bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elastic earthquake analysis of torsionally coupled multistorey buildings
Authors: Kan Christopher L. , Chopra Anil K. 
Published: March 2007

AbstractWith the aid of perturbation analysis of vibration frequencies and mode shapes it is shown that any lower vibration mode of a torsionally coupled building may be approximated as a linear combination of three vibration modes of the corresponding torsionally uncoupled system (a system with coincident centres of mass and resistance but all other properties are identical to the actual system): one translational mode along each of the two principal axes of resistance and one mode in torsional vibration. This result provides the motivation for a simpler—relative to the standard—procedure for analysing the response of torsionally coupled multistorey buildings to earthquake ground motion. To illustrate the application and accuracy of this procedure two numerical examples are presented.
A new look at the newmark, houbolt and other time stepping formulas. A weighted residual approach
Authors: Zienkiewicz O. C. 
Published: March 2007

AbstractThe Newmark time stepping algorithm which was introduced in 1959, using constants γ and β which average the integration process, can be rederived as the most general finite element‐weighted residual algorithm involving three consecutive sets of displacements. This derivation is much simpler than that involved originally in the New‐mark presentation, and indicates a very wide range of possibilities of approximation. The application of the process to four point (cubic) algorithms leads to another family of formulas of which the Houbolt algorithm is a particular case.The use of the generalized expressions in the context of first‐order equations is indicated and shows how some new, as well as some of the old, formulas can be developed.
Aseismic design implications of near‐fault san fernando earthquake records
Authors: Bertero Vitelmo V. , Mahin Stephen A. , Herrera Ricardo A. 
Published: March 2007

AbstractNear‐fault records of the 1971 San Fernando earthquake contain severe, long duration acceleration pulses which result in unusually large ground velocity increments. A review of these records along with the results of available theoretical studies of near‐fault ground motions indicates that such acceleration pulses may be characteristic of near‐fault sites in general.The results of an analytical study of a building severely damaged during the San Fernando earthquake indicate that such severe, long duration acceleration pulses were the cause of the main features of the observed structural damage. The implications of such pulses on current aseismic design methods, particularly those used to establish design earthquakes, are examined for buildings located near potential earthquake faults. Analytical studies of the non‐linear dynamic response of single and multiple degree‐of‐freedom systems to several near‐fault records, as well as to a more standard accelerogram, indicate that at near‐fault sites: (a) very large displacement ductilities may result for current levels of code design forces; (b) smoothed elastic design response spectra should reflect the larger ground velocities that may occur; and (c) peak inelastic response cannot reliably be inferred from elastic response predictions.
Mechanical and microstructural properties of hybrid poly(ethylene glycol)–soy protein hydrogels for wound dressing applications
Authors: Snyders Rony , Shingel Kirill I. , Zabeida Oleg , Roberge Christophe , Faure Marie‐Pierre , Martinu Ludvik , Klemberg‐Sapieha Jolanta E. 
Published: March 2007

AbstractBiomimetic hydrogel made of poly(ethylene glycol) and soy protein with a water content of 96% has been developed for moist wound dressing applications. In this study, such hybrid hydrogels were investigated by both tensile and unconfined compression measurements in order to understand the relationships between structural parameters of the network, its mechanical properties and protein absorptionin vitro. Elastic moduli were found to vary from 1 to 17 kPa depending on the composition, while the Poisson's ratio (≈0.18) and deformation at break (≈300%) showed no dependence on this parameter. Further calculations yielded the crosslinking concentration, the average molecular weight between crosslinks (MC) and the mesh size. The results show that reactions between PEG and protein create polymeric chains comprising molecules of PEG and protein fragments between crosslinks.MCis three times higher than that expected for a “theoretical network.” On the basis of this data, we propose a model for the 3D network of the hydrogel, which is found to be useful for understanding drug release properties and biomedical potential of the studied material. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Detection of salivary α‐amylase and lysozyme exposed on the pellicle formed in situ on different materials
Authors: Hannig Christian , Huber Karin , Lambrichts Ivo , Gräser Jan , D'Haen Jan , Hannig Matthias 
Published: March 2007

AbstractAmylase and lysozyme are components of the salivary pellicle, exposing considerable enzymatic activity in the immobilized state. The purpose of the present study was to elucidate the influence of different solid substrata on the amount and distribution of amylase and lysozyme exposed on the surface of the salivary pellicle formed in situ. Slabs of titanium, feldspar ceramic, and bovine enamel were fixed on the buccal sites of individual splints worn by three subjects for 3 or 30 min, respectively, to allow pellicle formation. Subsequently, slabs were removed from the splints and rinsed with running water. Detection of amylase and lysozyme was performed by FEI‐SEM after gold‐immunolabeling of the enzymes. Both enzymes were found to be distributed randomly at the pellicle surface. Irrespective of formation time and substratum, significantly more labeled lysozyme molecules (5.23 ± 4.5 μm−2) were detected compared with amylase (3.4 ± 2.9 μm−2). Neither the substratum nor the pellicle formation time had significant impact on the amount of the respective enzyme that could be detected. This study for the first time provides evidence, that amylase and lysozyme are exposed at the surface of the salivary pellicle formed in situ on titanium and ceramics. Both enzymes are distributed randomly on the surface of the pellicle, irrespective of the underlying substratum. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res 2007
Preliminary study of frontal lobe 1H MR spectroscopy in childhood‐onset schizophrenia
Authors: Thomas M. Albert , Ke Yong , Levitt Jennifer , Caplan Rochelle , Curran John , Asarnow Robert , McCracken James 
Published: March 2007

AbstractCerebral 1H MR spectra were recorded in 13 children and adolescents with schizophrenia and 12 healthy children and adolescents. Stimulated echo acquisition mode (STEAM) sequence was used to localize an 8‐ml voxel bilaterally in the frontal gray matter. The frontal gray matter metabolite ratios for NAA/Cr, Ch/Cr, Gix/Cr, and mI/Cr in schizophrenic children and adolescents were 1.08 ± .28, .64 ± .23, 1.09 ± .30, and .60 ± .24, respectively. In comparison, these ratios were 1.59 ± .35, .74 ± .27, 1.23 ± .36, and .58 ± .29 in healthy children and adolescents. Decrease in the frontal lobe NAA/Cr of schizophrenic children and adolescents was statistically significant (P < .001). In contrast, the MR spectra localized bilaterally in the occipital gray matter (8 ml) showed no significant changes between the patients and the controls. In the occipital gray matter, the metabolite ratios were 1.21 ± .26, .52 ± .08, 1.00 ± .11, and .55 ± .12 in patients versus 1.30 ± .23, .45 ± .10, 1.15 ± .20, and .48 ± .19 in controls. Our preliminary finding of reduced NAA/Cr ratio in the frontal gray matter is consistent with the neurodevelopmental models emphasizing dysfunction of frontal lobe areas in patients with schizophrenia.
Optimal dose of hepatobiliary contrast agent for MR cholangiography: Experimental study in rats
Authors: Hirohashi Shinji , Hirohashi Rina , Uchida Hideo , Kitano Satoru , Akira Megumi , Ono Wataru , Ohishi Hajime , Kato Naoki , Takahashi Masaya , Miyazawa Tomoaki 
Published: March 2007

AbstractThe purpose of this study is to clarify the optimal dose of gadolinium‐ethoxybenzyl‐diethylenetriaminepentaacetic acid (Gd‐EOB‐DTPA) for cholangiography in conventional T1‐weighted imaging. We divided 30 rats into three dose groups (3, 10, and 30 μmol/kg). For the in vitro study, we collected bile and measured the concentration of gadolinium in bile after Gd‐EOB‐DTPA injection. T1‐weighted images of the collected bile were obtained for measurement of signal intensity. For the in vivo study, we obtained T1‐weighted images before and after injection and evaluated bile duct/liver contrast by the signal intensity ratio and visual assessment of the images. The gadolinium concentration had an early peak; however, the signal intensity of the bile had a later peak because of the high gadolinium concentration during the early phase, which induced a T2‐shortening effect. Optimal bile duct/liver contrast was obtained in the 10‐μmol/kg groups at all time points. We conclude that the optimal dose of Gd‐EOB‐DTPA for MR cholangiography in rats is 10 μmol/kg, one‐third of the dose used in liver imaging.
Impact of climate variability on Alpine glaciers in northwestern Italy
Authors: Calmanti Sandro , Motta Luigi , Turco Marco , Provenzale Antonello 
Published: March 2007

AbstractWe analyzed glacier snout fluctuation data in Piedmont and Val d'Aosta (Italy) and studied the impact of climate variability on valley glaciers in the western Italian Alps. The study period covered about 70 years in the 20th century; we focused on the last 50 years where a large number of temperature and precipitation time series are available. Superposed onto a general recession trend, we detected strong oscillations on shorter time scales and we showed that they are significantly correlated with fluctuations in winter precipitation rates and average summer temperatures. On the basis of these results, we constructed a simple lagged‐linear empirical stochastic model that explained upto 66% of the variance of the snout fluctuation data. The model produces reliable out‐of‐sample predictions of the impact of climate variability on the glaciers of the western Alps and it can be used to estimate the average response of Alpine glaciers to different scenarios of climate change, provided the morphology of the individual glaciers does not change completely. Copyright © 2007 Royal Meteorological Society
Predictors of quality of life in old age: A cross‐validation study
Authors: Low Gail , Molzahn Anita E. 
Published: March 2007

AbstractA replication study was undertaken to validate a model of quality of life (QOL) generated in an earlier study on a random sample of 202 older adults. Pathways found to be significant were retested using QOL data from a convenience sample of 420 older adults. Using path analysis, we found that financial resources, health, and meaning in life directly and positively influenced QOL. Health, emotional support, and the physical environment indirectly affected QOL through purpose in life. All but one pathway were replicated, explaining 50.5% of the variance in QOL. Further explorations of the influence of spirituality, emotionally close ties, and opportunities for active engagement on QOL in older age are warranted. © 2007 Wiley Periodicals, Inc. Res Nurs Health 30: 141–150, 2007
Prenatal diagnosis of complete atrioventricular septal defect with truncus arteriosus
Authors: Chintala Kavitha , Gurczynski Jody , Aggarwal Sanjeev 
Published: March 2007

AbstractTruncus arteriosus (TA) is a rare cardiac anomaly constituting less than 1% of all congenital heart defects. Its association with complete atrioventricular septal defect (AVSD) is extremely unusual and only 12 cases diagnosed postnatally or postmortem have been reported so far. We describe the first case of truncus arteriosus with AVSD to be diagnosed prenatally by fetal echocardiography. Copyright © 2007 John Wiley & Sons, Ltd.
Development of a polyester‐rubber adhesive
Authors: Mather J. 
Published: March 2007

AbstractThe historical development of the polyester‐rubber adhesive Pexul is described. This substance can be used in single‐ or two‐stage dipping in conjunction with a resorcinol‐formaldehyde latex for the adhesion of polyester cords to rubber.The most effective formulation is a molecule consisting of two molecules of resorcinol linked to a central p‐chlorophenol molecule by means of formaldehyde (methylene links), but the commercial product contains many related compounds.Its mode of action is postulated to be (a) adhesion of the substance to the surface of the polyester as a result of good matching of the cohesive energy densities and hydrogen bonding between the polyester oxygen atoms and the phenolic hydroxyls; and (b) thermal polycondensation of the surface film to give a strongly adherent crosslinked film which simultaneously or subsequently reacts with RF‐latex to form a complete system capable of bonding to rubber.The determination of Pexul on dipped cords by chlorine analysis and by the use of trace metals and X‐ray fluorescence is described.
Hydration of a hydrophobic cavity and its functional role: A simulation study of human interleukin‐1β
Authors: Somani Sandeep , Chng Choon‐Peng , Verma Chandra S. 
Published: March 2007

AbstractMolecular dynamics simulations reveal that the hydrophobic cavity in human cytokine Interleukin‐1β is hydrated and can dynamically accommodate between one and four water molecules. These waters have residence times >> 500 ps and can give rise to detectable NOEs, in agreement with NMR observations of Ernst et al. (Science 1995; 267:1813–1817). The waters also display high positional disorder within the cavity, which explains why they have not been resolved crystallographically. The average distribution of water molecules over time within the cavity matches well the low resolution electron density extracted by Yu et al. (Proc Natl Acad Sci 1999; 96:103–108). The water molecules hydrate the hydrophobic cavity preferentially as complex clusters. These clusters result from a combination of hydrogen bonds between the waters and stabilizing interactions between the waters and aromatic rings forming the cavity. Free energy estimates suggest that it takes 4‐waters to hydrate the cavity in a thermodynamically stable manner leading to a gain in free energy of transfer from bulk of ∼∼3.6 kcal/mol. This arises from the existence of the water clusters in multiple hydrogen bonded states. In addition, the waters are found to migrate either individually or as clusters out of the cavity through several pathways. The upper limit for one‐dimensional diffusion of the waters within the protein matrix is 4 Å/ps (relative to 6 Å/ps for bulk). Simulations reveal pathways in addition to those identified crystallographically, with motions controlled by the rotations of sidechains. We find that only when the hydrophobic cavity is hydrated, do correlated motions couple distant sites with the sites that make contact with the receptor and this data partly offers an explanation of experimental mutagenesis data. Simulations, together with recent observations based on mutagenesis by Heidary et al. (J Mol Biol 2005; 353:1187–1198) that hydrogen bond networks couple motions across long distances in interleukin‐1 β, lead us to hypothesize that the hydration of the cavity (conserved across mammals) can thermodynamically enhance hydrogen bond networks to enable coupling across long distances by acting as a plug and this in turn enables a kinetic control of the rate of transmission of signals. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Strategies for managing a portfolio of alliances
Authors: Hoffmann Werner H. 
Published: March 2007

AbstractInterorganizational relationships are recognized as an increasingly important source of competitive advantage. Hence, goal‐oriented management of the alliance portfolio—all the alliances of the focal firm—plays a decisive role in company performance. Consequently, the configuration and development of the alliance portfolio become important strategic issues. In light of that, this article develops theoretical propositions that seek to clarify what determines the configuration and evolution of an alliance portfolio, and then presents the results of a longitudinal study to illustrate the developed theoretical framework. Building on contingency theory and a coevolutionary framework, we were able to identify three distinctive types of portfolio strategies at business level and to illustrate how they interact with the development of the business strategy and the business environment. Encompassing all this, the study illustrates and explains developmental paths and patterns in the evolution of an alliance portfolio. The developmental course typically evolves from adapting to shaping and to exploiting (stabilizing), according to the state of strategic uncertainty and the firm's resource endowment. A sudden increase in exogenous strategic uncertainty, however, can lead to a strategic shift back to an exploration or hybrid strategy. Copyright © 2007 John Wiley & Sons, Ltd.
Dietary linoleic, α‐linolenic and oleic acids are oxidized at similar rates in rats fed a diet containing these acids in equal proportions
Authors: Jones Peter J. H. 
Published: March 2007

AbstractThe objective of this study was to examine whether whole body oxidation rates of dietary linoleic, α‐linolenic and oleic acids differ when the acids are provided in identical quantities. Male rats were fed for 10 wk a 15% fat (w/w) diet containing equal amounts of linoleic, α‐linolenic and oleic acids (22.7, 23.0 and 23.2% of total fatty acids, respectively). At week 10, after overnight fasting, rats were intragastrically administered 20 μCi of either [1‐14C]‐labelled linoleic, α‐linolenic or oleic acid in a 200‐μL bolus of oil containing equal quantities of each fatty acid. The appearance of14CO2 in expired air was then monitored hourly for 12h for each animal. A preliminary study had shown that growth and food consumption patterns in animals consuming the oil containing equal quantities of each of the fatty acids paralleled the patterns of animals that were self‐selecting among separate diets, each of which contained one of the component oils. The appearance of14C, expressed as percent dose administered, peaked at 2–3 h post‐dose for14C‐labelled linoleic (5.28±0.37%/h), α‐linolenic (6.92±0.51%/h) and oleic (5.98±0.44%/h) acids. Statistically these values were not significantly different. Cumulative14CO2 excretion rates over 12 h were also similar for linoleic (27.2±0.9%), α‐linolenic (26.8±1.2%) and oleic (25.9±1.2%) acids. The results suggest that the rat's capacity to oxidize 18‐carbon unsaturated fatty acids is not affected by fatty acid unsaturation when these fatty acids are provided at equal dietary levels.
The distribution of brominated long‐chain fatty acids in sponge and symbiont cell types from the tropical marine spongeAmphimedon terpenensis
Authors: Garson Mary J. , Zimmermann Mary P. , Battershill Christopher N. , Holden Janet L. , Murphy Peter T. 
Published: March 2007

AbstractThe tropical marine spongeAmphimedon terpenensis (family Niphatidae, order Haplosclerida) has previously been shown to possess unusual lipids, including unusual fatty acids. The biosynthetic origin of these fatty acids is of interest as the sponge supports a significant population of eubacterial and cyanobacterial symbionts. The total fatty acid composition of the sponge was analyzed by gas chromatography/mass spectrometry of the methyl esters. Among the most abundant of the fatty acids in intact tissue were 16∶0, 18∶0 and 3,7,11,15‐tetramethylhexadecanoic (phytanic) acid. In addition, three brominated fatty acids, (5E,9Z)‐6‐bromo‐5,9‐tetracosadienoic acid (24∶2Br), (5E,9Z)‐6‐bromo‐5,9‐pentacosadienoic acid (25∶2Br) and (5E,9Z)‐6‐bromo‐5,9‐hexacosadienoic acid (26∶2Br) were also present. The three brominated fatty acids, together with phytanic acid, were isolated from both ectosomoal (superficial) and choanosomal (internal) regions of the sponge. Analysis of extracts prepared from sponge/symbiont cells, partitioned by density gradient centrifugation on Ficoll, indicated that phytanic acid and the three brominated fatty acids were associated with sponge cells only. Further, a fatty acid methyl ester sample from intact tissue ofA. terpenensis was partitioned according to phospholipid class, and the brominated fatty acids were shown to be associated with the phosphatidylserine and phosphatidylethanolamine fractions that are commonly present in marine sponge lipids. The phosphatidylcholine and phosphatidylglycerol fractions were rich in the relatively shorter chain fatty acids (16∶0 and 18∶0). The association of brominated long‐chain fatty acids (LCFA) with sponge cells has been confirmed. The findings allow comment on the use of fatty acid profiles in chemotaxonomy and permit further interpretation of LCFA biosynthetic pathways in sponges. The assignment of the sponge studied, which is currently placed asA. terpenensis, is being supported to some extent, but the species is unusual in having C25 fatty acids as the major constituent in this group. Other factors, such as season or microenvironmental conditions, may influence observed fatty acid composition which tends to reduce the usefulness of fatty acid profiles as markers in sponge chemotaxonomy.
The hydrolysis of soap solutions. III. Values of pH and the absence of fatty acid as free liquid or solid
Authors: McBain James W. , Laurent P. , John Lucille M. 
Published: March 2007

SummaryThe pH of the laurates, myristates, palmitates, and stearates of sodium and potassium at 25° and 50°C. was determined by use of a glass electrode. pH:concentration curves were constructed, and hydroxyl ion activity was calculated. In general, the concentration of hydroxyl ion ranges from 0.001 to 0.0001 N; for the less dilute solutions of the higher soaps, the upper limit is exceeded by several fold, and in the more dilute solutions the concentration may fall beneath the lower value. Solubilized hexane reduced the pH of potassium and sodium laurate but very slightly. Potassium or sodium chloride reduced the pH of soap solutions over a certain range but caused a slight increase in a narrow intermediate range.Using the pH values obtained, the actual concentration of fatty acid in the soap solutions was calculated, and was found to beless than the saturation concentrations obtained by conductivity measurements through the entire range investigated. Free fatty acid therefore never separates as such from pure soap solutions unless acted upon by excess of acid such as carbon dioxide.Percentage hydrolysis was calculated and curves were constructed. In general, the potassium soaps are hydrolyzed more than the corresponding sodium soaps; the difference is slight for the laurates but is considerably greater for the myristates, palmitates, and stearates in higher concentrations at 25°C. The difference is appreciably smaller at 50° than at 25°. Percentage hydrolysis for the laurates is very much less than for the higher soaps.
Some results on the Hochschild cohomology of group algebras
Authors: Pourabbas A. 
Published: March 2007

In this paper we investigate structure of the second cohomology of a discrete group

G
G

. First, for a

G
G

-set

S
S

we show that an isomorphism of vector spaces from

H

n

(

ℓ
1

(
G
)
,

ℓ
∞

(
S
)
)

\mathcal {H}^n(\ell ^1(G),\ell ^\infty (S))

onto

⨁

i
∈
I

∞

H

n

(

ℓ
1

(
G
)
,

ℓ
∞

(

C

)
)

\bigoplus _{i\in I}^\infty \mathcal {H}^n(\ell ^1(G),\ell ^\infty (\mathbb {C}))

exists, where

{

C

i

}

i
∈
I

\{\mathcal {C}_{i}\}_{i\in I}

is the set of orbits of

S
S

. Next we define the notion of pseudoderivation and apply it for the calculation of

H

b
,
2

2

(

ℓ
1

(
G
)
,

ℓ
∞

(
S
)
)

\mathcal {H}_{b,2}^2(\ell ^1(G),\ell ^\infty (S))

.