bluuebunny/crossref_metadata_2025 huggingface dataset:
Pyrophosphate:fructose 6-phosphate 1-phosphotransferase is involved in the mobilization of sugar reserves in the taproots of cold- and drought-stressed carrot plants
Authors: Kovács G. , Sorvari S. , Scott P. , Toldi O.
Published: April 2007

The purpose of this work was to further investigate the regulatory interplay between pyrophosphate:fructose 6-phosphate 1-phosphotransferase (PFP) and its positive effector, fructose 2,6-bisphosphate (Fru-2,6-P2), in the storage organs of cold- and drought-stressed plants. Since there is no detectable cytoplasmic fructose-1,6-bisphosphatase (cytFBPase) activity in the taproots of carrot plants, PFP is the only enzyme that can replace its function when stored starch is converted to transportable sucrose. The working hypothesis was that PFP is likely to be involved in the mobilisation of energy reserves and might have a special role in storage organs such as carrot taproots upon stress. Both cold and drought stress resulted in a marked increase in the endogenous Fru-2,6-P2levels. It is suggested that the significant changes in photosynthate allocation are the direct results of the stimulation of PFP activity by elevated Fru-2,6-P2levels. PFP stimulated by Fru-2,6-P2operated in the gluconeogenic direction in the taproots of stressed carrot plants, whereas the glycolytic direction was dominant in the non-stressed controls. This suggests that the metabolic status determining the net activity of PFP depends on the physiological stress situation, making PFP an important sensor of environmental changes. The experimental data indicated that PFP is involved in the mobilisation of energy reserves during unfavourable environmental changes by promoting the re-synthesis of transportable sucrose in taproots.
Physiological Stress Responses to Automated and Hand Vaccine Injection Procedures in Yearling Coho Salmon
Authors: Sharpe Cameron S
Published: April 2007

Juvenile coho salmon Oncorhynchus kisutch were subjected to automated and hand injection procedures, and their cortisol response to the procedures and a secondary stress challenge (1-h confinement) was compared. Both the hand and automated procedures elicited a variable but significant stress response and, after 1 h, decreased the ability of the fish to respond to the second challenge. After 24 h, hand-injected fish had elevated cortisol levels (83 ± 6.3 ng/mL [mean ± SE]) relative to the automatically injected (40 ± 6.3 ng/mL) and control fish (25 ± 4.9 ng/mL). Also, the hand-injected fish produced 28 ± 5.1 ng cortisol/mL in response to the stress challenge after 24 h, while the automatically injected and control fish produced two to three times as much. The elevated cortisol levels in the stress response and lack of a cortisol response to the stress challenge at 24 h indicate that the hand injection procedure had a protracted negative effect and suggest that the automatic injection system is a superior method for administering injections to juvenile salmonids.
Design and Testing of a Closed, Stirring Respirometer for Measuring Oxygen Consumption of Channel Catfish Eggs
Authors: Torrans Eugene L
Published: April 2007

A closed, stirring respirometer was designed to agitate small egg mass samples of channel catfish Ictalurus punctatus while measuring oxygen consumption by the eggs. Egg mass samples ranging in size from 15 to 46 g were placed on a screen platform above a magnetic stir bar in the respirometer; the degree of agitation was controlled with a magnetic stir plate. Dissolved oxygen (DO) concentration and temperature were measured with a luminescent DO sensor and meter. The respirometer was used to determine routine metabolic rate and limiting oxygen concentration (the presumed hypometabolic transition zone) on egg mass samples from 10 different spawns at 0 to 5 d postfertilization. Routine metabolic rate increased from 4.8 ± 1.3 (0 d postfertilization) to 174.0 ± 7.8 mg O2·kg−1·h−1 (5 d postfertilization). The limiting oxygen concentration increased similarly up to 87.0% ± 2.7% (maximum individual value = 95.9%) air saturation by 5 d postfertilization. The respirometer described could not be used for sac fry, but it proved effective with clumped channel catfish eggs. Preliminary channel catfish hatchery management recommendations are to maintain DO concentrations in hatchery troughs at air saturation at least during the last day of egg development.
ANALYSIS OF FACTORS THAT AFFECT RESPONDING IN A TWO‐RESPONSE CHAIN IN CHILDREN WITH DEVELOPMENTAL DISABILITIES
Authors: Kuhn Stephanie A. Contrucci , Lerman Dorothea C. , Vorndran Christina M. , Addison Laura
Published: April 2007

A sequence of behaviors consisting of appropriate responses, inappropriate responses, or a combination of both can be linked together in a behavior chain. Several operant processes may disrupt behavior chains. For example, one or more members of the behavior chain may be affected when reinforcement is withheld for the last response in the chain (extinction), when the last response is reinforced even if it occurs without the other responses in the chain (unchaining), or when access to the terminal reinforcer is available independent of responding (satiation). However, few studies have examined the effects of these types of procedures on responding that occurs in the context of behavior chains. The purpose of this study was to examine the effects of three clinically relevant procedures and processes (i.e., extinction, satiation, and unchaining) on behaviors that occur as part of a behavior chain. Overall, extinction and satiation resulted in a decrease in both responses in the chain. During the unchaining procedure, decreases were observed in the first response in the chain but not in the second response.
A PARADOXICAL EFFECT OF PRESESSION ATTENTION ON STEREOTYPY: ANTECEDENT ATTENTION AS AN ESTABLISHING, NOT AN ABOLISHING, OPERATION
Authors: Roantree Christina F. , Kennedy Craig H.
Published: April 2007

Previous studies have shown that presession attention for problem behavior can serve as an abolishing operation when attention functions as a positive reinforcer. In the current study, we show that the stereotypy of a child with severe disabilities was undifferentiated during standard analogue functional analysis conditions. However, when noncontingent presession attention was provided, stereotypy occurred for social attention as a positive reinforcer, suggesting that the antecedent manipulation functioned as an establishing operation.
Gingival Involvement of Oral Lichen Planus
Authors: Camacho‐Alonso Fabio , López‐Jornet Pía , Bermejo‐Fenoll Ambrosio
Published: April 2007

Background: Oral lichen planus (OLP) is one of the most common oral mucosa disorders. OLP gingival involvement is very frequently observed and is characterized by a wide range of clinical appearance, symptomatology, and locations. The purpose of this study was to analyze the prevalence and clinical aspects of gingival lesions in a series of 213 patients affected by OLP.

Methods: We analyzed the prevalence and clinical aspects (location, morphology, and symptomatology) of the gingival lesions in a total of 213 clinically and histopathologically assessed patients affected by OLP.

Results: Gingival lesions were diagnosed in 38.4% of cases. White lesions were the most frequently observed in the gingiva (42.7%), followed by mixed lesions (31.7%), and red lesions (25.6%). For the three clinical forms, the most frequent gingival location was the simultaneous involvement of the attached and marginal gingiva. None of the white lesions presented symptomatology, whereas most red lesions or mixed forms presented symptoms that varied from discomfort to severe oral pain or a burning sensation.

Conclusions: Considering the high frequency of gingival involvement in OLP, the diversity of clinical manifestations, and its potential relationship with general and oral health in patients, periodontists should be familiar with the most common clinical aspects of OLP in the gingiva.
PAHs and Trace Elements in PM2.5 at the Venice Lagoon
Authors: Gambaro Andrea , Manodori Laura , Toscano Giuseppa , Contini Daniele , Donateo Antonio , Belosi Franco , Prodi Franco , Cescon Paolo
Published: April 2007

The results of an experimental analysis carried out to investigate PM2.5 concentration levels and the content of polycyclic aromatic hydrocarbons, as well as inorganic trace elements in the atmospheric particles are presented. Measurements were taken with a micrometeorological station equipped with an optical PM2.5 detector, and simultaneously, particles were collected on filters for subsequent chemical analyses. The average value of daily PM2.5 concentration is 21.5 ug/m3 and real‐time measurements indicate that the average concentration during the day (8 am to 8 pm) is about 25 % lower than the nocturnal average. Short‐time averages of PM2.5 decrease when the wind speed increases as consequence of the more efficient mixing. Meteorological measurements indicate the presence of a local daily (breeze) circulation with wind blowing from the Alps or the Adriatic Sea and, during this circulation, larger concentrations were observed, with wind coming from the Alps. Days of high PM2.5 concentration with dominant anthropic or with prevalent crustal contributions were identified.

Regarding trace metals, their average concentrations are comparable to those found in others urban areas, except for Cd (3 ng m‐3), probably due to the presence of glass‐works in Murano. The highest concentrations are observed for K (99 ng m‐3) and Na (73 ng m‐3), which are the main constituents of marine spray, while the lowest concentrations are observed for elements such as Cs and Co (respectively 0.01 and 0.02 ng m‐3). Also the concentrations of PAH are comparable with those of other industrial areas, as their sum ranges from 0.16 ng m‐3 to 3.73 ng m‐3, but if considered as B(a)P toxicity equivalent, they are largely lower (0.036±0.026 ng m‐3). From the analyses of discriminating ratios, it has been found that the main origin of PAH in PM2.5 samples may be petrogenic, probably related to the presence of refinery and petrochemical plants on the mainland, although the contribution of combustion processes cannot be excluded.
GC/MS Analysis of Pesticides in the Ferrara Area (Italy) Surface Water: A Chemometric Study.
Authors: Pasti Luisa , Nava Elisabetta , Morelli Marco , Bignami Silvia , Dondi Francesco
Published: April 2007

The development of a network to monitor surface waters is a critical element in the assessment, restoration and protection of water quality. In this study, concentrations of 42 pesticides – determined by GC‐MS on samples from 11 points along the Ferrara area rivers – have been analyzed by chemometric tools. The data were collected over a three‐year period (2002‐2004). Principal component analysis of the detected pesticides was carried out in order to define the best spatial locations for the sampling points. The results obtained have been interpreted in view of agricultural land use. Time series data regarding pesticide contents in surface waters has been analyzed using the Autocorrelation function. This chemometric tool allows for seasonal trends and makes it possible to optimize sampling frequency in order to detect the effective maximum pesticide content.
Synthesis, characterization and properties of novel polyamides containing ferrocene unit and flexible spacers
Authors: Mehdipour‐Ataei Shahram , Babanzadeh Samal
Published: April 2007

Synthesis and characterization of ferrocene‐containing main‐chain polyamides are reported in this article. A new, interesting type of organometallic monomer (FDADO) based on ferrocene was prepared by interfacial condensation of 1,1′‐dichlorocarbonyl ferrocene with 2 mol 1,8‐diamino‐3,6‐dioxaoctane (DADO). A series of ferrocene‐based polyamides was prepared via polycondensation of the ferrocenyl diamine (FDADO) with different diacid chlorides using two different methods. The monomer and polymers were characterized by elemental analysis, infrared and NMR spectroscopy. The thermal stability and behavior of the synthesized polymers were evaluated by thermal gravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), and differential scanning calorimetry (DSC). The crystallinity of polymers was examined by X‐ray diffraction analysis. Inherent viscosity, solubility and flame‐retardancy of the polymers were also studied. The obtained polymers showed good heat‐resistance and flame‐retardancy, and improved solubility vs generally reported polyamides in some common organic solvents. Copyright © 2007 John Wiley & Sons, Ltd.
Morphology, nonisothermal crystallization behavior, and kinetics of poly(phenylene sulfide)/polycarbonate blend
Authors: Wu Defeng , Zhang Yisheng , Zhang Ming , Wu Lanfeng
Published: April 2007

The morphology and nonisothermal crystallization behavior of blends made of poly(phenylene sulfide) (PPS), with a amorphous polycarbonate (PC) were studied. The blend is found to be partially miscible by the dynamic mechanical thermal analysis (DMTA) and melt rheological measurements. The nonisothermal crystallization behavior of blend was studied by differential scanning calorimetry (DSC). The results show clearly that the crystallization temperatures of PPS component in the blend decrease with increasing of PC contents. The crystallization kinetics was then analyzed by Avrami, Jeziorny, and Ozawa methods. It can be concluded that the addition of PC decreases the PPS overall crystallization rate because of the higher viscosity of PC and/or partial miscibility of blend, despite of small heterogeneous nucleation effect by the PC phase and/or phase interface. The results of the activation energy obtained by Kissinger method further confirm that the amorphous PC in the partial miscible PPS/PC blend may act as a crystallization inhibitor of PPS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis and characterization of poly(ϵ‐caprolactone)‐b‐poly(ethylene glycol) block copolymers prepared by a salicylaldimine‐aluminum complex
Authors: Du Zi‐Xiu , Xu Jun‐Ting , Yang Yong , Fan Zhi‐Qiang
Published: April 2007

A series of poly(ϵ‐caprolactone)‐b‐poly(ethylene glycol) (PCL‐b‐PEG) block copolymers with different molecular weights were synthesized with a salicylaldimine‐aluminum complex in the presence of monomethoxy poly(ethylene glycol). The block copolymers were characterized by 1H NMR, GPC, WAXD, and DSC. The 1H NMR and GPC results verify the block structure and narrow molecular weight distribution of the block copolymers. WAXD and DSC results show that crystallization behavior of the block copolymers varies with the composition. When the PCL block is extremely short, only the PEG block is crystallizable. With further increase in the length of the PCL block, both blocks can crystallize. The PCL crystallizes prior to the PEG block and has a stronger suppression effect on crystallization of the PEG block, while the PEG block only exerts a relatively weak adverse effect on crystallization of the PCL block. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis of boron‐containing coupling agents and its effect on the interfacial bonding of fluoropolymer/TATB composite
Authors: Li Fan , Ye Lin , Nie Fude , Liu Yonggang
Published: April 2007

The four kinds of boron‐containing coupling agents were synthesized, which were applied to improve the interfacial bonding of fluoropolymer/1,3,5‐triamino‐2,4,6‐trinitrobenze (TATB) composite. The boron atom of the coupling agent molecule can form coordinate bond with the fluorine atom of fluoropolymer; and hydrogen atom in its amino group can form hydrogen bond with oxygen atom in nitro‐group of TATB. The interfacial performance of the composite was investigated by the measurement of contact angle, surface and interface tension, and adhesive work, and the interfacial bonding mechanism was studied by FTIR and XPS analysis. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Mechanical property investigation of single polymer particles with the variation of molecular structure of crosslinking monomer
Authors: Ok Kim Dong , Hee Jin Jeong
Published: April 2007

The effects of the swelling ratio (S/R), the existence of methyl side groups, the length and molecular structure of backbone chain of crosslinking monomer on the variation of mechanical properties of single polymer particle were investigated. For the study, monodisperse polymer particles were prepared via one‐step seeded polymerization using PMMA as seed particles and 1,n‐alkanediol di(meth)acrylate or (ethylene glycol)n di(meth)acrylate as crosslinking monomer. Recovery rate, K‐values, breaking strength, and breaking displacement were measured as mechanical properties and they were performed by using microcompression test. The following observations were made: (1) only breaking strength was closely related to the swelling ratio; (2) the existence of methyl side groups increased the K‐values but decreased the recovery rate of the polymer particles; and (3) K‐values were the most sensitive to the variation of backbone chain length of crosslinking monomer, and they were decreased with the increase of the backbone chain length of crosslinking monomer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Performance of the light emitting diodes versus conventional light sources in the UV light cured formulations
Authors: Anyaogu Kelechi C. , Ermoshkin Andrey A. , Neckers Douglas C. , Mejiritski Alex , Grinevich Oleg , Fedorov Andrei V.
Published: April 2007

UV light emitting diodes (LED) are compared with conventional light sources for curing acrylate formulations. Both polymerization rates and the properties of the resulting coatings were examined. UV LEDs are acceptable alternatives to conventional light sources for a variety of applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
How wild is the ocean? Assessing the intensity of anthropogenic marine activities in British Columbia, Canada
Authors: Ban Natalie , Alder Jackie
Published: April 2007

The intensity of marine activities in the exclusive economic zone (EEZ) of British Columbia, Canada, was quantified.

Humans use the ocean for a multitude of purposes, many of which have a direct impact on marine life and habitat. Yet such uses are seldom assessed in an integrated fashion.

Using a GIS approach, spatial information for 39 marine activities was mapped, including commercial and recreational fishing areas, transportation and infrastructure uses, and terrestrial activities along the coast of British Columbia.

A relative scale was used to rank both the impact of marine activities and the extent of stressors beyond the location of occurrence. Limited information on the latter led to the application of three ranges of buffer distances to the data (0–1 km, 0–5 km, and 0–25 km).

The most conservative estimate (⩽1 km buffers) indicates at least 83% of the continental shelf and slope of British Columbia is currently being used by humans. The largest buffer assumption shows 98% of the continental shelf and slope being affected by stressors from anthropogenic activities.

This analysis provides a baseline for assessing future changes in the state of British Columbia's marine environment, and could assist in identifying areas of conservation potential.

Copyright © 2007 John Wiley & Sons, Ltd.
Mg2Ru2Cl10O×16H2O.
Authors: Boufas Sihem , Merazig Hocine , Bendjeddou Lamia , Denes Georges , Beghidja Adel , Moliterni Anna Grazia
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Construction of Highly Substituted Stereodefined Dienes by Cross‐Coupling of α‐Allenic Acetates.
Authors: Schneekloth John S. Jr. , Pucheault Mathieu , Crews Craig M.
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Benzoxazolyl‐ and Benzothiazolylguanidines in Three‐Component Reactions.
Authors: Krylsky A. V. , Potapov A. Yu. , Krysin M. Yu. , Trefilova I. N. , Shikhaliev Kh. S.
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Aza‐Mannich Condensation of Sulfinimine Promoted by Tetrabutylammonium Fluoride: Synthesis of α,β‐Unsaturated Sulfinimine.
Authors: Bian Xiaoxia , Zhang Dan , Huang Zhiyan , Qin Yong
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
1,5‐Remote Stereocontrol Using Allylgermanes.
Authors: Castreno Pilar , Thomas Eric J. , Weston Anna P.
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Intramolecular Sulfur Transfer in N‐Enoyl Oxazolidine‐2‐thiones Promoted by Broensted Acids. Practical Asymmetric Synthesis of β‐Mercapto Carboxylic Acids and Mechanistic Insights.
Authors: Palomo Claudio , Oiarbide Mikel , Lopez Rosa , Gonzalez Pedro B. , Gomez‐Bengoa Enrique , Saa Jose M. , Linden Anthony
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Intramolecular [4 + 2] Cycloaddition of Furfurylsubstituted Homoallylamines to Allylhalides, Acryloyl Chloride and Maleic Anhydride.
Authors: Varlamov Alexey V. , Boltukhina Ekaterina V. , Zubkov Fedor I. , Nikitina Eugenia V. , Turchin Konstantin F.
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Ir‐Catalyzed Functionalization of 2‐Substituted Indoles at the 7‐Position: Nitrogen‐Directed Aromatic Borylation.
Authors: Paul Sulagna , Chotana Ghayoor A. , Holmes Daniel , Reichle Rebecca C. , Maleczka Robert E. Jr. , Smith Milton R. III
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
1,2‐Glycerol Carbonate: A Versatile Renewable Synthon.
Authors: Simao Ana‐Catarina , Lynikaite‐Pukleviciene Benita , Rousseau Cyril , Tatibouet Arnaud , Cassel Stephanie , Sackus Algirdas , Rauter Amelia P. , Rollin Patrick
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of 4‐Aminopyrido[3,2‐b]indole Derivatives.
Authors: Ryabova S. Yu. , Alekseeva L. M. , Lisitsa E. A. , Granik V. G.
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Lewis Acid Promoted Rearrangements of 1,3‐Dioxolanyl‐Substituted 1,2‐Oxazines into Novel Products with 1,3,6‐Trioxa‐7‐azacyclopenta[cd]indene Skeletons.
Authors: Pfrengle Fabian , Al‐Harrasi Ahmed , Reissig Hans‐Ulrich
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
C‐Alkyl 5‐Membered Ring Imino Sugars as New Potent Cytotoxic Glucosylceramide Synthase Inhibitors.
Authors: Faugeroux Vanessa , Genisson Yves , Andrieu‐Abadie Nathalie , Colie Sandra , Levade Thierry , Baltas Michel
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Proline Organocatalysis as a New Tool for the Asymmetric Synthesis of Ulosonic Acid Precursors.
Authors: Enders Dieter , Gasperi Tecla
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Oligonucleotide Analogues with Integrated Bases and Backbone. Part 13. Synthesis and Association of Ethynylene‐Linked Self‐Complementary Dimers.
Authors: Zhang Xiaomin , Bernet Bruno , Vasella Andrea
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Aromatic Compounds Produced by Periconia atropurpurea, an Endophytic Fungus Associated with Xylopia aromatica.
Authors: Teles Helder Lopes , Sordi Renata , Silva Geraldo Humberto , Castro‐Gamboa Ian , Bolzani Vanderlan da Silva , Pfenning Ludwig Heinrich , Magalhaes de Abreu Lucas , Costa‐Neto Claudio Miguel , Young Maria Claudia Marx , Araujo Angela Regina
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Perfluoroketene Dithioacetals: Versatile Building Blocks Toward Trifluoromethyl Heterocycles
Authors: Portella Charles , Bouillon Jean‐Philippe
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
β‐Fluoro Alcohols
Authors: Haufe G.
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Chemistry and Synthesis of Highly Oxygenated Alkaloids from Amaryllidaceae: Lycoricidine, Narciclasine, Pancratistatin, and Analogues
Authors: Chapleur Y. , Chretien F. , Ahmed S. Ibn , Khaldi M.
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
3‐(4′‐Geranyloxy‐3′‐methoxyphenyl)‐2‐trans‐propenoic Acid: A Novel Promising Cancer Chemopreventive Agent
Authors: Curini Massimo , Epifano Francesco , Genovese Salvatore , Marcotullio Maria Carla , Menghini Luigi
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Natural Products with Taxol‐like Antitumor Activity — Synthetic Approaches to the Sarcodictyins and Eleutherobin
Authors: Gennari Cesare
Published: April 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Urzeitliches Enzym im Auge
Authors: Groß Michael
Published: April 2007

Ein urzeitliches Enzym, dessen Funktion bei allen höheren Lebewesen von einer anderen Enzymfamilie übernommen wurde, hat in Säugetieren dennoch überlebt: als Strukturprotein in der Augenlinse.
Diffraction effects between foundations due to incident rayleigh waves
Authors: Triantafyllidis Th. , Neidhart Th.
Published: April 2007

The dynamic behaviour of a finite number of rigid, adjacent foundations on the surface of a linear‐elastic, isotropic and homogeneous halfspace due to a far‐field excitation of the Rayleigh type is the subject of the present work. The dynamic behaviour of this system differs from that of a single foundation subjected to the same excitation due to the existence of the natural coupling between adjacent foundations caused by the wave propagation through the underlying soil. For the determination of the diffraction forces acting on the foundations an analytical procedure is followed. The stresses at the interfaces between the foundations and subsoil are approximated by series expansions of orthogonal polynomials. It is interesting to notice that, apart from the loads appearing in the direction of incidence, additional loads perpendicular to the given incidence direction act on the foundations due to scattered waves. Their intensity depends on the excitation frequency and the distance between the foundations. The method followed here can be applied for the determination of the dynamic loads acting on fixed foundations in the case of a seismic excitation of relatively long duration.
Non‐linear earthquake response of concrete gravity dams part 1: Modelling
Authors: El‐Aidi Bahaa , Hall John F.
Published: April 2007

A finite element procedure to model the non‐linear earthquake response of concrete gravity dam systems is presented. A two‐dimensional idealization is adopted for the dam and water in order to simplify the analysis and reduce the computational effort. The foundation of the dam is modelled as a rigid rectangular massless plate attached to a three‐dimensional viscoelastic half‐space. The non‐linear behaviour is represented by smearing techniques and includes tensile cracking with subsequent opening, closing and sliding, as well as water cavitation in the reservoir. Special treatments are applied to suppress spurious oscillations in the water response associated with cavitation and to prevent cracks in the dam from spreading into wide zones. Experience from non‐linear analyses is cited as it affects the design of the algorithm.
Dependence of fourier spectrum amplitudes of recorded earthquake accelerations on magnitude, local soil conditions and on depth of sediments
Authors: Trifunac M. D.
Published: April 2007

New empirical scaling equations of Fourier amplitude spectra of strong earthquake shaking are presented for the site characterization in terms of local geologic and local soil conditions simultaneously. It is shown that using only the local soil site classification may lead to biased results, and it is suggested that both soil and geologic conditions should be used together in estimation of the site specific spectrum amplitudes.
Free‐field response from inclined body waves in a viscoelastic random medium
Authors: Hryniewicz Z. , Hermans A. J.
Published: April 2007

This paper deals with the free‐field response of the in‐plane motion resulting from a combination of inclined incident body waves. The amplification of waves in a viscoelastic layer with stochastic changes in the elastic properties and density is investigated. The method used is that of Karal and Keller and is based on the idea of the fundamental matrix. The third order correlations are neglected. The resulting integro‐differential equations for the average displacements are solved by the Laplace transform. Generally, analysis indicates that the stochastic changes in the shear modulus and density enhance the damping in a significant manner. However, increases in the waves' amplification can arise in the case of a small dimensionless frequency and uncorrelated stochastic changes of material parameters.
Modal analysis of vibrating viscoplastic composite beams on multiple supports
Authors: Fotiu P. , Irschik H.
Published: April 2007

A vibration analysis for viscoplastic, shear deformable composite beams is presented, where non‐linear strains consistently are treated as an additional loading of the linear elastic structure due to fictitious sources of eigenstresses. Therefore, linear solution methods such as mode superposition and Green's functions become applicable, and a fast, computer‐oriented solution strategy is developed. The non‐linear structural response is found as the sum of the corresponding linear elastic response and the solution due to the additional loading by the inelastic strains, where the sources of eigenstresses are calculated from the material's law in a time‐stepping procedure. The method is demonstrated using a composite sandwich beam with thin surface layers on multiple supports, which are excited independently. Elastoplastic material behaviour of endochronic type as well as a viscoplastic material's law are considered simultaneously.
A simple non‐linear model for the investigation of the effects of the gap closure at the abutment joints of short bridges
Authors: Maragakis Emmanuel A. , Thornton Greg , Saiidi Mehdi , Siddharthan Raj
Published: April 2007

Closure of the gap at the abutment joints of bridges has been the source of extensive damage during the 1971 San Fernando and more recent earthquakes. In this paper a model for the investigation of the effects of this gap closure is presented and analysed. The focus of the model is the representation of the non‐linear response of the bridge abutments, the foundation and the columns. The model is used for the investigation of the response of a short bridge located in California.
Reduction of vibration by control forces
Authors: Warburton G. B.
Published: April 2007

The concept of reducing vibrations in steady‐state problems by introducing appropriately chosen additional or control forces, which have the same frequency and phase as the original excitation forces, has been the subject of some recent papers. In this paper the normal mode method is used to determine the magnitudes of the control forces. This method is simpler in concept than earlier approaches. It is demonstrated that with a single control force resonant response of multi‐degree‐of‐freedom systems can be reduced substantially, particularly for the fundamental resonance in lightly and moderately damped systems.
Study of the earthquake response of the base‐isolated Law and Justice Center in Rancho Cucamonga
Authors: Papageorgiou Apostolos S. , Lin Bing‐Chang
Published: April 2007

The recorded earthquake response of a base‐isolated building—the Foothill Communities Law and Justice Center in Rancho Cucamonga—shaken by the 1985 Redlands earthquake (ML 4–8) is discussed and analysed by employing system identification techniques. The calculated response of one‐dimensional and three‐dimensional linear structural models is fitted to the recorded motions of the superstructure using the ‘modal minimization method’ for structural identification, in order to determine optimal estimates of the parameters of the dominant modes of the building. Simple one‐dimensional analyses are used to identify also the effective values of key parameters (e.g. damping) of the isolation system. Furthermore, the recorded motions obtained from the densely instrumented foundation (i.e. below the isolation bearings) of the structure and from the free‐field station located 330 ft

1 ft =0.3048 m; 1 mile=1.609 km.

from the building show how the presence of the structure affects the incoming seismic waves. It is observed that the transverse component of motion (i.e. the component which is perpendicular to the long dimension of the plan of the building) is affected by the presence of the structure considerably more than the longitudinal component. Factors contributing to this effect are the extreme length of the structure (414 ft) and the rotational motions of the superstructure caused by the spatial variability of ground motion. It is pointed out that, despite the fact that the shift in the effective frequency of the structure induced by the isolation was very small, the elastomeric bearings were very effective in reducing the accelerations transmitted to the structure. This is attributed to the damping capacity of the isolation. Based on the observed response of the building to this small earthquake it can be stated with confidence that the structure performed according to expectations.
A comparative study of performances of various base isolation systems, part II: Sensitivity analysis
Authors: Su Lin , Ahmadi Goodarz , Tadjbakhsh Iradj G.
Published: April 2007

A series of numerical experiments on the performance of different base isolation systems for a non‐uniform shear beam structure is carried out. Several base isolation systems are considered and the peak relative displacements and the maximum absolute accelerations of the base‐isolated structure and its base raft under a variety of conditions are evaluated. Several sensitivity analyses for variations in properties of the base isolator and the structure are carried out. A number of different earthquake excitations are also used in the study. The results show that performances of the base isolation systems are not sensitive to small variations in their natural period, damping or friction coefficient. The presence of a frictional element in the isolators reduces their sensitivity to severe variations in frequency content and amplitude of the ground acceleration. In particular, the resilient‐friction base isolators with or without sliding upper plate perform reasonably well under a variety of loading conditions. The rubber bearing type, however, leads to the lowest peak transmitted accelerations for moderate intensity earthquakes.
A fundamental solution due to a periodic point force in the interior of an elastic half‐space
Authors: Banerjee P. K. , Mamoon S. M.
Published: April 2007

The fundamental solution for a periodic point force in the interior of a three‐dimensional, homogeneous, isotropic, elastic half‐space is derived. The method of synthesis and superposition is employed to obtain the solution in the Laplace transform as well as the frequency domain. These correspond to the dynamic equivalent of Mindlin's static half‐space point force solutions. It is reduced, for certain limiting conditions, to the dynamic equivalent of Boussinesq's and Cerruti's problems of a normal and tangential periodic point force respectively, on the boundary of a half‐space. Also, static solutions of Mindlin, Boussinesq and Cerruti are recovered for small frequency parameters. Finally, results are presented and compared with other available solutions.
Sliders and tension controlled reinforced elastomeric bearings combined for earthquake isolation
Authors: Chalhoub Michel S. , Kelly James M.
Published: April 2007

Essential requirements from a base isolation system include wind restraint, stability and fail‐safe capacity. A new base isolation system that satisfies all three requirements and possesses other advantages was tested on the earthquake simulator at the University of California under the base of a one‐fourth scale nine storey steel structure. The base behaves as fixed for low magnitude inputs. When sliding starts the rubber bearings provide additional stiffness and recentering. Displacements are better controlled than the ones for a purely elastomeric isolation system. Vertical deflections due to large horizontal drift encountered in solely rubber systems are eliminated. The fail safe capacity is provided by tension restrainers installed inside the rubber bearings, and by the constant contact of the base with the sliders. Base shear hysteresis loops are drastically enlarged by the presence of the sliders.
Three‐dimensional boundary element reservoir model for seismic analysis of arch and gravity dams
Authors: Jablonski A. M. , Humar J. L.
Published: April 2007

The boundary element method has been successfully applied in the past to the analysis of hydrodynamic forces in two‐dimensional infinite as well as two‐ and three‐dimensional finite reservoirs subjected to seismic ground motions. This paper presents the results of more recent research on the application of the constant boundary element method to the 3D analysis of reservoir vibration. Special boundary conditions, previously used in the 2D case, to treat infinite radiation damping and damping from foundation soil and banks have been incorporated in this formulation. Numerical results for vibration of a 3D infinite rectangular reservoir as well as of a 3D infinite reservoir impounded by an arch dam are presented and compared with some existing results obtained by other researchers.
Floor response spectra for base‐isolated multi‐storey structures
Authors: Fan Fa‐Gung , Ahmadi Goodarz
Published: April 2007

A study of floor response spectra for a base‐isolated multi‐storey structure under sinusoidal and seismic ground excitations is carried out. Several base isolation systems including the laminated rubber bearing, the pure‐friction, the resilient‐friction, the Électricité de France and the sliding resilient‐friction systems are considered. A sinusoidal ground acceleration and several earthquake accelerograms (including those of El Centro 1940, Pacoima Dam 1971 and Mexico City 1985) are used to evaluate the floor response spectra. The characteristics of the spectra generated by different base isolation systems are studied, and the results are compared with those for the fixed‐base structure. It is shown that the structural contents can be protected against earthquakes by the use of properly designed base isolation systems. In particular, the laminated rubber bearing system appears to be remarkably effective in protecting the secondary systems under a variety of conditions.
System parameters of soil foundations for time domain dynamic analysis
Authors: Jean Wen‐Yu , Lin Tsung‐Wu , Penzien Joseph
Published: April 2007

Soil‐structure interaction analysis is usually carried out in the frequency domain, because the compliance functions of the half‐space are known only in the frequency domain. Since non‐linear analysis cannot be carried out in the frequency domain, a system with frequency independent parameters is used to represent the half‐space soil medium so that a nonlinear analysis in the time domain becomes possible. The objective of this paper is to propose a system with lumped parameters, which are independent of frequency, to represent the half‐space soil medium. The proposed frequency independent system consists of a number of real discrete structure elements; thus the existing dynamic analysis programs may be adoptable with little modification.

In this paper, the parameters are found by minimizing the sum of the squares of deviations between the steady‐state responses of the theoretical half‐space model and those of the lumped parameter system over a specified frequency range. Once the parameters have been found, the lumped parameter system can be used in practical applications for time domain dynamic analysis of either linear or non‐linear structures. In comparison with the dynamic response of the theoretical half‐space model, the lumped parameter system yields satisfactory results.
Vibration of linear structures due to jump‐discontinuous, non‐interrupted, stochastic processes
Authors: Mironowicz W. , Śniady P.
Published: April 2007

The solution of the problem of vibration of linearly elastic structures, caused by stochastic excitation of non‐interrupted, jump‐discontinuous character, is considered in the paper. Two types of excitation are examined. They form an enhancement of the continuous model which is most often used. The solution in the form of expected values, correlation functions and spectral densities of the deflection of the structure is formulated. Examples illustrating the solution are presented.
Stochastic response of rigid foundations
Authors: Pais Artur Luna , Kausel Eduardo
Published: April 2007

While the study of kinematic interaction (i.e. the dynamic response of massless foundations to seismic loads) calls, in general, for advanced analytical and numerical techniques, an excellent approximation was proposed recently by Iguchi.1,2 This approximation was used by the authors to analyse embedded foundations subjected to spatially random SH‐wave fields, i.e. motions that exhibit some degree of incoherence. The wave fields considered ranged from perfectly coherent motions (resulting from seismic waves arriving from a single direction) to chaotic motions, resulting from waves arriving simultaneously from all directions. Additional parameters considered were the shape of the foundation (cylindrical or rectangular) and the degree of embedment. It was found that kinematic interaction usually reduces the severity of the motions transmitted to the structure, and that incoherent motions do not exhibit the frequency selectivity (i.e. narrow valleys in the foundation response spectra) that coherent motions do.
On the accuracy of an implicit algorithm for pseudodynamic tests
Authors: Shing Pui‐Shum B. , Manivannan T.
Published: April 2007

The error‐propagation characteristics of an implicit time integration algorithm in pseudodynamic testing are examined. It is shown that the implicit algorithm is superior to explicit integration algorithms in terms of experimental error amplification. The influence of systematic experimental errors is studied and methods for controlling these errors are examined. In spite of the fact that the implicit algorithm is unconditionally stable, it is shown that the integration time interval in a pseudodynamic test is limited by the calibration range of the electronic hardware as well as the degree of participation of the higher modes. Furthermore, the tolerance for experimental errors decreases as the integration time interval increases.
Dynamic response of single‐span beam bridges to a series of moving loads
Authors: Klasztorny Marian , Langer Jan
Published: April 2007

The paper makes a contribution to the problem of a stream of loads crossing a single‐span beam bridge. There are considered the basic load models, in the form of a stream of fixed amplitude forces, unsprung masses and viscoelastic oscillators. The matrix equations of motion of the system are formulated and discussed. The problem of dynamic stability and steady‐state response of a bridge carrying a periodic stream of inertial loads is formulated and solved. The paper also includes a vibration study of a beam bridge subjected to a uniform stream of moving loads, of a limited or unlimited number of load cycles.
Influence of intensity of motion on the seismic response of structures with asymmetric force‐deformation curves
Authors: Ruiz Sonia E.
Published: April 2007

Asymmetrically yielding single‐degree‐of‐freedom elastoplastic systems are subjected to simulated accelerograms based on El Centro‐NS, 1940 ground motion (wide frequency band) to calculate the corresponding ductility demands. Results are compared with those corresponding to simulated accelerograms of the SCT‐EW, 1985 Mexico earthquake (narrow frequency band) obtained in a previous work. Results obtained reveal that the characteristics of the excitation influence the response of asymmetrically yielding structures and that the differences found on responses corresponding to both earthquakes are due to frequency content, duration and/or intensity of motion. The effect of the latter concepts is studied using modulating sinusoidal excitations as well as accelerograms recorded on soft and hard soils of Mexico City.

Two alternate expressions are proposed to evaluate the increase in ductility demands of structures with asymmetric force‐displacement curves with respect to symmetric ones. Those expressions take into account motion intensity and duration, as well as seismic design coefficient.