bluuebunny/crossref_metadata_2025 huggingface dataset:
Coupled lateral‐torsional behaviour of frame structures under earthquake loading
Authors: Maheri M. R. , Chandler A. M. , Bassett R. H.
Published: April 2007

A series of parametrically defined experimental model structures has been tested under earthquake base loading using the SERC national U.K. earthquake simulator. The models have been designed with variable ratios of torsional to lateral stiffness, and with both symmetric and asymmetric mass distributions. This paper first describes the tests carried out to determine the basic dynamic model properties and the establishment of idealized analytical models which give accurate predictions of model behaviour under steady‐state loading and free‐vibration conditions. Secondly, a detailed discussion is made of the two highly coupled structural models having uncoupled torsional to lateral frequency ratio Rf = 1.2, commenting on the ability of the modal analysis procedures to predict accurately the maximum recorded responses. It is concluded that the theory underestimates the significance of the fundamental torsional mode of vibration in the combined structural response, and overestimates the contribution of the first lateral mode. These effects compensate each other on the side of the structure which is most severely affected by torsional response, but produce large inaccuracies on the side of the building which is commonly assumed to be affected beneficially by torsional coupling.
Evaluation of factors influencing the inelastic seismic performance of torsionally asymmetric buildings
Authors: Chandler A. M. , Duan X. N.
Published: April 2007

This paper addresses some fundamentally contradictory conclusions drawn by Tso and Ying1 and the authors2 regarding the additional seismic ductility demand in asymmetric building structures and the adequacy of certain code torsional provisions. It also clarifies a number of issues arising from the different approaches employed in the two studies. The Mexico 76 and 87 code torsional provisions are taken as examples. Results show that the structural element at the stiff edge is the more critical and that the Mexico 76 code torsional provisions (among others) are inadequate, substantially underestimating the strength demand of this element. On the other hand, the Mexico 87 code torsional provisions are found to be over‐conservative. Recommendations are also given for improving the form and effectiveness of these code torsional provisions.
Analytical prediction of the collapse earthquake for R/C buildings: Case studies
Authors: Kappos Andreas J.
Published: April 2007

An analytical methodology for estimating the values of behaviour factors (q‐factors), suggested in a companion paper, is applied to two typical reinforced concrete structures, a frame and a dual system, designed according to current European trends in seismic design. The two case studies clearly indicated the need to consider both local and overall collapse criteria, since either one can be critical for the determination of the behaviour factor, depending on the type of the structure. The calculated values of q‐factors were close to, but higher than those specified by modern seismic codes, the larger discrepancy occurring in the case of the dual system.
A modal superposition pseudo‐force method for dynamic analysis of structural systems with non‐proportional damping
Authors: Claret A. M. , Venancio‐Filho F.
Published: April 2007

A modal superposition pseudo‐force method for the dynamic analysis of structural systems with non‐proportional damping is presented. The method combines the advantages of the classical modal superposition method and the pseudo‐force method. When the system damping is non‐proportional, the dynamic equilibrium equations in generalized coordinates are coupled through the damping terms. In the present method, these coupled equations are solved by an iterative process in which the coupling terms are treated as pseudo‐forces. A proof of the convergence of the iterative process is given. Numerical examples show the good convergence characteristics of the process and the good accuracy of the obtained results.
Shear hysteretic elasto‐plastic earthquake response of soil systems
Authors: Elgamal Ahmed‐W.
Published: April 2007

An analytical/numerical procedure is developed to calculate the shear hysteretic elasto‐plastic earthquake response of soil systems. Dynamic level ground response as well as earth‐dam response is evaluated on the basis of the analytical one‐dimensional (ID) shear‐beam and shear‐wedge models respectively. Soil is modelled as an elasto‐plastic hysteretic material following the principles of flow or incremental plasticity. Stiffness and strength degradation of this material may be specified as a function of accumulated plastic strain and associated pore‐pressure build‐up. The entire numerical procedure may be executed on a personal computer and consequently qualifies as a versatile tool in conducting preliminary design calculations or parametric‐type investigations. Using this procedure, the responses of the Mexico City SCT site during the September 19, 1985 earthquake, and the California Wildlife site during the November 24, 1987 earthquake are computed and compared to those actually observed.
Damage costs for houses and farms as a function of intensity in the 1987 edgecumbe earthquake
Authors: Dowrick David J.
Published: April 2007

This paper describes an analysis of damage costs to house and farm property in the Ms = 6.6 Edgecumbe, New Zealand earthquake of 2 March 1987. The study investigated damage ratios for dwellings, their contents and domestic motor vehicles. The damage costs were converted to damage ratios by dividing them by the total value of the relevant property in the intensity zones concerned. The mean values and statistical distributions of these damage ratios were then found, the lognormal distribution fitting very well.

The mean damage ratio for house buildings at MM intensity IX was 0.080 and the mean damage ratios were generally smaller than previous studies had shown. The mean damage ratios were similar for buildings and contents from MM6 to MM9, but there was no correlation between building and contents damage on an individual basis.
An improved response spectrum method for calculating seismic design response. Part 1: Classically damped structures
Authors: Singh M. P. , Maldonado G. O.
Published: April 2007

A good response spectrum method, used for calculating the seismic design response for design inputs defined in terms of response spectra, should be able to include the effect of the higher modes, even though they may be truncated and not explicitly considered in the analysis. It should also be able to include the intercorrelation of the retained modes as well as their correlation with truncated modes. Herein one such method based on a suitable combination of the mode displacement and mode acceleration formulations of structural dynamics is proposed. Several numerical examples are presented to demonstrate the efficiency of the proposed approach vis‐a‐vis some other commonly used response spectrum approaches.
Impact interactions between two vibration systems under random excitation
Authors: Jing Hung‐Sying , Young Mindhu
Published: April 2007

The exact stationary solutions of the random response of two special vibration systems with impact interactions are formulated in this paper. Between the two systems, the Hertz contact law is used to model the contact process during vibration. A clearance is also introduced. The excitation is assumed to be a stationary white Gaussian process with zero mean and acting on the two systems independently. By assuming the ratio of the excitation and damping parameter of each system to be the same, the exact solutions can be found through solving the time‐independent Fokker‐Planck equation. The effects of contact stiffness, clearance and the system properties on the response are discussed probabilistically. From this study, it is found that, under some cases, the contact phenomena still play an important role on the response even when the clearance is larger than three times the root mean square response of the corresponding linear systems.
Combined dynamic response of primary and multiply connected cascaded secondary subsystems
Authors: Falsone G. , Muscolino G. , Ricciardi G.
Published: April 2007

A method is proposed for the deterministic and stochastic non‐stationary analysis of linear composite systems with cascaded secondary subsystems subjected to a seismic input. This method makes it possible to evaluate, by means of a unitary formulation, the deterministic and non‐stationary stochastic response of both classically and non‐classically damped subsystems and of secondary subsystems multiply supported on the primary one, as well as the ground. The proposed procedure is very efficient from a computational point of view, because of the Kronecker algebra systematically employed. Indeed, by using this algebra, it is possible to obtain in a very compact and elegant form the eigenproperties of the composite system as a function of the eigenproperties of the two subsystems taken separately. Moreover, it is possible to write the first order differential equations governing the evolution of the second order moments of the response and to solve them in a simple way.
Response of multiply supported rigid plate to spatially correlated seismic excitations
Authors: Hao Hong
Published: April 2007

The ground motions produced by an earthquake at the multiple support points of large structures can differ considerably. In this study, the quasi‐static, the dynamic and the total structural responses of a multiply supported rigid plate to spatially varying multiple ground motion inputs are analysed. The results, together with those obtained by neglecting ground motion phase shifts and those by neglecting ground motion coherency losses, are compared with the corresponding structural responses to a single input. The comparisons show that the single input method overestimates translational responses and underestimates rotational responses. They also show that the responses are sometimes overestimated and sometimes underestimated by neglecting the coherency loss effects between the multiple ground motion excitations.
Time‐harmonic boussinesq problem for a continuously non‐homogeneous soil
Authors: Vrettos Christos
Published: April 2007

An analytical solution is presented for the response of a non‐homogeneous, compressible, elastic half‐space to a time‐harmonic vertical point load on its surface. The shear modulus is assumed to increase continuously with depth. The model is chosen so as to describe uniformly deposited cohesionless soils. Expressions for displacements and stresses in the interior of the half‐space medium are derived by means of Hankel transforms and contour integration. Selected numerical results are presented to demonstrate the influence of non‐homogeneity. Finally, some effects are pointed out to be used in connection with vibration tests for subsoil investigation.
Dynamic response of surface foundations on layered media
Authors: Swaddiwudhipong S. , Chow Y. K. , Tan S. C. , Phoon K. F.
Published: April 2007

The steady‐state dynamic responses of both flexible and rigid massless foundations with complex geometries on layered media are studied by the finite layer method. The discussion covers both the horizontal and vertical responses including the rocking mode of vibration. The effect of various parameters, namely, the size of the domain, the number of harmonic terms and the material damping of the soil media, on the convergence and accuracy of the results is investigated. Non‐homogeneous soil profiles are treated as a matter of course. The results obtained are compared with solutions by other theoretical methods.
Vibration of surface foundations of arbitrary shapes
Authors: Liou Gin‐Show
Published: April 2007

Presented is a systematic procedure for generating impedance (or compliance) matrices for foundations with arbitrary shapes, resting on an elastic half‐space medium. A technique to decompose prescribed harmonic tractions on the half‐space medium is employed to solve analytically the differential wave equations in cylindrical coordinates. However, the interaction stresses due to the vibration of a foundation with arbitrary shape are described in rectangular coordinates, and assumed to be piecewise constant in the region of the arbitrary shape. A coordinate transformation matrix is introduced for the piecewise constant tractions in order to use the solution of the differential wave equations in cylindrical coordinates. Finite element modelling is assumed in rectangular coordinates for the foundation itself. The impedance matrix is then obtained for the finite element model, using a variational principle and the reciprocal theorem. A simple example of a rigid square plate resting on a half‐space medium and subjected to vertical excitation is used to demonstrate the efficiency and effectiveness of the procedure. Some numerical aspects are investigated and some possible extensions of the procedure are also discussed.
The influence of preform on the modes of vibrating beams
Authors: Kelly James M. , Sackman Jerome L. , Javid Ahmad
Published: April 2007

A theoretical analysis is presented of a vibratory system in which it is possible to eliminate an unwanted mode of vibration by using that mode as an initial deformation of the system. The analysis shows that this is possible in straight beams with end restraints in axial deformation. The mathematical problem leads to an eigenvalue problem of a type not normally encountered.

In the paper examples are given for the changes in eigenfrequency and mode shape produced by the initial preformed shape of the beam for cases where the preform is proportional to a mode of the straight beam and when the preform is unrelated to any mode.

The analysis shows that, while elimination of a mode in the strict sense is not achieved, the results can be interpreted for practical purposes in this way.
Investigation of a Ni(Mg,Fe)O Cathode for Molten Carbonate Fuel Cell Applications
Authors: Randström S. , Lagergren C. , Scaccia S.
Published: April 2007

The Molten Carbonate Fuel Cell (MCFC) converts chemical energy into electrical energy and heat. Since the working temperature is high, less expensive materials can be used compared to low temperature fuel cells. However, the components of the fuel cell still need to be improved. The dissolution of the NiO cathode has, for a long time, been a problem for the Molten Carbonate Fuel Cell (MCFC) and this area is still the focus for MCFC component research. In this study, solubility measurements for a NiO cathode material doped with magnesium and iron are carried out and the electrochemical performance of this cathode material is tested under the standard conditions of the MCFC over 2,000 hours and compared with the performance of a standard NiO cathode. After operation, nickel precipitation in the matrices is investigated. It is concluded that a NiO cathode with magnesium and iron could be a viable candidate material for the MCFC.
Increased Metal Utilization in Carbon‐Supported Pt Catalysts by Adsorption of Preformed Pt Nanoparticles on Colloidal Silica
Authors: Zeng J. , Lee J. Y. , Chen J. , Shen P. K. , Song S.
Published: April 2007

Pt/C electrocatalysts, aimed at maximizing the electrochemical surface area (ECSA) and consequently the specific mass activity of fuel cell reactions, are obtained by firstly depositing Pt nanoparticles on colloidal silica (Pt‐silica), followed by the adsorption of the latter onto a carbon support. This method of catalyst preparation increases Pt metal utilization and generates accessible void space in the interpenetrating particle network of carbon and silica for the facile transport of reactants and products. Both electrochemical hydrogen adsorption/desorption and CO oxidation measurements show an increase in the ECSA using this approach. Methanol electrooxidation is used as a test reaction to evaluate the catalytic activity. It is found that the silica modified catalyst is three times as active as a catalyst prepared without silica, under otherwise identical conditions.
Intergenerational predictors of diurnal cortisol secretion in early childhood
Authors: Ben‐Dat Fisher Dahlia , Serbin Lisa A. , Stack Dale M. , Ruttle Paula L. , Ledingham Jane E. , Schwartzman Alex E.
Published: April 2007

The present study examined potential intergenerational links that may contribute to atypical patterns of diurnal cortisol secretion in early childhood. Salivary cortisol samples were collected across 1 waking day in 36 pre‐school children whose mothers are participants in an ongoing longitudinal project. Hierarchical Linear Modeling (HLM) identified statistically significant predictors of individual differences in daily cortisol trajectories. Children displayed relatively low post‐awakening values and flatter cortisol trajectories across the day as a function of unsupportive maternal behaviour, second‐hand smoke and maternal histories of social withdrawal in childhood. These results suggest that individual differences in young children's pattern of diurnal cortisol are associated with a variety of current and historical maternal characteristics and behaviours. The identification of intergenerational predictors of children's diurnal neuroendocrine functioning may provide new insights into the transfer of health and developmental risk from parent to child. Copyright © 2007 John Wiley & Sons, Ltd.
Central bank intervention and exchange rate volatility, its continuous and jump components
Authors: Beine Michel , Lahaye Jérôme , Laurent Sébastien , Neely Christopher J. , Palm Franz C.
Published: April 2007

We analyse the relationship between interventions and volatility at daily and intra‐daily frequencies for the two major exchange rate markets. Using recent econometric methods to estimate realized volatility, we employ bi‐power variation to decompose this volatility into a continuously varying and jump component. Analysis of the timing and direction of jumps and interventions imply that coordinated interventions tend to cause few, but large jumps. Most coordinated operations explain, statistically, an increase in the persistent (continuous) part of exchange rate volatility. This correlation is even stronger on days with jumps. Copyright © 2007 John Wiley & Sons, Ltd.
Speeding up parallel GROMACS on high‐latency networks
Authors: Kutzner Carsten , Van Der Spoel David , Fechner Martin , Lindahl Erik , Schmitt Udo W. , De Groot Bert L. , Grubmüller Helmut
Published: April 2007

We investigate the parallel scaling of the GROMACS molecular dynamics code on Ethernet Beowulf clusters and what prerequisites are necessary for decent scaling even on such clusters with only limited bandwidth and high latency. GROMACS 3.3 scales well on supercomputers like the IBM p690 (Regatta) and on Linux clusters with a special interconnect like Myrinet or Infiniband. Because of the high single‐node performance of GROMACS, however, on the widely used Ethernet switched clusters, the scaling typically breaks down when more than two computer nodes are involved, limiting the absolute speedup that can be gained to about 3 relative to a single‐CPU run. With the LAM MPI implementation, the main scaling bottleneck is here identified to be the all‐to‐all communication which is required every time step. During such an all‐to‐all communication step, a huge amount of messages floods the network, and as a result many TCP packets are lost. We show that Ethernet flow control prevents network congestion and leads to substantial scaling improvements. For 16 CPUs, e.g., a speedup of 11 has been achieved. However, for more nodes this mechanism also fails. Having optimized an all‐to‐all routine, which sends the data in an ordered fashion, we show that it is possible to completely prevent packet loss for any number of multi‐CPU nodes. Thus, the GROMACS scaling dramatically improves, even for switches that lack flow control. In addition, for the common HP ProCurve 2848 switch we find that for optimum all‐to‐all performance it is essential how the nodes are connected to the switch's ports. This is also demonstrated for the example of the Car‐Parinello MD code. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Explicit treatment of force contribution from alignment tensor using overdetermined linear equations and its application in NMR structure determination
Authors: Rathinavelan Thenmalarchelvi , Im Wonpil
Published: April 2007

Residual dipolar coupling (RDC) provides valuable information about the orientation of each internuclear vector in a macromolecule with respect to the static magnetic field. However, structure determination utilizing RDC still remains challenging without additional restraints such as NOE. In this context, a novel approach has been developed to efficiently extract structural information from RDC by successive application of singular value decomposition (SVD) method in the course of NMR structure determination. Force contribution from the alignment tensor is rigorously formulated in the context of SVD, and assessments have been made to verify its numerical accuracy. The efficacy of this approach is illustrated by showing that RDC restraints alone can restore a distorted β‐hairpin to native‐like structure using the replica‐exchange molecular dynamics simulations. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Comparison of solvation‐effect methods for the simulation of peptide interactions with a hydrophobic surface
Authors: Sun Yu , Dominy Brian N. , Latour Robert A.
Published: April 2007

In this study we investigated the interaction behavior between thirteen different small peptides and a hydrophobic surface using three progressively more complex methods of representing solvation effects: a united‐atom implicit solvation method [CHARMM 19 force field (C19) with Analytical Continuum Electrostatics (ACE)], an all‐atom implicit solvation method (C22 with GBMV), and an all‐atom explicit solvation method (C22 with TIP3P). The adsorption behavior of each peptide was characterized by the calculation of the potential of mean force as a function of peptide‐surface separation distance. The results from the C22/TIP3P model suggest that hydrophobic peptides exhibit relatively strong adsorption behavior, polar and positively‐charged peptides exhibit negligible to relatively weak favorable interactions with the surface, and negatively‐charged peptides strongly resist adsorption. Compared to the TIP3P model, the ACE and GBMV implicit solvent models predict much stronger attractions for the hydrophobic peptides as well as stronger repulsions for the negatively‐charged peptides on the CH3‐SAM surface. These comparisons provide a basis from which each of these implicit solvation methods may be reparameterized to provide closer agreement with explicitly represented solvation in simulations of peptide and protein adsorption to functionalized surfaces. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Active Ammonia excretion in the giant mudskipper, Periophthalmodon schlosseri (Pallas), during emersion
Authors: Chew Shit F. , Sim Mei Y. , Phua Zhi C. , Wong Wai P. , Ip Yuen K.
Published: April 2007

The main objective of this study was to determine whether active NH4+ excretion occurred in the giant mudskipper, Periophthalmodon schlosseri, during emersion. Our results demonstrated that continual ammonia excretion in P. schlosseri during 24 hr of emersion resulted in high concentrations (∼30 mmol l−1) of ammonia in fluid collected from the branchial surface. For fish injected intraperitoneally with 8 μmol g−1 ammonium acetate (CH3COONH4) followed by 24 hr of emersion, the cumulative ammonia excreted was significantly greater than that of the control injected with sodium acetate. More importantly, the ammonia excretion rate at hour 2 in fish injected with CH3COONH4 followed by emersion was greater than that in fish immersed in water as reported elsewhere, with the greatest change in the ammonia excretion rate occurring at hour 2. Assuming that the rate of endogenous ammonia production remained unchanged, 33% of the exogenous ammonia was excreted through the head region, presumably through the gills, during the first 6 hr of emersion. Indeed, at hour 6, the ammonia concentration in the branchial fluid increased to an extraordinarily high concentration of >90 mmol l−1. Therefore, our results confirm for the first time that P. schlosseri can effectively excrete a high load of ammonia on land, and corroborate the proposition that active NH4+ excretion through its gills contributes in part to its high tolerance of aerial exposure. Only 4.6% of the exogenous ammonia was detoxified to urea. The glutamate contents in the muscle and liver also increased significantly, but the glutamine contents remained unchanged. J. Exp. Zool. 307A:357–369, 2007. © 2007 Wiley‐Liss, Inc.
Anomalous concentration dependence of the coordination behavior of Cl− ion to Ln3+ ion (Ln3+ = rare‐earth ion) in anhydrous LnCl3 alcohol solutions
Authors: Yoshimura Y. , Hirayama K. , Makiguchi H.
Published: April 2007

Raman spectroscopic measurements were carried out for the anhydrous LnCl3·20ROH·XLiCl solutions (Ln3+ = La3+− Lu3+, X = 0–3; ROH = MeOH, EtOH, n‐PrOH) in the liquid state. The salt concentration (X) dependence of the wavenumber for the Ln–Cl stretching Raman band (νLn–Cl) is examined in conjunction with the formation of chloro‐rare‐earth complexes. We have obtained very intriguing results including the fact that the chloro complexations of the middle rare‐earth ions (e.g. gadolinium, holmium ions, etc.) in the MeOH and EtOH solutions show peculiar behavior with regard to the salt concentration dependence: the νLn–Cl wavenumber increases with the increasing chloride concentration. However, the νLn–Cl wavenumbers of the light and heavy rare‐earth (e.g. lanthanum, lutetium, etc.) salt solutions show normal behavior; i.e. νLn–Cl decreases with the increasing chloride concentration. On the other hand, in the n‐PrOH solutions, the νLn–Cl frequency in the solutions of all the rare‐earth elements exhibits a normal behavior. We now present a possible mechanism for this anomalous concentration dependence of coordination of Cl− ions to Ln3+ ions in anhydrous LnCl3 alcohol solutions. Copyright © 2007 John Wiley & Sons, Ltd.
What business people need to know about IT: an accounting perspective
Authors: Skok Walter , Tan Bian
Published: April 2007

Strategic change within organizations is often enabled by technology, which changes at a rapid pace. This paper offers a solution to the frustrating problem faced by business managers and executives in keeping up with the fast‐moving changes in computing, communications and associated technology. The paper is in three parts.

First, it outlines the problems associated with the so‐called business/IT divide, which is the communications gap that is blamed for many of the failures and difficulties associated with the management, development and use of information systems and technologies.

Second, it reviews the literature on approaches for coping mechanisms and proposes a framework that business professionals can follow to keep abreast with emerging technology and its potential application. This provides a continuous monitoring process over the life cycle of the technology.

Finally, the framework is tested by considering its potential for smaller accounting practices, as an example of a business community that is in urgent need of assistance in this area. Conclusions are drawn and recommendations made for ways in which accounting managers and staff can keep abreast of technology developments and minimize the risks associated with the deployment of technologies within their organizations.

Copyright © 2007 John Wiley & Sons, Ltd.
The business planning process: maintaining strategic fit
Authors: Bloodgood James M.
Published: April 2007

A wide range of business planning processes have been offered by academics and practitioners alike, yet little has been said about how firms should go about changing their process when managers perceive it to no longer be effective.

This paper uses a recent change in the business planning process by a US manufacturing firm to examine how the planning process can be effectively changed. In particular, the matching of the process to the current internal and external conditions the firm is facing is emphasized.

Copyright © 2007 John Wiley & Sons, Ltd.
Management buy‐outs: strategies for success
Authors: Clifford Graham , Beaver Graham
Published: April 2007

Management buy‐outs have become an established feature of business life. Changes in the environment have forced many large organizations to take a measured examination of their product portfolio and to consider where it is best to concentrate scarce resources.

Areas and activities which are thought to be peripheral to the core business of the company are ripe for divestment.

Potential buy‐out managers need a strategy, both for steering the business through the acquisition process and for its subsequent management and direction. This paper examines some of the strategies that have been deployed using case examples from original research and comments on their effectiveness or otherwise.

Copyright © 2007 John Wiley & Sons, Ltd.
Enhanced cholesterol‐ and triglyceride‐ lowering effect of West African green tea
Authors: Rehrah Djaafar , Ahmedna Mohamed , Yu Jianmei , Goktepe Ipek , Hurley Steven , Hanner Tracy , Rao‐Patel Anuradha
Published: April 2007

‘The Vert’ is a special type of green tea widely consumed in West Africa and locally associated with many health benefits. However, limited research has been conducted to evaluate its health benefits, such as its enhanced hypolipidemic potential. The objectives of this study were to (1) evaluate the cholesterol‐ and triglyceride‐lowering effects of West African green tea (WAGT) as affected by diet and tea intake, (2) determine the impact of WAGT consumption on the CHD risk ratio, and (3) explore possible mechanisms through which WAGT improves serum lipid profile. Forty‐five male Wistar rats were randomly assigned to one of nine treatment combinations, three diets (regular, high‐cholesterol, and trans‐fat diets) and three fluid sources (no tea, diluted tea, and concentrated tea). After 6 weeks of feeding, animal blood, liver, and feces were harvested. Total cholesterol, HDLc, LDLc, and triglycerides in serum, liver, and feces were determined. The concentrations of bile acids in feces were also measured. WAGT significantly lowered serum and liver cholesterol (30% and 15%, respectively) and increased serum HDL cholesterol (30%). It also reduced liver enlargement caused by storage of excess lipids in high‐cholesterol diet. Overall, the CHD risk ratio was cut by two‐thirds in rats fed high‐cholesterol diet and WAGT. A marked increase in fecal total lipids, cholesterol (60%), and bile acids (50%) was observed in rats that consumed WAGT compared to the control group. These beneficial effects could be attributed to the significantly high flavonoid content of WAGT. Copyright © 2007 Society of Chemical Industry
Applied statistical analysis for strange attractors and related problems
Authors: Kontorovich Valeri
Published: April 2007

Nowadays, the number of chaos applications has grown considerably. The applied theory of chaotic dynamic systems requires new tools for its statistical analysis. In this paper the so‐called ‘model distribution’ approach based on the cumulants and their equations is presented in order to obtain a statistical characterization of the chaos generated by differentiable dynamic systems; as examples, the Lorenz and Chua attractors are considered. The fractional analysis of system dynamics is considered as well. Copyright © 2007 John Wiley & Sons, Ltd.
Persistent multifocal conduction block in vasculitic neuropathy with IgM anti‐gangliosides
Authors: Notturno Francesca , Caporale Christina M. , Di Muzio Antonio , Uncini Antonino
Published: April 2007

A 30‐year‐old man with essential cryoglobulinemia presented with an axonal neuropathy and was found to have vasculitis at nerve biopsy. After 44 months, in accord with clinical deterioration, motor conduction studies showed excessive temporal dispersion multifocally, with partial conduction block persisting for 3 years. Antibody testing showed the presence of IgM anti‐GM1, anti‐GD1a, and anti‐GM2 antibodies. Transitory conduction block has been reported occasionally in patients with vasculitis. The persistent multifocal conduction abnormalities found in this patient were more likely due to a superimposed immunomediated demyelination rather than to chronic nerve ischemia secondary to vasculitis. Muscle Nerve, 2007
Cervical myelopathy caused by retrograde intraneural dissection of anesthetic solution
Authors: Cochrane Thomas I.
Published: April 2007

Brachial plexus block is a generally safe procedure for postoperative analgesia following shoulder surgery. This report describes brachial plexus block complicated by intraneural dissection of anesthetic solution, resulting in severe damage to the upper spinal cord. Other investigators have hypothesized that this rare complication is caused by accidental needle placement within the substance of the cord. This case demonstrates that the complication can occur despite a peripherally located needle. Muscle Nerve, 2007
Complex chromosome 8;21 translocation with associated hyperdiploidy in acute myeloid leukemia (FAB‐M2)
Authors: Corral María del Pilar , Villa Olaya , Alfaro Elizabeth M. , Alonso Cristina N. , Baro Cristina , Felice Maria S. , Rossi Jorge , Solé Francesc , Gallego Marta S.
Published: April 2007

We present a case of acute myeloblastic leukemia (AML‐M2) with a complex t(8;21) translocation and additional acquired chromosomes yielding a hyperdiploid karyotype. AML1/ETO transcript was observed by reverse transcription‐polymerase chain reaction. Fluorescence in situ hybridization (FISH), spectral karyotyping (SKY), and comparative genomic hybridization (CGH) were performed to further identify the chromosomes observed by G banding. The patient was treated according to our current protocol for AML. He remains in complete remission +11 months from diagnosis. Further follow‐up of this patient and the analysis of a larger number of children are needed to define whether the gains of the specific extra chromosomes modify the good prognosis that t(8;21) confers to this subgroup of AML. Pediatr Blood Cancer 2008;50:651–654. © 2007 Wiley‐Liss, Inc.
Lower Critical Solution Temperatures, Part I Polymethylene in n‐alkanes
Authors: Kodama Yashinori , Swinton Findlay L.
Published: April 2007

Lower critical solution temperatures (LCST's) of three linear polyethylenes of differing molecular weights were measured visually in various n‐alkanes ranging from n‐hexane to n‐tridecane. The LCST observed increases with decreasing molecular weight of polyethyline and with increasing the chain length of the n‐alkanes.

The limiting LCST's, θL for polyethylene/n‐alkane systems were obtained by extrapolating to the infinite molecular weight of polyethylene using a Shultz‐Flory plot.

Flory's equation of state theory is discussed in conjunction with the conventional Flory‐Huggins theory and the equation of state parameters for the pure solvents are obtained according to the Flory theory. The θL temperatures for polyethylene in n‐hexane, n‐heptane, and n‐octane are calculated in accordance with Flory's and Patterson's equations and compared with the experimental values. The θL temperatures are found to be well predicted by one version of the Flory theory.
Method for reactivity ratio determination in high‐conversion copolymerisations by means of 1H‐n.m.r. spectroscopy
Authors: Natansohn Almeric
Published: April 2007

Copolymerisation of methyl methacrylate and styrene is carried out in the n.m.r. spectrometer's sample tube, measuring the comonomer concentration against time evolution. The data are processed according to the integrated Mayo‐Lewis and Fineman‐Ross equations in order to obtain the reactivity ratios values. The applicability, advantages and limits of the method are discussed.
Polymers and Polymer Science in Dentistry
Authors: Braden Michael
Published: April 2007

Polymers (including some with no other commercial applications) find a wide variety of uses in dentistry. Appropriate physical measurements can reveal potential difficulties with materials intended for dental use. Viscoelastic measurements show that the glass transition temperature of pourable polymethyl methacrylate resins which are polymerised at ambient temperature are too low to avoid the possibility of distortion by heat in use: this results from the presence of residual monomer which irritates soft tissue. The uptake of water by the materials is important in dental applications but standard tests often fail to distinguish the effects of equilibrium absorption and rate of uptake properly characterised by the diffusion coefficient.

Cationic polymerisation of ethylene imine derivatives has applications in dentistry and the ‘command’ setting of acrylic materials by ultra‐violet light can be convenient. Soft acrylic or silicone linings for dentures are also discussed.
Chemistry, Properties and Orthopaedic Applications of Acrylic Cements
Authors: Pearson Geoffrey P. , Jones David F.
Published: April 2007

The early development and use of acrylic cement in orthopaedic surgery has been reviewed by Charnley. This paper is an attempt to describe the chemical background to the use of acrylics as bone cements with particular reference to the well recognised rise in temperature during the setting of the cement, a phenomenon of concern to some surgeons but easily explained if not overcome by classical reaction kinetics. The influence of the operating theatre temperature on the speed of setting is discussed. The fears that some surgeons may have that the incorporation of barium sulphate as a radio‐opacifier into the cement could reduce the compressive strength of the latter are allayed. The mechanical properties of the set cement are discussed and some criticism is levied at the various International Standards proposed for some cements. The paper concludes by reviewing some of the work carried out at Bradford in an attempt to produce modified cements designed to overcome some of the shortcomings of the existing materials.
Design of Polymeric Immunomicrospheres for Cell Labelling and Cell Separation
Authors: Rembaum Alan , Margel Shlomo
Published: April 2007

Immunomicrospheres consist of hydrophilic cross‐linked particles with antibodies bound to their surface. These particles find specific receptors on living or fixed cells and there fore can label cell sub‐populations and the labelled cells can be observed by means of a scanning, electron or light‐microscope. To label cells with polymeric particles, biocompatible microspheres are needed preferably with a narrow distribution of sizes in the range 10 to 10,000 Å.

Particles having a gel‐like nature and high porosity seem to meet the biocompatibility requirement and they do not stick non‐specifically to cell membranes. Use of cross‐linking agents renders the microspheres insoluble in common solvents. Therefore, subsequent reactions with molecules of biochemical interest are possible in various media.

Five classes of hydrophilic cross‐linked microspheres with functional groups e.g. carboxyl, hydroxyl, amide and/or pyridine groups were synthesised. These functional groups were used to bind covalently antibodies and other proteins to the surface of the microspheres. To optimise the derivatisation technique, polyglutaraldehyde immunomicrospheres have been prepared and utilised. Specific populations of human and murine lymphocytes were labelled with microspheres synthesised either by the emulsion or the ionising radiation technique. The labelling of the cells by means of microspheres containing an iron core led to a successful separation of B from T lymphocytes by means of a magnetic field.
Ultrahigh Molecular Weight Polyethylene (UHMW‐PE): Application in Artificlal Joints
Authors: Berzen J. , Birnkraut H. W. , Braun G.
Published: April 2007

The molecular weight of UHMW‐PE has an important influence on its physical properties. Different methods are applied to determine the molecular weight of the original powder and semi‐finished products.

The main processing methods such as compression moulding, extrusion, and injection moulding are described, also operations for the preparation of parts for medical use and sterilisation methods.

Abrasion, chemical resistance, and its compatibility with body tissue are basic properties for the medical use of UHMW‐PE. The bio‐mechanical properties of the material in the form of a hip joint can be tested in a simulator.
Slow elastic modulus changes in plasticised poly (vinyl chloride)
Authors: Leharne Stephen A. , Park Geoffrey S. , Norman Ronald H.
Published: April 2007

The Young's Modulus of PVC plasticised with various dialkylphthalates at concentrations from 40–120 phr that has been subject to a short heat treatment at 100°C, increases linearly with the logarithm of the time of storing at temperatures from 20–100°C. Both the Young's Modulus and its rats of increase with time is found to increase with increasing size of plasticiser to increase with decreasing concentration of plasticiser and to pass through a maximum with changing temperature of storage at a temperature of about 38°C. These effects can be explained if it is assumed that the elasticity results from a network linked by crystallites that can be melted on heating and reformed on storing at a lower temperature. The density of the plasticiser compositions is found to increase with time and this together with the development of endothermic DSC peaks support the hypothesis that changes in rigidity result from changes in crystallinity. The endothermic peak occurs at an almost constant temperature independent of plasticiser concentration or the size of the plasticiser molecule. It is suggested that the effect of these variables on the the melting point is nullified by the changes they also produce in crystallite size.
Light scattering characterisation of polymers II. Analyses of high molecular weight polystyrene
Authors: Suzuki Hidematsu
Published: April 2007

For light scattering analysis of an extremely high molecular weight polymer with large size in solution, use of mixtures of a given polymer with its low molecular weight homologue is described to have great advantages. With such bimodal mixtures as test samples, one can alter the unknown form of the angular variations of scattered lights to a form to be expected and widen the range of the linearity with sin2 (ø/2), where ø is the scattering angle. According to the considerations, a sample of linear polystyrene was successfully analysed on a commercial apparatus, Fica 50 to have the weight‐average molecular weight of 27 million.
On the meniscus depletion ultracentrifugation I. Pseudoideal solutions
Authors: Suzuki Hidematsu
Published: April 2007

In view of the recent advances in the theory of sedimentation equilibrium, the meniscus depletion is reformulated and extended to reveal its potentialities. To cope with poly disperse materials such that fringes become unresolvable near the cell bottom, an extrapolation method is proposed using the newly defined average molecular weights at a given radial position. The main purpose of the method is to pave the way for determining the number‐average molecular weight of a sample. Its applications to a linear polystyrene sample having the weight‐average molecular weight of twenty seven million are reported in this paper. Uses and limitations of the present method are discussed in detail.
Water binding properties of hydrogel polymers for reverse osmosis and related applications
Authors: Pedley Derek G. , Tighe Brian J.
Published: April 2007

Differential scanning calorimetry (DSC) has been used in the study of a series of hydrogels in an attempt to correlate water binding and transport properties. DSC and oxygen transport studies were carried out on a series of styrene‐2‐hydroxyethyl methacrylate copoly‐mers. The transport of dissolved oxygen through those copolymers that contained no freezing water was found to be negligible in comparison to those in which both freezing and non‐freezing water was present. This correlates well with the observation that the dense layer of asymmetric cellulose acetate reverse osmosis membranes was found to contain little or no free water.

On this basis, the use of DSC in the design of a hydrogel that contains little or no freezing water (to promote salt rejection) with a reasonably high total water content (to maximise water flux) for use in reverse osmosis, is described. The resultant copolymer of acrylamide, methacrylic acid and styrene has a total equilibrium water content (30 per cent) that is twice that of a typical dense cellulose acetate used in reverse osmosis and a very low (< 1 per cent) freezing water content.

Examination of the fine structure of the melting endotherms and freezing exotherms associated with various hydrogels shows several interesting features which are interpreted in terms of the existence of a continuum of water states. These range from water that is unaffected by its polymeric environment to water (on average two or less molecules per monomer repeat unit) that is hydrogen bonded to functional groups in the polymer.
Heterogeneous crystallisation of polyethylene terephthalate
Authors: Ibbotson Christopher , Sheldon Ronald P.
Published: April 2007

An examination of the effect of various inorganic and organic additives on the crystallisation behaviour of polyethylene terephthalate has been made. Various methods of mixing the polymer and additives were also investigated and one involving screw extrustion was finally adopted. Crystallisation studies were carried out using Differential Scanning Calorimetry under dynamic and isothermal modes covering both normal and cold‐crystallisation conditions. Using screw extrusion mixed material it was found that almost all additives produced some nucleating effect as indicated by an increase in the rate of crystallisation. In particular, sodium benzoate and sodium stearate (1 per cent w/w) had the greatest effect, decreasing the initial cold‐crystallisation temperature and increasing the temperature of equivalent half‐times of isothermal crystallisation, both by about 20°C.
The action of heat on the polyorganosiloxanes derived from the minerals biotite and pseudowollastonite by trimethylsilylation
Authors: Cook Colin B. , Currell Brian R. , Midgley Henry G. , Parsonage John R. , Thakur Chandra P.
Published: April 2007

The polyorganosiloxanes prepared by the trimethylsilylation of mineral silicates contain Q [SiO4/2] units and M [CH3)3 SiO1/2] units. Investigations into the behaviour of these materials in the temperature range 100‐1000°C and for times varying from 2‐64 hours have shown that a variety of reactions take place with a general increase in number average molecular weight (Mn). Organophilic polyorganosiloxanes with Mn > 6000 can be obtained by heat treatment under vacuum or a stream of nitrogen. The thermal stability of the polymer derived from pseudowollastonite in closed systems in the presence of acid/base catalysts is also reported. This work is part of a general programme to prepare higher molecular weight Q/M polymers with more potential uses as industrial materials than the initially prepared trimethylsilylated derivatives.
Some reactions of the methyl groups of the trimethylsilyl derivative of the mineral pseudowollastonite
Authors: Cook Colin B. , Currell Brian R. , Midgley Henry G. , Parsonage John R.
Published: April 2007

The trimethylsilylation of pseudowollastonite gives a polyorganosiloxane (Mn, 890). The aim of this work was to increase the molecular weight of this initial or pre‐polymer and to bond into the molecule further functional groups. The methyl groups of the trimethylsilyl moiety have been converted to a series of organic derivatives: ‐> Si(CH3)2CH2X; × = C1, Br, I, Ac, OH: which are capable of further reaction to give higher molecular weight homologues. As expected the ‐>Si(CH3)2CH2OH group reacts readily with chlorosilancs whilst the original pre‐polymer hydroxyl groups give disappointing yields in these and other reactions owing to their sterically hindered environment.