bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drying Oils and Related Products
Authors: Poth Ulrich 
Published: April 2004

AbstractThe article contains sections titled:1.Definitions2.History3.Chemical Compositions4.Sources and Types4.1.Linseed Oil4.2.Perilla Oil4.3.Tung Oil4.4.Oiticica Oil4.5.Fish Oils4.6.Safflower Oil4.7.Sunflower Oil4.8.Soybean Oil4.9.Cottonseed Oil4.10.Dehydrated Castor Oil4.11.Tall Oil5.Production6.Testing and Specifications7.Film Formation7.1.Properties of Drying Oils for Film Formation7.2.Cross‐Linking by Reaction with Oxygen7.3.Influence of Catalysts on Cross‐Linking7.4.Yellowing8.Modifications8.1.Boiled Oils8.2.Stand Oils8.3.Blown Oils8.4.Factice, Sulfurized Oils8.5.Isomerized Oils8.6.Copolymers8.7.Maleinized Oils8.8.Oil Boiling with Rosin, Copal, and Amber8.9.Oil Boiling with Phenolic Resins8.10.Modifications by Transesterification8.11.Modifications Based on Fatty Acids9.Application, Importance, and Future Aspects
Felts
Authors: Dornedden Friedrich 
Published: April 2004

Abstract

The article contains sections titled:

1.

Introduction

2.

Felting Process

3.

Pressed Felts

3.1.

Raw Materials

3.2.

Production

3.2.1.

Batt Production

3.2.2.

Piece Felts

3.2.3.

Formed Felts

3.3.

Properties

3.4.

Uses

3.5.

Testing

4.

Needled Felts

4.1.

Production

4.2.

Properties and Uses
Flavors and Fragrances
Authors: Fahlbusch Karl‐Georg , Hammerschmidt Franz‐Josef , Panten Johannes , Pickenhagen Wilhelm , Schatkowski Dietmar , Bauer Kurt , Garbe Dorothea , Surburg Horst 
Published: April 2004

AbstractThe article contains sections titled:1.Introduction1.1.The Chemical Senses1.2.Definition1.3.History1.4.Odor Descriptors, Odor Thresholds, Odor Value1.4.1.Qualitative Measurements1.4.2.Quantitative Measurements1.4.2.1.Odor Threshold1.4.2.2.Odor Value1.5.Regulations and Labeling Requirements1.5.1.Flavors1.5.2.Fragrances2.Single Fragrance and Flavor Compounds2.1.Aliphatic Compounds2.1.1.Hydrocarbons2.1.2.Alcohols2.1.3.Aldehydes and Acetals2.1.4.Ketones2.1.5.Acids and Esters2.1.6.Miscellaneous Compounds2.2.Acyclic Terpenes2.2.1.Hydrocarbons2.2.2.Alcohols2.2.3.Aldehydes and Acetals2.2.4.Ketones2.2.5.Acids and Esters2.2.5.1.Geranyl and Neryl Esters2.2.5.2.Linalyl and Lavandulyl Esters2.2.5.3.Citronellyl Esters2.2.6.Miscellaneous Compounds2.3.Cyclic Terpenes2.3.1.Hydrocarbons2.3.2.Alcohols and Ethers2.3.3.Aldehydes and Ketones2.3.4.Esters2.3.5.Miscellaneous Compounds2.4.Other Cycloaliphatic Compounds2.4.1.Alcohols2.4.2.Aldehydes2.4.3.Ketones2.4.4.Esters2.5.Aromatic Compounds2.5.1.Hydrocarbons2.5.2.Alcohols and Ethers2.5.3.Aldehydes and Acetals2.5.4.Ketones2.5.5.Esters of Araliphatic Alcohols and Aliphatic Acids2.5.6.Aromatic Acids2.5.7.Esters Derived from Aromatic and Araliphatic Acids2.5.7.1.Benzoates2.5.7.2.Phenyl acetates2.5.7.3.Cinnamates2.5.8.Miscellaneous Compounds2.6.Phenols and Phenol Derivatives2.6.1.Phenols, Phenyl Esters, and Phenyl Ethers2.6.2.Phenol Alcohols and their Esters2.6.3.Phenol Aldehydes2.6.4.Phenol Ketones2.6.5.Phenol Carboxylates2.7.O‐ and O, S‐Heterocycles2.7.1.Cyclic Ethers2.7.2.Lactones2.7.3.Glycidates2.7.4.Miscellaneous Compounds2.8.N‐ and N, S‐Heterocycles3.Natural Raw Materials in the Flavor and Fragrance Industry3.1.Introduction3.2.Isolation of Natural Fragrance and Flavor Concentrates3.2.1.Essential Oils3.2.2.Extracts3.3.Survey of Natural Raw Materials4.Quality Control5.Economic Aspects6.Toxicology and Environmental Aspects
Flocculants
Authors: Burkert Hans , Hartmann Jürgen 
Published: April 2004

AbstractThe article contains sections titled:1.Introduction2.Classification of Flocculants2.1.Inorganic Flocculants2.2.Natural Organic Flocculants2.3.Synthetic Organic Flocculants2.3.1.Chemical Structure2.3.2.Production Requirements3.Flocculation Mechanisms3.1.Double Layer Compression3.2.Specific Ion Adsorption3.3.Polymer Charge Patch3.4.Polymer Bridging4.Uses5.Choice of Optimum Flocculant6.Legal Aspects7.Economic Aspects
Fluorine Compounds, Organic
Authors: Siegemund Günter , Schwertfeger Werner , Feiring Andrew , Smart Bruce , Behr Fred , Vogel Herward , McKusick Blaine 
Published: April 2004

AbstractThe article contains sections titled:1.Introduction2.Production Processes2.1.Substitution of Hydrogen2.2.Halogen ‐ Fluorine Exchange2.3.Synthesis from Fluorinated Synthons2.4.Addition of Hydrogen Fluoride to Unsaturated Bonds2.5.Miscellaneous Methods2.6.Purification and Analysis3.Fluorinated Alkanes3.1.Fluoroalkanes and Perfluoroalkanes3.2.Chlorofluoroalkanes3.3.Bromofluoroalkanes3.4.Iodofluoroalkanes4.Fluorinated Olefins4.1.Tetrafluoroethylene4.2.Hexafluoropropene4.3.1,1‐Difluoroethylene4.4.Monofluoroethylene, Monofluoroethylene4.5.3,3,3‐Trifluoropropene4.6.3,3,3‐Trifluoro‐2‐(trifluoromethyl)‐prop‐1‐ene4.7.Chlorofluoroolefins5.Fluorinated Alcohols6.Fluorinated Ethers6.1.Perfluoroethers6.1.1.Low Molecular Mass Perfluoroethers6.1.2.Perfluorinated Epoxides6.1.3.High Molecular Mass Perfluoroethers6.2.Perfluorovinyl Ethers6.3.Partially Fluorinated Ethers7.Fluorinated Ketones and Aldehydes7.1.Fluoro‐ and Chlorofluoroacetones7.2.Perhaloacetaldehydes7.3.Fluorinated 1,3‐Diketones8.Fluorinated Carboxylic Acids and Fluorinated Alkanesulfonic Acids8.1.Fluorinated Carboxylic Acids8.1.1.FluorinatedAcetic Acids8.1.2.Long‐Chain Perfluorocarboxylic Acids8.1.3.Fluorinated Dicarboxylic Acids8.1.4.Tetrafluoroethylene ‐ Perfluorovinyl Ether Copolymers with Carboxylic Acid Groups8.2.Fluorinated Alkanesulfonic Acids8.2.1.Perfluoroalkanesulfonic Acids8.2.2.Fluorinated Alkanedisulfonic Acids8.2.3.Tetrafluoroethylene ‐ Perfluorovinyl Ether Copolymers with Sulfonic Acid Groups9.Fluorinated Tertiary Amines10.Aromatic Compounds with Fluorinated Side‐Chains10.1.Properties10.2.Production10.3.Uses11.Ring‐Fluorinated Aromatic, Heterocyclic, and Polycyclic Compounds11.1.Mono‐ and Difluoroaromatic Compounds11.1.1.Properties11.1.2.Production11.1.3.Uses11.2.Highly Fluorinated Aromatic Compounds11.3.Perhaloaromatic Compounds11.4.Fluorinated Heterocyclic and Polycyclic Compounds11.4.1.Ring‐Fluorinated Pyridines11.4.2.Trifluoromethylpyridines11.4.3.Fluoropyrimidines11.4.4.Fluorotriazines11.4.5.Polycyclic Fluoroaromatic Compounds12.Economic Aspects13.Toxicology and Occupational Health13.1.Fluorinated Alkanes13.2.Fluorinated Olefins13.3.Fluorinated Alcohols13.4.Fluorinated Ketones13.5.Fluorinated Carboxylic Acids13.6.Other Classes
Fluoropolymers, Organic
Authors: Carlson D. Peter , Schmiegel Walter 
Published: April 2004

AbstractThe article contains sections titled:1.Introduction2.Fluoroplastics2.1.Introduction2.2.Polytetrafluoroethylene2.2.1.Production2.2.2.Properties2.2.3.Processing2.2.4.Uses2.3.Tetrafluoroethylene‐Hexafluoropropylene Copolymers2.3.1.Production2.3.2.Properties2.3.3.Processing2.3.4.Uses2.4.Tetrafluoroethylene‐Perfluoro‐(Propyl Vinyl Ether) Copolymers2.4.1.Production2.4.2.Properties2.4.3.Processing2.4.4.Uses2.5.Tetrafluoroethylene‐Ethylene Copolymers2.5.1.Production2.5.2.Properties2.5.3.Processing2.5.4.Uses2.6.Polychlorotrifluoroethylene2.6.1.Production2.6.2.Properties2.6.3.Processing2.6.4.Uses2.7.Chlorotrifluoroethylene‐Ethylene Copolymers2.7.1.Production2.7.2.Properties2.7.3.Processing2.7.4.Uses2.8.Poly(Vinylidene Fluoride)2.8.1.Production2.8.2.Properties2.8.3.Processing2.8.4.Uses2.9.Poly(Vinyl Fluoride)2.9.1.Production2.9.2.Properties2.9.3.Processing2.9.4.Uses3.Fluoroelastomers3.1.Introduction3.2.Elastomers Based on Vinylidene Fluoride3.2.1.Production3.2.2.Properties3.2.3.Processing3.2.4.Uses3.3.Elastomers Based on Tetrafluoroethylene‐Perfluoro(Methyl Vinyl Ether) Copolymers3.3.1.Production3.3.2.Properties3.3.3.Processing and Uses3.4.Elastomers Based on Tetrafluoroethylene‐Propylene Copolymers3.4.1.Production3.4.2.Properties3.4.3.Processing3.4.4.Uses4.Toxicology and Occupational Health4.1.Fluoroplastics4.2.Fluoroelastomers5.Economic Aspects
Gelatin
Authors: Babel Wilfried , Schulz Dieter , Giesen‐Wiese Monika , Seybold Uwe , Gareis Herbert , Dick Eberhard , Schrieber Reinhard , Schott Annelore , Stein Winfried 
Published: April 2004

AbstractThe article contains sections titled:1.Introduction2.Structure and Properties2.1.Structure2.2.Physical Properties2.3.Chemical Properties2.4.Microbiological Analysis2.5.Quality Specifications3.Raw Materials and Production3.1.Raw Materials3.2.Production4.Uses4.1.General Aspects4.2.Food Industry4.3.Pharmaceuticals4.4.Cosmetics4.5.Photography4.6.Technical Gelatin and Glue4.6.1.Matches4.6.2.Coated Abrasives4.6.3.Paper Sizing4.6.4.Adhesives4.6.5.Other Uses5.Economic Aspects
Glass Ceramics
Authors: H. W. S. De Jong Bernard , W. Adams Jane , G. Aitken Bruce , E. Dickinson James , J. Fine Gerald 
Published: April 2004

AbstractThe article contains sections titled:1.Introduction2.Nucleation and Crystallization of Glass Ceramics2.1.Homogeneous Nucleation2.2.Heterogeneous Nucleation2.3.Crystal Growth2.4.Heat Treatment3.Nature of Crystalline Phases3.1.Metastability3.2.Physical Properties3.2.1.Thermal Properties3.2.2.Transparency3.2.3.Electrical Properties3.2.4.Mechanical Properties3.2.5.Durability3.3.Microstructure4.Types of Glass Ceramics4.1.Silicate‐Based Glass Ceramics4.2.Aluminosilicate Glass Ceramics4.3.Fluorosilicate Glass Ceramics
Gluconic Acid
Authors: Hustede Helmut , Haberstroh Hans‐Joachim , Schinzig Elisabeth 
Published: April 2004

AbstractThe article contains sections titled:1.Introduction2.Physical Properties3.Chemical Properties4.Production4.1.Chemical Oxidation4.2.Electrochemical Oxidation4.3.Catalytic Oxidation4.4.Methods Involving Biotechnology5.Uses6.Economic Aspects7.Physiology, Product Specifications
High‐Performance Fibers
Authors: Mera Hiroshi , Takata Tadahiko 
Published: April 2004

AbstractThe article contains sections titled:1.Definition and Classification2.Heat‐Resistant Fibers2.1.Introduction2.2.Solution‐Spun Heat‐Resistant Fibers2.2.1.Aramid Fibers2.2.2.Polyazole and Polyimide Fibers2.3.Melt‐Spun Heat‐Resistant Fibers2.3.1.Novoloid Fibers2.3.2.Fibers from Engineering Plastics3.High‐Strength and High‐Modulus (HS ‐ HM) Fibers3.1.Introduction3.2.Solution‐Spun HS ‐ HM Fibers3.2.1.Para‐Oriented Aramid Fibers3.2.1.1.Production3.2.1.2.Properties3.2.1.3.Uses3.2.2.HS ‐ HM Fibers from Some Aramid‐Related Polymers3.2.3.Polyazole and Polyimide Fibers3.2.3.1.Polyazole Fibers3.2.3.2.Polyimide Fibers3.3.Melt‐Spun HS ‐ HM Fibers
Solid Acid‐Catalysed Michael‐Type Conjugate Addition of Indoles to Electron‐Poor CC Bonds: Towards High Atom Economical Semicontinuous Processes
Authors: Bandini Marco , Fagioli Matteo , Umani‐Ronchi Achille 
Published: April 2004

AbstractIn this paper a novel application of solid acid catalysts in the chemoselective Friedel–Crafts (FC) alkylation of indoles is reported. The optimal protocol allows highly functionalised indolyl compounds to be synthesised in excellent yields through conjugate addition of indoles with α,β‐unsaturated ketones and nitro compounds. Finally, the use of commercial Amberlyst‐15 as the heterogeneous catalyst for highly atom efficient continuous and semicontinuous Friedel–Crafts processes is described.
SIMPLE mutation in demyelinating neuropathy and distribution in sciatic nerve
Authors: Bennett Craig L. , Shirk Andrew J. , Huynh Huy M. , Street Valerie A. , Nelis Eva , Van Maldergem Lionel , De Jonghe Peter , Jordanova Albena , Guergueltcheva Velina , Tournev Ivailo , Van den Bergh Peter , Seeman Pavel , Mazanec Radim , Prochazka Tomas , Kremensky Ivo , Haberlova Jana , Weiss Michael D. , Timmerman Vincent , Bird Thomas D. , Chance Phillip F. 
Published: April 2004

AbstractCharcot–Marie–Tooth neuropathy type 1C (CMT1C) is an autosomal dominant demyelinating peripheral neuropathy caused by missense mutations in the small integral membrane protein of lysosome/late endosome (SIMPLE) gene. To investigate the prevalence of SIMPLE mutations, we screened a cohort of 152 probands with various types of demyelinating or axonal and pure motor or sensory inherited neuropathies. SIMPLE mutations were found only in CMT1 patients, including one G112S and one W116G missense mutations. A novel I74I polymorphism was identified, yet no splicing defect of SIMPLE is likely. Haplotype analysis of STR markers and intragenic SNPs linked to the gene demonstrated that families with the same mutation are unlikely to be related. The clustering of the G112S, T115N, and W116G mutations within five amino acids suggests this domain may be critical to peripheral nerve myelination. Electrophysiological studies showed that CMT1C patients from six pedigrees (n = 38) had reduced nerve conduction velocities ranging from 7.5 to 27.0m/sec (peroneal). Two patients had temporal dispersion of nerve conduction and irregularity of conduction slowing, which is unusual for CMT1 patients. We report the expression of SIMPLE in various cell types of the sciatic nerve, including Schwann cells, the affected cell type in CMT1C.
Effect of polyethylene‐graft‐maleic anhydride as a compatibilizer on the mechanical and tribological behaviors of ultrahigh‐molecular‐weight polyethylene/copper composites
Authors: Zhou Jiansong , Yan Fengyuan 
Published: April 2004

AbstractUltrahigh‐molecular‐weight polyethylene/copper (UHMWPE/Cu) composites compatibilized with polyethylene‐graft‐maleic anhydride (PE‐g‐MAH) were prepared by compression molding. The effects of the compatibilizer on the mechanical, thermal, and tribological properties of the UHMWPE/Cu composites were investigated. These properties of the composites were evaluated at various compositions, and worn steel surfaces and composite surfaces were examined with scanning electron microscopy and X‐ray photoelectron spectroscopy. The incorporation of PE‐g‐MAH reduced the melting points of the composites and increased their crystallinity to some extent. Moreover, the inclusion of the PE‐g‐MAH compatibilizer greatly increased the tensile rupture strength and tensile modulus of the composites, and this improved the wear resistance of the composites. These improvements in the mechanical and tribological behavior of the ultrahigh‐molecular‐weight‐polyethylene‐matrix composites with the PE‐g‐MAH compatibilizer could be closely related to the enhanced crosslinking function of the composites in the presence of the compatibilizer. Moreover, the compatibilizer had an effect on the transfer and oxidation behavior of the filler Cu particulates, which could be critical to the application of metallic‐particulate‐filled polymer composites in engineering. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 948–955, 2004
Preparation of conductive polyaniline fibers by a continuous forming‐drawn processing routine
Authors: Liu Weijin , Gao Guang 
Published: April 2004

AbstractPolyaniline fibers were prepared with a continuous forming‐drawn processing routine that better met practical production requirements. The continuous forming drawing of the fibers was conducted successfully with the following methods. A reducing agent was added to a polymer solution during the dissolution of a polyaniline emeraldine base in N‐methyl‐2‐pyrrolidinone (NMP). After the entire wet‐spinning process was finished, the fibers were reoxidized and doped to obtain electric conductivity. The as‐spun fibers were predrawn at a low drawing ratio in a warm water bath before a plasticization drawing process on a hot plate. After the fibers were predrawn, some solvent was still kept in the fibers and used as a plasticizer of the fibers so that the plasticization drawing process would be performed successfully. The spinning conditions that affected the mechanical properties and conductivity of the fibers were the content of NMP in the coagulation bath, the coagulation‐bath temperature, the warm‐water‐bath temperature, the predrawing ratio, the hot‐plate temperature, the plasticization drawing ratio, and the reoxidation and protonation treatment time. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 956–960, 2004
Environmental responsibility in SMEs: does it deliver competitive advantage?
Authors: Simpson Mike , Taylor Nick , Barker Karen 
Published: April 2004

AbstractSmall and medium sized enterprises (SMEs) can gain a competitive advantage and create sustainable business by adopting environmental good practices. However, the perceptions of SMEs and their approach to environmental improvements suggest that there are some fundamental misunderstandings and difficulties in achieving this in practice. A questionnaire‐based study of SMEs and their responses to the current requirements of environmental good practice was carried out in South Yorkshire. Follow‐up interviews and factory visits were also carried out. The study aimed to assess the ability of SMEs to create a competitive advantage by adopting environmental good practice and making environmental improvements to their business. The main findings were that most organizations surveyed believed environmental issues to be issues affecting their business. However, the meeting of these requirements was seen as a cost that was not transferable to customers in terms of added benefits and few organizations could show that it led to a competitive advantage. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
The effect of desferrioxamine on peroxynitrite‐induced oxidative damage in erythrocytes
Authors: Ertabak Aytu , Kutluay Türker , Ünlü Ali , Türközkan Nurten , Çimen Behzat , Yaman Halil 
Published: April 2004

AbstractThe aim of this study was to investigate the effect of desferrioxamine on peroxynitrite‐mediated damage in erythrocytes by measuring the 3‐nitrotyrosine level and glutathione peroxidase and Na+‐K+ ATPase activities in vitro. 3‐Nitrotyrosine levels were determined by HPLC; glutathione peroxidase and Na+‐K+ ATPase activities were measured by spectrophotometry. Peroxynitrite increased the 3‐nitrotyrosine level but decreased both enzyme activities. In the presence of desferrioxamine, glutathione peroxidase activity was increased with a decrease in the 3‐nitrotyrosine level. Desferrioxamine was found to possess an important antioxidant activity as assessed in an in vitro system, reducing protein nitration, restorating enzyme activities and maintaining erythrocyte membrane integrity. Copyright © 2004 John Wiley & Sons, Ltd.
Unimolecular Reactivity of Strong Metal–Cation Complexes in the Gas Phase: Ethylenediamine–Cu+
Authors: Alcamí Manuel , Luna Alberto , Mó Otilia , Yáñez Manuel , Tortajada Jeanine , Amekraz Badia 
Published: April 2004

AbstractThe gas‐phase reactions between ethylenediamine (en) and Cu+ have been investigated by means of mass spectrometry techniques. The MIKE spectrum reveals that the adduct ions [Cu+(H2NCH2CH2NH2)] spontaneously decompose by loosing H2, NH3 and HCu, the loss of hydrogen being clearly dominant. The spectra of the fully C‐deuterated species show the loss of HD, NH3 and CuD but no losses of H2, D2, NH2D, NHD2, ND3 or CuH are observed. This clearly excludes hydrogen exchange between the methylene and the amino groups as possible mechanisms for the loss of ammonia. Conversely, methylene hydrogen atoms are clearly involved in the loss of molecular hydrogen. The structures and bonding characteristics of the Cu+(en) complexes as well as the different stationary points of the corresponding potential energy surface (PES) have been theoretically studied by DFT calculations carried out at B3LYP/6‐311+G(2df,2p)//B3LYP/6‐311G(d,p) level. Based on the topology of this PES the most plausible mechanisms for the aforementioned unimolecular fragmentations are proposed. Our theoretical estimates indicate that Cu+ strongly binds to en, by forming a chelated structure in which Cu+ is bridging between both amino groups. The binding energy is quite high (84 kcal mol−1), but also the products of the unimolecular decomposition of Cu+(en) complexes are strongly bound Cu+‐complexes.
Crew roster scheduling by the extended cooperative genetic algorithm
Authors: Adachi Nobue , Kobayashi Shigenobu 
Published: April 2004

AbstractA hybrid scheme that combines an annealing method and an extended cooperative genetic algorithm (cGA) obtained by treating the problem of scheduling a flight crew roster as a multiobjective problem is proposed. The setting of the problem of scheduling of an airplane operating crew roster and the construction of the solution method for multiobjective optimization are discussed and the efficacy of the scheme proposed is verified. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(10): 44–53, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20107
Mini‐review: The nuclear protein HMGB1 as a proinflammatory mediator
Authors: Erlandsson Harris Helena , Andersson Ulf 
Published: April 2004

AbstractThe intranuclear architectural protein that is termed high mobility group box chromosomal protein 1 (HMGB1) was recently identified as a potent proinflammatory mediator when present extracellularly. HMGB1 has been demonstrated to be a long‐searched‐for nuclear danger signal passively released by necrotic, as opposed to apoptotic, cells that will induce inflammation. Furthermore, HMGB1 can also be actively secreted by stimulated macrophages or monocytes in a process requiring acetylation of the molecule, which enables translocation from the nucleus to secretory lysosomes. Subsequenttransport out of the cells depends on a secretion signal mediated by either extracellular lysophophatidyl‐choline or ATP. HMGB1 passively released from necrotic cells and HMGB1 actively secreted byinflammatory cells are thus molecularly different. Extracellular HMGB1 acts as a cytokine by signaling via the receptor for advanced glycated end‐products and via members of the Toll‐like receptor family. The initiated inflammatory responses include the production of multiple cytokines, chemoattraction of certain stem cells, induction of vascular adhesion molecules and impaired function of intestinalepithelial cells. Therapeutic administration of HMGB1 antagonists rescues mice from lethal sepsis, even when initial treatment is delayed for 24 h after the onset of infection, establishing a clinically relevant therapeutic window that is significantly wider than for other known cytokines.
Conformational Effects on the Photoinduced Energy Transfer in a Star‐Shaped Pentaporphyrin with Nucleosidic Linkers
Authors: Flamigni Lucia , Talarico Anna Maria , Ventura Barbara , Marconi Giancarlo , Sooambar Chloé , Solladié Nathalie 
Published: April 2004

AbstractThe photophysical properties of a pentameric array (FB‐Zn4) containing peripheral Zn porphyrins and a free‐base core, connected by nucleosidic linkers, have been determined and compared with the properties of the model dyad (FB‐Zn) and of their individual components. The flexibility of the nucleosidic linkers allows the dyad to take two different conformations corresponding to a bent and an almost fully extended form of the linker, which are characterized by a chromophore separation of ca. 2 nm and ca. 3 nm, respectively. Energy transfer from the zinc porphyrin to the free‐base porphyrin occurs, in the bent conformation, with a rate of 3.6 × 109 s−1. Conversely, in the extended conformation, the Zn porphyrin decay is unperturbed, which is in good agreement with the expected dipole−dipole (Förster) energy transfer mechanism. In the pentameric array, the Zn porphyrin luminescence is quenched with a rate of 3.6 × 109 s−1 in 15% of the population, whilst the luminescence of the Zn porphyrin is unquenched for ca. 35% of the population. For comparison with the dyad, these two cases are assigned as arrays with a single linkage in a bent configuration and arrays with all linkages in the extended configuration, respectively. However, the most striking feature in the pentaporphyrin is that 50% of the Zn porphyrin excited state population exhibits a fast non‐radiative deactivation (rate ca. 1010 s−1) which also involves the free‐base porphyrin core to some extent. This behavior is attributed to a strongly interacting conformation with the Zn porphyrins folded over the central free‐base porphyrin. The proposed model is supported by CD spectroscopy, complexation experiments with bases, and the reactivity of the excited state towards external quenchers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)