bluuebunny/crossref_metadata_2025 huggingface dataset:
Multitasking and Value of Travel Time Savings
Authors: Ettema Dick , Verschuren Laura
Published: January 2008

This paper investigates the relationship between multitasking during travel and the valuation of travel time (VOT). By building on the literature on travel time valuation and multitasking, both the attitude toward multitasking and actual multitasking behavior are hypothesized to have a potential impact on the VOT. The basic assumption is that if travel time can be used for other purposes or if it becomes more enjoyable as it is increasingly accommodated by information and communication technology tools, travel time is valued less negatively, and the VOT will be lower. To test these hypotheses, a stated preference survey was carried out among commuters in the Dutch Eindhoven region. With estimated discrete choice models, the analyses indicate that monochronic individuals, who dislike engaging in activities simultaneously, have a higher VOT, as one would expect. Commuters who listen to music while commuting have a lower VOT. Commuters who read for their work while commuting have a higher VOT, probably related to a more task-oriented attitude. Overall, the findings suggest that actual multitasking behavior and attitudes toward multitasking have a significant impact on the VOT and cannot be neglected in policy analyses.
Automobiles, Trips, and Neighborhood Type
Authors: Shay Elizabeth , Khattak Asad J.
Published: January 2008

Transportation analysts have long recognized a role for the environment in travel behavior; techniques for incorporating the built environment into travel research remain in active development. This study uses multiple environmental representations to model automobile ownership and travel decisions with a single data set and model structure to test relationships already reported in the literature and to lay the foundation for extending this framework to additional travel modeling. Simple environmental measures, indices generated by factor analysis, and a neighborhood typology derived from cluster analysis of the factors, along with common household measures, are used to find the factors to provide information about travel that the clusters and direct measures do not. Automobile ownership and trips showed the expected relationships, with the former sensitive to sociodemographic factors and the latter sensitive also to the environment. Modes related differently to environmental factors; specifically, walk trips were strongly associated with accessibility and walkability, whereas drive trips were insensitive to these factors but were associated with other factors.
Impact of Carpooling on Trip-Chaining Behavior and Emission Reductions
Authors: Concas Sisinnio , Winters Philip L.
Published: January 2008

Within an activity-based framework, the hypothesis that carpooling imposes a constraint on the way individuals organize their activities was tested, with resulting impacts on traffic peak congestion and trip-chaining behavior. The hypothesis was tested by estimating the joint probability density functions (PDFs) of subsistence, maintenance, and discretionary trips made by carpool and single-occupancy vehicle (SOV) users. Results show that whereas SOV maintenance and discretionary activities are linked to subsistence trips in a joint undertaking, carpool activities suggest discontinuity in the formation of trip chains. A comparison of the joint PDF of subsistence and discretionary activities reveals that trips are conducted either before or after the commute schedule; this results in a temporal shift that reduces peak-period traffic congestion and emission pollution. Marked differences are found to exist between SOV and carpool trip-chaining behavior. Carpoolers are more likely to engage in a greater number of cold-start trip chains; this behavior uncovers a potential negative impact on emission pollution. These findings suggest that a comprehensive approach to the evaluation of carpool programs must take into account the benefits as well as any ensuing negative externalities.
Will Reducing Parking Standards Lead to Reductions in Parking Supply?
Authors: Engel-Yan Joshua , Hollingworth Brian , Anderson Stuart
Published: January 2008

To promote land-efficient development that supports nonautomobile modes of transportation, many municipalities are trying to implement parking policies that minimize parking oversupply and use existing parking supply more effectively. A commonly proposed strategy is for municipalities to lower their minimum parking standards. However, parking supply decisions are based on many factors, and experience shows that reducing parking standards does not always lead to corresponding reductions in parking supply. Using the results of an extensive commercial parking survey conducted across the City of Toronto, Canada, this study develops an empirical approach to determine whether reductions in parking standards are likely to lead to reductions in the amount of parking supplied by new development. It is proposed that the proportion of existing sites supplying less parking than existing standards require can be used as an indicator of the likelihood of developers to respond to reductions in parking standards by providing less parking. This assumes that the development characteristics of surveyed sites can be considered representative of current development practices. Applying such an analysis to Toronto, it is expected that reducing the parking standards for general office, medical office, and general retail uses will be a successful strategy in encouraging new development to provide fewer parking spaces on average. Such a strategy will be less successful for bank and large grocery uses, which tend to provide more parking and are less sensitive to minimum parking standards.
Multifunctional Magnetic Gold Nanocomposites: Human Epithelial Cancer Detection via Magnetic Resonance Imaging and Localized Synchronous Therapy
Authors: Lee J. , Yang J. , Ko H. , Oh S. , Kang J. , Son J. , Lee K. , Lee S.‐W. , Yoon H.‐G. , Suh J.‐S. , Huh Y.‐M. , Haam S.
Published: January 2008

Novel multifunctional magnetic gold nanocomposites (MGNCs) were synthesized for synchronous cancer therapy and diagnosis via magnetic resonance imaging (MRI). The MGNCs consist of magnetic kernels (aggregates of ultra‐sensitive MnFe2O4 magnetic nanocrystals wrapped in polymer) as effective MR contrast agents and silica–gold nanocomposites as hyperthermal therapeutic agents. A therapeutic antibody, Erbitux (ERB), was conjugated for specific tumor cell targeting both to localize the near‐IR laser beam and to image their events through MRI. ERB‐conjugated MGNCs selectively recognize the target cancer cell lines. Fluorescence images and MRI analysis show that the MGNCs are effectively taken up by the cells. ERB‐conjugated MGNCs have an excellent synchronous therapeutic efficacy as a result of the therapeutic antibody and near‐IR laser‐induced surface plasmon resonance. Consequently, MGNCs clearly demonstrate selective imaging and treatment of human epithelial cancer simultaneously.
Self‐Organization of Ink‐jet‐Printed Triisopropylsilylethynyl Pentacene via Evaporation‐Induced Flows in a Drying Droplet
Authors: Lim J. A. , Lee W. H. , Lee H. S. , Lee J. H. , Park Y. D. , Cho K.
Published: January 2008

We have demonstrated the influence of evaporation‐induced flow in a single droplet on the crystalline microstructure and film morphology of an ink‐jet‐printed organic semiconductor, 6,13‐bis((triisopropylsilylethynyl) pentacene (TIPS_PEN), by varying the composition of the solvent mixture. The ringlike deposits induced by outward convective flow in the droplets have a randomly oriented crystalline structure. The addition of dichlorobenzene as an evaporation control agent results in a homogeneous film morphology due to slow evaporation, but the molecular orientation of the film is undesirable in that it is similar to that of the ring‐deposited films. However, self‐aligned TIPS_PEN crystals with highly ordered crystalline structures were successfully produced when dodecane was added. Dodecane has a high boiling point and a low surface tension, and its addition to the solvent results in a recirculation flow in the droplets that is induced by a Marangoni flow (surface‐tension‐driven flow), which arises during the drying processes in the direction opposite to the convective flow. The field‐effect transistors fabricated with these self‐aligned crystals via ink‐jet printing exhibit significantly improved performance with an average effective field‐effect mobility of 0.12 cm2 V–1 s–1. These results demonstrate that with the choice of appropriate solvent ink‐jet printing is an excellent method for the production of organic semiconductor films with uniform morphology and desired molecular orientation for the direct‐write fabrication of high‐performance organic electronics.
Influence of Electric Field on Microstructures of Pentacene Thin‐Films in Field‐Effect Transistors
Authors: Cheng H. L. , Chou W. Y. , Kuo C. W. , Wang Y. W. , Mai Y. S. , Tang F. C. , Chu S. W.
Published: January 2008

We report on electric‐field‐induced irreversible structural modifications in pentacene thin films after long‐term operation of organic field‐effect transistor (OFET) devices. Micro‐Raman spectroscopy allows for the analysis of the microstructural modifications of pentacene in the small active channel of OFET during device operation. The results suggest that the herringbone packing of pentacene molecules in a solid film is affected by an external electric field, particularly the source‐to‐drain field that parallels the a–b lattice plane. The analysis of vibrational frequency and Davydov splitting in the Raman spectra reveals a singular behavior suggesting a reduced separation distance between pentacene molecules after long‐term operations and, thus, large intermolecular interactions. These results provide evidence for improved OFET performance after long‐term operation, related to the microstructures of organic semiconductors. It is known that the application of large electric fields alters the semiconductor properties of the material owing to the generation of defects and the trapping of charges. However, we first suggest that large electric fields may alter the molecular geometry and further induce structural phase transitions in the pentacene films. These results provide a basis for understanding the improved electronic properties in test devices after long‐term operations, including enhanced field‐effect mobility, improved on/off current ratio, sharp sub‐threshold swing, and a slower decay rate in the output drain current. In addition, the effects of source‐to‐drain electric field, gate electric field, current and charge carriers, and thermal annealing on the pentacene films during OFET operations are discussed.
Unprecedented Dual Alignment Mode and Freedericksz Transition in Planar Nematic Liquid Crystal Cells Doped with Gold Nanoclusters
Authors: Qi H. , Kinkead B. , Hegmann T.
Published: January 2008

We demonstrate that alkylthiol‐capped gold nanoclusters doped into nematic liquid crystals (N‐LCs) with positive dielectric anisotropy give rise to an unprecedented dual alignment mode and electro‐optical response, which has a potential impact on current liquid crystal (LC) display technologies and N‐LC optical‐biosensor design. By fine‐tuning experimental conditions (temperature, electric field, and alignment), N‐LCs doped with gold nanoclusters can be aligned and electrically reoriented either like N‐LCs with a positive dielectric anisotropy in a planar cell or, alternatively, as N‐LCs with a negative dielectric anisotropy in a homeotropic cell, both at lower threshold voltages than the pure N‐LC.
Producers' complex risk management choices
Authors: Pennings Joost M.E. , Isengildina‐Massa Olga , Irwin Scott H. , Garcia Philip , Good Darrel L.
Published: January 2008

Producers have a wide variety of risk management instruments available, making their choice(s) complex. The way producers deal with this complexity can vary and may influence the impact that the determinants, such as risk aversion, have on their choices. A recently developed choice bracketing framework recognizes that producers are unable to evaluate all alternatives simultaneously and that to manage a complex task, they often group or bracket individual alternatives and their consequences together in choice sets. Data on 1,105 U.S. producers show that producers do not use all available combinations of risk management tools and that the influence of the determinants of producer's risk management decisions are not necessarily the same across risk management strategies within and across bracketing levels. The findings may help resolve puzzling results on the role that well‐known determinants of risk management behavior have on producers' choices, extending knowledge on producers' risk management behavior. Further, the findings have managerial implications for policy makers and agribusiness companies that provide risk management services. [EconLit citations: M000, G1000, Q130] © 2008 Wiley‐Liss, Inc.
Public approval of plant and animal biotechnology in South Korea: an ordered probit analysis
Authors: Govindasamy Ramu , Onyango Benjamin , Hallman William K. , Jang Ho‐Min , Puduri Venkata
Published: January 2008

This study analyzes predictors of South Korean public acceptance of the use of biotechnology to create genetically modified food products. Results indicate that those consumers with above average knowledge of specific outcomes of genetic modification were more likely to approve of the use of plant or animal genetic modification for the creation of new food products than those with inaccurate or no knowledge. Moreover, younger South Korean consumers were more likely than older consumers to approve of the use of biotechnology to create both plant and animal based foods. Further, the study produced evidence of different levels of approval of biotechnology among consumers from different residential areas, income levels and political affiliation. Thus, those living in cities, those with incomes above 40 million Won, and those who described themselves as having a liberal political affiliation were found to have a higher approval level for animal biotechnology. [JEL Classification: Q13, M31, D12] © 2008 Wiley Periodicals, Inc.
Aluminum Oxidation Catalysis under Aqueous Conditions: Highly Enantioselective Sulfur Oxidation Catalyzed by Al(salalen) Complexes
Authors: Matsumoto Kazuhiro , Yamaguchi Tetsufumi , Fujisaki Junichi , Saito Bunnai , Katsuki Tsutomu
Published: January 2008

Asymmetric oxidation catalysis with an aluminum‐based complex was achieved by a combination of newly synthesized chiral aluminum(salalen) complexes (salalen=half‐reduced salen=salan/salen‐hybridized [ONNO]‐type tetradentate ligand; salan=reduced salen, salen=N,N′‐ethylenebis(salicylideneiminato)) derived from binol (1,1′‐bi‐2,2′‐naphthol) with aqueous hydrogen peroxide as the oxidant. The combination was found to be efficient for asymmetric sulfur oxidation. Various sulfides were smoothly converted into the corresponding sulfoxides with high to excellent enantioselectivity. Thioacetals are also good substrates for the oxidation.
Rapid determination of gatifloxacin in biological samples and pharmaceutical products using europium‐sensitized fluorescence spectrophotometry
Authors: Guo Changchuan , Dong Peng , Chu Zhijie , Wang Lei , Jiang Wei
Published: January 2008

A europium‐sensitized fluorescence spectrophotometry method using an anionic surfactant, sodium dodecyl benzene sulphonate (SDBS), was developed for the determination of gatifloxacin (GFLX). The GFLX–Eu3+–SDBS system was studied and it was found that SDBS significantly enhanced the fluorescence intensity of the GFLX–Eu3+ complex (about 25‐fold). The optimal experimental conditions were determined as follows: excitation and emission wavelengths of 338 and 617 nm, pH 7.5, 3.0 × 10–6 mol/L europium(III), and 5.0 × 10–5 mol/L SDBS. The enhanced fluorescence intensity of the system (ΔIf) showed a good linear relationship with the concentration of GFLX over the range 1.0 × 10–8–8.0 × 10–7 mol/L with a correlation coefficient of 0.9990. The detection limit (S:N = 3) was determined as 1.0 × 10–9 mol/L. This method has been successfully applied for the determination of GFLX in pharmaceuticals and human urine/serum samples. Compared with most other methods reported, the rapid and simple procedure proposed here offered higher sensitivity, wider linear range and good stability. The luminescence mechanism of the system is also discussed in detail. Copyright © 2008 John Wiley & Sons, Ltd.
The indication for postchemotherapy lymph node dissection in clinical stage IS nonseminomatous germ cell tumor
Authors: Dash Atreya , Carver Brett S. , Stasi Jason , Bajorin Dean F. , Motzer Robert J. , Bosl George J. , Sheinfeld Joel
Published: January 2008

BACKGROUND

The initial management of patients with clinical stage IS (cIS) nonseminomatous germ cell tumor (NSGCT) has evolved from primary retroperitoneal lymph node dissection (RPLND) to induction chemotherapy. The objectives of the current study were to determine the clinical outcome, patterns of relapse, and incidence of teratoma in the retroperitoneum for men with cIS NSGCT.

METHODS

Between 1988 and 2004, 24 patients with cIS stage NSGCT were evaluated and treated at Memorial Sloan‐Kettering Cancer Center. Clinical and pathologic data were obtained from the institutional prospective database. Seven patients underwent primary RPLND, and 17 patients received induction chemotherapy as initial management. Clinical outcomes, patterns of relapse, and pathologic findings were reported.

RESULTS

Six of the 7 patients who underwent primary RPLND had viable germ cell tumor (GCT) present. Four of those patients did not receive adjuvant chemotherapy, and all experienced systemic relapse. Of the 17 patients who received induction chemotherapy, 3 patients underwent elective postchemotherapy RPLND (PC‐RPLND), and 14 patients were followed expectantly. Four patients who were followed expectantly relapsed in the retroperitoneum and underwent PC‐RPLND. Of the 7 patients who underwent PC‐RPLND, 1 patient had fibrosis (14%), but 6 patients (86%) had teratoma, including 1 patient who also had a viable GCT in the retroperitoneum. Overall, the incidence of teratoma or viable GCT in the retroperitoneum after chemotherapy was 43% (6 of 14 patients). At a median follow‐up of 35 months, 23 men remained alive, and 1 man had died of disease.

CONCLUSIONS

The current data suggest that patients with cIS stage NSGCT will benefit from adjuvant PC‐RPLND. Cancer 2008. © 2008 American Cancer Society.
High‐temperature infrared and dielectric properties of large sapphire crystal for seeker dome application
Authors: Wang Guigen , Zhang Mingfu , Han Jiecai , He Xiaodong , Zuo Hongbo , Yang Xinhong
Published: January 2008

In this paper, large‐sized (∅︁230 mm × 210 mm, 27.5 kg) sapphire was successfully grown by SAPMAC (sapphire growth technique with micro‐pulling and shoulder‐expanding at cooled center) method; and hemisphere dome (140 mm diameter, 5 mm thickness) was fabricated from as‐grown boule. Also, its high temperature infrared transmission (2∼7 µm, 20–800°C) and microwave dielectric properties (8–16.5 GHz, 30–1300°C) were investigated. The experimental results show that sapphire crystal exhibits high infrared transmittance (3 μm, 80–86%), essentially negligible dielectric loss (4.9×10‐5–3.7×10‐4), but fairly high dielectric constants (ε=9.4–12.5) in the temperature range of 30–1300°C. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The use of intuition in mediation
Authors: Rooney Greg
Published: January 2008

How mediators make decisions about what to do in the mediation session is one of the least understood, but most important, issues in the study of mediation. This article explores a number of different approaches, including the use of intuition. It examines the effectiveness of developing premediation strategies and hypotheses and their impact on the mediator's ability to engage with the parties in the here‐and‐now of the mediation session.
Synthesis and Structure of Dinucleotides with S‐Type Sugar Puckering and Noncanonical ϵ and ζ Torsion Angle Combination (ν2,ϵ,ζ‐D‐CNA)
Authors: Dupouy Christelle , Lavedan Pierre , Escudier Jean‐Marc
Published: January 2008

The synthesis of the diastereoisomers of ν2,ϵ,ζ‐D‐CNA dinucleotide building units of nucleic acids and their (2′,5′)‐ν2,ϵ′,ζ′‐D‐CNA analogues, in which the ϵ and ζ torsional angles are stereocontrolled by a dioxaphosphorinane ring structure (D‐CNA family) is described from a common 3‐deoxy‐3‐(hydroxymethyl)‐D‐allofuranose intermediate. NMR spectroscopic and circular dichroism structure analysis of ν2,ϵ,ζ‐D‐CNA shows that the sugar puckering is fixed in the C‐2′‐endo conformation and that these D‐CNA structuralelements allow stabilization of the ϵ/ζ torsion angle combinations, which are significantly different from the typical combinations observed in canonical A‐ or B‐form duplexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Radiosynthesis of [11C]ximelagatran via palladium catalyzed [11C]cyanation
Authors: Airaksinen Anu J. , Andersson Jan , Truong Phong , Karlsson Olle , Halldin Christer
Published: January 2008

N‐hydroxyamidines (amidoximes) may be used in prodrug technology in improving oral bioavailability of drugs containing amidino functional groups. In the body, amidoximes are reduced quickly to amidines by enzymes that are present in several organs. Ximelagatran is a benzamidoxime and ethyl ester prodrug of melagatran, which is a thrombin inhibitor. Our aim was to develop a fast and efficient labeling route for the synthesis of [11C]ximelagatran ([11C]3) with a label in a metabolically stable position. [11C]3 was synthesized via a two‐step synthesis sequence, starting from palladium catalyzed [11C]cyanation of its corresponding bromide precursor (2‐[2‐(4‐bromo‐benzylcarbamoyl)‐azetidin‐1‐yl]‐1‐cyclohexyl‐2‐oxo‐ethyl amino‐acetic acid ethyl ester) (1), followed by a reaction with hydroxylamine. [11C]3 was synthesized with 27±17% total overall decay corrected yield (specific radioactivity of 2360±165 Ci/mmol at EOS), with a total synthesis time of 45 min. A fast and efficient labeling route for the synthesis of [11C]3 was developed. Copyright © 2008 John Wiley & Sons, Ltd.
Radioiodine labelling of a small chemotactic peptide, utilizing two different prosthetic groups: a comparative study
Authors: Rossouw Daniel D.
Published: January 2008

The use of iodobenzoates as pre‐labelled prosthetic groups in the radioiodination of peptides is becoming increasingly popular. The utilization of an iodovinyl ester unit as an alternative conjugation agent for the preparation of a radioiodinated peptide conjugate (peptide‐[123I]I‐PEA) was investigated in this study. A pre‐labelled unit, containing a tetrafluorophenyl ester group, was purified on a small C18 column and the dimethylformamide eluate was used directly in the conjugation step. Similar methodology was applied for a comparative radiosynthesis of an iodobenzoate analogue (peptide‐[123I]IB), using a succinimidyl ester. The influences of various reaction parameters on conjugation yields were investigated while maintaining a fixed amount of peptide. At high activity levels (more than 200 MBq) the conjugation yield of peptide‐[123I]I‐PEA was very sensitive to relatively large reaction volumes and increased amount of base. By optimizing these parameters, the formation of radiochemical impurities was minimized. Under similar conditions, peptide‐[123I]I‐PEA formed much faster than peptide‐[123I]IB. Sep‐Pak C18 purification afforded conjugates with radiochemical purities both in excess of 98% and free from unreacted peptide. Recovered conjugation yields of peptide‐[123I]I‐PEA in 50% ethanol were in excess of 60%, while those for peptide‐[123I]IB were less than 40%. Copyright © 2008 John Wiley & Sons, Ltd.
The protein fluorescence and structural toolkit: Database and programs for the analysis of protein fluorescence and structural data
Authors: Shen Chi , Menon Rajiv , Das Dipanwita , Bansal Nidhi , Nahar Neha , Guduru Neelima , Jaegle Stephen , Peckham Joan , Reshetnyak Yana K.
Published: January 2008

Protein fluorescence is a powerful tool for studying protein structure and dynamics if we have a means to interpret the spectral data in terms of protein structural properties. Our previous research successfully provided this support through the development of individual software modules implementing the algorithms for fluorescence and structural analyses. Now we have integrated the developed software modules, introduced a new program for the assignment of tryptophan residues to spectral‐structural classes, and created a web‐based toolkit PFAST: protein fluorescence and structural toolkit: http://pfast.phys.uri.edu/. PFAST contains three modules: (1) FCAT is a fluorescence‐correlation analysis tool, which decomposes protein fluorescence spectra to reveal the spectral components of individual tryptophan residues or groups of tryptophan residues located close to each other, and assigns spectral components to one of five previously established spectral‐structural classes. (2) SCAT is a structural‐correlation analysis tool for the calculation of the structural parameters of the environment of tryptophan residues from the atomic structures of the proteins from the Protein Data Bank (PDB), and for the assignment of tryptophan residues to one of five spectral‐structural classes. (3) The last module is a PFAST database that contains protein fluorescence and structural data obtained from results of the FCAT and SCAT analyses. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Conformational and dynamics changes induced by bile acids binding to chicken liver bile acid binding protein
Authors: Eberini Ivano , Guerini Rocco Alessandro , Ientile Anna Rita , Baptista António M. , Gianazza Elisabetta , Tomaselli Simona , Molinari Henriette , Ragona Laura
Published: January 2008

The correlation between protein motions and function is a central problem in protein science. Several studies have demonstrated that ligand binding and protein dynamics are strongly correlated in intracellular lipid binding proteins (iLBPs), in which the high degree of flexibility, principally occurring at the level of helix‐II, CD, and EF loops (the so‐called portal area), is significantly reduced upon ligand binding. We have recently investigated by NMR the dynamic properties of a member of the iLBP family, chicken liver bile acid binding protein (cL‐BABP), in its apo and holo form, as a complex with two bile salts molecules. Binding was found to be regulated by a dynamic process and a conformational rearrangement was associated with this event. We report here the results of molecular dynamics (MD) simulations performed on apo and holo cL‐BABP with the aim of further characterizing the protein regions involved in motion propagation and of evaluating the main molecular interactions stabilizing bound ligands. Upon binding, the root mean square fluctuation values substantially decrease for CD and EF loops while increase for the helix‐loop‐helix region, thus indicating that the portal area is the region mostly affected by complex formation. These results nicely correlate with backbone dynamics data derived from NMR experiments. Essential dynamics analysis of the MD trajectories indicates that the major concerted motions involve the three contiguous structural elements of the portal area, which however are dynamically coupled in different ways whether in the presence or in the absence of the ligands. Motions of the EF loop and of the helical region are part of the essential space of both apo and holo‐BABP and sample a much wider conformational space in the apo form. Together with NMR results, these data support the view that, in the apo protein, the flexible EF loop visits many conformational states including those typical of the holo state and that the ligand acts stabilizing one of these pre‐existing conformations. The present results, in agreement with data reported for other iLBPs, sharpen our knowledge on the binding mechanism for this protein family. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Expanding GPCR homology model binding sites via a balloon potential: A molecular dynamics refinement approach
Authors: Kimura S. Roy , Tebben Andrew J. , Langley David R.
Published: January 2008

Homology modeling of G protein‐coupled receptors is becoming a widely used tool in drug discovery. However, unrefined models built using the bovine rhodopsin crystal structure as the template, often have binding sites that are too small to accommodate known ligands. Here, we present a novel systematic method to refine model active sites based on a pressure‐guided molecular dynamics simulation. A distinct advantage of this approach is the ability to introduce systematic perturbations in model backbone atoms in addition to side chain adjustments. The method is validated on two test cases: (1) docking of retinal into an MD‐relaxed structure of opsin and (2) docking of known ligands into a homology model of the CCR2 receptor. In both cases, we show that the MD expansion algorithm makes it possible to dock the ligands in poses that agree with the crystal structure or mutagenesis data. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Incisional Hernia after McBurney Incision: Retrospective Case‐control Study of Risk Factors and Surgical Treatment
Authors: Beltrán Marcelo A. , Cruces Karina S.
Published: January 2008

Background

Few reports have dealt with incisional hernias originating at a McBurney incision after appendectomy. The purpose of the present study was to identify risk factors for development of incisional hernia at a McBurney incision, and to describe our experience with the treatment of this kind of hernia.

Patients and methods

We reviewed 4,862 files of patients older than 15 years of age operated on for acute appendicitis. Some 4,523 (93%) of that group were operated on through a McBurney incision, and 34 (0.7%) of them developed incisional hernia. To identify risk factors for development of incisional hernia we used binary logistic regression analysis.

Results

The following risk factors were identified: female gender (p = 0.011), diabetes (p < 0.0001), peritonitis, abscess or phlegmon as the cause of the first operation (p = 0.009), wound infection (p = 0.034), seroma (p = 0.023), the use of catgut to suture the aponeurosis (p < 0.0001), and interrupted suture to the aponeurotic layer (p = 0.046). Twenty‐two hernias were repaired with Mayo‐herniorrhaphy and 12 with a subaponeurotic polypropylene prosthesis. Recurrences developed in 3 patients, none in hernias repaired with prosthesis.

Conclusions

The risk of incisional hernia after a McBurney incision for acute appendicitis was very low; we recommend the repair of this uncommon incisional hernia with current standard tension‐free prosthetic techniques.
Micellization Behavior of Mixtures of Sodium Dioctylsulfosuccinate with Sodium Dodecylsulfate in Water
Authors: Singh O. G. , Ismail K.
Published: January 2008

Mixtures of sodium dioctylsulfosuccinate (AOT) and sodium dodecylsulfate (SDS) that were studied in water at 25 °C by using surface tension, conductance, emf and fluorescence emission methods exhibit synergism in the region where the mole fraction of AOT in the bulk solution (α1) is less than 0.7 and ideality in the region where α1 ≥ 0.7. The molal conductance versus the concentration behavior of an aqueous solution of AOT is found to be different from that of other ionic surfactants with the exception of bile salts. Composition of the mixed micelle was evaluated and discussed using the Rubingh's and the Rodenas–Valiente–Villafruela (RVV) treatments. The values of the counter ion binding constant determined from the emf data show that the counter ion binding behavior of the mixed micelle is controlled entirely by AOT. The free energy for mixed micelle formation was calculated using a modified equation. The aggregation number determined by the fluorescence quenching method indicated that in the mixed micelle, as α1 increases, the number of molecules of AOT remains constant and that of SDS decreases. Characteristics of the adsorption layer of the mixed surfactant system were also examined using the theoretical treatment of Rosen and Hua.
PKC zeta controls DNA topoisomerase‐dependent human caspase‐2 pre‐mRNA splicing
Authors: Solier Stéphanie , De Cian Marie-Cécile , Bettaieb Ali , Desoche Lydie , Solary Eric , Corcos Laurent
Published: January 2008

Caspase‐2 exists as two main isoforms: the caspase‐2L long isoform, which is pro‐apoptotic, and the caspase‐2S short isoform, which may be anti‐apoptotic. Topoisomerase inhibitors drive inclusion of exon 9, specific for Casp‐2S mRNA, and lower Casp‐2S mRNA and protein. With cell lines engineered to express various PKC isoforms, we demonstrate that PKC zeta, but not PKCalpha, positively regulates Casp‐2S mRNA assembly triggered by topoisomerase inhibitors. In addition, exon 9 inclusion is lowered in mitosis but increased in the G1/S phase. Hence, the control of caspase‐2 exon 9 inclusion by topoisomerase inhibitors depends on phosphorylation and/or dephosphorylation events, and on the cell cycle phase.
Effects of Amazonian forest fragmentation on the interaction between plants, insect herbivores, and their natural enemies
Authors: Fáveri Sarita B. , Vasconcelos Heraldo L. , Dirzo Rodolfo
Published: January 2008

We evaluated the effects of forest fragmentation on herbivory on central Amazonian trees. Levels of herbivory were measured on leaves from a total of 1200 saplings from 337 species. There was a positive and significant effect of forest fragment area on herbivore damage, with plants from continuous forest having twice as much damage as plants in the smallest fragments studied (1 ha). Measurements of herbivory rates on two species, however, indicate that the effect can be species-specific. Forest area had a positive and linear effect on rates of herbivory inHenriettella caudata(Melastomataceae), whereas inProtium hebetatum(Burseraceae), rates of herbivory were greater in the 10-ha fragments than in the 1-ha fragments and in continuous forest. There is no evidence that the nutritional and defensive characteristics of the leaves of the species we studied changed as a result of forest fragmentation, at least not in a manner consistent with the observed herbivory patterns. Herbivore predation levels, measured with artificial caterpillars, also showed no significant relationship with forest area. Therefore, neither of these top-down and bottom-up forces could explain the observed patterns of herbivory. It is suggested, instead, that forest fragmentation may affect the dispersal of insect herbivores, and reduce their abundances on small forest isolates. Altered patterns of herbivory on tree saplings may have important consequences for forest structure and dynamics.
Boundary alignment enables 11-month-olds to segment vowel initial words from speech
Authors: SEIDL AMANDA , JOHNSON ELIZABETH K.
Published: January 2008

Past research has indicated that English-learning infants begin segmenting words from speech by 7·5 months of age (Jusczyk & Aslin, 1995). More recent work has demonstrated, however, that 7·5-month-olds' segmentation abilities are severely limited. For example, the ability to segment vowel-initial words from speech reportedly does not appear until 13·5 to 16 months of age (Mattys & Jusczyk, 2001; Nazzi, Dilley, Jusczyk, Shattuck-Hufnagel & Jusczyk, 2005). In this paper, we report on three experiments using the Headturn Preference procedure that investigate both phonetic and phonological factors influencing 11-month-olds' segmentation of vowel-initial words from speech. We replicate earlier findings suggesting that infants have difficulty segmenting vowel-initial words from speech. In addition we extend these findings by demonstrating that under certain conditions, infants are capable of segmenting vowel-initial words from speech at a much younger age than earlier studies have reported. Our findings suggest that infants' ability to segment vowel-initial words from speech is tightly constrained by acoustic-phonetic factors such as pitch movement at the onset of vowel-initial words and segmental strengthening. These experiments underscore the complexity of early word segmentation, and highlight the importance of including contextual factors in developmental models of word segmentation.
Factors accounting for the ability of children with SLI to learn agreement morphemes in intervention
Authors: PAWŁOWSKA MONIKA , LEONARD LAURENCE B. , CAMARATA STEPHEN M. , BROWN BARBARA , CAMARATA MARY N.
Published: January 2008

The aim of this study was to uncover factors accounting for the ability of children with specific language impairment (SLI) to learn agreement morphemes in intervention. Twenty-five children with SLI who participated in a six-month intervention program focused on teaching third person singular -s or auxiliary is/are/was showed a wide range of use of the target morpheme after intervention. Regression analyses showed that age and two factors expected to be related to agreement – the use of noun plural -s and subject/verb constructions prior to intervention – significantly predicted progress in the acquisition of agreement morphemes. In contrast, the pretreatment use of morphemes hypothesized to be unrelated to agreement was not a significant predictor of progress. The results indicate that the ability of children with SLI to learn agreement morphemes relies on their prior ability to use noun plural and subject/verb constructions.
The influence of discourse context on children's provision of auxiliary BE
Authors: THEAKSTON ANNA L. , LIEVEN ELENA V. M.
Published: January 2008

Children pass through a stage in development when they produce utterances that contain auxiliary BE (he's playing) and utterances where auxiliary BE is omitted (he playing). One explanation that has been put forward to explain this phenomenon is the presence of questions in the input that model S-V word order (Theakston, Lieven & Tomasello, 2003). The current paper reports two studies that investigate the role of the input in children's use and non-use of auxiliary BE in declaratives. In Study 1, 96 children aged from 2 ; 5 to 2 ; 10 were exposed to known and novel verbs modelled in questions only or declaratives only. In Study 2, naturalistic data from a dense database from a single child between the ages of 2 ; 8 to 3 ; 2 were examined to investigate the influence of (1) declaratives and questions in the input in prior discourse, and (2) the child's immediately previous use of declaratives where auxiliary BE was produced or omitted, on his subsequent use or non-use of auxiliary BE. The results show that in both the experimental and naturalistic contexts, the presence of questions in the input resulted in lower levels of auxiliary provision in the children's speech than in utterances following declaratives in the input. In addition, the children's prior use or non-use of auxiliary BE influenced subsequent use. The findings are discussed in the context of usage-based theories of language acquisition and the role of the language children hear in their developing linguistic representations.
Perseverant responding in children's picture naming*
Authors: BOOTH JOSEPHINE , VITKOVITCH MELANIE
Published: January 2008

Two groups of children were given pictures of animals to name as quickly as they could. The groups comprised 40 nursery aged children (mean age 3 ; 11) and 40 Year 2 children (mean age 6 ; 9) attending primary school in London. The 30 animals were presented one by one, on cards, and any errors made by the children were noted. Consistent with a similar object naming study with adults (Vitkovitch, Kirby & Tyrrell, 1996) and a study with children (Gershkoff-Stowe, 2002), picture naming errors referred to earlier named objects. However, while adults showed below-chance interference from objects that had only just been named (Lag 1), children were most susceptible to interference from very recently named objects (see also Gershkoff-Stowe, 2002). Furthermore, the proportion of younger children making Lag 1 errors was higher than the proportion of older children making Lag 1 errors. The results are discussed in relation to the activation levels of lexical representations.
Child-directed speech: relation to socioeconomic status, knowledge of child development and child vocabulary skill
Authors: ROWE MEREDITH L.
Published: January 2008

This study sought to determine why American parents from different socioeconomic backgrounds communicate in different ways with their children. Forty-seven parent–child dyads were videotaped engaging in naturalistic interactions in the home for ninety minutes at child age 2 ; 6. Transcripts of these interactions provided measures of child-directed speech. Children's vocabulary comprehension skills were measured using the Peabody Picture Vocabulary Test at 2 ; 6 and one year later at 3 ; 6. Results indicate that: (1) child-directed speech with toddlers aged 2 ; 6 predicts child vocabulary skill one year later, controlling for earlier toddler vocabulary skill; (2) child-directed speech relates to socioeconomic status as measured by income and education; and (3) the relation between socioeconomic status and child-directed speech is mediated by parental knowledge of child development. Potential mechanisms through which parental knowledge influences communicative behavior are discussed.
Development of Aberration-Corrected Electron Microscopy
Authors: Smith David J.
Published: January 2008

The successful correction of spherical aberration is an exciting and revolutionary development for the whole field of electron microscopy. Image interpretability can be extended out to sub-Ångstrom levels, thereby creating many novel opportunities for materials characterization. Correction of lens aberrations involves either direct (online) hardware attachments in fixed-beam or scanning TEM or indirect (off-line) software processing using either off-axis electron holography or focal-series reconstruction. This review traces some of the important steps along the path to realizing aberration correction, including early attempts with hardware correctors, the development of online microscope control, and methods for accurate measurement of aberrations. Recent developments and some initial applications of aberration-corrected electron microscopy using these different approaches are surveyed. Finally, future prospects and problems are briefly discussed.
Relation of material exchange between sea ice and water to a coupled ice‐ocean ecosystem at the Hokkaido coastal region of the Okhotsk Sea
Authors: Nishi Yoshiki , Tabeta Shigeru
Published: January 2008

In this paper, the material exchange between the sea ice and the water just below the ice, and its relation to the lower trophic ice system are examined using field observations in the Hokkaido coastal region of the Okhotsk Sea and a coupled ice‐ocean ecosystem model which in detail formulates the material exchange between the ice and the water. The accuracy of the model is confirmed by a comparison of the results of the numerical computation with the observations. The estimation of the transport of the organic carbon and nutrients based on the computation demonstrates that the physical coupling effect between the ice and water plays a prominent role in supplying the nutrients from the water to the ice ecosystem and in efficiently releasing the organic matter produced by the primary producer in the ice (ice algae). As a result, this study quantitatively clarifies that the physical coupling effect, tidal mixing, and biological activity in the ice drive the material cycle in the ice and water under the ice.
Understanding catchment behavior through stepwise model concept improvement
Authors: Fenicia Fabrizio , Savenije Hubert H. G. , Matgen Patrick , Pfister Laurent
Published: January 2008

Lack of data is one of the main limitations for hydrological modeling. However, it is often used as a justification for over simplifying, poorly performing models. If we want to enhance our understanding of hydrological systems, it is important to fully exploit the information contained in the available data, and to learn from model deficiencies. In this paper, we propose a methodology where we systematically update the model structure, progressively incorporating new hypotheses of catchment behavior. We apply this methodology to the Alzette river basin in Luxembourg, showing how stepwise model improvement helps to identify the behavior of this catchment. We show that the most significant improvement of the evolving model structure is associated to the characterization of antecedent wetness. This is improved accounting for interception, which affects vertical storage distribution, and accounting for rainfall spatial heterogeneity, which influences storage variations in the horizontal dimension. Overall, our results suggested that, due to the damping effect of the basin, the description of fast catchment response benefits more from spatially distributed information than that of slow catchment response.
Fate and transport of pathogens in a fractured aquifer in the Salento area, Italy
Authors: Masciopinto Costantino , La Mantia Rosanna , Chrysikopoulos Constantinos V.
Published: January 2008

This study investigates the fate and transport of pathogens introduced by artificial groundwater recharge at the Nardò fractured aquifer in the Salento area, Italy. Wastewater effluents from a municipal treatment plant with known pathogen concentrations were injected into a sinkhole and the migration of pathogens in the fractured aquifer was monitored at six sampling wells. The fate of pathogens was quantified by a mathematical model describing colloid transport in a set of three‐dimensional, parallel fractures with spatially variable aperture. The number of parallel fractures and their average fracture aperture were determined from appropriate field pumping and tracer tests. The aperture spatial distribution was described by an experimental semivariogram developed from available field data obtained from two tracer tests and 34 pumping tests. The experimental results suggest that for the municipal wastewater injected into the Nardò aquifer the required most conservative set back distance for drinking wells should be over 8000 m.
Sensitivity of Arctic ozone loss to stratospheric H2O
Authors: Feck T. , Grooß J.‐U. , Riese M.
Published: January 2008

Likely causes of a future increase in stratospheric H2O are a rise in tropospheric CH4 and H2 leakages from an increased integration of hydrogen into the energy supply system. Here we evaluate the impact of potential future stratospheric H2O increases on Arctic ozone loss by comparing ozone loss proxies based on two different mechanisms of chlorine activation. In particular, the H2O dependence of the volume of air is analyzed where temperatures are low enough to form nitric acid trihydrate, denoted as VPSC, and for Cl activation on liquid sulfate aerosols, denoted as VACl. We show that VACl increases faster than VPSC with increasing H2O mixing ratios in the altitude range of 400 K to 550 K potential temperature. As a consequence, the additional ozone column loss is expected to be most pronounced for cold winters and large H2O increases and to be significantly higher when VACl is used as a proxy.
Evidence of a change in oceanic fixed nitrogen with decadal climate change in the North Pacific subpolar region
Authors: Watanabe Yutaka W. , Shigemitsu Masahito , Tadokoro Kazuaki
Published: January 2008

Using four pentadecadal hydrographic time series of biogeochemical properties over the North Pacific subpolar region, we found that the linear trends of these properties over this region due to sea surface stratification. Decadal periodicity of 18 years was also found although there were the opposite phases between the eastern and western sides. Despite decreasing trends of DO with an increase of PO4, N* in the subsurface water showed an increasing trend of 0.18 μmol kg−1 y−1. N* in the surface water had also an increase of 0.12 μmol kg−1 y−1 with a decrease of Si/N. With considering the decease of N/P and increase of Si/N in diatoms under iron‐deficient conditions, this finding is evidence that a shift of phytoplankton has already occurred due to the progress in stratification with the depletion of iron derived from deep water, despite being a relatively high primary production region.