bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface plasmon resonance as a tool for the estimation of adsorbed polymeric layer characteristics: Theoretical considerations and experiment
Authors: Koutsioubas Alexandros G. , Spiliopoulos Nikolaos , Anastassopoulos Dimitrios L. , Vradis Alexandros A. , Priftis George D.
Published: June 2007

The potential application of Surface Plasmon Resonance (SPR) spectroscopy in evaluating the thickness and volume fraction of adsorbed macromolecular layers is discussed in this work. The sensitivity of SPR spectroscopy to different layer concentration and to the layer extension normal to the surface (thickness) is theoretically illustrated. A new approach for the interpretation of SPR data is presented, which is applicable whenever the functional form of the density profile is known. The use of the proposed procedure for the fitting of experimental results from PS‐PEO brush self‐assembly on alumina surface has allowed the determination of the layer parameters, which have been found to be in accordance with theoretical mean‐field and scaling predictions, being also in good agreement with previous results from neutron reflectivity experiments. Furthermore, it has been confirmed that the dependence of the brush layer thicknessdon the molecular weightMwobeys the scaling lawd∼Mw0.63. Since surface plasmon measurements can be acquired quite fast, it is suggested that under the present analysis scheme, the technique may be implemented to probe the average conformational properties of adsorbed macromolecular layers during their formation or under external stimuli. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2060–2070, 2007
Increasing oncologists' skills in eliciting and responding to emotional cues: evaluation of a communication skills training program
Authors: Butow Phyllis , Cockburn Jill , Girgis Afaf. , Bowman Deborah , Schofield Penelope , D'Este Catherine , Stojanovski Elizabeth , Tattersall Martin H. N.
Published: June 2007

Purpose: Psychological morbidity in cancer patients is common, but often undetected and untreated. We developed a communication skills training (CST) program targeting this issue, and evaluated its impact on doctor behaviour.

Patients and Methods: Thirty of 35 oncologists from six teaching hospitals in six Australian cities, participated. The CST was a 1.5‐day intensive face‐to‐face workshop incorporating presentation of principles, a DVD modelling ideal behaviour and role‐play practice, followed by four 1.5 h monthly video‐conferences incorporating role‐play of doctor‐generated scenarios. Doctors were randomized to receive the CST or not. Simulated patient interviews were videotaped and coded at baseline, after CST and 6 months later. Doctors completed questionnaires assessing stress and burnout at the same time points.

Results: Doctors in the intervention group displayed more creating environment and fewer blocking behaviours at both follow‐ups; however, these differences did not reach statistical significance. Intervention doctors valued the training highly, but did not report substantial reductions in stress and burnout.

Conclusions: This short training programme demonstrated a positive effect on aspects of doctor behaviour. Video‐conferencing after a short training course may be an effective strategy for delivering CST. Copyright © 2007 John Wiley & Sons, Ltd.
‘It's going to shorten your life’: framing of oncologist–patient communication about prognosis
Authors: Rodriguez Keri L. , Gambino Frank J. , Butow Phyllis N. , Hagerty Rebecca G. , Arnold Robert M.
Published: June 2007

In this qualitative study, we used grounded theory techniques to analyze transcripts of 29 first‐time encounters between oncologists and patients referred to them with previously diagnosed, incurable cancer. We found that 23 (79%) of the transcripts included 166 examples of prognostic talk. The language used ranged from general to personal, with 25% of statements mentioning no patients (e.g., ‘the tumor will usually come back’), 13% mentioning patients other than the current patient (e.g., ‘some patients with tumor response will be around for 2–5 years’), 11% mentioning the current patient in the context of others (e.g., ‘on average, people like you live a couple of years’), and 51% directly focusing on the patient (e.g., ‘this thing's going to kill you eventually’). More statements pertained to treatment‐related prognosis than to disease‐related prognosis (67 versus 33%). While 31% of statements focused on negative outcomes (loss framing), the remainder either focused on positive outcomes (gain framing) or discussed a combination of positive and negative outcomes (mixed framing). When discussions focused on negative outcomes, general and indirect language was commonly used, perhaps to buffer the patient from news of the poor prognosis. Copyright © 2007 John Wiley & Sons, Ltd.
Chemical processes in the atmospheric pressure plasma treatment of benzene
Authors: Franceschi Pietro , Guella Graziano , Scarduelli Giorgina , Tosi Paolo , Dilecce Giorgio , De Benedictis Santolo
Published: June 2007

In this paper, we present the first multi‐diagnostic investigation of the chemical processes occurring in nitrogen–benzene plasmas at atmospheric pressure. Plasma treatment results in extended deposit formation on the reactor surfaces. In our experiment, the composition of the deposit has been investigated by several well established analytical techniques (NMR, FT‐IR, and GC‐MS). The most abundant molecule synthesized in the plasma turns out to be biphenyl, while the polymeric, tholin‐like, fraction of the deposit show the presence of CN, NH and NH2 functions. To get further insights on the characteristics of the discharge, optical emission spectra have also been recorded and studied.

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Lead optimization and insecticidal activity of analogues of daphneolone isolated from Stellera chamaejasme L.
Authors: Chen Lin , Wang Xinliang , Lu Tao , Hou Taiping
Published: June 2007

Starting from the chemical structure of the botanical aphicides 1,5‐diphenyl‐1‐pentanone and 1,5‐diphenyl‐2‐penten‐1‐one, extracted from Stellera chamaejasme L., the authors designed and synthesized a series of novel compounds following the concept of bioisosterism. Their structures were established on the basis of 1H NMR and GC‐MS spectra, and the insecticidal activities of the compounds were evaluated against Aphis gossypii Glover. The results demonstrated that the substitution of a heterocycle for the phenyl ring was favourable. Thus, further modification of compound 2n, containing a furan ring, which showed excellent activity (LC50 = 0.85 g L−1), is of some promise. Copyright © 2007 Society of Chemical Industry
Novel life stage targets against plum curculio, Conotrachelus nenuphar (Herbst), in apple integrated pest management
Authors: Wise John C , Kim Ki , Hoffmann Eric J , Vandervoort Christine , Gökçe Ayhan , Whalon Mark E
Published: June 2007

In this study the authors employed the plant‐insect‐chemistry (PIC) triad to investigate two novel life stage targets against the plum curculio (PC), Conotrachelus nenuphar (Herbst), in apple integrated pest management (IPM). Laboratory treated apple bioassays were used to determine if the insect growth regulator (IGR) insecticides novaluron and tebufenozide have physiological effects on PC larvae following adult exposure. Curative activity bioassays were conducted for IGR, neonicotinoid, oxidiazine and organophosphate insecticides on PC larvae post‐infestation, and fruit penetration profiles of insecticides were developed. The results revealed that novaluron exhibits activity on PC larvae via vertical transmission following exposure of mated females to treated substrate. Surface treatments of azinphos‐methyl, thiacloprid and thiamethoxam to preinfested fruit resulted in significant reductions in larval emergence. For all compounds, 50% or more of the total recovered active ingredient was from apple skin, and for azinphos‐methyl, indoxacarb and thiamethoxam it was greater than 80%. For azinphos‐methyl, novaluron, methoxyfenozide and thiacloprid, however, active ingredient was recovered from every section of the apple, from skin to core. Implications for twenty‐first century IPM are discussed. Copyright © 2007 Society of Chemical Industry
All II‐VI magnetic resonant tunneling diodes as voltage controlled spin filters
Authors: Supp D. , Slobodskyy T. , Slobodskyy A. , Gould C. , Schmidt G. , Molenkamp L. W.
Published: June 2007

We have fabricated resonant tunneling diodes based ZnSe/(Zn,Be)Se with Mn added in the quantum well. The I/V characteristics show a clear resonance which, when an external magnetic field is applied splits into two separate peaks. The splitting can be explained by a giant Zeeman splitting of the quantized levels in the well and can be fitted by a simple model using two independent spin channels. The experiments demonstrate resonant transport through spin split levels and indicate that the device may be suitable as a voltage controlled spin filter. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In‐situ X‐ray diffraction during epitaxial growth of ZnSe‐based heterostructures on (001)GaAs
Authors: Benkert Andreas , Schumacher Claus , Neder Reinhard B. , Brunner Karl
Published: June 2007

We developed a real‐time in‐situ X‐ray (RIX) diffraction technique for the detailed layer characterisation during epitaxial deposition of ZnSe‐based alloys on (001)GaAs substrates. A conventional molecular beam epitaxy chamber was equipped with a Cu X‐ray tube. The 113 reflection of the deposited structure is detected in static geometry by a CCD and is immediately analyzed in terms of strain, composition, thickness and strain relaxation behavior of the deposited layer. The in‐situ monitoring of ZnCdSe layers reveals a delay of heteroepitaxial growth start on GaAs, a gradual layer degradation due to dislocation formation, and a critical thickness for plastic relaxation which depends on the Cd content, consistent with an energy‐balance model. ZnCrSe alloy layers can be deposited with Cr content up to 2% at low substrate temperature TS = 210 °C. The layers appear to be epitaxial alloys with good quality, but a broadening of the Bragg peaks without a significant plastic relaxation is observed. Epitaxial growth and layer properties are studied as function of deposition conditions. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electronic structure of zinc‐blende MnTe within the GW approximation
Authors: Fleszar A. , Potthoff M. , Hanke W.
Published: June 2007

Using the local spin‐density approximation (LSDA) and the (non self‐consistent) GWapproach, the (quasiparticle) band structure is calculated forMnTe in zinc‐blende geometry. Different parameters characterizing the electronic structure are computed for an antiferromagnetic and the ferromagnetic phase and compared with the experiment. The strong Hubbard‐type repulsion on the Mn‐3d orbitals and the p ‐d hybridization are seen to be responsible for substantial defects found in the LSDA picture. It is discussed to which extent these can be improved upon by means of the GW approach. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of lattice dynamics and magnetic properties of II‐VI layers and interfaces by Raman spectroscopy
Authors: Geurts J. , Bass U. , Lentze M. , Wagner V.
Published: June 2007

We report on the lattice dynamics of abrupt and intermixed interfaces of II‐VI‐layers and quantum dots, studied by Raman spectroscopy from embedded CdSe monolayers in BeTe, and from CdSe quantum dots in ZnSe. It is demonstrated that the best CdSe/BeTe interface quality is achieved, when CdTe interface bonds are applied. The corresponding vibration modes are described very well by density functional calculations, and they also reveal the onset of CdSe quantum dot formation. For these interfaces, the reduced symmetry (i.e. non‐equivalence of [011] and [01‐1] in‐plane axes) is analyzed from the polarization dependent Raman scattering intensity. Similar results are presented for Raman scattering from Te surface dimers on BeTe(100). Furthermore, the (s,p)‐d exchange energy of diluted magnetic II‐VI semiconductors is studied by spin flip Raman spectroscopy. For n‐doped (Zn,Mn)Se, a doping‐induced reduction of the exchange energy and enhancement of the spin relaxation time T is demonstrated. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical characterization of thermally annealed self‐assembled ZnCdSe quantum dots
Authors: Margapoti E. , Worschech L. , Mahapatra S. , Slobodskyy T. , Tribu A. , Aichele T. , Brunner K. , Schmidt G. , Molenkamp L. W. , André R. , Kheng K. , Bougerol C. , Forchel A.
Published: June 2007

Post‐growth thermal annealing, (TA) in combination with mesa‐fabrication technologies, was applied to tune the shape and material composition of ZnCdSe quantum dots (QDs). The QDs were studied by means of photoluminescence spectroscopy. An enhancement of QD homogeneity due to TA is demonstrated by substantial narrowing of the QD emission, observed from large QD ensembles. Energy shifts of QD luminescence, exceeding 100 meV after thermal annealing, were observed. Tracing the evolution of single exciton lines, the activation energy of an enhanced diffusion process in small mesas was determined. Distinct changes of quantum dot symmetries were identified through a reduction of the exciton fine structure splitting. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experiments on single levitated particles: a novel approach for investigations of electronic properties of structured II‐VI‐semiconductor nanoparticles in selected environments
Authors: Graf C. , Lewinski R. , Dembski S. , Langer B. , Rühl E.
Published: June 2007

A novel approach for investigations of the electronic structure of II‐VI semiconductor nanoparticles in selected environments is presented. CdSe/ZnS core shell nanoparticles are dispersed in a liquid non‐volatile siloxane graft/block copolymer and injected in an electrodynamic trap, where a single liquid microdroplet is stably stored under ultra high vacuum conditions. In this way, it is possible to investigate quantum dots by soft X‐ray spectroscopies in a liquid environment, which is not influenced by any outer surface. NEXAFS spectra of stored nanoparticles were recorded at the Zn 2p‐, S 2p‐, and Cd 3d‐edge by measuring X‐ray excited optical luminescence or the element‐selective charging current of single, trapped microdroplets. The spectra are compared to those of similar CdSe/ZnS nanoparticles, which are dispersed in a controlled way in solid silica colloids as well as to those of matrix materials. An analysis of the data reveals that the electronic structure of the ZnS shell is significantly influenced by the outer functionalization and the dispersive media whereas the electronic structure of the core is shown to be independent from the surroundings. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamical symmetries and quantum transport through nanostructures
Authors: Kiselev M. N.
Published: June 2007

We discuss the manifestation of dynamical symmetries in quantum transport through nanostructures. The dynamical symmetry SO (4) manifested in the singlet‐triplet excitations is shown to be responsible for several exotic effects in nano‐devices: non‐equilibrium Kondo effect in T‐shape Double Quantum Dots, phonon‐induced Kondo effect in transition‐metal‐organic complexes, Kondo shuttling in Nano‐Electromechanical Single Electron Transistor. We consider the interplay between charge U (1) and spin SU (2) fluctuations in the vicinity of Stoner instability point and a non‐monotonic behavior of a Tunneling Density of States in metallic quantum dots. The experiments showing important role of dynamical symmetries in nanostructures are briefly reviewed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure and relaxation effects in thin semiconducting films and quantum dots
Authors: Kumpf Christian , Stahl Andreas , Gierz Isabella , Schumacher Claus , Mahapatra Suddhasatta , Lochner Florian , Brunner Karl , Schmidt Georg , Molenkamp Laurens W. , Umbach Eberhard
Published: June 2007

The structural properties of two epitaxial model systems were investigated, NiMnSb thin films on a (In,Ga)As/InP(001) substrate and free‐standing CdSe quantum dots on a ZnSe(001) surface. For the first system the influence of surface‐oxidation on the relaxation behavior of the entire film was investigated by a comparison of capped and uncapped samples. We found that the critical thickness for pseudomorphic growth is more than doubled by the protective capping layers. For the second system under investigation a determination of the size and shape of the quantum dots was performed. They have a cylindrical shape with an almost constant diameter of ≈10 nm and a height of about 2 nm, whereby the lowermost region widens up to about 14 nm. The entire quantum dots are strained. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Angle‐resolved photoemission on ZnSe(001): determination of conduction band quasiparticle shifts
Authors: Fleszar A. , Hanke W. , Weigand W. , Kumpf C. , Heske C. , Umbach E. , Plucinski L. , Johnson R. L.
Published: June 2007

Angle‐resolved photoemission measurements have been performed on the ZnSe(001) surface and analyzed using ab initio LDA and GW calculations. The key point of this analysis consists of a comparison between measured and calculated photoemission spectra. We suggest that matching the main dispersive peaks in experiment and theory leads to the determination of quasiparticle shifts of the conduction bands relative to their LDA position. It is found that these experimental shifts largely exceed the calculated GW‐quasiparticle shifts leading to an increased free‐electron‐like character of the photoemission final states as compared to the LDA calculations. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Movement and pinning of dislocations in SiC
Authors: Eberlein T. A. G. , Jones R. , Blumenau A. T. , Öberg S. , Briddon P. R.
Published: June 2007

SiC bipolar devices show a degradation under forward‐biased operation due to the formation and rapid propagation of stacking faults in the active region of the device. It is believed that the observed rapid stacking fault growth is due to a recombination‐enhanced dislocation glide (REDG) mechanism at the bordering partial dislocations having either Si or C core atoms. We investigated the effect of charge on the dislocation kinks and found that only silicon kinks have a deep filled band above the valence band. Trapping of holes into this band permits dislocation glide at room temperature. This mechanism is distinct from REDG as it requires only holes to be trapped at a Si partial and not in addition electrons in stacking fault states. We furthermore looked at the pinning of dislocations by nitrogen and boron and found a strong pinning of the C core by N and of the Si core by B. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantitative Structure–Activity Relationship Study of Binding Affinity of Azole Compounds with CYP2B and CYP3A
Authors: Itokawa Daisuke , Nishioka Tomoki , Fukushima Junji , Yasuda Tomoyo , Yamauchi Aiko , Chuman Hiroshi
Published: June 2007

An azole compound is considered to be a good probe for analyzing the binding affinity with various cytochrome P450 (CYP) proteins because of its coordination ability regarding the heme iron in the proteins. Eighteen azole compounds including commercial fungicides were examined for their binding to rat liver microsomal CYP2B and CYP3A using a type II spectral change. The binding affinities determined were analyzed in relation to the molecular properties of the azole compounds. Good correlation with the bilinear model was observed between the binding affinities and the partition coefficient (log P). The model suggested that the optimum log P values of the azole compounds were nearly the same for these two CYPs. The sequence homology of amino acid residues around the substrate recognition site is significantly high between CYP2B and CYP3A. It was reported that sizes of the binding pocket in CYP2B and CYP3A are not much different. These explain why the optimum log P values in the correlation equations for CYP2B and CYP3A was nearly the same.
Doped helium clusters analyzed through quantum chemistry methods
Authors: de Lara–Castells M. P. , Prosmiti R. , López–Durán D. , Delgado–Barrio G. , Villarreal P. , Gianturco F. A. , Jellinek J.
Published: June 2007

A quantum‐chemistry‐like methodology developed recently to study molecules solvated in atomic clusters is reviewed, and the results of its application to diatomic molecules immersed in helium clusters are presented and discussed. The methodology is based on treating the atoms of the solvent cluster as the “electrons” and the solvated molecule (“BC”) as a structured “nucleus” of the combined solvent‐solute system. The “electron”‐“electron” and “electron”‐“nucleus” interactions are represented by parametrized two‐body and ab initio three‐body potentials, respectively. The “intranuclear” (intramolecular) energy is mimicked by a parametrized pair potential energy function. The methodology furnishes the wave functions, and thereby it allows for computation of the infrared or Raman spectra of the solvated molecules. The computed spectra are then compared with the measured ones. In agreement with the experimental observations, the computed spectra of the solvated molecule show considerable differences depending on whether the solvent cluster is comprised of pure bosonic (4He), pure fermionic (3He), or both bosonic and fermionic helium atoms. The differences in the spectra are explained in terms of the differences in the spin‐statistics of the solvent clusters. The bosonic vs fermionic nature of the solvent is also reflected in the selection rules. In the case of a polar molecule, the Q‐branch of the spectrum is forbidden when the molecule is solvated in a bosonic cluster, and it becomes allowed when the solvent is a fermionic cluster. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
On‐column tryptic mapping of proteins using metal‐ion‐chelated magnetic silica microspheres by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Li Yan , Yan Bo , Xu Xiuqing , Deng Chunhui , Yang Pengyuan , Shen Xizhong , Zhang Xiangmin
Published: June 2007

Peptide mapping analysis, utilizing an easily replaceable and regenerable on‐column enzymatic microreactor with metal‐ion‐chelated adsorption of enzyme on magnetic silica microspheres, combined with matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS), was developed. Firstly, magnetic microspheres of small size and strong magnetism were prepared through solvothermal reaction. Thereafter, by introducing tetraethyl orthosilicate (TEOS), magnetic silica (MS) microspheres were formed. Trypsin could then be immobilized onto the MS microspheres based on the Lewis acid‐base interaction through the divalent cation chelators such as iminodiacetic acid (IDA), which was chemically bound to the microspheres through the introduction of glycidoxypropyltrimethoxysilane (GLYMO). The trypsin‐immobilized MS microspheres were then locally packed into the capillary by the application of a strong magnetic field using a magnet. The performance of the method was exemplified with digestion of bovine serum albumin for 5 min at 50°C and the result was comparable to the 12 h in‐solution digestion. The ability of regeneration of the prepared on‐column microreactor and good reproducibility of microreactor before and after regeneration were also demonstrated. Copyright © 2007 John Wiley & Sons, Ltd.
Evaluation of high‐field asymmetric waveform ion mobility spectrometry coupled to nanoelectrospray ionization for bioanalysis in drug discovery
Authors: Hatsis Panos , Brockman Adam H. , Wu Jing‐Tao
Published: June 2007

The potential of high‐field asymmetric waveform ion mobility spectrometry (FAIMS) coupled to nanoelectrospray ionization (nanoESI) as a method to improve sample throughput for bioanalysis in a discovery pharmaceutical setting was explored in this work. The ability of FAIMS to separate gas‐phase ions in the millisecond timescale was exploited to eliminate the need for liquid chromatography. Samples were introduced into the FAIMS electrodes/mass spectrometer using offline nanoESI at 20 nL/min and 1.5 kV. Signals were averaged for 30 s after which the next sample could be analyzed. The separation of simple mixtures, e.g., the removal of metabolite and endogenous interferences from parent drug, was demonstrated. Moreover, the application of nanoESI attenuated the ion suppression effects that normally plague conventional electrospray. On average, approximately two‐thirds of the neat sample signal intensity was preserved in extracted plasma samples. Standard curves were prepared for several compounds and linearity was obtained over approximately two to three orders of magnitude. This methodology was further tested with the analysis of plasma samples from a mouse pharmacokinetic study. Concentration values determined using nanoESI‐FAIMS were comparable to those determined using conventional LC/MS as demonstrated by percent differences of less than 30%. This work demonstrated the proof of concept that the combination of FAIMS and nanospray ionization can be a potentially useful tool to improve the throughput of discovery bioanalysis. Copyright © 2007 John Wiley & Sons, Ltd.
Meta‐analysis of genetic association studies under different inheritance models using data reported as merged genotypes
Authors: Salanti Georgia , Higgins Julian P. T.
Published: June 2007

Meta‐analysis of population‐based genetic association studies is often challenged by obstacles associated with the underlying inheritance model. For a simple genetic variant with two alleles, a recessive, dominant or co‐dominant model is typically assumed. In the absence of a strong biological rationale for a particular inheritance model, a recently suggested inheritance‐model‐free approach can be implemented. To enable a flexible choice among these models, summary results from each of the three genotypes are required. Incompatibility of the data across studies because of different inheritance models is a common problem. For instance, if the underlying model is dominant, studies that have assumed the recessive model and presented the results accordingly, have so far been excluded from the meta‐analysis.

We show how to combine data and make inferences under any inheritance model, irrespective of the models assumed within each study and the way that data are presented. Within a Bayesian framework we describe prospective models for binary
and continuous outcomes, and retrospective models for binary outcomes. The methods exploit an assumption of Hardy–Weinberg equilibrium, prior information about genotype prevalence or assumption of a specific inheritance model. On application to meta‐analyses of the associations between a polymorphism in the lipoprotein lipase gene and coronary heart disease or high‐density lipoprotein cholesterol, we observe substantial gains in precision when there is a large proportion of studies in which different inheritance models have been assumed. Copyright © 2007 John Wiley & Sons, Ltd.
Sequential analysis of latent variables using mixed‐effect latent variable models: Impact of non‐informative and informative missing data
Authors: Sébille Véronique , Hardouin Jean‐Benoit , Mesbah Mounir
Published: June 2007

Sequential methods allowing for early stopping of clinical trials are widely used in various therapeutic areas. These methods allow for the analysis of different types of endpoints (quantitative, qualitative, time to event) and often provide, in average, substantial reductions in sample size as compared with single‐stage designs while maintaining pre‐specified type I and II errors. Sequential methods are also used when analysing particular endpoints that cannot be directly measured, such as depression, quality of life, or cognitive functioning, which are often measured through questionnaires. These types of endpoints are usually referred to as latent variables and should be analysed with latent variable models. In addition, in most
clinical trials studying such latent variables, incomplete data are not uncommon and the missing data process might also be non‐ignorable. We investigated the impact of informative or non‐informative missing data on the statistical properties of the double triangular test (DTT), combined with the mixed‐effects Rasch model (MRM) for dichotomous responses or the traditional method based on observed patient's scores (S) to the questionnaire. The achieved type I errors for the DTT were usually close to the target value of 0.05 for both methods, but increased slightly for the MRM when informative missing data were present. The DTT was very close to the nominal power of 0.95 when the MRM was used, but substantially underpowered with the S method (reduction of about 23 per cent), irrespective of whether informative missing data were present or not. Moreover, the DTT using the MRM allowed for reaching a conclusion (under H0 or H1) with fewer patients than the S method, the average sample number for the latter increasing importantly when the proportion of missing data increased. Incorporating MRM in sequential analysis of latent variables might provide a more powerful method than the traditional S method, even in the presence of non‐informative or informative missing data. Copyright © 2007 John Wiley & Sons, Ltd.
A composite design for transition from a preliminary to a full‐scale study
Authors: Lachin John M. , Younes Naji
Published: June 2007

In drug development, a sequence of studies are conducted to evaluate effectiveness (or efficacy) and safety, such as a Phase II study to assess pharmacological activity or safety that is then followed by a definitive Phase III study to assess clinical effectiveness. Rather than conducting separate successive studies, we describe a design in which the patients enrolled in a preliminary (e.g. Phase II) study are continued into a subsequent full‐scale (e.g. Phase III) study. This design also applies to a study that uses an internal pilot with a preliminary assessment of efficacy or safety. The combined preliminary to full‐scale design potentially reduces the total numbers of patients required and the total duration of the program. The design allows a futility or safety stopping boundary for the preliminary study result that is specified in terms of a lower critical Z‐value
(ZL) and the pursuant type II error probability incurred under a specified alternative hypothesis of a beneficial effect or no toxicity at that stage. This boundary also leads to a deflation of the type I error probability for the final test at the completion of the full‐scale study, such that a critical value for the final test
(ZF) can be determined that provides the desired level of the type I error probability exactly. Thus, it is possible to determine sample sizes at the two stages, and critical values
ZL and
ZF that provide specified type I and II error probabilities for the combined study. We describe the design using large‐sample normally distributed Z‐tests at the two phases, including a test for means, or proportions or survival times, or combinations thereof, such as a test for means at Phase II followed by a test for proportions at Phase III.

We compare the properties of this design versus the conduct of two successive studies, and explore the factors that influence the operating characteristics of the design. We also discuss the practical considerations in the implementation of the design. Copyright © 2007 John Wiley & Sons, Ltd.
Complex engineered, organizational and natural systems
Authors: Rouse William B.
Published: June 2007

This paper describes an effort to determine the rationale and content for a research agenda in complex systems. This effort included a workshop conducted with 50 thought leaders in complex engineered, organizational, and natural systems. The results of this workshop were subsequently presented to seven groups in academia and industry across the United States. In this way, additional comments, suggestions, and insights were gained from roughly 200 participants in these presentations. The objectives of these eight events were to understand the underlying issues that cause us to perceive a system to be complex, and formulate a set of fundamental research questions whose pursuit would advance abilities to address these issues. © 2007 Wiley Periodicals, Inc. Syst Eng: 260–271, 2007
Ductility factors of symmetrical structures with restricted inelasticity
Authors: Georgoussis George K.
Published: June 2007

A simple elasto‐plastic analysis of symmetrical buildings composed of different types of bents is presented. Plasticity in bents is assumed to be restricted to the beams, where significant curvature ductility factors may be attained without loss of strength, and the behaviour of inelastic structures may be traced from elastic to ultimate deflections on the grounds that the external load is monotonically increasing with an invariant shape throughout the loading history. The outlined procedure is based on the concept of the continuous medium and a comprehensive consideration of the structural post‐elastic behaviour of common mixed‐bent‐type buildings is possible by means of parameter variations. Therefore it is suitable for a simple pushover elasto‐plastic analysis in a parametric form. The proposed method of analysis is based on the technique of decomposing a cantilever structural system into two components: a flexural and a shear–flexure subsystem. With this decomposition, not only the axial deformations in the column members of all bents are taken into account in the calculation of deflections, but also different types of bents may be combined in symmetrical buildings. Design charts relating the overall ductility factor with the maximum rotation ductility factor at the ends of the beams are presented for the case of a triangularly distributed external load, together with the formulation that defines the post‐elastic load–deflection curve. These data may be found useful for practising engineers at the stage of a preliminary structural application. Copyright © 2007 John Wiley & Sons, Ltd.
Seismic analysis of inelastic moment‐resisting frames Part I: Modified force analogy method for end offsets
Authors: Wong Kevin K. F. , Wang Zhe
Published: June 2007

An analytical method of performing inelastic structural dynamic analysis based on the force analogy method to study real moment‐resisting frames with plastic hinge offsets from member ends and rigid panel zones is proposed. New stiffness matrices used in the force analogy method for members with two ends being rigid are theoretically derived using the unit displacement method. Through static condensation, each term in the stiffness matrices is found to be modified simply through multiplying by a scale factor. This is an enhancement to the original force analogy method or other conventional methods, where the condensed form reduces the size of the structural problem by eliminating the unnecessary additional degrees of freedom that must be placed at the plastic hinges. But more importantly, this is a significant improvement on other conventional methods where the present inelastic analysis procedure is more of a theoretical nature rather than numerical. Numerical simulation for seismic analysis is performed on a single degree of freedom system, and the results show that plastic hinge end offsets have significant effects on the seismic response and therefore they should be carefully considered in dynamic analysis. The companion paper further discusses the influence of panel zone deformation on the dynamic response based on the method proposed in this part of the research. Copyright © 2007 John Wiley & Sons, Ltd.
Seismic analysis of inelastic moment‐resisting frames Part II: Energy dissipation in deformable panel zones
Authors: Wong Kevin K. F. , Wang Zhe
Published: June 2007

The simple analytical method developed in the companion paper is applied to study the dynamic behavior and energy dissipation of inelastic structures with panel zone deformation using rotational springs. Both shear deformation and inelastic behaviors of the panel zone are modeled using rotational springs to capture the actual vibration characteristics of the overall structural responses. The modified force analogy method with static condensation proposed in the companion paper is employed to study the effects of panel zone deformation on the dynamic behavior of inelastic structures, while rigid end offsets are also included to give a more accurate structural model. Based on this proposed analytical method, numerical simulation is first performed to study the responses of a one‐story one‐bay moment‐resisting frame. Results show that rigidity of panel zones plays a major role in the overall structural responses during earthquake excitations. Numerical simulations are then performed on a multi‐degree of freedom structure to demonstrate the use of the proposed method. Comparison of results between modeling structures with various panel zone rigidities and yield moments in the rotational springs shows that significant differences in both structural responses and energy dissipations exist between the models, and therefore the effects of panel zone deformation should be considered in dynamic analysis. Copyright © 2007 John Wiley & Sons, Ltd.
Experimental and analytical studies on tall buildings with a high‐level transfer story
Authors: Wu Meiliang , Qian Jiaru , Fang Xiaodan , Yan Weiming
Published: June 2007

Shaking‐table tests of three scaled Plexiglas models of tall buildings with a transfer story at story five, seven or nine, respectively, were carried out. The experimental results show that with increasing transfer story level the natural frequencies of the structures show little change and the change of mode shapes is not significant. The maximum elastic responses of acceleration, interstory drift ratio and base shear force might increase or decrease. Elastic and elasto‐plastic time history analyses of tall buildings with different levels of transfer story were performed to study the seismic behavior of tall buildings with a high‐level transfer story. The analytical results show that for tall buildings with a high‐level transfer story the maximum elastic interstory drift ratios become small at the transfer story. With increasing transfer story level, the maximum ratio of base shear force to total weight, and the maximum elastic and elasto‐plastic interstory drift ratios, might increase or decrease. Reducing the stiffness below the transfer story will increase the interstory drift ratio. Deformations of the floor slab increase the elastic internal forces of support columns near the transfer story. Copyright © 2007 John Wiley & Sons, Ltd.
Dynamic control of structures subjected to constraints
Authors: Lee Eun‐Taik , Chung Heon‐Soo , Eun Hee‐Chang
Published: June 2007

This study presents a dynamic equation of constrained motion and illustrates its validity through a dynamic analysis on the structural control by a constraint. Minimizing a function of the variation in kinetic energy at constrained and unconstrained states with respect to the velocity variation, the dynamic equation is derived and it is shown that the result compares with the generalized inverse method proposed by Udwadia and Kalaba. It is investigated that the responses of a 10‐story building are controlled by a constraint due to the installation of a two‐bar structure. The structural responses are affected by various factors like the length of each bar, damping, stiffness of the bar structure, and the boundary positions between two structures. Under an assumption that the bars have the same mass density, this study determines the optimal boundary positions to minimize the total responses of the structure, and compares the responses and control forces by optimal feedback control with the results. Copyright © 2007 John Wiley & Sons, Ltd.
Seismic isolation columns for earthquake‐resistant structures
Authors: Briman V. , Ribakov Y.
Published: June 2007

Seismic isolation is a well‐known trend in earthquake design of structures. It enables a reduction in structural response to earthquakes and minimizes possible damage to buildings. This paper deals with a new constructive solution for seismic isolation, adapted to a structural scheme traditionally used in the Mediterranean region; it is usually presented as an open ground floor with a system of reinforced‐concrete columns, supported on single bases. The best‐known base isolation systems, implemented in existing structures, are elastomeric bearings and friction pendulums. The proposed solution is based on the idea of pendulum suspension brackets installed in seismic isolation columns. The main differences between existing solutions and the proposed one are that the latter requires no additional space for its installation, its lifetime corresponds to that of the structure, and no service is required during the entire period. The proposed solution provides additional damping and, like other base isolation systems, shifts the vibration period of the structure, reducing its spectral response. Since its size is compact, the ground‐floor columns of existing structures with low seismic capacity may easily be replaced by the proposed ones. It yields significant improvement in structural seismic response. Numerical simulation shows that buildings where the proposed system is installed are likely to sustain minimal damage, or none at all, whereas traditionally designed ones may suffer major damage or even collapse due to the same earthquake. Copyright © 2007 John Wiley & Sons, Ltd.
Practical design issues of tuned mass dampers for torsionally coupled buildings under earthquake loadings
Authors: Ueng Jin‐Min , Lin Chi‐Chang , Wang Jer‐Fu
Published: June 2007

In this study, a new design procedure was developed for reducing the dynamic responses of torsionally coupled buildings, particularly existing buildings, under bilateral earthquake excitations, by incorporating the vibration control effectiveness of passive tuned mass dampers (PTMDs) . Some practical design issues such as the optimal location for installation, movement direction and numbers of PTMD are considered in this study. The optimal parameters of the PTMD system are determined by minimizing the mean square displacement response ratio of the controlled degree of freedom between the building with and without PTMDs. In addition, parametric studies of the PTMD planar position and the detuning effect are undertaken to determine their influence on the response control efficacy. The numerical results from two typical multistory torsionally coupled buildings under bidirectional ground accelerations, recorded at the 1979 El Centro earthquake, verify that the proposed optimal PTMDs are more effective and more robust in reducing the building responses. Copyright © 2007 John Wiley & Sons, Ltd.
Robustness of base‐isolated high‐rise buildings under code‐specified ground motions
Authors: Takewaki I.
Published: June 2007

The robustness of base‐isolated high‐rise buildings is investigated under code‐specified ground motions. Friction‐type bearings are often used in base‐isolated high‐rise buildings to make the natural period of those buildings much longer. While additional damping can be incorporated into every story in passive controlled structures with inter‐story type passive members, that can be incorporated into the base‐isolation story only in the base‐isolated building. This fact leads to the property that, as the number of stories of the building becomes larger, the damping ratio reduces. This characteristic may cause some issues in the evaluation of robustness of base‐isolated high‐rise buildings. The purpose of this paper is to reveal the robustness of base‐isolated high‐rise buildings. A kind of inverse problem for the target drift in the base‐isolation story is formulated in order to determine the required quantity of additional viscous damping. It is demonstrated numerically that, as the base‐isolated building becomes taller, the damping ratio becomes smaller and the ratio of the friction‐type bearings in the total damping becomes larger. This may lead to the conclusion that base‐isolated high‐rise buildings have smaller robustness than base‐isolated low‐rise buildings. Copyright © 2007 John Wiley & Sons, Ltd.
The “business intelligence” challenge in the context of regional risk
Authors: Kinsinger Paul C.
Published: June 2007

The world of intelligence is about understanding external factors we cannot control in order to reduce the risk and increase the reward. Indeed, business intelligence (BI) flourishes today in the United States because market economics and, even more important, the way business is done here, pump out information 24‐7‐365 the way a heart on steroids pumps out blood. In this article, I offer an overview of BI within the context of four countries that are the subject of in‐depth study in this issue of Thunderbird International Business Review: Iraq, the United Arab Emirates, Croatia, and Bosnia and Herzegovina. All four nations offer interesting and varied examples for the international manager doing business in countries where risk is often a key factor that must be considered when making business decisions. © 2007 Wiley Periodicals, Inc.
Optimal shape of an elastic rod in flexural – torsional buckling
Authors: Atanackovic T.M.
Published: June 2007

Optimal shape of an elastic rod subjected to flexural‐torsional buckling is studied. The rod with constant‐cross section is the strongest rod for the case when a rod is subjected to equal end moments only. For the case when the rod is loaded with compressive force and the moment, optimal shape is determined by numerical integration for several values of parameters. In deriving the optimality conditions, the Pontriyagin's principle was used.
Analytical solution for three‐dimensional stresses in a short length FGM hollow cylinder
Authors: Jabbari M. , Mohazzab A.H. , Bahtui A. , Eslami M.R.
Published: June 2007

This paper presents the general theoretical analysis of three‐dimensional mechanical and thermal stresses for a short hollow cylinder made of functionally graded material. The steady‐state temperature, displacements, and stresses distributions are derived due to the general mechanical and thermal boundary conditions, as functions of radial, circumferential and longitudinal directions. The material properties vary continuously along the thickness direction according to power functions of radial direction. The temperature and Navier equations are solved analytically, using the generalized Bessel function and Fourier series. A direct method of solution of Navier equations is presented.
Rayleigh–Stokes problem for non‐Newtonian medium with memory
Authors: Zierep J. , Bohning R. , Fetecau C.
Published: June 2007

The solution of the governing equation for second grade fluid is discussed analytical by Fourier sine transform and numerical. We found an interesting memory behaviour for the Rayleigh–Stokes problem.