts, and the role of parens patriae in competence hearings held in juvenile court. We examine competence abilities in a developmental framework. Examining practice standards is timely because adjudicative competence in preadolescent defendants has taken on recent significance. The last decade saw changes in the stringency of delinquency statutes, increased emphasis on adversarial approaches to juvenile proceedings, and a de‐emphasis on rehabilitation and parens patriae protections. Statutory changes and increased referrals have heightened inquiry into the meaning of preadolescent adjudicative competence. Copyright © 2001 John Wiley & Sons, Ltd.
Murderers' and sexual offenders' experiences of police interviews and their inclination to admit or deny crimes
Authors: Holmberg Ulf , Christianson Sven‐Åke
Published: August 2002

This research concerns murderers' and sexual offenders' experiences of Swedish police interviews and their attitudes towards allegations of these serious crimes. The explorative study is based on a questionnaire answered by 83 men convicted of murder or sexual offences. Results show that when police officers interview murderers and sexual offenders, the individuals perceive attitudes that are characterized by either dominance or humanity. Logistic regression shows that police interviews marked by dominance are mainly associated with a higher proportion of denials, whereas an approach marked by humanity is associated with admissions. When suspects feel that they are respected and acknowledged, they probably gain more confidence and mental space, allowing them to admit criminal behaviour. Copyright © 2002 John Wiley & Sons, Ltd.
Entrapment of the lingual nerve due to an ossified pterygospinous ligament
Authors: Peuker Elmar T. , Fischer Gerhard , Filler Timm J.
Published: August 2002

During a routine dissection course at the University of Muenster (Germany) an unusual course of the lingual nerve was found with entrapment of the nerve between a widely ossified pterygospinous ligament and the medial pterygoid muscle. Furthermore, the nerve‘s mobility was restricted by a more distal anastomosis with the inferior alveolar nerve. Although incomplete or complete ossification of the pterygospinous ligament is not uncommon, the combination with a medial course of the lingual nerve has not been described before. Besides practical importance for surgeons and anesthetists, the entrapment of the lingual nerve may lead to lingual numbness and pain associated with speech impairment. Clin. Anat. 14:282–284, 2001. © 2001 Wiley‐Liss, Inc.
The natural substrate for nitric oxide synthase activity
Authors: Alaghband‐Zadeh Jamshid , Mehdizadeh Siroos , Khan Nusrat S , Farrell Anne O' , Bitensky Lucille , Chayen Joseph
Published: August 2002

There has been little evidence to indicate that arginine is the natural substrate for generating nitric oxide synthase (NOS) activity. It is now shown that carnosine, which is widely distributed in tissues, is likely to be the true substrate. In tissue sections it gives a stronger NOS reaction than does arginine. Copyright © 2001 John Wiley & Sons, Ltd.
Transfer student adjustment
Authors: Laanan Frankie Santos
Published: August 2002

This chapter discusses the trends surrounding transfer students and highlights issues affecting these students. Also presented is a synthesis of research on transfer students, post‐transfer adjustment process, and perspectives on college adjustment.
Chirality and the origin of life: In situ enantiomeric separation for future space missions
Authors: Rodier C. , Laurent C. , Szopa C. , Sternberg R. , Raulin F.
Published: August 2002

Two different methods of derivatization were studied in order to select and optimize one for the in situ enantiomeric separation of amino acids present in Martian samples. The method, using DMF‐DMA [N,N‐dimethylformamide dimethyl acetal], is simple and easily automated. However, byproducts of the reaction interfere in the gas chromatograms and mass spectrometry detection is needed for in situ analysis. The chloroformate derivatization has several advantages, including the use of achiral robust capillary column, room temperature reaction, and short analysis. The choice of the definitive derivatization method will depend on the energy and time devoted to the analysis of amino acids in the next Mars exploration missions. Chirality 14:527–532, 2002. © 2002 Wiley‐Liss, Inc.
Chiral asymmetry in spiral galaxies?
Authors: Kondepudi Dilip K. , Durand Daniel J.
Published: August 2002

Spiral galaxies are chiral entities when coupled with the direction of their recession velocity. As viewed from the Earth, the S‐shaped and Z‐shaped spiral galaxies are two chiral forms. What is the nature of chiral symmetry in spiral galaxies? In the Carnegie Atlas of Galaxies that lists photographs of a total of 1,168 galaxies, we found 540 galaxies, classified as normal or barred spirals, that are clearly identifiable as S‐ or Z‐ type. The recession velocities for 538 of these galaxies could be obtained from this atlas and other sources. A statistical analysis of this sample reveals no overall asymmetry but there is a significant asymmetry in certain subclasses: dominance of S‐type galaxies in the Sb class of normal spiral galaxies and a dominance of Z‐type in the SBb class of barred spiral galaxies. Both S‐ and Z‐type galaxies seem to have similar velocity distribution, indicating no spatial segregation of the two chiral forms. Chirality 13:351–356, 2001. © 2001 Wiley‐Liss, Inc.
Tetranuclear titanium 7,7′‐modified binaphtholate cluster as a novel chiral Lewis acid catalyst
Authors: Mikami Koichi , Ueki Makoto , Matsumoto Yousuke , Terada Masahiro
Published: August 2002

Chiral tetranuclear Ti cluster, a cubic structure constituted of four Ti atoms and OHs, and six (R)‐binaphthols (BINOL) bridged two Ti atoms as ligands, is shown to be a novel chiral Lewis acid catalyst for the [2+3] cycloaddition reaction with nitrones. The chiral Ti clusters with 7,7′‐substituted (R)‐BINOL ligands was synthesized to give enhanced enantiomeric excesses up to 78% ee. Chirality 13:541–544, 2001. © 2001 Wiley‐Liss, Inc.