bluuebunny/crossref_metadata_2025 huggingface dataset:
A [2]Catenane Containing 1,1′‐Binaphthyl Units and 1,10‐Phenanthroline Fragments: Synthesis and Intermolecular Energy Transfer Processes
Authors: Koizumi Masatoshi , Dietrich‐Buchecker Christiane , Sauvage Jean‐Pierre
Published: February 2004

A chiral copper(I)‐complexed [2]catenane consisting of two interlocking 38‐membered rings, each ring incorporating a 2,9‐diphenyl‐1,10‐phenanthroline (dpp) and an (S)‐1,1′‐binaphthyl group, has been prepared by means of a transition metal template strategy. Demetalation afforded the corresponding free chiral [2]catenane. The coordination polyhedron of the Cu(dpp)2 core in this chiral copper(I)‐complexed [2]catenane reflects the distortion of the chiral 1,1′‐binaphthyl units, as evidenced by the circular dichroism (CD) measurements. Emission measurements demonstrated that in the two‐chromophore compounds (S)‐6 and (S,S)‐9, efficient energy transfer between the 1,1′‐binaphthyl component and the dpp unit takes place in solution at room temperature. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Fully Stereoselective Nucleophilic Addition to a Novel Chiral Pyrroline N‐Oxide: Total Syntheses of (2S,3R)‐3‐Hydroxy‐3‐methylproline and Its (2R)‐Epimer
Authors: Merino Pedro , Revuelta Julia , Tejero Tomas , Cicchi Stefano , Goti Andrea
Published: February 2004

A new total synthesis of (2S,3R)‐3‐hydroxy‐3‐methylproline has been performed via a key intermediate chiral pyrroline N‐oxide, obtained from (R)‐citramalic acid. This nitrone underwent nucleophilic addition of furyllithium with complete stereoselectivity through a preferential attack anti to the methoxymethoxy group. The correct stereochemistry was established through an oxidation−reduction sequence, which allowed inversion of configuration at C‐2. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Mild Conditions for Copper‐Catalysed N‐Arylation of Pyrazoles
Authors: Cristau Henri‐Jean , Cellier Pascal P. , Spindler Jean‐Francis , Taillefer Marc
Published: February 2004

Copper‐catalysed N‐arylation of pyrazoles with aryl or heteroaryl bromides or iodides, which can include functional substituents, was performed under the mildest conditions yet described, with excellent yields and selectivity, by the use as catalyst of a combination of cuprous oxide with a set of inexpensive, chelating oxime‐type ligands not previously known to promote such reactions. Other original bi‐, tri‐ or tetradentate ligands providing nitrogen and/or oxygen as chelating atoms were also successfully tested in this type of arylation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
An empirical analysis of the relationship between the hedge ratio and hedging horizon: A simultaneous estimation of the short‐ and long‐run hedge ratios
Authors: Chen Sheng‐Syan , Lee Cheng‐Few , Shrestha Keshab
Published: February 2004

This article analyzes the effects of the length of hedging horizon on the optimal hedge ratio and hedging
effectiveness using 9 different hedging horizons and 25 different commodities. We discuss the concept of
short‐ and long‐run hedge ratios and propose a technique to simultaneously estimate them. The
empirical results indicate that the short‐run hedge ratios are significantly less than 1 and increase with
the length of hedging horizon. We also find that hedging effectiveness increases with the length of hedging
horizon. However, the long‐run hedge ratio is found to be close to the naïve hedge ratio of unity. This
implies that, if the hedging horizon is long, then the naïve hedge ratio is close to the optimum hedge ratio.
© 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:359–386, 2004
Enantioselective Synthesis of 2‐(2‐Arylcyclopropyl)glycines: Conformationally Restricted Homophenylalanine Analogs
Authors: Demir Ayhan S. , Sesenoglu Özge , Ülkü Dincer , Arici Cengiz
Published: February 2004

Starting from simple aromatic aldehydes and acetylfuran, (E)‐1‐(furan‐2‐yl)‐3‐arylprop‐2‐en‐1‐ones (2) were synthesized in high yields. Cyclopropanation of the CC bond with trimethylsulfoxonium iodide (Me3SO+I−) furnished (furan‐2‐yl)(2‐arylcyclopropyl)methanones 3 in 90–97% yields. Selective conversion of cyclopropyl ketones to their (E)‐ and (Z)‐oxime ethers 5 and oxazaborolidine‐catalyzed stereoselective reduction of the CN bond followed by separation of the formed diastereoisomers, furnished (2‐arylcyclopropyl)(furan‐2‐yl)methanamines 6 in optically pure form and high yield. Oxidation of the furan ring of (S,S,S)‐, (S,R,R)‐, (R,S,S)‐, and (R,R,R)‐6a afforded the four stereoisomers of α‐(2‐phenylcyclopropyl) glycine (1a).
Preparation and (E/Z)‐Isomerization of the Diastereoisomers of Violaxanthin
Authors: Molnár Péter , Deli József , Zsila Ferenc , Steck Andrea , Pfander Hanspeter , Tóth Gyula
Published: February 2004

Violaxanthin A (=(all‐E,3S,5S,6R,3′S,5′S,6′R)‐5,6 : 5′,6′‐diepoxy‐5,6,5′,6′‐tetrahydro‐β,β‐carotene‐3,3′‐diol =syn,syn‐violaxanthin; 5) and violaxanthin B (=(all‐E,3S,5S,6R,3′S,5′R,6′S)‐5,6 : 5′,6′‐diepoxy‐5,6,5′,6′‐tetrahydro‐β,β‐carotene‐3,3′‐diol=syn,anti‐violaxanthin; 6) were prepared by epoxidation of zeaxanthin diacetate (1) with monoperphthalic acid. Violaxanthins 5 and 6 were submitted to thermal isomerization and I2‐catalyzed photoisomerization. The structure of the main products, i.e., (9Z)‐5, (13Z)‐5, (9Z)‐6, (9′Z)‐6, (13Z)‐6, and (13′Z)‐6, was determined by their UV/VIS, CD, 1H‐NMR, 13C‐NMR, and mass spectra.
Factors Influencing the Course of the Macrocyclization of α,ω‐Diamines with Esters of α,ω‐Dicarboxylic Acids
Authors: Gryko Dorota , Gryko Daniel T. , Sierzputowska‐Gracz Hanna , Pia̧tek Piotr , Jurczak Janusz
Published: February 2004

The efficient synthesis of eight new macrocyclic amides (lactams) via reaction of diesters with diamines under normal dilution conditions is described. The role of intermolecular H‐bond formation and steric hindrance is discussed based on 1H‐ and 15N‐NMR studies of appropriate model compounds. Principles for the optimal choice of esters that can be efficiently transformed into diamides have been developed.
Synthesis of (±)‐Glaucine and (±)‐Neospirodienone via an One‐Pot BischlerNapieralski Reaction and Oxidative Coupling by a Hypervalent Iodine Reagent
Authors: Huang Wei‐Jan , Singh Om V. , Chen Chung‐Hsiung , Lee Shoei‐Sheng
Published: February 2004

Condensation of 3,4‐dimethoxybenzeneethanamine (3d) and various benzeneacetic acids, i.e., 4a–e, via a practical and efficient one‐pot Bischler–Napieralski reaction, followed by NaBH4 reduction, produced a series of 1‐benzyl‐1,2,3,4‐tetrahydroisoquinolines, i.e., 5a–e, in satisfactory yields (Scheme 3). Oxidative coupling of the N‐acyl and N‐methyl derivatives 6a–e of the latter with hypervalent iodine ([IPh(CF3COO)2]) yielded products with two different skeletons (Scheme 4). The major products from N‐acyl derivatives 6a–c were (±)‐N‐acylneospirodienones 2a–c, while the minor was the 3,4‐dihydroisoquinoline 7. (±)‐Glaucine (1), however, was the major product starting from N‐methyl derivative 6e. Possible reaction mechanisms for the formation of these two types of skeleton are proposed (Scheme 5).
Silver and Gold Trinuclear Complexes Based on 3‐Substituted or 3,5‐Disubstituted Pyrazolato Ligands. X‐Ray Crystal Structure of cyclo‐Tris{μ‐[3,5‐bis(4‐phenoxyphenyl)‐1H‐pyrazolato‐κN1 : κN2]}trigold Dichloromethane ([Au(μ‐$\rm{ pz^{pp_2 }}$)]3⋅CH2Cl2)
Authors: Torralba M. Carmen , Ovejero Paloma , Mayoral M. José , Cano Mercedes , Campo José A. , Heras José V. , Pinilla Elena , Torres M. Rosario
Published: February 2004

Ten new silver and gold trimeric complexes of the type [M3(μ‐pz′)3] (M=Au, Ag), where pz′ indicate pyrazolato ligands derived from mesogenic 3,5‐disubstituted 1H‐pyrazoles $\rm{ Hpz^{R_2}}$ or non‐mesogenic 3‐substituted 1H‐pyrazoles HpzR (R=C6H4OCnH2n+1), were synthesized and characterized. The gold and silver complexes 7, 8, 10, and 11 containing symmetric pyrazolato ligands as bridging groups ($\rm{ pz^{R_2}}$; R=C6H4OCnH2n+1, n=4 ($\rm{ pz^{bp_2 }}$) and 8 ($\rm{ pz^{op_2 }}$)) exhibited a trigonal symmetric structure. The same results were obtained for the related silver derivatives 16–18 with 3‐substituted pyrazolato ligands (pzR; R=C6H4OCnH2n+1, n=4 (pzbp), 12 (pzddp), and 18 (pzodp)). By contrast the 3‐substituted pyrazolato‐gold compounds 13–15 adopted an asymmetric molecular structure related to the position of the substituents on the trinuclear core. The thermal behavior of these complexes was investigated by differential scanning calorimetry and polarized‐light microscopy. The mesomorphism of the parent 3,5‐disubstituted pyrazoles is avoided in their corresponding trinuclear complexes 7, 8, 10, and 11. However, the metal derivatives 14 and 17 containing the asymmetric 3‐[4‐(dodecyloxy)phenyl]pyrazolato ligand were found to have liquid‐crystal properties. These compounds exhibited monotropic behavior with columnar mesophases that could be related to the disc‐like shape of the molecular core and the appropriate length of the alkyloxy chain. For comparative purposes, the X‐ray structure of the related gold complex [Au3(μ‐$\rm{ pz^{pp_2 }}$)3] (9) having phenoxyphenyl substituents at the 3‐ and 5‐positions of the pyrazolato ligand is also described. The molecular structure is formed by a non‐planar (AuNN)3 core, containing three Au‐atoms bridged by three pyrazolato ligands. The molecular packing is described as a columnar organization, the shortest Au ⋅⋅⋅Au distance being 4.639(1) Å between consecutive trimers.
Selective Inhibition of Collagen‐Induced Platelet Aggregation by a Cyclic Peptide from Drymaria diandra
Authors: Hsieh Pei‐Wen , Chang Fang‐Rong , Wu Chin‐Chuang , Wu Kuen‐Yuh , Li Chien‐Ming , Wang Wei‐Ya , Gu Ling‐Chia , Wu Yang‐Chang
Published: February 2004

Four cyclic peptides, diandrine A–D (1–4), were isolated from the MeOH extract of Formosan Drymaria diandra. Their structures were elucidated by chemical and spectroscopic analyses as cyclo(‐Gly1‐Pro2‐Trp3‐Pro4‐Tyr5‐Phe6‐), cyclo(‐Gly1‐Pro2‐Leu3‐Pro4‐Leu5‐Trp6‐Ser7‐Ser8‐), cyclo(Gly1‐Gly2‐Pro3‐Tyr4‐Trp5‐Pro6‐), and cyclo(Gly1‐Gly2‐Pro3‐Tyr4‐Trp5‐Pro6‐), respectively. Compounds 3 and 4 were stable conformational isomers. Cyclopeptide 1 showed a selective inhibitory effect on collagen‐induced platelet aggregation with an IC50 value of 44.2 μM.
Synthesis of Cyclopenta[b]indol‐1‐ones and Carbazol‐4‐ones from N‐(2‐Halophenyl)‐Substituted Enaminones by Intramolecular Heck Reaction
Authors: Sørensen Ulrik S. , Pombo‐Villar Esteban
Published: February 2004

An efficient synthetic route towards N‐methylated or nonmethylated 3,4‐dihydrocyclopent[b]indol‐1(2H)‐ones (3) and 1,2,3,9‐tetrahydrocarbazol‐4(4H)‐one (10) was elaborated, based on Pd‐catalyzed intramolecular Heck reaction. The chemoselectivity of the cyclization was studied in the case of the bi‐ and trifunctional substrates 12 and 17, respectively. In the latter case, depending on the catalyst, either the brominated indole 18 or the tetracyclic compound 19 were obtained by single and double Heck reaction, respectively.
New Low‐Molecular‐Mass Gelators Based on L‐Lysine: Amphiphilic Gelators and Water‐Soluble Organogelators
Authors: Suzuki Masahiro , Yumoto Mariko , Kimura Mutsumi , Shirai Hirofusa , Hanabusa Kenji
Published: February 2004

The new L‐lysine alkali‐metal salts 1–5 (M+=Na+ and K+) with different alkyl groups at the Nα‐position were easily synthesized, and their hydro‐ and organogelation properties were investigated. All compounds were H2O‐soluble, and some salts, especially the potassium salts, functioned as a hydrogenator that could gel water below 2 wt‐%. These salts also had organogelation abilities for many organic solvents.
Exploring differential attrition rates among system of care evaluation participants
Authors: Rogers Kelly N. , Fernandez Maria , Thurber Lori , Smitley Andy
Published: February 2004

The purpose of the present study is to investigate differential attrition rates in terms of both demographic characteristics and initial levels of child functioning of participants in North Carolina's system of care evaluation. Participants included 303 families (78 dropped out of the study, a 26% attrition rate). Families dropped out of the evaluation for three main reasons: refusal to participate, moving, or inability to contact the family. The majority of families who dropped out of the study did so after completing only the baseline interview. Differential attrition did not exist in terms of demographic characteristics, but there was some support for possible differential attrition indicated by initial levels of child functioning in some cases. Additionally, higher parental education level predicted longer participation in longitudinal evaluation. Recommendations and implications for applied research are offered. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 167–176, 2004.
A thermostable maltose‐tolerant α‐amylase from Aspergillus tamarii
Authors: Moreira Fabiana Guillen , Lenartovicz Veridiana , Peralta Rosane Marina
Published: February 2004

An homogeneous fraction of α‐amylase from Aspergillus tamarii was obtained by means of a very easy purification procedure. The enzyme is a glycoprotein containing 32% saccharide and MW of 37.5 kDa. Optimal of pH and temperature with starch as substrate were 4.5–6.5 and 50–55 °C. The enzyme was stable for several hours at temperature up to 65 °C. Starch, amylose, and amylopectin were the substrates preferentially hydrolysed and maltose and maltotriose were the main end products. The values of KM and Vmax for starch were 2 g/l and 880 μmoles reducing sugars/min.mg of protein, respectively. The purified enzyme was remarkably insensitive to end product inhibition, being only slightly inhibited by maltose and glucose up to 1.0 M.
Evaluation of some fungi and bacteria for biocontrol of anthracnose disease of cowpea
Authors: Adebanjo A. , Bankole S. A.
Published: February 2004

The efficacy of some fungal and bacterial isolates obtained from cowpea phylloplane in inhibiting the in vitro and in vivo growth of Colletotrichum lindemuthianum, causal agent of anthracnose of cowpea was investigated. Inhibition of growth of the pathogen with production of zones of inhibition was observed for Aspergillus flavus, A. ochraceus, Penicillium aurantiogriseum, Bacillus subtilis‐BS21, B. subtilis‐BS22 and B. subtilis‐BS23. Inhibition of growth on contact was recorded for A. niger while Trichoderma viride‐TH14 and T. viride‐TH31hyperparasitized the pathogen. The two isolates of T. viride and all tested bacteria significantly reduced seedling infection from anthracnose infested seeds in pot experiments. Spray application of T. viride‐TH31 on inoculated cowpea plants in the field effectively suppressed the incidence and severity of anthracnose disease, and significantly increased yield over the control. The antagonist was more effective when applied twice weekly than once in a week.
Effect of potential on the corrosion behavior of a new titanium alloy for dental implant applications in fluoride media
Authors: Al‐Mayouf A. M. , Al‐Swayih A. A. , Al‐Mobarak N. A.
Published: February 2004

The effect of fluoride ion concentration and pH on the corrosion behavior of TCA (60 Ti 10 Ag 30 Cu), which is a new Ti alloy with low melting point, pure Titanium (Ti), and TAV (TiAl6V4) was examined using open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) at different potentials. Results show that the corrosion resistance of TCA and Ti decrease at anodic potentials compared with results obtained at OCP. At one potential the corrosion resistance decrease depends on NaF concentration and pH. TAV shows less resistance against corrosion in fluoride containing saliva. TCA has potentials more positive than Ti and TAV due to surface enrichment of Cu and Ag as Ti dissolves which accelerates the cathodic reaction. Fluoride ion may not hinder the growth of oxide layers on the surfaces of the electrodes. It will have influence on the properties of the oxide layer causing them to be not protective against corrosion in acid media containing fluoride ions.
Corrosion failure of marine steel in sea‐mud containing sulfate reducing bacteria
Authors: Yanliang H.
Published: February 2004

The corrosion failure behavior of marine steel is affected by stress, which exists in offshore structures at sea‐mud region. The sulfate reducing bacteria (SRB) in the sea‐mud made the steel more sensitive to stress corrosion cracking (SCC) and weaken the corrosion fatigue endurance. In this paper, a kind of natural sea‐mud containing SRB was collected. Both SCC tests by slow strain rate technique and corrosion fatigue tests were performed on a kind of selected steel in sea‐mud with and without SRB at corrosion and cathodic potentials. After this, the electrochemical response of static and cyclic stress of the specimen with and without cracks in sea‐mud was analyzed in order to explain the failure mechanism. Hydrogen permeation tests were also performed in the sea‐mud at corrosion and cathodic potentials. It is concluded that the effect of SRB on environment sensitive fracture maybe explained as the consequences of the acceleration of SRB on corrosion rate and hydrogen entry into the metal.
Inhibitorwirksamkeit beim Langzeitschutz von Stahlbehältern für die chemische Oberflächenvorbereitung gegen örtliche Korrosion durch salzsäurehaltige Prozesslösungen
Authors: Stieglitz U. , Schulz W.‐D.
Published: February 2004

Die Wirksamkeit handelsüblicher Säureinhibitoren wird durch eine Auslagerung von Grobblechen aus Behälterstahl über 1000 Stunden in technisch gebräuchlichen Lösungen der Feuerverzinkung untersucht. Örtliche Korrosion ist als Muldenkorrosion in Gegenwart von Säureinhibitoren vor allem in Salzsäurebeizen (20 g/l HCl) bei Raumtemperatur und in salzsäurehaltigen Reinigern (10–30 g/l HCl) bei 40°C aufgetreten, wenn Zusatzbedingungen erfüllt sind. Örtliche Korrosion wird vorwiegend durch eine Unterschreitung der Inhibitorkonzentration (0,2 g/l) in Verbindung mit einer minimalen Salzsäurekonzentration (10–30 g/l) ausgelöst. Aber auch Oxidationsmittel wie Eisen(III)‐Ionen (5–10 g/l), Luftsauerstoff und freies Chlor (100–1000 mg/l) führen zu örtlicher Korrosion. In Spülbädern (2–10 g/l HCl) und Flussmittellösungen aus Zinkchlorid und Ammoniumchlorid (pH‐Wert: 2,0–5,5) ist keine örtliche Korrosion entstanden, sondern Flächenkorrosion. Im untersuchten Langzeitbereich sind Säureinhibitoren gegen Flächenkorrosion sehr gut wirksam (Hemmwerte bis 99%).
Polygones
Authors: Mazoyer Virginie
Published: February 2004

In first, we recall some properties of polygons under the action of an irregular monoid which may be written M = G ∪ I, where G is a group and I the only one ideal. Then, we completely describe monoids when G has only one orbit on I. We also describe all possible polygons and types of their elements. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Arithmetic of divisibility in finite models
Authors: Mostowski Marcin , Wasilewska Anna E.
Published: February 2004

We prove that the finite‐model version of arithmetic with the divisibility relation is undecidable (more precisely, it has Π01‐complete set of theorems). Additionally we prove FM‐representability theorem for this class of finite models. This means that a relation R on natural numbers can be described correctly on each input on almost all finite divisibility models if and only if R is of degree ≤0′. We obtain these results by interpreting addition and multiplication on initial segments of finite models with divisibility only. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
All hydrocarbon main‐chain thermotropic liquid crystalline polymers, poly(1,1′‐biphenylene‐4,4′‐alkenediyl)s, prepared by the ADMET method and their hydrogenated polymers, poly(1,1′‐biphenylene‐4,4′‐alkanediyl)s
Authors: Joo Sung‐Hoon , Jin Jung‐Il
Published: February 2004

A series of poly(4,4′‐biphenylenealkenylene)s and copolymers were prepared by the acyclic diene metathesis (ADMET) polymerization of 4,4′‐bis(alkenylene)1,1′‐biphenyls. Unsaturated polymers thus prepared were then hydrogenated to produce the corresponding saturated polymers. All the polymers were found to be thermotropic and to form solidlike smectic phases in melt. Their liquid crystallinity (LC) was studied by differential scanning calorimetry (DSC), X‐ray diffractometry, and polarizing microscopy. We observed that one of the phenylene units of the biphenyl structure could selectively be hydrogenated at an elevated temperature. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1335–1349, 2004
Functionalization of polyethylene/silane copolymers in posttreatment reactions
Authors: Lipponen S. , Seppälä J.
Published: February 2004

7‐Octenyldimethylphenylsilane was copolymerized with ethylene via Et(Ind)2ZrCl2 methylaluminoxane catalyst system without loss of catalyst activity or decrease in molar mass. The comonomer contents in the polymer samples were at a level of 0.15–1.0 mol % and the reactive phenylsilane groups were posttreated to different alcoxy‐ and halosilane groups, for example, SiF, SiCl, SiOCH3, and SiOCH2CH3. The posttreatment reactions had no major effect on the molar masses or on the thermal properties (measured with differential scanning calorimetry) of the copolymers. The reaction pathways were nearly independent of the comonomer contents and the reactions reached 70–100% conversions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1461–1467, 2004
Chemically functionalized clay vinyl ester nanocomposites: Effect of processing parameters
Authors: Yebassa D. , Balakrishnan S. , Feresenbet E. , Raghavan D. , Start P. R. , Hudson S. D.
Published: February 2004

The primary objective of this study was to improve montmorillonite clay‐platelet separation in vinyl ester resin matrix by organically modifying the nanoclay platelet with a partially reactive onium salt. The reactive onium salt (ω‐undecylenyl amine hydrochloride) was synthesized from commercial ω‐undecylenyl alcohol through a series of synthetic conversions. Nonreactive onium salt (undecyl amine hydrochloride) was made from commercial undecyl amine. These salts were characterized with 1H and 13C NMR and Fourier transform infrared techniques. The relative amounts of exfoliated, intercalated, and as‐treated clay and the size of the clay particle aggregates depended significantly on the composition of clay and the processing conditions. When the clay was ion‐exchanged with a mixture of reactive and nonreactive onium salts, a partially exfoliated vinyl ester resin polymer nanocomposite was formulated. The addition of a comonomer styrene and high‐intensity ultrasonic mixing produced vinyl ester nanocomposite with the highest degree of clay‐platelet exfoliation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1310–1321, 2004
Implementing the reversible addition–fragmentation chain transfer process in PREDICI
Authors: Wulkow Michael , Busch Markus , Davis Thomas P. , Barner‐Kowollik Christopher
Published: February 2004

There is currently a highly controversial debate about the nature of the reversible addition–fragmentation chain transfer (RAFT) mechanism. In this debate, kinetic computer modeling is frequently used as a powerful tool to correlate experimental data with theoretical models to deduce the rate coefficients that govern the process. Frequently, the PREDICI program package has been used as a simulation tool. Recently, the implementation and mathematical basis of the RAFT process, with respect to PREDICI, have been criticized. This communication discusses the mathematical and mechanistic implementation of the RAFT process in the PREDICI program package and elucidates the well‐founded mathematical basis of the approach. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1441–1448, 2004
Theoretical calculation of the reduced viscosity of aqueous suspensions of charged spherical particles
Authors: Nishida Koji , Kiriyama Kohei , Kanaya Toshiji , Kaji Keisuke , Okubo Tsuneo
Published: February 2004

The origin of the variety of characteristics of the reduced viscosity of aqueous suspensions of charged spherical particles has been an unsolved problem. To solve the problem, the reduced viscosity due to interparticle electrostatic interactions between charged spherical particles are calculated as a function of particle concentration with scanning various parameters, such as diameter of particle, number of charges per particle, and added‐salt concentration. The result successfully reproduced the variety of characteristics. Of all the scanned parameters, the diameter of the particle has a significant role to display the variety of characteristics when other parameters are fixed. When the diameter is very small (∼0 Å), the calculated reduced viscosity of aqueous suspensions of charged spherical particles increases with decreasing particle concentration and it shows a maximum. This behavior is very similar to the reduced viscosity of linear chain polyelectrolyte solutions. Whereas, when the diameter is large (>2000 Å), the calculated reduced viscosity decreases with decreasing particle concentration and it does not show a maximum. When the diameter is <1000 Å, the calculated reduced viscosity shows both the maximum and minimum. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1068–1074, 2004
The writing is on the wall, but are we reading it?
Authors: Snowden Andrew
Published: February 2004

The demographic time bomb is alive and ticking some 10 years after the initial warnings of its presence began to be sounded. So what have we done about it and how can we reconcile the needs of the emerging society with the environmental challenges that threaten our very existence over the long term? This article explores the issues and challenges the packaging industry to take up the gauntlet. Copyright © 2003 John Wiley & Sons, Ltd.
The modelling of VLF Trimpis using both finite element and 3D Born Modelling
Authors: Baba K. , Nunn D. , Hayakawa M.
Published: February 2004

This paper investigates the numerical modelling of VLF Trimpis produced by a D region inhomogeneity on the Great Circle Path. Two different codes are used. The first is a 2D finite element method (FEM) code, whose solutions are valid in the non‐Born limit. The second is a 3D model that invokes the Born approximation. The predicted Trimpis from these codes compare closely, thus confirming the validity of both models. The modal scattering matrices have a comparable structure, and indicate strong scattering between the dominant TM modes. Analysis of the scattering matrix from the FEM code delineates the Born regime. For a LIE with a radius of 100kms, the Born approximation becomes invalid at an electron density perturbation of about 8 el/cc.
A Hf‐Nd isotopic correlation in ferromanganese nodules
Authors: Albarède Francis , Simonetti Antonio , Vervoort Jeffrey D. , Blichert‐Toft Janne , Abouchami Wafa
Published: February 2004

The 176Hf/177Hf ratio was measured on 34 ferromanganese nodules, mostly from the Atlantic ocean. The different ocean basins are isotopically distinct with the extreme compositions being less radiogenic in the Atlantic (єHf ∼ +1) than in the Pacific (єHf ∼ +9). A good correlation of єHf and єNd is observed amongst most samples which supports that Hf isotopic compositions in nodules reflect those of ambient seawater. For a given єNd, єHf is more radiogenic in ferromanganese nodules than in rocks from either the mantle or the crust. This correlation makes the coupled Hf‐Nd systems a potential paleoceanographic tool. It is argued that a zircon‐free clayish component of probable eolian origin may account for the radiogenic Hf in nodules.
Observations of OH, HO2, H2O, and O3 in the upper stratosphere: Implications for HOx photochemistry
Authors: Jucks K. W. , Johnson D. G. , Chance K. V. , Traub W. A. , Margitan J. J. , Osterman G. B. , Salawitch R. J. , Sasano Y.
Published: February 2004

Balloon‐borne observations of concentrations of OH, HO2, H2O, and O3 in the middle and upper stratosphere are used to test our understanding of HOx photochemistry. Assuming our photochemical model is complete, the measured [OH] and [HO2] above 38 km (where HOx partitioning is no longer dependent on [NO]) are modeled best by calculations that use a 25% reduction in the ratio of the reaction rate constants for O+HO2 and O+OH as well as either a 25% reduction of the rate constant of OH+HO2 (the primary HOx sink) or a 25% increase in HOx production. All of these changes are consistent with the uncertainties in the recommended rate constants. The kinetic parameters required to explain our observations of [OH] and [HO2] do not lead to a resolution of the long‐standing “ozone deficit problem” above 45 km.
Past and future changes in global tropospheric ozone: Impact on radiative forcing
Authors: Brasseur Guy P. , Kiehl Jeffrey T. , Müller Jean‐François , Schneider Tim , Granier Claire , Tie XueXi , Hauglustaine Didier
Published: February 2004

Calculations by a global three‐dimensional chemical transport model of the atmosphere suggest that increased surface emissions of chemical compounds caused by industrial activities at mid‐latitudes in the northern hemisphere and by biomass burning in the tropics since the middle of the 19th century have produced an increase in the abundance of tropospheric ozone along with a reduction in the oxidizing capacity of the atmosphere (globally averaged OH concentration reduced by 17% and methane lifetime enhanced by 1.5 years). These perturbations in tropospheric ozone result in a change in annually averaged radiative forcing of 0.37 W m−2 (0.62 W m−2 in the northern hemisphere during the summer months). Future changes (1990–2050) in tropospheric ozone associated with population increase and economic development (primarily in developing countries) are expected to be largest in the tropics, specifically in South and Southeast Asia. Further changes in the oxidizing capacity of the atmosphere could be small if the abundance of tropospheric water vapor increases as a result of anticipated climate change.
On the problem of the heliospheric interface response to the cycles of the solar activity
Authors: Baranov Vladimir B. , Zaitsev Nikolay A.
Published: February 2004

The effects of the solar activity cycle on the problem of the solar wind interaction with the supersonic LISM flow have been investigated. Our calculations have shown that the response of the position of the termination shock to the changes of the solar wind parameters is within 12% from the mean location. The response of the heliopause (HP) is much smaller, and the response of the bow shock (BS) is negligible.

The existence of the BS is also discussed. In particular, we show that the Richardson [1997] scenario in which the BS disappears because of the TS motion cannot be physically realized.
Climate variability and trends from operational satellite spectral data
Authors: Harries John E. , Brindley Helen E. , Geer Alan J.
Published: February 2004

‘Fingerprint’ correlation studies of air temperatures have recently suggested the emergence of climate change patterns that are consistent with those simulated by Global Climate Models. Here we investigate the possibility of searching for climate change patterns within directly observed satellite radiance fields in order to utilise the vast amount of data available. As a first example of a technique which could be employed we extend the commonly used pattern matching statistics to develop a ‘spectral‐spatial fingerprint’ method for the detection of climate change. To illustrate the technique, we apply it to two satellite channels: HIRS ch.12, sensitive to upper tropospheric water vapour, and SSU ch.1, sensitive to mid‐stratospheric temperatures centred at 15 hPa.
Seasonal U.S. temperature and precipitation anomalies associated with El Niño: Historical results and comparison with 1997‐98
Authors: Harrison D. E. , Larkin N. K.
Published: February 2004

Extreme weather occurred in many parts of the United States during the 1997–98 El Niño. We compare the 1997–98 autumn, winter, and spring temperature and precipitation anomalies with the historical El Niño period anomalies. About 90% of the contiguous U.S. has one or more statistically significant historical weather associations with El Niño. The 1997–98 wet anomalies and the autumn and winter temperature anomalies resemble their historical counterparts. Taken together, about 80% of the U.S. experienced extreme seasonal anomalies during 1997–98; 20% of the U.S. experienced 50‐year‐record winter temperature anomalies. However, these percentages are not remarkable.
Ocean surface air temperature derived from multiple data sets and artificial neural networks
Authors: Gautier Catherine , Peterson Pete , Jones Charles
Published: February 2004

This paper presents a new method to derive monthly averaged surface air temperature, Ta, from multiple data sets. Sea Surface Temperature (SST) from the National Centers for Environmental Prediction (NCEP) and total precipitable water (W) from the SSM/I sensor are used as inputs to Artificial Neural Networks (ANN). Surface air temperature (Ta) measurements from the Surface Marine Data (SMD) are used to develop and evaluate the methodology. When globally evaluated with SMD data, the bias of the new method is small (0.050°C ± 0.26°C), and the accuracy expressed as root‐mean square (rms) differences has a small global mean (0.73°C ± 0.37°C). These biases and rms differences are smaller than those obtained using NCEP reanalyses and TIROS Operational Vertical Sounder (TOVS) data products. When evaluated with the TOGA‐TAO array measurements over the tropical Pacific, the ANN mean bias and rms differences have similarly small values, 0.37°C and 0.61°C, respectively.
A geodynamic framework for eastern Mediterranean kinematics
Authors: Lundgren Paul , Giardini Domenico , Russo Raymond M.
Published: February 2004

We use a finite element model incorporating plate motion boundary conditions, fault constraints, and space geodetic velocities to calculate eastern Mediterranean plate kinematics and to estimate the motion of the region's major faults. We then use subsets of these constraints to generate models testing different scenarios of driving forces (slab roll‐back at the Hellenic arc, Arabian plate push, gravitational collapse of W. Anatolia) to match the expected pattern of deformation. We find that models combining only trench rollback and Arabian push are unable to provide a good match to the observed deformation across western Anatolia and the Aegean and that we need to introduce the effects of mantle corner flow and gravitational collapse to fit observations.
Formation of power‐law energy spectra in space plasmas by stochastic acceleration due to whistler‐mode waves
Authors: Ma Chun‐yu , Summers Danny
Published: February 2004

A non‐relativistic Fokker‐Planck equation for the electron distribution function is formulated incorporating the effects of stochastic acceleration by whistler‐mode waves and Coulomb collisions. The stationary solution f to the equation, subject to a zero‐flux boundary condition, is found to be a generalized Lorentzian (or kappa) distribution, which satisfies f ∝ υ2(κ+1) for large velocity υ where κ is the spectral index. The parameter κ depends strongly on the relative wave intensity R. Taking into account the critical energy required for resonance of electrons with whistlers, we calculate a range of values of R for each of a number of different space plasmas for which kappa distributions can be expected to be formed. This study is one of the first in the literature to provide a theoretical justification for the formation of generalized Lorentzian (or kappa) particle distribution functions in space plasmas.
Layered structure of energetic oxygen ions in the dayside magnetosheath
Authors: Zong Q.‐G. , Wilken B.
Published: February 2004

On January 10 and 11, 1997, a coronal mass ejection (CME) encountered the Earth's magnetosphere and produced a moderate geomagnetic storm (Dst = −84 nT). During this event, the GEOTAIL spacecraft was skimming the dayside magnetopause, and observed a number of magnetopause crossings in response to the varying solar wind dynamic pressure. Around 1200 UT on January 10, GEOTAIL was traveling in the vicinity of the magnetopause at 1500 LT. Energetic oxygen ion bursts were repeatedly observed by the HEP/LD spectrometer on board GEOTAIL. This was a period of strong southward IMF related to the magnetic cloud structure of the CME. Two of these events with clear energy dispersion effects lasted from 1050 to 1113 UT, on January 10. This can be explained by invoking a quasi‐steady layered structure of the energetic oxygen ions in the magnetosheath with the higher energy particles further away from the magnetopause than the lower energy ones. The observed energy dispersion is interpreted as a result of a crossing through this spatial layer due to the arrival of a filamentory pressure pulse in the solar wind. It is suggested that the existence of the structured oxygen layer is the result of particle leakage through the dayside magnetopause into magnetosheath.
Correlation of cusp MeV helium with turbulent ULF power spectra and its implications
Authors: Chen Jiasheng , Fritz Theodore A.
Published: February 2004

A new magnetospheric phenomenon called a cusp energetic particle (CEP) event was observed by the POLAR spacecraft. CEP events were detected in the dayside polar cusp near the apogee of POLAR and could last for hours, in which the measured helium ions had energies up to 8 MeV [Chen et al., 1997a, 1998]. A fundamental question is where do the cusp MeV ions come from? To answer this question, we have compared the ion flux in the CEP events with that in both the upstream and the downstream from the bow shock and found that bow shock acceleration cannot explain the measured ion flux in the CEP events. We have further determined the power spectra of the local magnetic field turbulence calculated over the September 18, 1996 CEP event periods for fluctuations in the ultra‐low frequency (ULF) ranges, corresponding to periods of about 0.33–500 seconds. It is found that the integrated power of the turbulent spectra over the ULF ranges is correlated with the intensity of the MeV helium flux. These new results provides the first direct observation evidence that the high‐altitude dayside cusp is a new acceleration region of the magnetosphere.
The high‐pressure melting curve of Allende meteorite
Authors: Kavner Abby , Jeanloz Raymond
Published: February 2004

Laser‐heated diamond‐cell experiments on Allende meteorite, a natural analog for undifferentiated terrestrial planetary mantles, yield a melting curve increasing from ∼2200 to 3200 K over the pressure range of 15–70 GPa, significantly below that of peridotite that is representative of the Earth's current upper mantle. Samples quenched from high temperatures and pressures reveal structures that may mimic the initial stages of differentiation between core and mantle materials. Micron‐scale chemical analyses support the idea that sulfur is enriched, and silicon, oxygen and aluminum are depleted, in the (potentially core‐forming) metal relative to the silicate phases.
Evidence for strong shear velocity reductions and velocity gradients in the lower mantle beneath Africa
Authors: Ritsema Jeroen , Ni Sidao , Helmberger Donald V. , Crotwell H. Philip
Published: February 2004

We present data which indicate that the broad, low shear velocity anomaly beneath southern Africa is stronger and more extensive than previously thought. Recordings of earthquakes in the southwestern Atlantic Ocean at an array of broadband seismic stations in eastern Africa show anomalously large propagation time delays of the shear phases S, ScS, and SKS which vary rapidly with epicentral distance. By forward modeling, we estimate that the low velocity anomaly extends from the core‐mantle boundary about 1500 km up into the mantle and that the average shear velocity within this structure is 3% lower than in standard models such as PREM. Strong velocity contrasts exist at its margins (2% over about 300 km). These seismic characteristic are consistent with recent numerical simulations of lower mantle mega‐plume formation.
Ice diapirs on Europa: Implications for liquid water
Authors: Rathbun Julie A. , Musser George S. , Squyres Steven W.
Published: February 2004

Early examinations of Galileo images of Europa revealed features that look like low topographic domes. These small (5–10 km in radius) domes have been interpreted as surface manifestations of diapirs. As a way to probe the subsurface structure of Europa, we investigate the possibility that thermally‐driven ice diapirism created these surface features. We use a previously developed analytic model for rising diapirs to estimate the initial radii of the diapirs, their initial depth, the temperature of the medium through which they rise and their formation timescales. We assume that the diapirs originate at the boundary layer between solid ice and whatever underlies it, whether it be liquid water or solid rock. Our results show that the diapirs originate at a depth of no more than a few tens of kilometers. Since the H2O layer on Europa is substantially thicker than this, our results support the view that liquid water recently existed beneath the ice on Europa at this location, at a depth of no more than a few tens of kilometers. Further, the ice must have been warm (250–270 K) and was therefore likely to have been convecting.
A test, using atmospheric data, of a method for estimating oceanic eddy diffusivity
Authors: Kushner Paul J. , Held Isaac M.
Published: February 2004

G. Holloway has proposed a simple method to estimate the effective horizontal eddy diffusivity for oceanic tracers using satellite measurements of sea‐surface height variability. In this method, the diffusivity is assumed to scale as the r.m.s. eddy geostrophic streamfunction. This method should apply analogously in an atmospheric context, in which the energetic eddies are well resolved in data sets and models, and in which both the effective diffusivity and tracer fluxes can be directly calculated. We evaluate Holloway's method using lower‐tropospheric daily atmospheric reanalysis data, and find that at a given height the method succesfully yields estimates of the divergent part of the atmospheric sensible heat flux, to within a fairly uniform scaling factor.
Longterm increases in western Mediterranean salinities and temperatures: Anthropogenic and climatic sources
Authors: Krahmann Gerd , Schott Friedrich
Published: February 2004

The deep water of the western Mediterranean Sea is known to have become warmer and saltier since about the 1950s. The causes of these changes have, however, not yet been sactisfactorily determined. Previous studies speculated on decreasing precipitation, greenhouse warming and/or anthropogenic reduction of the freshwater flux into the eastern Mediterranean. Here we report on results from a new oceanographic database of the western Mediterranean Sea together with determinations of longterm changes of the fresh water budget. We analyzed temperature and salinity data of the past 40 years to detect deviations from the longterm average. Certain areas and depth ranges are showing increases in temperature or salinity some of which have been found earlier and some which are new. From the regional and vertical distribution we conclude that the observed increases of temperature and salinity in the western Mediterranean Sea are caused both by changes in atmospheric conditions as described by the NAO‐index and by the regulation of Spanish rivers.
A magnetotelluric profile across Central Java, Indonesia
Authors: Ritter O. , Hoffmann‐Rothe A. , Müller A. , Dwipa S. , Arsadi E. M. , Mahfi A. , Nurnusanto I. , Byrdina S. , Echternacht F. , Haak V.
Published: February 2004

Along a N30°E striking profile in central Java, Indonesia we recorded broadband magnetotelluric data at 8 sites in the period range 0.01 s–10000s. A preliminary analysis of apparent resistivity, phase and magnetic transfer function data favours a one‐dimensional interpretation of most sites for the upper 3–5 km of the crust and a two‐ or three‐ dimensional structure for the lower crust. Several conductive features can be distinguished: (i) a strong “ocean effect” at the southern most site, (ii) a zone of very high conductivity in the central part of the profile, and (iii) a conductor in the north that cannot be caused by the shallow Java sea. We discuss tentatively causes for these anomalies. The conductor in the central part of the profile is probably connected with volcanic or geothermal activity, while the anomaly in the north could be an expression of processes associated with an active fault zone.
Intermittence and modulation of mesoscale variability
Authors: Wang L. , Koblinsky C. , Howden S. , Beckley B.
Published: February 2004

We studied both the fast and slow modulation of mesoscale variability in the western Kuroshio Extension region (along track 119) by analyzing 4‐year TOPEX/Poseidon altimetry data. Bulk of the mesoscale variability lies near the axis of the Kuroshio Extension and the western boundary current along the east coast of Japan. It is found that both the intensity and spreading of mesoscale variability in the frequency band has significant, both abrupt and slow, variations. The slow modulation may be mainly caused by low‐frequency variation in the background mean flow, while the abrupt change is primarily due to strong nonlinear processes.
Impact of diurnal variability on UARS synoptic products
Authors: Sassi Fabrizio , Salby Murry
Published: February 2004

We examine the impact of diurnal variability on the synoptic behavior of ozone observed by the Upper Atmosphere Research Satellite (UARS). Synoptic products generated via Kalman filtering are compared against those recovered via Fast Fourier Synoptic Mapping (FFSM). In FFSM products, tracer anomalies defining distinct air masses that originate from different latitudes are approximately conserved. In Kalman products, the same anomalies and the accompanying air masses are diluted with their surroundings. The origin of these differences is traced to the different space‐time spectrum inherent to the two synoptic products. In the spectrum of Kalman products, high zonal wavenumbers are exaggerated at low frequency relative to their counterparts in FFSM. This pathological behavior appears to result through aliasing from diurnal variability that is undersampled in the UARS observations. We discuss the relevance of these findings to subsequent analyses and to estimating momentum sources in the middle atmosphere.
Wave power dropouts associated with radial field intervals in high speed solar wind
Authors: Horbury T. S. , Lucek E. A. , Balogh A. , McComas D. J.
Published: February 2004

Examination of 770 days of heliospheric magnetic field data recorded within polar solar wind by the Ulysses spacecraft revealed a number of occasions when the wave power decreased by more than an order of magnitude for several hours. These power dropouts were found to be associated with intervals when the magnetic field was closely aligned with the radial direction. A case by case study showed that there was no obvious signature in bulk plasma parameters. A statistical study of 24 intervals when the field was close to radial for at least 6 hours showed that the wave power in those intervals was significantly lower than that outside. There were no significant power changes when the field lay close to either the Parker spiral or an arbitrary direction. Although they are likely to be of solar origin, the exact source for these events is not clear.