bluuebunny/crossref_metadata_2025 huggingface dataset:
Interstrain Inhibition in the Sweet Potato PathogenStreptomyces ipomoeae: Purification and Characterization of a Highly Specific Bacteriocin and Cloning of Its Structural Gene
Authors: Zhang Xiujun , Clark Christopher A. , Pettis Gregg S.
Published: April 2003

Strains of the sweet potato soil rot pathogenStreptomyces ipomoeaehad previously been divided into three groups based on their ability to inhibit one another during pairwise cocultivation. While group I strains are not antagonistic to members of the other groups, group II and group III strains produce separate substances that are inhibitory to strains outside their respective cognate groups. Here, we purified the group III inhibitory substance from the culture supernatant of a representative strain and found that it consists of a single 10-kDa cationic protein which is bacteriolytic forS. ipomoeaegroup I and II strains but which showed no inhibitory function against other streptomycetes or other bacterial genera tested. The structural gene for the inhibitor was cloned from a chromosomal library of the producing strain, and while the gene sequence revealed that the inhibitor is initially made in a larger precursor form, the deduced mature protein showed no significant homology to other known proteins. Our results demonstrate thatS. ipomoeaegroup III inhibitory activity is manifested in the form of a highly specific, potentially novel bacteriocin, which we have designated ipomicin.
Selection and Identification of a
Listeria monocytogenes
Target Strain for Pulsed Electric Field Process Optimization
Authors: Lado Beatrice H. , Yousef Ahmed E.
Published: April 2003

Nine
Listeria monocytogenes
strains were treated individually with a continuous pulsed electric field (PEF) apparatus, and their sensitivities to the treatment were compared at 25 kV/cm. When cell suspensions of these strains in 0.1% NaCl (pH 7.0) were treated at 23°C for 144 μs, inactivation ranged from 0.7 to 3.7 log
10
CFU/ml. Inactivation by 72-μs PEF treatments at 37°C ranged from 0.3 to 2.5 log
10
CFU/ml.
L. monocytogenes
OSY-8578 was substantially more resistant than other strains when cells were PEF treated in 0.1% NaCl, whereas Scott A was one of the most sensitive strains. The superiority of OSY-8578's resistance to that of Scott A was confirmed in 50% diluted acid whey (pH 4.2). Changes in sensitivity to PEF during phases of growth were minimal in OSY-8578 and substantial in Scott A. Use of
L. monocytogenes
OSY-8578, therefore, is recommended in studies to optimize PEF processes that target
L. monocytogenes
. The nine
L. monocytogenes
strains were genotyped with pulsed-field gel electrophoresis (PFGE) and arbitrarily primed PCR (AP-PCR) techniques. These strains were better differentiated with PFGE than with AP-PCR. The target strain (OSY-8578) was characterized by both molecular typing techniques, but resistance to PEF, in general, was not associated with a particular genotype group.
Real-Time Reverse Transcription-PCR Analysis of Expression of Halobenzoate and Salicylate Catabolism-Associated Operons in Two Strains of
Pseudomonas aeruginosa
Authors: Corbella M. E. , Puyet A.
Published: April 2003

Pseudomonas aeruginosa
JB2 can use 2-chlorobenzoate (2-CBa), 3-CBa, 2,3-dichlorobenzoate (2,3-DCBa), and 2,5-DCBa as sole carbon and energy sources, whereas strain 142 can only grow on 2-CBa and 2,4-DCBa. Both strains, however, harbor the same halobenzoate 1,2-dioxygenase (
ohbAB
) and chlorocatechol (
clcABD
) degradation genes necessary for the metabolism of
ortho
-CBas. In addition, the
hybABCD
operon, encoding a salicylate 5-hydroxylase, is also found in both strains. The expression of
ohbAB
,
hybABCD
, and
clcABD
operons was measured in cultures grown on different CBas as the sole carbon source and also in glucose-grown cells supplemented with CBas as inducers. A method to standardize real-time reverse transcription-PCR experimental data was used that allows the comparison of semiquantitative mRNA accumulation in different strains and culture conditions. In both strains, the
ohb
and
hyb
systems were induced in cells grown on 2-CBa or DCBas, whereas
clc
was induced only by DCBas. Repression by catabolite was observed both on
ohb
and
clc
systems in glucose-grown cells. Chlorocatechol 1,2-dioxygenase activity in JB2 was detected even in
clc
-repressed conditions, confirming the presence of additional isofunctional genes previously detected in
P. aeruginosa
142. Although similar levels of induction of
ohbAB
were observed in strain JB2 grown on either benzoate, monochlorobenzoates, or DCBas, the
ohbAB
operon of strain 142 was only strongly induced by growth on 2-CBa and, to a lesser extent, on 2,4-DCBa. This observation suggests that regulation of the
ohbAB
operon may be different in both strains. The concomitant induction of
ohb
and
hyb
by CBas may allow the formation of hybrid halobenzoate dioxygenase(s) composed of Ohb/Hyb dioxygenase subunits and Hyb ferredoxin/ferredoxin reductase components.
Engineering
Streptomyces clavuligerus
Deacetoxycephalosporin C Synthase for Optimal Ring Expansion Activity toward Penicillin G
Authors: Wei Chia-Li , Yang Yunn-Bor , Wang Wen-Ching , Liu Wen-Chi , Hsu Jyh-Shing , Tsai Ying-Chieh
Published: April 2003

The deacetoxycephalosporin C synthase (DAOCS) from
Streptomyces clavuligerus
was engineered with the aim of enhancing the conversion of penicillin G into phenylacetyl-7-aminodeacetoxycephalosporanic acid, a precursor of 7-aminodeacetoxycephalosporanic acid, for industrial application. A single round of random mutagenesis followed by the screening of 5,500 clones identified three mutants, G79E, V275I, and C281Y, that showed a two- to sixfold increase in the
k
cat
/

K
m

ratio compared to the wild-type enzyme. Site-directed mutagenesis to modify residues surrounding the substrate resulted in three mutants, N304K, I305L, and I305M, with 6- to 14-fold-increased
k
cat
/

K
m

values. When mutants containing all possible combinations of these six sites were generated to optimize the ring expansion activity for penicillin G, the double mutant, YS67 (V275I, I305M), showed a significant 32-fold increase in the
k
cat
/

K
m

ratio and a 5-fold increase in relative activity for penicillin G, while the triple mutant, YS81 (V275I, C281Y, I305M), showed an even greater 13-fold increase in relative activity toward penicillin G. Our results demonstrate that this is a robust approach to the modification of DAOCS for an optimized DAOCS-penicillin G reaction.
Detection of Frequency Resonance Energy Transfer Pair on Double-Labeled Microsphere and
Bacillus anthracis
Spores by Flow Cytometry
Authors: Zahavy E. , Fisher M. , Bromberg A. , Olshevsky U.
Published: April 2003

Development of an ultrasensitive biosensor for biological hazards in the environment is a major need for pollutant control and for the detection of biological warfare. Fluorescence methods combined with immunodiagnostic methods are the most common. To minimize background noise, arising from the unspecific adsorption effect, we have adapted the FRET (frequency resonance energy transfer) effect to the immunofluorescence method. FRET will increase the selectivity of the diagnosis process by introducing a requirement for two different reporter molecules that have to label the antigen surface at a distance that will enable FRET. Utilizing the multiparameter capability of flow cytometry analysis to analyze the double-labeling/FRET immunostaining will lead to a highly selective and sensitive diagnostic method. This work examined the FRET interaction of fluorescence-labeled avidin molecules on biotin-coated microspheres as a model system. As target system, we have used labeled polyclonal antibodies on
Bacillus anthracis
spores. The antibodies used were purified immunoglobulin G (IgG) molecules raised in rabbits against
B. anthracis
exosoporium components. The antibodies were fluorescence labeled by a donor-acceptor chromophore pair, alexa488 as a donor and alexa594 as an acceptor. On labeling the spores with alexa488-IgG as a donor and alexa594-IgG as an acceptor, excitation at 488 nm results in quenching of the alexa-488 fluorescence (
E
q
= 35%) and appearance of the alexa594 fluorescence (
E
s
= 22%), as detected by flow cytometry analysis. The FRET effect leads to a further isolated gate (FL1/FL3) for the target spores compared to competitive spores such as
B. thuringiensis
subsp.
israelensis
and
B. subtilis.
This new approach, combining FRET labeling and flow cytometry analysis, improved the selectivity of the
B. anthracis
spores by a factor of 10 with respect to
B. thuringiensis
subsp.
israelensis
and a factor of 100 with respect to
B. subtilis
as control spores.
Improving the Thermostability of Raw-Starch-Digesting Amylase from a
Cytophaga
sp. by Site-Directed Mutagenesis
Authors: Shiau Rong-Jen , Hung Hui-Chen , Jeang Chii-Ling
Published: April 2003

A heat-stable raw-starch-digesting amylase (RSDA) was generated through PCR-based site-directed mutagenesis. At 65°C, the half-life of this mutant RSDA, which, compared with the wild-type RSDA, lacks amino acids R178 and G179, was increased 20-fold. While the wild type was inactivated completely at pH 3.0, the mutant RSDA still retained 41% of its enzymatic activity. The enhancement of RSDA thermostability was demonstrated to be via a Ca
2+
-independent mechanism.
Molecular Characterization of
Vibrio cholerae
O139 Bengal Isolated from Water and the Aquatic Plant
Eichhornia crassipes
in the River Ganga, Varanasi, India
Authors: Bhanumathi R. , Sabeena F. , Isac Sree Renjini , Shukla B. N. , Singh D. V.
Published: April 2003

A collection of ten strains of
Vibrio cholerae
O139, comprising six isolates from
Eichhornia crassipes
, two from water of the River Ganga, and one each from a well and a hand pump, were characterized. All the strains carried the CTX genetic element (
ctxA
,
zot
, and
ace
) except for the
st
gene and carried structural and regulatory genes for toxin-coregulated pilus (
tcpA
,
tcpI
, and
toxR
), adherence factor (
ompU
), and accessory colonization factor (
acfB
); all produced cholera toxin (CT). These strains were resistant to trimethoprim, sulfamethoxazole, streptomycin, and to the vibriostatic agent pteridine. Results obtained by ribotyping and enterobacterial repetitive intergenic consensus sequence-PCR fingerprint analysis indicate that multiple clones of toxigenic-pathogenic
V
.
cholerae
O139 were present in the aquatic environment.
Lack of Association between Serum Paraoxonase 1 Activities and Increased Oxidized Low-Density Lipoprotein Levels in Impaired Glucose Tolerance and Newly Diagnosed Diabetes Mellitus
Authors: Kopprasch Steffi , Pietzsch Jens , Kuhlisch Eberhard , Graessler Juergen
Published: April 2003

Several in vitro investigations showed that serum paraoxonase 1 (PON1) that is located on high-density lipoprotein reduces or prevents low-density lipoprotein (LDL) oxidation and therefore retards atherosclerosis. Accordingly, the well documented loss of PON1 activity in patients with overt diabetes mellitus was causally related to the development of micro- and macroangiopathy in the disease course. Because vascular complications start already in prediabetic states, e.g. impaired glucose tolerance (IGT), we investigated serum PON1 activities and circulating levels of oxidized LDL (oxLDL) in 125 IGT subjects, 75 patients with newly diagnosed diabetes mellitus type 2, and 403 individuals with normal glucose tolerance. Using three different substrates (paraoxon, phenylacetate, p-nitrophenylacetate) we found that PON1 activity is not significantly altered in IGT and diabetes mellitus subjects, respectively, when compared with normoglycemic controls. Both IGT subjects and diabetes mellitus patients had significantly increased levels of oxLDL in the circulation. However, serum PON1 activity variations and glutamine/arginine phenotype were not related to the levels of oxLDL. The data suggest that 1) PON1 activity loss is an event occurring later in the course of diabetes mellitus; and 2) PON1 does not affect oxidation of circulating LDL, at least in early diabetes mellitus.
Luteinizing Hormone Signaling and Breast Cancer: Polymorphisms and Age of Onset
Authors: Powell B. L. , Piersma D. , Kevenaar M. E. , van Staveren I. L. , Themmen A. P. N. , Iacopetta B. J. , Berns E. M. J. J.
Published: April 2003

Estrogen exposure has repeatedly been shown to associate with the risk of developing breast cancer. Estrogen synthesis is under the control of LH and FSH, where LH, through its receptor (LHR), stimulates production of ovarian androgens; and FSH, their aromatization to estrogens. Here, we investigated whether functional polymorphic variants in the LH signaling pathway are associated with the risk of breast cancer or its clinical phenotype.

A PCR-restriction fragment length polymorphism genotyping approach was used to investigate this in 266 breast cancers. The LHR18insLQ allele does not seem to influence breast cancer risk. However, women who were homozygous for the LHR18insLQ allele were, on average, 8.3 yr younger at diagnosis, compared with those homozygous for the wild-type LHR allele (mean age, 51.9 yr vs. 60.2 yr; P = 0.03). Trends were observed for associations between LHR18insLQ carriers and nodal involvement or larger tumor size. Patients who were LHR18insLQ carriers revealed a significantly worse overall survival, compared with those who were homozygous for LHR [hazard ratio = 2.4; 95% CI (1.3–4.3); P = 0.006]. In contrast, no associations between the LH genotype and any of the clinical parameters were observed. Our findings suggest that the LHR18insLQ gene polymorphism determines an earlier age of disease onset and is prognostic for poor outcome of breast cancer.
One-Dimensional PbS/Polymer Nanocomposite of Core/Sheath Structure Fabricated by Hydrothermal Polymerization and Simultaneous Sulfidation
Authors: Zeng Jing-hui , Zhu Yu , Yang Jian , Liu Yuan-fang , Qian Yi-Tai
Published: April 2003

A novel hydrothermal method has been developed for the synthesis of rod-shaped PbS/poly(vinyl acetate) composites. These one-dimensional (1-D) PbS/polymer composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), and Raman spectroscopy. The results show that the products are of rod-shaped core/sheath structure with good crystallinity.
Photochromism of Dinuclear Tungsten Complexes with Disulfur and Ethylene-1,2-dithiolate Ligands
Authors: Shibahara Takashi , Nishiura Kasumi , Tsuboi Masanobu , Akashi Haruo , Sakane Genta
Published: April 2003

Novel photochromic and non-photochromic ethylene-1,2- dithiolato dinuclear tungsten complexes, [W2(µ-S2)(µ-S2C2Ph2)2(S2C2Ph2)2] (2a) and [W2(µ-S2)2(µ-S4)(S2C2Ph2)2] (2b), respectively, were synthesized and characterized.
Synthesis, Structure and Optical Refractive Effect of Dibutyltin(IV) Complex of [Ph2P(S)NP(S)Ph2]−
Authors: Niu Yunyin , Wang Yuxiao , Song Yinglin , Liu Shixiong , Zheng Hegen , Xin Xinquan
Published: April 2003

Reaction of n-Bu2SnCl2 with K[Ph2P(S)NP(S)Ph2] in CH3CN gives the spirobimetallocyclic complex bis(tetraphenyldithioimidodiphosphinato)dibutyltin (IV), {n-Bu2Sn[Ph2P(S)NP(S)Ph2]2} in which π–π stacking interactions by the phenyl rings of the ligands exist. The nonlinear optical (NLO) properties were studied with an 8 ns-pulsed laser at 532 nm. Its optical responses to the incident light exhibit strong refractive effect with n2 = 5.4 × 10−18 m2 W−1 in a 1.2 × 10−4 mol dm−3 DMF solution.
Water-Soluble Trialkylphosphine-Ruthenium(II) Complexes as Efficient Catalysts for Hydrogenation of Supercritical Carbon Dioxide
Authors: Kayaki Yoshihito , Suzuki Tomoyuki , Ikariya Takao
Published: April 2003

A water-soluble ruthenium(II) complex bearing tris(hydroxymethyl)phosphine, RuCl2[PH(CH2OH)2]2[P(CH2OH)3]2, is highly effective for the catalytic hydrogenation of supercritical carbon dioxide (scCO2) under scCO2–H2O multi-phasic conditions.
Nanocrystalline TiO2 Electrodes Prepared by Water-Medium Screen Printing Technique
Authors: Zhang Dongshe , Ito Seigo , Wada Yuji , Kitamura Takayuki , Yanagida Shozo
Published: April 2003

A water-medium screen printing technique was developed for making mesoporous TiO2 electrodes by using two types of commercial nanocrystalline TiO2 powders and three types of water-soluble cellulosic thickeners. Treatment of the electrodes with a TiCl4 aqueous solution improved the overall conversion efficiency of the dye-sensitized solar cells based on these mesoporous TiO2 electrodes.
Extraordinary Catalytic Behavior of CeO2 in Partial Oxidation of Methane
Authors: Roh Hyun-Seog , Jun Ki-Won , Baek Seung-Chan , Park Sang-Eon
Published: April 2003

CeO2 exhibits extraordinary catalytic activity in partial oxidation of methane to synthesis gas. Total combustion was observed at stoichiometric feed ratio, while oscillatory partial oxidation was achieved at O2 deficient feed ratio.
Novel Finding of the Effect of Triple Bond on the Photochemical cis–trans Isomerization of C=C Double Bond
Authors: Sakakibara Hirokazu , Ikegami Masashi , Isagawa Kakuzo , Tojo Sachiko , Majima Tetsuro , Arai Tatsuo
Published: April 2003

Both cis- and trans-1, 2-bis(phenylethynyl)ethenes (1) gave fluorescence emission with considerably high quantum yield and intersystem crossing to the triplet state which underwent cis–trans isomerization. On the basis of the results, a novel potential energy surface of isomerization of 1 was proposed.
Ethylene Polymerization Behavior of New Titanium Complexes Having Two Phenoxy–Pyridine Chelate Ligands
Authors: Inoue Yoshihisa , Nakano Takashi , Tanaka Hidetsugu , Kashiwa Norio , Fujita Terunori
Published: April 2003

Two new titanium complexes having two phenoxy–pyridine chelate ligands were synthesized and investigated for their potential as ethylene polymerization catalysts. On activation with Ph3C+B−(C6F5)4 / i-Bu3Al, one of the complexes, bis[2-(2′-pyridyl)phenolato] titanium complex, exhibited high activity (227–564 kg-PE/mol-cat·h) and produced high molecular weight polyethylene (Mv; 140000–3230000) at 25–75 °C.
Biomimetic Intradiol-Cleavage of Catechols with Incorporation of Both Atoms of O2: The Role of the Vacant Coordination Site on the Iron Center
Authors: Ogo Seiji , Yamahara Ryo , Funabiki Takuzo , Masuda Hideki , Watanabe Yoshihito
Published: April 2003

This is the first example of model system for the active site of protocatechuate 3,4-dioxygenase to display intradiol-cleavage of catechols with incorporation of two oxygen atoms of O2 promoted by iron complexes.
Effects of Chemical Modification of Lipase on Its Enantioselectivity in Organic Solvents
Authors: Ueji Shin-ichi , Tanaka Hiroyuki , Hanaoka Takahito , Ueda Ai , Watanabe Keiichi , Kaihatsu Kunihiro , Ebara Yasuhito
Published: April 2003

The chemical modification of lipase with the hydrophobic group such as Z (benzyloxycarbonyl) or Z(NO2) (p-nitro-Z) is found to bring about a marked improvement of the enantioselectivity in isopropyl ether and an inversion of the solvent effects on the enantioselectivity.
A Geometrical Isomeric Pair of Novel Cobalt(III) Complexes Containing Diphenylphosphine: cis- and trans-[Co(dtc)2(PHPh2)2]BF4 (dtc = N,N-Dimethyldithiocarbamate)
Authors: Suzuki Takayoshi , Iwatsuki Satoshi , Takagi Hideo D , Kashiwabara Kazuo
Published: April 2003

The stable title cobalt(III) complexes containing PHPh2 have been prepared and investigated for their crystal structures and spectroscopic properties. The cis-isomer was converted photochemically to the trans-isomer, which isomerized thermally to the original cis-isomer. The structural parameters and the ligand-field strengths of the PHPh2 complexes were not predictable from the σ-donicity of PHPh2.
Addition of HCl to a Base-Stabilized Hydrido(silylene)tungsten Complex and Reactivity of the Adduct toward LiAlH4
Authors: Sakaba Hiroyuki , Hirata Takeshi , Kabuto Chizuko , Horino Hiroshi
Published: April 2003

The reaction of cis-Cp*(CO)2HW=SiPh2·Py (1, Py = pyridine) with HCl gave an adduct Cp*(CO)2H2WSiPh2Cl (2). Treatment of 2 with excess LiAlH4 afforded an anionic complex Li[cis-Cp*(CO)2HWSiHPh2] (4), and the same product was obtained by the reaction of 1 with LiAlH4.
Protonation of Bis-μ-diethylsilyl Complex {(C5Me5)Ru(μ-η2-HSiEt2)}2(μ-H)(H): Enhancement of Bonding Interaction between Bridging Silicon and Hydride Ligands
Authors: Takao Toshiro , Yoshida Shigeru , Suzuki Hiroharu
Published: April 2003

A bis-µ-diethylsilyl complex {Cp*Ru(µ-η2-HSiEt2)}2(µ-H)(H) (2a; Cp* = η5-C5Me5) reacted with CF3SO3H to afford a cationic bis-µ-diethylsilane complex [{Cp*Ru(µ-η2:η2-H2SiEt2)}2(µ-H)][X] (4a, X = CF3SO3, BPh4). An X-ray diffraction study of 4a-BPh4 revealed its pseudo C2 symmetric structure and µ-η2:η2-coordination of the bridging silicon.
Syntheses and Characterization of Disilane Unit Containing Polytitana- and Polyzirconasiloxanes
Authors: Gunji Takahiro , Gomi Takeshi , Sanji Takanobu , Abe Yoshimoto
Published: April 2003

Disilane unit containing polytitana- and polyzirconasiloxanes were synthesized by the reaction of 1,1,2,2-tetramethyl-1,2-disilanediol with bis(2,4-pentanedionato)titanium diisopropoxide or bis(2,4-pentanedionato)zirconium diisopropoxide. These polymers consisted of disilane unit and metalloxane bonding as main chain with pendants of methyl and 2,4-pentanedionato groups and terminals of isopropoxy and silanol groups. On the other hand, a cyclotitanasiloxane was prepared by the reaction of 1,1,2,2-tetramethyl-1,2-disilanediol with titanocene dichloride in the presence of triethylamine.
A Convergent, Homochiral Bis(amino alcohol) for Obtaining High Enantioselectivity in the Addition of Diethylzinc to Aldehydes
Authors: Ooi Takashi , Saito Akira , Maruoka Keiji
Published: April 2003

A new bimetallic approach using dibenzofuran derivative as a requisite spacer has been introduced to achieve high asymmetric induction in the addition of diethylzinc to aldehydes with otherwise ineffective amino alcohol residue.
Highly Diastereoselective Photochromic Cyclization of an Indolylfulgide Derivative Possessing C2-Symmetric Chiral Diol as an Auxiliary
Authors: Yokoyama Yasushi , Okuyama Tomoyuki , Yokoyama Yayoi , Asami Masatoshi
Published: April 2003

An indolylfulgide derivative possessing an orthoester-type functional group on the acid anhydride moiety with a C2-symmetric (S,S)-1,2-bis(1-hydroxypropyl)benzene was prepared. Irradiation of 313-nm light produced the colored form in 90% diastereomer excess. The [α]D values for the colorless and the colored forms in toluene were +82° and −420°, respectively.
Cobalt Doped Orthorhombic LiMnO2 as Cathode Materials for Lithium-Ion Batteries
Authors: Myung Seung-Taek , Komaba Shinichi , Kumagai Naoaki , Kurihara Koutarou
Published: April 2003

Orthorhombic type LiCoxMn1−xO2 (0 ≤ x ≤ 0.14) oxides have been synthesized by hydrothermal treatment of (CoxMn1−x)3O4 precursors and LiOH aqueous solution at 170 °C. As-synthesized powders showed well-ordered β-NaMnO2 structures, and the products were single crystalline particle oxides from TEM observations. The particle size decreased with increasing the amount of Co substituent. Much more improved capacity upon 100 cycling was clearly seen in orthorhombic LiCo0.1Mn0.9O2, comparing to orthorhombic LiMnO2.
Preparation of Mesoporous TiO2 Photocatalyst by Selective Dissolving of Titania–Silica Binary Oxides
Authors: Zhang Qinghong , Gao Lian , Zheng Shan
Published: April 2003

Mesoporous TiO2 photocatalyst, which consisted of uniform mesopores (pore size about 4 nm) and with anatase framework and huge surface area as high as 329 m2 g−1, was prepared by selectively dissolving of silica in Ti–Si binary oxides.
Preparation and Characterization of a Cyclic Compound Consisting of Bis(diphenylphosphino)acetylene Joined Alkyne-Bridged Dicobalt Fragments
Authors: Hong Fung-E , Chang Hao , Chang Yu-Chang , Ko Bao-Tsan
Published: April 2003

A cyclic compound, [Co2(CO)4(µ2-HC≡CSiMe3)(PPh2C≡CPPh2)]2  2, was identified from the reaction of bis(diphenylphosphino)acetylene with an alkyne-bridged dicobalt complex, (µ2-HC≡CSiMe3)Co2(CO)6  1. Crystal structure of 2 shows that it is a twelve-membered ring complex comprised of two DPPA coordinated pseudo-tetrahedral Co2C2 units. Further reaction of 2 with two equivalents of Co2(CO)8 resulted in the conversion of 2 into [Co2(CO)6{µ-P, P-(µ-PPh2C≡CPPh2)}] [Co2(CO)4(µ-HC≡CSiMe3)] 3.
Cyclic Voltammetric Responses in Hybrid Formation of 2′-Anthraquinone-Modified Oligonucleotide with DNA
Authors: Yamana Kazushige , Kumamoto Satoshi , Nakano Hidehiko , Matsuo Yoshiaki , Sugie Yosohiro
Published: April 2003

Electrochemical properties of oligonucleotides possessing an anthraquinonylmethyl group at 2′-sugar residue have been investigated. The anthraquinone oligomers exhibited measurable changes in cyclic voltammeric responses upon hybridization with DNA.
Hydrolytic Activity of ZnIIZnII and ZnIIBaII Complexes toward Tri(p-nitrophenyl) Phosphate and Di(p-nitrophenyl) Phosphate: A Functional Model of Heterobimetallic Phosphodiesterase
Authors: Arimura Keisuke , Ohba Masaaki , Yokoyama Takushi , Okawa Hisashi
Published: April 2003

Dinuclear hydroxo ZnIIZnII and ZnIIBaII core complexes, derived from a macrocyclic compartmental ligand, are examined in their hydrolytic activity toward tri(p-nitrophenyl) phosphate (TNP) and sodium di(p-nitrophenyl) phosphate (NaDNP) in aqueous DMSO. TNP is hydrolyzed by both complexes. On the other hand, DNP− is hydrolyzed by the ZnBa complex but not by the ZnZn complex.
Effects of Molecular Association in the Radical-Cations of 1,8-Bis(ethylenedithiotetrathiafulvalenyl)naphthalene
Authors: Iyoda Masahiko , Hasegawa Masashi , Kuwatani Yoshiyuki , Nishikawa Hiroyuki , Fukami Kentaro , Nagase Shigeru , Yamamoto Gaku
Published: April 2003

The π–π interaction of the tetrathiafulvalenyl groups in 1,8-bis(ethylenedithiotetrathiafulvalenyl)naphthalene was investigated. The novel electronic properties of neutral and cationic tetrathiafulvalenes have been revealed on the basis of the X-ray analysis, spectral analyses, and DFT calculations.
Superoxide Anion Generation via Electron-Transfer Oxidation of Catechin Dianion by Molecular Oxygen in an Aprotic Medium
Authors: Nakanishi Ikuo , Fukuhara Kiyoshi , Ohkubo Kei , Shimada Tomokazu , Kansui Hisao , Kurihara Masaaki , Urano Shiro , Fukuzumi Shunichi , Miyata Naoki
Published: April 2003

Superoxide anion (O2•−) was generated via an electron-transfer oxidation of catechin dianion, which was produced in the reaction of catechin with two equivalents of methoxide anion, by molecular oxygen in acetonitrile. From the detailed spectroscopic and kinetic analyses was determined the rate constant for the formation of O2•− to be 5.8 × 10−2 mol−1 dm3 s−1.
Convenient Synthesis of (3S,5S)-5-Hydroxy- and (3R,5S)-5-Chloropiperazic Acids of a Peptide Antibiotic, Monamycin G3
Authors: Ushiyama Reiko , Yonezawa Yasuchika , Shin Chung-gi
Published: April 2003

Convenient synthesis of (3S,5S)-5-hydroxy- and (3R,5S)-5-chloropiperazic acids, which are the important constituting moieties of an antibiotic monamycin G3, and their possible stereoisomers constructing of similar antibiotics was achieved from d- and l-glutamic acids in short steps.
Fluorescence Responses on Ion Recognition with 2-(4-Dialkylaminophenyl)ethoxyantimony(V) Tetraphenylporphyrin
Authors: Andou Yoshito , Shima Kensuke , Shiragami Tsutomu , Yasuda Masahide
Published: April 2003

The effects of metal ions on the fluorescence spectra of 2-phenylethoxyhydroxyantimony(V) tetraphenylporphyrin hexa-fluorophosphate (1a–c) involving azacrown ether on axial ligands were investigated. Trivalent metal ions such as Al3+, In3+, Ga3+, and Lu3+ which undergo the complexation with the azacrown ether remarkably enhanced the fluorescence quantum yields.
Dynamics of Silylenes in Polysilylenes with Structural Defects by Excimer Laser Flash Photolysis
Authors: Seki Shu , Tsuji Shou , Matsui Yoshinori , Tagawa Seiichi
Published: April 2003

The dynamics of silylene extrusion reaction was observed in polysilylene with Si branchings by using KrF excimer laser flash photolysis technique. The initial yield of silyl radicals was seen to be dependent on the backbone structure of polysilylenes, whereas the yield of silylenes was almost proportional to the number of the linear Si units in their backbones.
UV Absorption and Fluorescence Properties of Pyrene Derivatives Having Trimethylsilyl, Trimethylgermyl, and Trimethylstannyl Groups
Authors: Maeda Hajime , Inoue Yohtaro , Ishida Hideki , Mizuno Kazuhiko
Published: April 2003

UV absorption maxima of trimethylsilyl-, trimethylgermyl-, and trimethylstannyl-substituted pyrenes shifted to longer wavelength than that of unsubstituted pyrene. Absorption maxima of mono-, bis-, tris-, and tetrakis(trimethylsilyl)pyrenes shifted to longer wavelength consecutively at intervals of 10 nm. Fluorescence intensities and lifetimes decreased in the order of Me3SiAr > Me3GeAr > Me3SnAr. Fluorescence intensity of 1,3,6,8-tetrakis(trimethylsilyl)pyrene was the largest among those of a series of pyrenes.
Dynamics of Water Molecules in Micropores of AlPO4-5 and SAPO-5 Studied by 1H NMR
Authors: Gotoh Kazuma , Ishimaru Shin’ichi , Ikeda Ryuichi
Published: April 2003

Dynamics of water molecules in one-dimensional micropores AlPO4-5 and SAPO-5 frameworks was studied by measuring 1H NMR spectra, second moment M2 of line-width and spin-lattice relaxation time T1. Although the presence of two kinds of water molecules free and bound on the capillary wall were reported in AlPO4-5, our NMR T1 results imply the absence of two kinds of H2O motions, but the motional rate distributes from slow to fast jumps in both AlPO4-5 and SAPO-5.
Synthesis, Structure, and Reactions of a Novel Triarylsilanol with a Bowl-Type Framework: A Silanol Extremely Resistant to Self-Condensation
Authors: Goto Kei , Okumura Tomoko , Kawashima Takayuki
Published: April 2003

A novel nano-scale triarylsilanol bearing a bowl-shaped framework was synthesized, the structure of which was established by X-ray crystallographic analysis. The silanol was found to be extremely resistant to self-condensation whereas it reacted easily with appropriate molecules to give the corresponding derivatives.
The First [5]Supercyclodextrin Whose Cyclopentameric Array Is Held Only by a Mechanical Bond
Authors: Kaneda Takahiro , Yamada Takashi , Fujimoto Tatsuhiko , Sakata Yoshiteru
Published: April 2003

The first [5]supercyclodextrin 1s whose nano-sized cyclopentameric array is held only by a mechanical bond was synthesized by the pentakis-azo coupling of a new hermaphrodite monomer 2 with 2-naphthol as a stopper, isolated by chromatography, and characterized by MS, 2D NMR, and vis spectral methods with the help of computer simulation.
Palladium-Catalyzed Reductive Dimerizations of Highly Functionalized Allenes
Authors: Oh Chang , Yoo Hee Sang , Jung Seung Hyun
Published: April 2003

A palladium compound in the presence of an equivalent of formic acid catalyzed reductive dimerizations of various allenes to the corresponding dienes.
Hydrothermal Synthesis and Characterization of SnS2 Nanocrystals
Authors: Wang Chunrui , Tang Kaibin , Yang Qing , Qian Yitai , Xu Cunyi
Published: April 2003

Nanocrystalline SnS2 was synthesized by a hydrothermal reaction between SnCl4·5H2O and thiourea (NH2CSNH2) at 140–200 °C. XRD pattern indicated that the as-prepared sample was β-phase SnS2. The as-prepared SnS2 mainly consisted of hexagon slices with average diameter of 30–200 nm. A Raman spectrum of the as-synthesized β-SnS2 was presented.
Synthesis and Properties of Tetrathiafulvalene-Substituted Ferrocenes
Authors: Iyoda Masahiko , Takano Takahiro , Otani Naoki , Ugawa Kohei , Yoshida Masato , Matsuyama Haruo , Kuwatani Yoshiyuki
Published: April 2003

1-Tetrathiafulvalenylferrocene and its derivatives have been synthesized in moderate to good yields employing palladium-catalyzed cross-coupling. The oxidation potentials of the title compounds revealed enhanced donor ability of the TTF unit, whereas the donor ability of the ferrocene moiety decreased markedly. The radical-cation salts derived from 1-tetrathiafulvalenylferrocenes are semiconductors.
Dehydrogenative Coupling of Monohydrosilanes Mediated by (2-Phosphinoethyl)silylrhodium(I) Complex
Authors: Okazaki Masaaki , Ohshitanai Shin , Tobita Hiromi , Ogino Hiroshi
Published: April 2003

Treatment of HSiMe2Ph with a square-planar rhodium(I) complex Rh[(κ2-Si,P)-Me2SiCH2CH2PPh2](Pme3)2 gave rise to selective dehydrogenative coupling of hydrosilanes to afford (SiMe2Ph)2 and RhH2[(κ2-Si,P)-Me2SiCH2CH2PPh2](Pme3)2.
Rh–Pt Heterobimetallic Complexes with Unsymmetrically Bridging Organosilyl Ligands: Crystal Structure and Dynamic Behavior in Solution
Authors: Tanabe Makoto , Osakada Kohtaro
Published: April 2003

Pt{SiH(C6H4F-4)2}2(Pme3)2 reacts with Rh (I) complexes to afford new Rh–Pt heterobimetallic complexes with bridging hydrido and diarylsilyl ligands. These complexes were characterized by X-ray crystallography. The NMR spectra exhibit dynamic behavior of hydrogen atoms and three Pme3 ligands bonded to Rh center in solution.
Dehydrogenative Silylation of Ketones Catalyzed by Diphosphinidenecyclobutene-Coordinated Platinum(II) Complexes
Authors: Ozawa Fumiyuki , Yamamoto Shogo , Kawagishi Seiji , Hiraoka Masatomi , Ikeda Shintaro , Minami Tatsuya , Ito Shigekazu , Yoshifuji Masaaki
Published: April 2003

Methylplatinum triflate coordinated with 1,2-diphenyl-3,4-bis[(2,4,6-tri-t-butylphenyl)phosphinidene]cyclobutene serves as a highly selective catalyst for dehydrogenative silylation of ketones with HSiMe2Ph in the presence of pyridine as a co-catalyst, giving silyl enol ethers in high yields.
Photochemical Cycloaddition of C78 with Disilirane
Authors: Han Aihong , Wakahara Takatsugu , Maeda Yutaka , Niino Yasuyuki , Akasaka Takeshi , Yamamoto Kazunori , Kako Masahiro , Nakadaira Yasuhiro , Kobayashi Kaoru , Nagase Shigeru
Published: April 2003

The photochemical cycloaddition of C78(C2v+D3) with disilirane 1 only gave the adducts of C78(C2v). The D3 isomer of C78 did give no adduct with 1. The two mono-adducts were firstly isolated by a multi-stage HPLC, and characterized on the basis of the spectroscopic data. The electrochemical properties were also investigated by means of differential pulse voltammetry.
Variation of Susceptibility as Observed by Magnetic Levitation of Liquid Droplets
Authors: Fujita Toma , Dushkin Ceco , Nawa Masayoshi , Nakabayashi Seiichiro
Published: April 2003

The magnetic force is applied for the precisely controlled levitation of salt-containing water droplets in oil phase. This levitation phenomena analyses were achieved by the analytical calculation of the inhomogeneous space distribution of the field and force in the bore of a vertical superconducting magnet. The tiny effects on the droplet position are explained as variation of the diamagnetic susceptibility in the course of levitation.
Separation of copper(II) and aluminium(III) from fresh waters by solid phase extraction on a complexing resin column
Authors: Pesavento Maria , Biesuz Raffaela , Alberti Giancarla , Sturini Michela
Published: April 2003

The solid‐phase extraction (SPE) of copper(II) and aluminium(III) from fresh waters on an ion‐exchange complexing resin containing iminodiacetic groups (Chelex 100) has been examined. Quantitative recovery of the metal ions was related to the breakthrough profile that, for some samples, could not be evaluated directly. A method is suggested for evaluation, instead, of the sorption curves, on the basis of passing different volumes of sample through the column. This enables evaluation of important properties, for instance the central point of the breakthrough curve, Vf. The column used was a small one, containing 0.10 g dry Chelex 100. The metal ion was eluted with a small volume of acid solution, 10 mL of 0.5 mol L–1 HNO3; this resulted in good preconcentration factors. For copper(II) it was found that fresh waters of similar composition could have different Vf in the same column. This was ascribed to different reaction coefficients (αM(I)) of copper(II) in the considered samples, which affects Vf. By use of the proposed SPE procedure it is possible to evaluate the reaction coefficient of copper(II). The values of αM(I) for two different drinking waters at pH 7.7 were found to be 3.70×1012 and less than 4.40×1011. Similar results were obtained for aluminium(III).
Isoelectric focusing in soil science
Authors: Alianiello Francesco
Published: April 2003

Applications of isoelectric focusing (IEF) in soil science are illustrated. The materials studied, i. e. humic substances and organic fertilisers, and their behaviour when subjected to IEF are briefly described. Preliminary studies carried out on soil indicate a relation between the isoelectric point and molecular weight, and a connection with humification has been hypothesised; therefore, assessment of soil conditions could be an application of IEF. Another application is evaluation of the stabilisation of organic fertilisers. Finally, IEF can be used to distinguish different organic matrices, as such and in mixtures with mineral fertilisers.
Nitrated polynuclear aromatic hydrocarbons in ambient air in Italy. A brief overview
Authors: Cecinato Angelo
Published: April 2003

When nitrated polynuclear aromatic hydrocarbons (NPAH) were recognised as long‐term toxic compounds and were also identified in several anthropogenic emissions and among the by‐products of photochemical smog they became objects of investigation in ambient air in both polluted and clean environments. In Italy the first investigations focussing on atmospheric NPAH were performed in the early eighties and encompassed both the canyon streets and dwelling areas of Rome. Because NPAH were indicated as markers of vehicle emission, new investigations were performed in other cities and also in rural and (nominally) unpolluted locations. In general, the first measurements of NPAH were episodic and could not be assumed to be strictly representative of the sites investigated. In contrast, nowadays consistent data bases on NPAH have been built up and are discussed in the technical literature, so that both neat concentrations and the yearly timed variation of the most important NPAH congeners have been measured in Italian air. Although concentrations of NPAH in air are usually much lower than those of PAH, owing to their very high potency in inducing mutations and tumours NPAH are regarded as having an important health impact on populations living in Italian urban areas. In this regard the genotoxicity of atmospheric aerosols is partly associated with nitrofluoranthenes and nitropyrenes whereas nitronaphthalenes and methylnitronaphthalenes seem to contribute to that of the gaseous organic fraction. Several civic and regional administrations are introducing control of atmospheric NPAH among ways of improving air quality in cities.
Preparation of Silk‐Like Fibers Designed by Self‐Assembled Ionic Polypeptides
Authors: Hachisu Masakazu , Ohkawa Kousaku , Yamamoto Hiroyuki
Published: April 2003

Natural protein fibers, such as silk, having high‐performance characteristics have been important materials in biopolymer research. This article reports the development of a silk‐like extensible poly(α,L‐amino acid) fiber inspired by self‐assembly of polypeptides in living systems. Electrostatic interaction was employed as the driving force for building the fiber, and we succeeded in spinning the fiber from an aqueous solution interface between poly(α,L‐lysine) (PLL) and poly(α,L‐glutamic acid) (PLG). When the PLL/PLG fiber was formed, the conformations of PLL and PLG were changed from random to β‐structures. A remarkable feature of the PLL/PLG fiber is the high extensibility. Mechanical stretching of the PLL/PLG fiber resulted in a change from an extensible fiber to a rigid and strong fiber. These features depend on the molecular conformation and the deviation in the amino acid composition of the PLL/PLG fibers. This concept and the poly(α,L‐amino acid) fibers themselves allow the production of new protein fibers and aid the development of the science of protein folding as well as giving insight into the noncovalent interactions involved in self‐assembly.

SEM micrograph showing that the surface of the stretched fiber is smooth.

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SEM micrograph showing that the surface of the stretched fiber is smooth.
Lipschitz estimates for generalized commutators of fractional integrals with rough kernel
Authors: Lu Shanzhen , Zhang Pu
Published: April 2003

Let $ T ^{A} _{\Omega, \alpha} $ (0 < α < n) be the generalized commutator generated by fractional integral with rough kernel and the m–th order remainder of the Taylor formula of a function A. In this paper, the (Lp, Lr) (r > 1) boundedness, the weak (L1, Ln/(n–α–β)) boundedness and the (Lp, Ḟβ, ∞p) boundedness of $ T ^{A} _{\Omega, \alpha} $ are discussed, when DγA belongs to the Lipschitz function spaces.
Synthesis, Characterization, and AC Impedance Properties of a Novel Ion‐Conducting Polymer
Authors: Pietschnig Rudolf , Langkau Tatjana , Neuser Rolf , Hipler Frank , Hambrock Julia , Schäfer Sven
Published: April 2003

This paper describes the preparation and characterization of a novel ion‐conducting polymeric material (2). The backbone consists of alternating alkenylidene and sulfanylidene units with adjacent hydroxy groups. Fitting of the experimental impedance data of 2 in a Bode plot reveals a conductivity of 6.6 × 10−2 S · cm−1 and a capacitance of 2.2 × 10−5 F at room temperature. The deuterated derivative of 2 shows significantly lower conductivity, suggesting that the conductivity of 2 can be attributed to proton migration.

Bode plot of fresh 2; experimental vs simulated; equivalent circuit (R(RQ)).

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Bode plot of fresh 2; experimental vs simulated; equivalent circuit (R(RQ)).
Synthesis and Characterization of Long‐Chain‐Branched Polyolefins with Metallocene Catalysts: Copolymerization of Ethylene with Poly(ethylene‐co‐propylene) Macromonomer
Authors: Kolodka Edward , Wang Wen‐Jun , Zhu Shiping , Hamielec Archie
Published: April 2003

Poly(ethylene‐co‐propylene) macromonomer (EPM) was synthesized in a high‐temperature continuous stirred tank reactor (CSTR) with [C5Me4(SiMe2NtBu)]TiMe2 (CGC‐Ti) as the catalyst system. PE samples with EPM long chain branching (LCB) were produced by semi‐batch copolymerization of ethylene and EPM with CGC‐Ti. The LCB frequencies were up to 21.8 EPM side chains per PE backbone. The effects of temperature and ethylene pressure on the degree of EPM grafting and catalyst activity were examined.

Incorporation of EPM into a growing PE chain forming an LCB polymer.

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Incorporation of EPM into a growing PE chain forming an LCB polymer.
Synthesis and Characterization of α,ω‐Heterofunctional Poly(ethylene oxide) Macromonomers
Authors: Yilmaz Faruk , Cianga Ioan , Ito Koichi , Senyo Takamichi , Yagci Yusuf
Published: April 2003

A novel α,ω‐heterofunctional poly(ethylene oxide) (PEO) macromonomer possessing methacryloyl and thienyl end groups was prepared by ring‐opening polymerization of ethylene oxide initiated by potassium thienylethoxide and termination of the living PEO ends with methacryloyl chloride. Incorporation of methacryloyl and thienyl groups was confirmed by free‐radical and oxidative polymerization processes, respectively, and by means of 1H NMR analysis.

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The formation of metal clusters in solution and on biopolymers investigated by first‐principles molecular dynamics
Authors: Colombi Ciacchi L. , De Vita A. , Seidel R. , Mertig M. , Pompe W.
Published: April 2003

We investigate the molecular mechanisms of platinum cluster nucleation and growth in solution and on biopolymers by means of first‐principles molecular dynamics. In contrast with a classical picture where clusters nucleate by aggregation of metallic Pt(0) atoms, we find that Pt–Pt bonds can form between dissolved Pt(II) complexes already after a single reduction step. Furthermore, we observe that small clusters grow by addition of unreduced PtCl2(H2O)2complexes, consistently with an autocatalytic growth mechanism. Moreover Pt(II) ions covalently bound to biopolymers are found to act as preferred nucleation sites for the formation of clusters. This is a consequence of the strong donor character of the organic ligands which induce the formation of stronger metal‐metal bonds than those obtained in solution. In fact, in metallization experiments we obtain a clean and purely heterogeneous metallization of single DNA molecules leading to thin and uniform Pt cluster chains extended over several microns.
ℋ︁‐matrices for the convection‐diffusion equation
Authors: Le Borne S.
Published: April 2003

Hierarchical matrices (ℋ︁‐matrices) provide a technique for the sparse approximation of large, fully populated matrices. This technique has been shown to be applicable to stiffness matrices arising in boundary element method applications where the kernel function displays certain smoothness properties. The error estimates for an approximation of the kernel function by a separable function can be carried over directly to error estimates for an approximation of the stiffness matrix by an ℋ︁‐matrix, using a certain standard partitioning and admissibility condition for matrix blocks. Similarly, ℋ︁‐matrix techniques can be applied in the finite element context where it is the inverse of the stiffness matrix that is fully populated. Here one needs a separable approximation of Green's function of the underlying boundary value problem in order to prove approximability by matrix blocks of low rank. Unfortunately, Green's function for the convection‐diffusion equation does not satisfy the required smoothness properties, hence prohibiting a straightforward generalization of the separable approximation through Taylor polynomials. We will use Green's function to motivate a modification in the (hierarchical) partitioning of the index set and as a consequence the resulting hierarchy of block partitionings as well as the admissibility condition. We will illustrate the effect of the proposed modifications by numerical results.
A short overview of ℋ︁2‐matrices
Authors: Börm Steffen , Hackbusch Wolfgang
Published: April 2003

ℋ︁2‐matrices are a refined version of hierarchical matrices, which in turn are based on the panel‐clustering approach for approximating certain integral operators. Their main advantage, as compared with their predecessors, is that the associated algorithms are of significantly lower complexity while providing the same order of accuracy. Under certain conditions, it is even possible to reach optimal complexity.
ADOL‐C: Automatic Differentiation Using Operator Overloading in C++
Authors: Walther Andrea , Griewank Andreas , Vogel Olaf
Published: April 2003

In this paper, we present two strategies for the implementation of Automatic Differentiation (AD) based on the operator overloading facility in C++. Subsequently, we describe the capabilities of the AD‐tool ADOL‐C that applies operator overloading to differentiate C‐ and C++‐code. Finally, we discuss some applications of ADOL‐C.
Automatic Balancing of the Unsymmetrical Rigid Rotor
Authors: Ryzhik B. , Duckstein H. , Sperling L.
Published: April 2003

The paper is devoted to the investigation of an automatic balancing device for rigid rotors. It presents some new results concerning automatic balancing, namely the effect of partial unbalance compensation and reduction of vibrations in the region after the first critical speed.
Stabilitätsanalyse einer Scheibenbremse bei periodischer Parametererregung
Authors: Schmalfuss C. , Wedig W. , Ams A.
Published: April 2003

Ein mechanisches Modell mit vier Freiheitsgraden beschreibt die Scheibenbremse eines Personenkraftwagens. Nach Herleitung der Bewegungsdifferentialgleichnungen wird eine Stabilitätsanalyse bei periodischer Parametererregung (Floquet–Theorie) durchgeführt. Umfangreiche Parametervariationen zeigen den Einfluß einzelner Parameter bezüglich des Stabilitätsverhaltens des Systems.
Regen‐Wind‐induzierte Schwingungen ‐ Ursache und Beschreibung
Authors: Seidel C. , Dinkler D.
Published: April 2003

1986 entdeckte Y. Hikiami [1] an der Meikonishi Brücke in Japan ein Schwingungsphänomen, das bei gleichzeitigem Auftreten von Regen und Wind an geneigten Kabeln bzw. Hängern entstehen kann. Hierbei sind die beobachteten Schwingungen durch große Amplituden und hohe Frequenzen charakterisiert. Das Phänomen ließ sich seitdem an vielen anderen Brücken weltweit nachweisen.