bluuebunny/crossref_metadata_2025 huggingface dataset:
The physical action of three diatomaceous earths against the cuticle of the flour mite Acarus siro L. (Acari: Acaridae)
Authors: Cook Dean A , Wakefield Maureen E , Bryning Gareth P
Published: October 2007

Experiments examined the accepted modes of action of the desiccant dust, diatomaceous earth (DE), against the flour mite, Acarus siro (L.) (Astigmata). Adult mites were exposed to three DE products for periods of 3, 18 and 72 h under conditions designed to allow partial desiccation of the mites without causing mortality. After exposure, the DE dust particles were washed off the mite bodies, and both the DE and the mites were examined for presence of cuticular hydrocarbons by gas chromatography–mass spectroscopy (GC‐MS) analysis. GC‐MS identified seven major cuticular lipids of chain length C13C26 that may have a role in the waterproofing of A. siro. After 18 h exposure, n‐tridecane and several different long‐chain fatty acid ethyl esters were detected on one of the DE products. After 72 h, n‐tridecane was detected on all three DE products. Mite samples retained after removal of the DEs were examined by microscopy. Tentative evidence was observed by conventional low‐power microscopy that might indicate uniform removal of the epicuticle. However, a detailed examination by scanning electron microscopy showed no signs of abrasion. © Crown copyright 2007. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
An Atom Counting QSPR Protocol
Authors: Giri Santanab , Roy Dehesh R. , Van Damme Sofie , Bultinck Patrick , Subramanian Venkatesan , Chattaraj Pratim K.
Published: October 2007

A simple descriptor, viz the number of carbon (NC)/non‐hydrogenic (NNH) atoms present in a molecule, is proposed for the development of useful Quantitative Structure–Property–Relationship (QSPR) models. This work is prompted by that of Randic and Basak (J. Chem. Inf. Comput. Sci. 2001, 41, 614–618) who have shown that this descriptor is superior to the simple connectivity index and is marginally worse than the variable connectivity index for analyzing the toxicity of aliphatic ethers. It is tested in the present work in models pertaining to the estimation of boiling point of alcohols, enthalpy of vaporization of Polychlorinated Biphenyls (PCBs), n‐octanol/water partition coefficient of PCBs and chloroanisoles, pKa values of carboxylic acids, phenols, alcohols, etc. High values of various regression coefficients (R2, $\rm{ R_{{\rm{CV}}}^2 }$, $\rm{ R_{{\rm{Ad}}}^2 }$) suggest the significance of this descriptor which further improves in the resulting two‐parameter QSPR models with electrophilicity or its local variant as an additional descriptor. Other statistical quantities are also analyzed for gaining additional insights into the proposed models. Although the atom number is not the best possible descriptor in a QSPR model in all cases, its simplicity provides it a special place in the development of those models. The present analysis extends the work of Randic and Basak by delineating the situations when NC/NNH performs well vis‐a‐vis the other descriptors.
Tayloring standard TDDFT approaches for computing UV/Vis transitions in thiocarbonyl chromophores
Authors: Preat Julien , Jacquemin Denis , Perpète Eric A.
Published: October 2007

We report the development of an accurate computational procedure for the calculation of the n → π* (λmax−1) and π → π* (λmax−2) transitions of a set of thiocarbonyl derivatives. To ensure converged results, all calculations are carried out using the 6‐311+G(2df,p) basis set for time‐dependent calculations, and the 6‐311G(2df,p) for the ground‐state geometrical optimization. Starting with two hybrids, PBE0 and B3LYP, the Hartree–Fock exchange percentage (α) used is optimized in order to reach excitation energies that fit experimental data. It turns out that BLYP(α) is the more adequate functional for calibration. For the n → π* excitation, the optimal α value lies in the 0.10–0.20 interval, whereas for the π → π* process setting α equal to 0.10 provides the most accurate results. The corresponding mean absolute errors (MAE) are limited to 17 nm for λmax−1, and to 10 nm for λmax−2, allowing a consistent and accurate prediction of both transitions. We also assess the merits of the ZINDO//AM1 scheme and it turns out that the semi‐empirical method only provides a poor prediction of the λmax of thiocarbonyl derivatives, especially for the n → π* transition. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Mercury telluride crystals encapsulated within single walled carbon nanotubes: A density functional study
Authors: Kuganathan Navaratnarajah , Green Jennifer C.
Published: October 2007

The structure and binding energies of mercury telluride crystals encapsulated within single walled carbon nanotubes (SWNTs) have been studied using density functional theory. The energies of three different pseudo one‐dimensional crystals of HgTe with 4:4, 3:3, and 2:2 coordination are compared. The initial structure for the 4:4 crystal was a 2 × 2 cubic motif derived from rock salt bulk structure, the 3:3 crystal corresponds to a novel structure found when HgTe was intercalated within SWNTs, and the 2:2 crystal is a chain motif derived from cinnabar (HgS) bulk structure. The isolated 3:3 crystal was found to be the most thermodynamically stable of the three structures. Calculations were performed on the 3:3 crystal inserted into three different SWNTs, (15, 0), (9, 9), and (17, 0), in order to investigate the perturbations on the molecular and electronic structure of the crystal and the SWNT, and the energy of formation of the HgTe@SWNT composites. The calculated structures are in good agreement with the experimental high resolution transmission electron microscopy images of the HgTe@SWNT composite. The calculated binding energies and density of states show that the interaction between nanotubes and the HgTe crystals is noncovalent. Since the energy difference of the “free” 4:4 and 3:3 structures is small and of the order of magnitude of the binding energies with the nanotubes, we carried out calculations on 4:4 HgTe structure inserted in to two different SWNTs, (15, 0) and (17, 0). The calculated binding energies show that, when the 4:4 structure is inserted into the smallest tube, the resultant composite has an energy comparable to the 3:3 structure, suggesting that this polymporph may also be found experimentally. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Theory of chemical bonds in metalloenzymes. VII. Hybrid‐density functional theory studies on the electronic structures of P450
Authors: Shoji Mitsuo , Isobe Hiroshi , Saito Toru , Yabushita Hirotaka , Koizumi Kenichi , Kitagawa Yasutaka , Yamanaka Shusuke , Kawakami Takashi , Okumura Mitsutaka , Hagiwara Masayuki , Yamaguchi Kizashi
Published: October 2007

A first principle investigation has been carried out for intermediate states of the catalytic cycle of a cytochrome P450. To elucidate the whole catalytic cycle of P450, the electronic and geometrical structures are investigated not only at each ground state but also at low‐lying energy levels. Using the natural orbital analysis, the nature of chemical bonds and magnetic interactions are investigated. The ground state of the Compound 1 (cpd1) is calculated to be a doublet state, which is generated by the antiferromagnetic coupling between a triplet Fe(IV)O moiety and a doublet ligand radical. We found that an excited doublet state of the cpd1 is composed of a singlet Fe(IV)O and a doublet ligand radical. This excited state lies 20.8 kcal mol−1 above the ground spin state, which is a non‐negligible energy level as compared with the activation energy barrier of ΔE# = 26.6 kcal mol−1. The reaction path of the ground state of cpd1 is investigated on the basis of the model reaction: 3O(3p) + CH4. The computational results suggest that the reactions of P450 at the ground and excited states proceed through abstraction (3O‐model) and insertion (1O‐model) mechanisms, respectively. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Novel silicon nanorings: Persilacyclacenes at DFT
Authors: Kassaee M. Z. , Arefrad H. , Ghambarian M.
Published: October 2007

Structures, energies, and aromatic characters are compared and contrasted for a series of [n]persilacyclacenes with n = 6–12: Si24H12, Si28H14, Si32H16, Si36H18, Si40H20, Si44H22, and Si48H24, respectively, at B3LYP levels (n, number of fused benzenoid rings). These are a brand of silicon nanorings that bear a resemblance to the shortest zig‐zag silicon nanotubes (SiNTs), henceforth referred to as SiNRs. The NBO results show nearly sp2‐hybridization for virtually all Si atoms of our SiNRs. This is in contrast to most reports where sp3‐hybridization is proposed for typical SiNTs. Comparison between the optimized SiNRs and their corresponding planar (polyacenic) forms shows longer bond lengths for the former, due to their curvatures. Except for sterically hindered Si24H12 (n = 6), all even SiNRs (n = 8, 10, and 12), are more aromatic than the odd ones (n = 7, 9, and 11). Such a higher aromaticity is witnessed inside, outside, and on the surface of the scrutinized SiNRs. Also, except for Si44H22 (n = 11), the energy gaps (ΔEHOMO−LUMO) for the odd set of SiNRs, as well as the even set, appear inversely proportional to their corresponding diameters, per se. Except for the sterically hindered SiNRs with n = 6 or 7, all the even SiNRs enjoy a higher stability (aromaticity) and conductivity for showing lower ΔEHOMO−LUMO than the odd ones. Evidently, the ideal diameter for persilacyclacenes (SiNRs) studied is from 0.92 to 1.42 nm, corresponding to n = 8–12, respectively. Higher than 1.42 nm causes structural disorders while lower than 0.92 brings about bond localization due to the high‐steric effects. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Efficient identification and quantification of proteins using isotope‐coded 1‐(6‐methylnicotinoyloxy)succinimides by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Tsumoto Hiroki , Murata Chie , Miyata Naoki , Kohda Kohfuku , Taguchi Ryo
Published: October 2007

We describe a convenient and useful method for the identification and relative quantification of proteins using light and heavy reagents, 1‐(6‐methylnicotinoyloxy)succinimides (6‐CH3‐Nic‐NHS and 6‐CD3‐Nic‐NHS, respectively). This method is based on the chemical derivatization of amino groups of tryptic peptides with these reagents, i.e., the basic moiety of the reagents thus incorporated into both the N‐terminal amino group and the ε‐amino group of the lysine residue would improve the ionization efficiency of tryptic peptides. An increase in protein sequence coverage is achieved by derivatization with these reagents or by combination of mass values before and after derivatization. Since a combination of 6‐CH3‐Nic‐NHS and d3‐labeled reagent (6‐CD3‐Nic‐NHS) generates a 3 Da mass difference per reaction site, the d3‐labeled reagent shifts the mass values of d0‐labeled peptides according to the number of reactive amino groups in the peptides. In the case of tryptic peptides, the mass values of C‐terminal arginine and lysine peptides are shifted by 3 and 6 Da, respectively. Further, the 3 Da mass difference between 6‐CH3‐Nic‐NHS and 6‐CD3‐Nic‐NHS offers a means for the relative quantification of protein by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. Copyright © 2007 John Wiley & Sons, Ltd.
Neutral loss analysis of amino acids by desorption electrospray ionization using an unmodified tandem quadrupole mass spectrometer
Authors: Corso Gaetano , Paglia Giuseppe , Garofalo Daniela , D'Apolito Oceania
Published: October 2007

A new method to analyze free amino acids using desorption electrospray ionization (DESI) has been implemented. The method is based on the neutral loss mode determination of underivatized amino acids using a tandem quadrupole mass spectrometer equipped with an unmodified atmospheric interface. Qualitative and quantitative optimization of DESI parameters, including ESI voltage, solvent flow rate, angle of collection and incidence, gas flow and temperatures, was performed for amino acids detection. The parameters for DESI analysis were evaluated using a mixture of valine, leucine, methionine, phenylalanine and tyrosine standards. A few microliters of this mixture were deposited on a slide, dried and analyzed at a flow rate of 2 µL/min. The optimal ionization response was obtained using laboratory glass slides and an equivalent solution of water/methanol doped with 2% of formic acid. The method specificity was evaluated by comparing product ion spectra and neutral loss analysis of amino acids obtained either by DESI or by electrospray ionization flow injection analysis (ESI‐FIA). To evaluate the quantitative response on amino acids analyzed by DESI, calibration curves were performed on amino acid standard solutions spiked with a fixed amount of labelled amino acids. The method was also employed to analyze free amino acids from blood spots, after a rapid solvent extraction without other sample pretreatment, from positive and negative subjects. The method enables one to analyze biological samples and to discriminate healthy subjects from patients affected by inherited metabolic diseases. The intrinsic high‐throughput analysis of DESI represents an opportunity, because of its potential application in clinical chemistry, for the expanded screening of some inborn errors of metabolism. Copyright © 2007 John Wiley & Sons, Ltd.
Duality theory of the optimal two‐blockH∞problem
Authors: Djouadi S. M. , Birdwell J. D.
Published: October 2007

This paper provides the Banach duality theory structure of the optimal two‐blockH∞problem. Alignment conditions are obtained and show that the optimal solution is flat or allpass in general, and is unique in the single‐input single‐output case. The optimal solution is shown to satisfy an extremal identity, which gives a necessary and sufficient condition for a controller to be optimal. Moreover, nearly optimal control laws are shown to satisfy an approximate allpass condition. It is also proved that under specific conditions a Hankel–Toeplitz operator achieves its norm on the discrete spectrum, therefore generalizing a similar result obtained formerly for finite‐dimensional (rational) systems. The norm of this Hankel–Toeplitz operator corresponds to the optimal two‐blockH∞performance. The dual description leads naturally to a numerical solution based on convex programming for linear time‐invariant (possibly infinite‐dimensional) systems. Copyright © 2007 John Wiley & Sons, Ltd.
Estimating adult Chinook salmon exposure to dissolved gas supersaturation downstream of hydroelectric dams using telemetry and hydrodynamic models
Authors: Johnson Eric L. , Clabough Tami S. , Peery Christopher A. , Bennett David H. , Bjornn Theodore C. , Caudill Christopher C. , Richmond Marshall C.
Published: October 2007

Gas bubble disease (GBD) has been recognized as a potential problem for fishes in the Columbia River basin. GBD results from exposure to gas supersaturated water created by discharge over dam spillways. Spill creates a downstream plume of water with high total dissolved gas supersaturation (TDGS) that may be positioned along either shore or mid‐channel, depending on dam operations. We obtained spatial data on fish migration paths and migration depths for adult spring and summer Chinook salmon, Oncorhynchus tshawytscha, during 2000. Migration paths were compared to output from a two‐dimensional (2‐dimensional) hydrodynamic and dissolved gas model to estimate the potential for GBD expression and to test for behavioural avoidance of the high TDGS plume. We observed salmon swam sufficiently deep in the water column to receive complete hydrostatic compensation 95.9% of the time spent in the Bonneville Dam tailrace and 88.1% of the time in the Ice Harbor Dam tailrace. The majority of depth uncompensated exposure occurred at TDGS levels >115%. Adult Chinook salmon tended to migrate near the shoreline and they tended to remain in relatively deep water. Adults moved into the high dissolved‐gas plume as often as they moved out of it downstream of Bonneville Dam, providing no evidence that adults moved laterally to avoid areas with elevated dissolved gas levels. When water depths decreased due to reduced river discharge, adults tended to migrate in the deeper navigation channel downstream from Ice Harbor Dam. The strong influence of dam operations on the position of the high‐TDGS plume and shoreline‐orientation behaviours of adults suggest that exposure of adult salmonids to high‐TDGS conditions may be minimized using operational conditions that direct the spilled water mid‐channel. Our approach illustrates the potential for combined field and modelling efforts to estimate the fine‐scale environmental conditions encountered by fishes in natural and regulated rivers. Published in 2007 by John Wiley & Sons, Ltd.
Long‐term changes in macroinvertebrate communities of a heavy metal polluted stream: the river Nent (Cumbria, UK) after 28 years
Authors: Armitage Patrick D. , Bowes Michael J. , Vincent Helen M.
Published: October 2007

The macroinvertebrate fauna of the river Nent, a heavy metal polluted upland stream in northern England, first surveyed in 1976, was re‐examined in 2004 to assess long‐term changes in relation to activities in the catchment which have included, a river restoration project, works associated with the development of a mine heritage site and the removal of a chicken farm and more effective organic pollution control measures. The degree of change between years in total abundance, numbers of taxa and community composition varied considerably between sites. Two tributary sites showed marked changes between years due to a reduction in acidity in one and changed substratum in the other but in the main river no significant difference in total taxa and total abundance was observed between years, although seasonal differences were significant. Multivariate community analyses grouped 1976 samples with those taken in 2004 but revealed a clear separation between upper and lower Nent sites. This observed difference may be related to increased algal cover in the lower sites in conjunction with geomorphological features of the lower Nent. Environmental assessment methodology River Invertebrate Prediction and Classification System (RIVPACS) identified ‘sensitive’ faunal groups and indicated that the extensive impact of zinc pollution in the main river has remained practically the same between 1976 and 2004. This persistence of community structure despite the heavily disturbed nature of the river is attributed to relative constancy in instream habitat conditions. The recent activities in the catchment have had little effect on the overall controllers of faunal communities in this system, zinc concentrations and geomorphological characteristics of the stream. However, further disturbances involving movement of spoil heaps and channel alterations in the upper catchment may increase both sediment and heavy metal loadings to the river. Copyright © 2007 John Wiley & Sons, Ltd.
Thinking about systems: student and teacher conceptions of natural and social systems
Authors: Sweeney L. Booth , Sterman John D.
Published: October 2007

Many in the system dynamics community argue that children are natural systems thinkers. Here we study how middle school students and teachers think about everyday settings involving feedback, stocks and flows, time delays and nonlinearities, prior to any formal training in these concepts. We develop instruments to elicit understanding of systems concepts and test them with students and teachers from two middle schools in the U.S.A. We find, with some exceptions, generally limited intuitive systems thinking abilities. “Open‐loop” or one‐way causal thinking is common. Explanations lack references to time horizons and time delays. Significant misconceptions of stock and flow structures appear regardless of age. Teachers generally outperformed students, although one‐quarter of the students performed at the median level for teachers. We discuss the nature of students' and teachers' intuitive models of dynamic systems, explore potential barriers to understanding dynamic systems, and discuss implications for effective teaching of systems concepts. Copyright © 2007 John Wiley & Sons, Ltd.
System dynamics in the U.K.: a journey from Stirling to Oxford and beyond
Authors: Morecroft John , Wolstenholme Eric
Published: October 2007

We review the history of and survey current system dynamics activity in the United Kingdom. Copyright © 2007 John Wiley & Sons, Ltd.
A brief history of system dynamics in continental Europe
Authors: Milling Peter M.
Published: October 2007

The paper provides a brief review of system dynamics activity in continental Europe. Copyright © 2007 John Wiley & Sons, Ltd.
The history and conclusions of The Limits to Growth
Authors: Meadows Donella H. , Meadows Dennis
Published: October 2007

In this unpublished memoir, written in the early 1990s, the late Dana Meadows reflects on the history of The Limits to Growth, including its origins, conclusions, and the reactions it generated. This memoir had been condensed and edited by Dennis Meadows. Copyright © 2007 John Wiley & Sons, Ltd.
Making system dynamics useful: a personal memoir
Authors: Roberts Edward B.
Published: October 2007

During the many years that I was a founding member of the MIT Industrial Dynamics (ID) Group, later system dynamics (SD), I focused on trying to apply SD concepts, tools and techniques to the real world and to having real impact. That orientation originated from listening to Jay Forrester as he related his personal history and communicated his personal values to our group and to me individually in his forceful and influential manner. Here I review that history and some lessons I learned. As this is a personal memoir I do not attempt to review the entire field, but concentrate entirely on my years of activity in the SD field from 1958 to 1993 and on the aspects most familiar to me, i.e., my own teaching and research and the work of Pugh–Roberts Associates, Inc. Copyright © 2007 John Wiley & Sons, Ltd.
Forecasting turning points in shipping freight rates: lessons from 30 years of practical effort
Authors: Randers Jørgen , Göluke Ulrich
Published: October 2007

We argue that it is possible to explain much of the history of the world's shipping markets since 1950 as the interaction of two balancing feedback loops: a capacity adjustment loop which creates a roughly 20‐year wave, and a capacity utilization adjustment loop which generates a roughly 4‐year cycle. We show how this insight has been used rather successfully since the early 1980s for practical forecasting of turning points in freight rates and the “sentiment” in the shipping market 1_4 years ahead of time. The basic mechanisms in the shipping system create a strong “deterministic backbone” which is visible through the exogenous noise, and hence predictable with useful precision. Our experience leads to a number of questions concerning system dynamics best practice for future research. Copyright © 2007 John Wiley & Sons, Ltd.
System dynamics applied to project management: a survey, assessment, and directions for future research
Authors: Lyneis James M. , Ford David N.
Published: October 2007

One of the most successful areas for the application of system dynamics has been project management. Measured in terms of new system dynamics theory, new and improved model structures, number of applications, number of practitioners, value of consulting revenues, and value to clients, “project dynamics” stands as an example of success in the field. This paper reviews the history of project management applications in the context of the underlying structures that create adverse dynamics and their application to specific areas of project management, synthesizes the policy messages, and provides directions for future research and writing. Copyright © 2007 John Wiley & Sons, Ltd.
System dynamics—the next fifty years
Authors: Forrester Jay W.
Published: October 2007

Fifty years after its creation, I review the current status of the field of system dynamics and assess prospects for the next fifty. I focus on the challenges the field must face if it is to realize its potential.

The first 50 years of system dynamics have established an introduction to the field. We have shown the importance of achieving a better understanding of complex systems in nature and human affairs. Now, the field is on a plateau ready to launch the next great thrust forward.

We can better understand the present status of system dynamics by comparison to professions that have developed earlier. We are now at about the same state of advancement that engineering was when MIT first opened its doors in 1865, or that medicine was in the late 1800s when the Johns Hopkins School of Medicine was established.

We have as much to learn yet about high‐order nonlinear feedback structures around us as those earlier professions have already learned about their fields in the last 150 years. Now is the time to plan how the next 50 years can start to close this huge knowledge gap.

Like those early days in more mature professions, we do not yet have universities devoted to 4‐year and 6‐year programs in system dynamics. Like the older professions at their beginning, we do not yet have the equivalent of programs in science and biology in kindergarten through 12th grade education to prepare students for more advanced study at the university level. Nevertheless, there has been major progress in system dynamics during the last 50 years just as there had been in those older professions before they became formalized in advanced educational programs and before they were publicly recognized. Copyright © 2007 Jay W. Forrester.
Attenuation of photoelectrons and Auger electrons leaving nickel deposited on a gold surface
Authors: Zemek J. , Jiricek P. , Houdkova J. , Olejnik K. , Jablonski A.
Published: October 2007

Attenuation lengths of signal electrons are very important in surface metrology. Contrary to inelastic mean free paths (IMFP), the attenuation length is determined by both inelastic and elastic scattering events of the signal electrons in the solid. Therefore, application of attenuation lengths leads to improved accuracy in measurements of length on a nanometer scale. In the present work, photoelectron and Auger‐electron spectra (AES) in regions of Au 4f, Ni 3p, Ni 2p, and Au MNN were recorded from nickel overlayers deposited in situ, step by step, on a gold surface. The experiment was coupled with advanced calculations of electron transport for the nickel/gold system. An overlayer growth mode has been elucidated by a line‐shape analysis of the Ni 2p spectra with the QUASES‐Tougaard software and from extensive Monte Carlo calculations of electron transport in the overlayer/substrate system with the SESSA software. The QUASES‐Tougaard analysis indicated three‐dimensional island growth followed by a continuous nickel overlayer for thicknesses exceeding 2 nm. The attenuation of electron intensities described by the effective attenuation length (EAL), calculated with the NIST SRD 100 database [Simulation of Electron Spectra for Surface Analysis (SESSA) software] and the NIST SRD 82 database, was found in close agreement for all electron transitions considered. The measured EAL values compared well with EALs calculated for Au 4f, Ni 3p, and Ni 2p photoelectrons, whereas the EAL derived from the measured Au MNN intensity–thickness plot was found to be about 20% less than the predicted values. Copyright © 2007 John Wiley & Sons, Ltd.
Modelling multisera data: The estimation of new joint and conditional epidemiological parameters
Authors: Hens N. , Aerts M. , Shkedy Z. , Theeten H. , Van Damme P. , Beutels Ph.
Published: October 2007

Testing humans for infectious diseases is often done by assessing the presence or absence of disease‐specific antibodies in serum samples. For feasibility and economical reasons, these sera are often tested for more than one antigen. Studying diseases with similar transmission routes can govern new insights for disease dynamics. We use flexible marginal and conditional models to model multisera data on the Varicella‐Zoster virus and the Parvo B19‐virus in Belgium. Next form the derivation of the age‐dependent marginal force of infection (FOI), we introduce new epidemiological parameters: the age‐dependent joint and conditional FOI. These parameters allow us to study the association among the occurrence and acquisition of both infections. Furthermore, we show how to test for association and whether the infection‐specific age‐dependent FOI curves are proportional and consequently whether separable mixing in the population holds. Copyright © 2007 John Wiley & Sons, Ltd.
Variation among schools on classroom practices in science based on TIMSS‐1999 in Turkey
Authors: Aypay Ahmet , Erdoğan Mehmet , Sözer Mehmet A.
Published: October 2007

The purpose of this study was to investigate the differences among schools using student responses in the Trends in Mathematics and Science Study–1999 (TIMSS‐99) data. Schools were classified into two groups based on eighth grade students' overall achievement in science. Two different discriminant function analyses were performed to distinguish high‐ and low‐performing schools, based both on classroom practices and factor structures (student‐centered activities, teacher‐centered activities, attitudes toward technology use, socioeconomic status [SES], and doing well in science). The results indicate that there were significant differences between the two classifications of schools on ten variables regarding classroom practices and activities, and 29 variables regarding classroom practices, attitudes toward science, use of the computer and overhead projector (OHP), parental background characteristics, and need to do well in science. Contrary to general expectations, technology use (computer, OHP, etc.) was found to be negatively related to science achievement. Teachers should be trained on how to use technology in their classrooms. Turkey recently revised its curriculum to a student‐centered approach and this might increase students' ability to transfer knowledge into real life. Teachers and schools should pay more attention to SES effects. Teachers should also work toward building students' confidence in science. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 44: 1417–1435, 2007
Decrease of hirudin degradation by deleting the KEX1 gene in recombinant Pichia pastoris
Authors: Ni Zhenhua , Zhou Xiangshan , Sun Xueqian , Wang Ya , Zhang Yuanxing
Published: October 2007

Our previous study on recombinant hirudin production in Pichia pastoris demonstrated that, although the total productivity of hirudin was fairly high, its degradation was still severe, even if many engineering methods were applied to improve cell viability and reduce the release of intracellular proteinases. In this work, a pop‐in/pop‐out method, replacing the auxotrophic marker ARG4 gene with the resistant marker sh ble gene, was used to delete the KEX1 gene to reduce hirudin degradation in P. pastoris GS115Hir. Using this strategy, hirudin degradation was greatly decreased. At the same wet cell weight and cell viability, the percentage of intact hirudin Hir65 in total hirudin in strain GS115HirΔkex1 was always kept as high as 90% in the initial stage of the methanol fermentation phase and above 62% even in the later stage of the methanol fermentation phase, whereas the percentage for the undeleted strain GS115Hir was only about 40% in the whole methanol fermentation phase. As a result, the intact hirudin Hir65 concentration could maximally reach 2.4 g/l in GS115HirΔkex1 while it was only 1.1 g/l in GS115Hir. Copyright © 2007 John Wiley & Sons, Ltd.
Colony growth and dispersal in the ant‐tended aphid,Aphis craccivoraKoch, and the non‐ant‐tended aphid,Acyrthosiphon pisumHarris, under the absence of predators and ants
Authors: Tokunaga Emi , Suzuki Nobuhiko
Published: October 2007

To elucidate the potential for colony growth and the dispersal of aphids in relation to the ant attendance, the mobility, tolerance of starvation, colony growth, and dispersal were examined in the ant‐tendedAphis craccivoraKoch and the non‐ant‐tendedAcyrthosiphon pisumHarris under the absence of predators and ants. The increase of the dispersal rate with density was more conspicuous inAc. pisumthanAp. craccivora.The success rate of dispersal was higher inAc. pisumthanAp. craccivora. These results would be derived from the higher ability of dispersal by walking inAc. pisumthanAp. craccivora. The longer legs, higher walking speed, and stronger tolerance of starvation inAc. pisummight result in a higher ability of dispersal by walking. These traits may have developed in relation to non‐ant attendance, becauseAc. pisumaphids frequently escape from natural enemies by dropping from the host plant. On the other hand,Ap. craccivorahave not developed morphological and behavioral traits concerning dispersal by walking, because increasing colony size without dispersal is likely to be advantageous for ant attraction. Escaping behaviors ofAp. craccivorafrom natural enemies have not been well developed due to the ant's defense against natural enemies. The proportion of alatae inAp. craccivorawas higher than inAc. pisuminstead of a lesser ability for dispersal by walking inAp. craccivora. The differences in ant attendance have been influenced in the development of morphological and behavioral traits concerning the dispersal ability, and then, different potentials for reproduction and dispersal have developed in ant‐tended aphids and non‐ant‐tended aphids.
The Dependent Poisson Race Model and Modeling Dependence in Conjoint Choice Experiments
Authors: Ruan Shiling , MacEachern Steven N. , Otter Thomas , Dean Angela M.
Published: October 2007

Conjoint choice experiments are used widely in marketing to study consumer preferences amongst alternative products. We develop a class of choice models, belonging to the class of Poisson race models, that describe a ‘random utility’ which lends itself to a process-based description of choice. The models incorporate a dependence structure which captures the relationship between the attributes of the choice alternatives and which appropriately moderates the randomness inherent in the race. The new models are applied to conjoint choice data and are shown to have performance markedly superior to that of independent Poisson race models and of the multinomial logit model.
Basestock Oils for Lubricants from Mixtures of Corn Oil and Synthetic Diesters
Authors: Pop Loredana , Puşcaş Cosmina , Bandur Geza , Vlase Gabriela , Nuţiu Remus
Published: October 2007

Environmentally friendly vegetable oils and their derivatives represent alternatives to mineral‐based lubricants. Vegetable oils have high biodegradability and low production costs. Their poor thermo‐oxidative stability and poor low temperature properties are disadvantages in their use as lubricant basestocks. In our study we used corn oil and diester mixtures, which become lubricants when additives are introduced. These mixtures of corn oil and di‐2‐ethylhexyl‐adipate (DOA) and di‐2‐ethylhexyl‐sebacate (DOS) offer a wide range of kinematic viscosities, pour points lower than −39 °C and flash points over 218 °C. The diameters of wear scars measured under four‐ball testing (40 daN) are less than 0.90 mm and the copper strip corrosion test result is 1a. The differential scanning calorimetry study and thermogravimetric study under nitrogen atmosphere and in synthetic air are reported. From these studies a higher thermal stability was observed for corn oil than for diester oils. The thermo‐oxidative instability occurred at temperatures higher than 350 °C. The low production cost of corn oil and its mixtures with diesters makes them an attractive alternative to mineral oil lubricants.
Entwicklung der Zähne
Authors: Koch M.J.
Published: October 2007

Die Zahnentwicklung verläuft in Stadien: Bereits ab der 6. Embryonalwoche bildet sich die Zahnleiste, frühzeitig werden Zahnzahl und Zahnform determiniert. Danach werden – ebenfalls in Stadien – die Zahnhartsubstanzen gebildet. Genetisch bedingte Zahnveränderungen sind nicht selten. Die Zahnzahl kann verändert sein (meist eine verringerte Zahnzahl), was oft auch gemeinsam mit einer Zahnformanomalie (Zapfenzähne, verkleinerte Zähne) auftritt. Hypodontie kommt isoliert (Prävalenz zwischen 1% und 5%) oder im Rahmen von genetisch bedingten Syndromen vor, etwa bei einer Reihe von ektodermalen Dysplasien, bei Rieger-Syndrom, Witkop-Syndrom usw. Zugrunde liegen können Mutationen von Transkriptionsfaktoren. Genetisch bedingte Veränderungen der Struktur von Zahnhartsubstanzen sind seltener (Prävalenz <0,1%). So gibt es verschiedenartige Formen der Amelogenesis imperfecta, verursacht durch Mutationen der spezifischen Zahnschmelzproteine. Die Dentinogenesis imperfecta kann dagegen sowohl für die isolierte genetisch bedingte Dentinveränderung stehen (Mutation des DSPP-Gens) als auch für die Zahnbeteiligung im Rahmen der Osteogenesis imperfecta.
The effect of community-prescribed ankle–foot orthoses on gait parameters in children with spastic cerebral palsy
Authors: Hayek Shlomo , Hemo Yoram , Chamis Sam , Bat Reuven , Segev Eitan , Wientroub Shlomo , Yzhar Ziva
Published: October 2007

Purpose

To evaluate the efficacy of ankle foot orthoses (AFOs) prescribed in the community for children with cerebral palsy (CP).

Methods

Fifty-six children (32 boys and 24 girls, mean age 8.9 years, range 4–17) who were diagnosed as having CP were enrolled. They were grouped according to the type of CP, diplegic ( n = 38) and hemiplegic ( n = 18). Three-dimensional gait analyses while patient were barefoot and with AFOs were obtained and analyzed.

Results

The spatio-temporal findings were the most significantly changed as a result of AFO use. In the hemiplegic group, stride length was 11.7% ( p = 0.001) longer with AFOs in both affected (10.2%) and non-affected (12.4%) legs, and cadence was reduced by 9.7%; walking speed was not affected. In the diplegic group, stride length with AFOs was 17.4% longer compared to barefoot ( p < 0.001) and walking velocity improved by 17.8% ( p < 0.001); cadence was unchanged. AFOs also increased ankle dorsiflexion at initial contact in both groups. In the hemiplegic group, AFOs produced an average 9.4° increase of dorsiflexion at initial contact (IC) on the affected side ( p < 0.001) and 5.87° on the unaffected side ( p = 0.007), and an increase of 9.9° ( p < 0.001) dorsiflexion at swing, on the affected side. In the diplegic group, dorsiflexion at IC was increased by 13.4° on the right side and 7.8° on the left side ( p = 0.05; p > 0.001, respectively) and an increase of 6° ( p = 0.005) at swing. In the hemiplegic group of patients, knee flexion at initial contact on the affected side was reduced by 8.5° ( p = 0.032) while in the diplegic group we found no influence. The number of patients that reached symmetry at initial double support tripled (from 5.6 to 16.7%) with the use of AFOs.

Conclusions

Our results showed that the use of AFOs improves spatio-temporal gait parameters and gait stability in children with spastic cerebral palsy. It has a lesser effect on proximal joint kinematics. Children with spastic hemiplegia display greater improvement than those with spastic diplegia.
Phylogenetic and evolutionary analysis of the septin protein family in metazoan
Authors: Cao Lihuan , Ding Xiangming , Yu Wenbo , Yang Xianmei , Shen Suqin , Yu Long
Published: October 2007

Septins, a conserved family of cytoskeletal GTP‐binding proteins, were presented in diverse eukaryotes. Here, a comprehensive phylogenetic and evolutionary analysis for septin proteins in metazoan was carried out. First, we demonstrated that all septin proteins in metazoan could be clustered into four subgroups, and the representative homologue of every subgroup was presented in the non‐vertebrate chordate Ciona intestinalis, indicating that the emergence of the four septin subgroups should have occurred prior to divergence of vertebrates and invertebrates, and the expansion of the septin gene number in vertebrates was mainly by the duplication of pre‐existing genes rather than by the appearance of new septin subgroup. Second, the direct orthologues of most human septins existed in zebrafish, which suggested that human septin gene repertoire was mainly formed by as far as before the split between fishes and land vertebrates. Third, we found that the evolutionary rate within septin family in mammalian lineage varies significantly, human SEPT1, SEPT 10, SEPT 12, and SEPT 14 displayed a relative elevated evolutionary rate compared with other septin members. Our data will provide new insights for the further function study of this protein family.
A different pathway in the endoplasmic reticulum stress‐induced expression of human HRD1 and SEL1 genes
Authors: Kaneko Masayuki , Yasui Saori , Niinuma Yoshifumi , Arai Kiho , Omura Tomohiro , Okuma Yasunobu , Nomura Yasuyuki
Published: October 2007

Human HRD1 and SEL1 are components of endoplasmic reticulum‐associated degradation (ERAD), which is a retrograde transport mechanism from the ER to the cytosol for removing unfolded proteins. The expression of HRD1 and SEL1 was induced by ER stress‐inducing agents and overexpression of both ER stress‐responsive transcription factors, ATF6 and XBP1. Inhibition of IRE1 and ATF6 revealed that ER stress‐induced HRD1 and SEL1 expressions are mediated by IRE1‐XBP1‐ and ATF6‐dependent pathways, respectively. These results suggest that the ER stress‐induced ERAD gene expressions are mediated by different pathways, which are attributed to the differences in the promoter regions.
Function of a separate NH3‐pore in Aquaporin TIP2;2 from wheat
Authors: Bertl Adam , Kaldenhoff Ralf
Published: October 2007

Functional analysis of heterologously expressed TaTIP2;2 by means of stopped‐flow spectrometric studies provide evidence for water and ammonia conductivity. A series of experiments under increasing pH indicate that the gaseous NH3, rather than the ammonium ion
urn:x-wiley:00145793:media:feb2s001457930701099x:feb2s001457930701099x-math-si2
was transported. Results from inhibitor studies strongly suggest that NH3 is not transported in file with water, but through a separate pathway, which could be supplied by the 5th central pore in a tetramer conformation.
Characterization of nuclear localization and nuclear export signals of yeast actin‐binding protein Pan1
Authors: Kamińska Joanna , Sędek Magdalena , Wysocka-Kapcińska Monika , Żołądek Teresa
Published: October 2007

Pan1 is an actin patch‐associated protein involved in endocytosis. Our studies revealed that in oleate‐grown cells Pan1 is located in the nucleus as well as in patches. One of three putative nuclear localization signals (NLS) of Pan1, NLS2, directed β‐galactosidase (β‐gal) to the nucleus. However, GFP‐Pan1886−1219, containing NLS2, was found in the cytoplasm indicating that it may contain a nuclear export signal (NES). A putative Pan1 NES, overlapping with NLS3, re‐addressed NLSH2B‐NES/NLS3‐β‐gal from the nucleus to the cytoplasm. Inactivation of the NES allowed NLS3 to be effective. Thus, Pan1 contains functional NLSs and a NES and appears to shuttle in certain circumstances.
Molecular imaging of endogenous mRNA expression in a mouse tumor model by adenovirus harboring trans‐splicing ribozyme
Authors: Hong Seung-Hee , Jeong Jin-Sook , Lee Yoon-Jong , Jung Haeng-Im , Kim Kyung Tae , Kim Yun-Hee , Lee Yeon-Su , Lee Seong-Wook , Bae Chang-Dae , Park Joobae , Kim In-Hoo
Published: October 2007

We previously showed that a trans‐splicing ribozyme reprograms tumor‐related genes at the mRNA level, resulting in the expression of therapeutic genes and that this approach can be efficiently employed to target specific molecules. Here, we show that trans‐splicing ribozyme technology can be applied in molecular imaging of specific RNA expression in living animals. We exemplify this concept successfully by imaging mouse cytoskeleton‐associated protein 2 (mCKAP2) expression in intrahepatic tumor nodules using systemically delivered adenovirus harboring mCKAP2‐specific trans‐splicing ribozyme.
Locked 5Zs‐biliverdin blocks the Meta‐RA to Meta‐RC transition in the functional cycle of bacteriophytochrome Agp1
Authors: Seibeck Sven , Borucki Berthold , Otto Harald , Inomata Katsuhiko , Khawn Htoi , Kinoshita Hideki , Michael Norbert , Lamparter Tilman , Heyn Maarten P.
Published: October 2007

The bacteriophytochrome Agp1 was reconstituted with a locked 5Zs‐biliverdin in which the C4
C5 and C5–C6 bonds of the methine bridge between rings A and B are fixed in the Z and syn configuration/conformation, respectively. In Agp1‐5Zs the photoconversion proceeds via the Lumi‐R intermediate to Meta‐RA, but the following millisecond‐transition to Meta‐RC is blocked. Consistently, no transient proton release was detected. The photoconversion of Agp1‐5Zs is apparently arrested in a Meta‐RA‐like intermediate, since the subsequent syn to anti rotation around the C5–C6 bond is prevented by the lock. The Meta‐RA‐like photoproduct was characterized by its distinctive CD spectrum suggesting a reorientation of ring D.
Tetrahydropteridine deficiency impairs mitochondrial function in Dictyostelium discoideum Ax2
Authors: Kim Hye-Lim , Choi Yong Kee , Kim Do Hyung , Park Sun Ok , Han Jin , Park Young Shik
Published: October 2007

A putative cellular function of tetrahydropteridines (l‐erythro‐tetrahydrobiopterin and d‐threo‐tetrahydrobiopterin) was investigated in Dictyostelium discoideum Ax2 using a mutant disrupted in the gene encoding sepiapterin reductase (SR). The SR mutant, which produces about 3% of tetrahydropteridines if compared to wild‐type, was elucidated to have several functional defects related to mitochondria and oxidative stress: retarded growth, poor spore viability, impaired mitochondrial function, and increased susceptibility to oxidative stress induced by hydroxylamine or cumene‐hydroperoxide. However, the physiological defects were almost completely rescued by extrachromosomal expression of Dictyostelium SR. The results strongly suggested that tetrahydropteridines in Dictyostelium are associated with mitochondrial function, probably via direct protection against oxidative stress.
The medical profession and the defense and promotion of sexual and reproductive rights
Authors: Briozzo L. , Faúndes A.
Published: October 2007

The values of the medical profession and other healthcare providers allow assessment of the relationship between physicians, healthcare teams, patients, and healthcare networks regarding the defense and promotion of sexual and reproductive health and rights. This paper questions the traditional model of the relationship between healthcare professionals and patients, based on the classic paternalistic role of the physician. It describes the tools available to the medical profession and healthcare teams for the promotion of sexual and reproductive rights, and proposes specific actions that would lead to improvements for women and communities.
An Evaluation of a Clinical Method to Assess Malunion of Little Finger Metacarpal Fractures
Authors: WESTBROOK A. P. , DAVIS T. R. C.
Published: October 2007

This study assessed the reliability, responsiveness and validity of two clinical measurements for the assessment of malunion of little finger metacarpal neck and shaft fractures. Both compared the relative lengths of the ring and little fingers in the injured and contralateral hands. One measurement was taken with the metacarpophalangeal joints extended (straight-MCP), and the other with them flexed to 90° (90-MCP). Ninety-five percent of the differences between the relative lengths of the ring and little fingers in the two hands of 50 normal subjects were less than 3 mm and the 95% limits of agreement for repeat measurements (intra-observer reproducibility) was ±1 mm for both measurements. Both measurements were significantly altered in a group of 218 patients with a past history of a metacarpal shaft or neck fracture. Although both measurements correlated with the patient’s assessment of the cosmetic result ( p = 0.01), neither measurement correlated with the severity of palmar angulation of the fracture at presentation. It is concluded that these measurements are reliable and responsive, but their validity is uncertain.