bluuebunny/crossref_metadata_2025 huggingface dataset:
The Importance of Play in Promoting Healthy Child Development and Maintaining Strong Parent-Child Bonds
Authors: Ginsburg Kenneth R. ,   and the Committee on Communications,   and the Committee on Psychosocial Aspects of Child and Family Health
Published: January 2007

Play is essential to development because it contributes to the cognitive, physical, social, and emotional well-being of children and youth. Play also offers an ideal opportunity for parents to engage fully with their children. Despite the benefits derived from play for both children and parents, time for free play has been markedly reduced for some children. This report addresses a variety of factors that have reduced play, including a hurried lifestyle, changes in family structure, and increased attention to academics and enrichment activities at the expense of recess or free child-centered play. This report offers guidelines on how pediatricians can advocate for children by helping families, school systems, and communities consider how best to ensure that play is protected as they seek the balance in children’s lives to create the optimal developmental milieu.
Access to Optimal Emergency Care for Children
Authors:   Committee on Pediatric Emergency Medicine
Published: January 2007

Millions of pediatric patients require some level of emergency care annually, and significant barriers limit access to appropriate services for large numbers of children. The American Academy of Pediatrics has a strong commitment to identifying barriers to access to emergency care, working to surmount these obstacles, and encouraging, through education and system changes, improved levels of emergency care available to all children.
GRP offshore: applications and design for fire
Authors: Davies J. M. , Currie P.
Published: December 2006

In many respects, advanced glass-reinforced plastic (GRP) composites appear to be excellent, well-researched construction materials looking for practical applications that are economically viable. However, this simplistic overview is not valid for offshore installations, where the combination of high strength, light weight and supreme resistance to corrosion has ensured their economic viability. In many potential practical applications, the main hindrance to their widespread acceptance is cost. However, in the demanding offshore environment, it is more likely to be their performance in fire. Offshore, the main applications that have been considered to date are pipes, tanks and vessels including fire deluge systems, fire protection systems, cladding panels, gratings and stairways. The most successful practical applications have been in pipework and fluid handling. More recently, a feasibility study has been carried out that considers the use of composites for the primary structural members of offshore platforms. This paper will briefly review these applications before proceeding to summarise some of the research that has been carried out at the University of Manchester in order to demonstrate that advanced composites can meet the design requirements for offshore applications. Particular attention will be given to the fire performance of composites, and it will be shown that, although all the plastic materials used in the manufacture of composites are flammable, it is not necessary to be pessimistic regarding their performance in hydrocarbon fires, even in certain fire-critical situations.
Agricultural water policy in China: challenges, issues, and options
Authors: Giordano Mark
Published: January 2007

Agriculture is still by far the largest consumer of water in China. However, industrial, urban and now environmental water uses are rapidly growing. While in the past these new water needs could have been met through additional development or allocations, today scarcity – in terms of quantity, quality or both – means that new utilization often comes at the expense of other uses, in particular agricultural. The increasing pressure on agricultural water use comes at a time when rural poverty reduction and national food security are major national goals. The key questions are thus whether and how policy reform can contribute to changes in water use which maintain agricultural production and enhance rural livelihoods while at the same time freeing water for new, higher value uses outside the agricultural sector. This paper provides both an overview of the major issues behind these questions as well as a synthesis of the papers included in this special issue and their insights into the answers to those questions.
Orthoconic antiferroelectric liquid crystals containing biphenyl, terphenyl, or naphthyl mesogenic unit
Authors: Dąbrowski R. , Drzewiński W. , Dziaduszek J. , Gąsowska J. , Henderson P. , Kula P. , Otón J. , Bennis N.
Published: December 2006

Three homologous series of orthoconic (45 degree tilt) antiferroelectric liquid crystals containing either naphthyl or terphenyl groups as mesogenic unit have been synthesized and their mesomorphic behaviour investigated by DSC and polarized light microscopy, and their properties discussed. X-ray diffraction studies have shown the presence of a de Vries-type smectic A phase which does not exhibit a layer shrinkage on transition to the ferroelectric smectic C phase. Mixtures of the new materials have been formulated and their electro-optical properties investigated for their use in surface stabilized orthoconic antiferroelectric liquid crystal (SSOAFLC) devices
Low viscosity, high birefringence liquid crystalline compounds and mixtures
Authors: Dąbrowski R. , Dziaduszek J. , Ziółek A. , Szczuciński Ł. , Stolarz Z. , Sasnouski G. , Bezborodov V. , Lapanik W. , Gauza S. , Wu S.
Published: December 2006

Two types of fast switching mixtures with high positive dielectric anisotropy were described. The first type, with a birefringence below 0.3, was designed for devices operating at room or lower temperatures and the second one, with a birefringence higher than 0.3 for devices operating at elevated temperatures.
Bistability in dual-frequency nematic liquid crystals
Authors: Palto S. , Barnik M.
Published: December 2006

Different modes of bistable switching in liquid crystals with frequency inversion of the dielectric anisotropy sign are discussed. The study is performed by numerical simulation and experimentally. It is shown that dual frequency driving can be effectively used to control switching between topologically equivalent and non-equivalent director field distributions. The experimental results on temperature performance of the dual-frequency switching and possible driving methods for energy consumption and expanding the temperature range are presented.
Modifying electrooptics of orthoconic antiferroelectric liquid crystal cells by manufacturing procedures
Authors: Spadło A. , Bennis N. , Dąbrowski R. , Quintana X. , Otón J. , Geday M.
Published: December 2006

Orthoconic antiferroelectric liquid crystals (AFLCs) having 45° tilt angle have been proposed to overcome the problem of reduced contrast usually exhibited by regular antiferroelectric displays. However, the pitch of the helix induced by chirality is customarily short in existing orthoconic materials, making it difficult to achieve surface stabilized configurations when the material’s pitch is smaller than the cell thickness.

In this work, the influence of different manufacturing procedures on the electrooptical behaviour of orthoconic AFLCs is studied. Using the same orthoconic AFLC mixture, aligning surfaces and manufacturing protocol, we have observed two dissimilar responses, true orthoconic behaviour, and orthoconic V-shape response. The electrooptical response depends ultimately on the rubbing strategy adopted in either case.
REACH: Better Knowledge and Better Use of Chemicals in the European Union
Authors: De Avila Cristina , Sandberg Eva C.
Published: December 2006

REACH is the proposed new chemicals regulation in the European Union. It builds on existing legislation, parts of which have been operating for 40 years, while tackling the identified shortcomings of the current system. The main objective of REACH is to improve the knowledge on chemicals,
their properties and uses. In order to achieve this objective it is essential that industry assumes its responsibility to hold the knowledge on the substances they are manufacturing or importing and to share this knowledge with the authorities and their downstream users. REACH will require
all substances manufactured and imported at and above one tonne per year to be registered. Through the Registration procedure, the obligation of industry to hold and share with authorities their knowledge of chemicals will materialise. REACH aims also to control better the use of substances
of very high concern, this obviously includes the restriction of certain substances or certain uses. Through the Authorisation procedure, REACH will allow controlled use of substances of very high concern, such as carcinogens, mutagens and reprotoxic substances, substances that are persistent,
bioaccumulative and toxic, and substances that are very persistent and very bioaccumulative. Increased knowledge and increased control, supplemented by substitution of dangerous substances and the fostering of innovation, will have as clear results a higher level of protection of human health
and the environment, but additionally will bring along the opportunity to rebuild confidence in chemicals.
What Impact Will REACH Have on Consumer Protection?
Authors: Bormann Peter , Kappes Dag , Odermatt Paul , Reinhard Eva
Published: December 2006

In the last decades, several regulatory approaches have been taken in order to ensure the safe management of chemicals. The major drawback of the current EU and Swiss legislations is the distinction made between so-called 'existing' and 'new' chemicals, based on their time of marketing.
While all new chemicals have to be tested for potential harmful effects to human health and the environment, there exist no similar requirements for the approximately 30'000 existing chemicals found on the market. Considering that 26% of existing and 60% of new chemicals that have been so
far officially assessed and listed in Annex I of Directive 67/548/EEC, have irritating and/or sensitizing effects, it has to be assumed that several thousand chemicals consumers are exposed to are not appropriately labelled with respect to potential risks. REACH is intended to create a system
which is based on information about all chemicals. Especially for chemicals marketed at high quantities REACH will indeed improve the current situation and eliminate safety gaps. Chemicals marketed at lower quantities, however, will not be subject to equally profound assessments. It remains
to be seen whether substance-tailored requirements will compensate for the weaknesses of a quantity-based safety and information system, especially in respect to consumer protection. REACH will generate a lot of knowledge, some of which will be publicly available. However, the newly created
knowledge refers mostly to substances. No central database containing information about products on the market, in particular their compositions, is planed. Crucially, major parts of risk assessments and identifications will be performed by industry that therefore has to take a major responsibility
onboard. The success of REACH will depend on the way the private sector will manage this important safety system and whether consumers and other stakeholders can build up trust and confidence. The former Swiss Toxicity Law outmatched the current legislation and REACH in several aspects. It
did not distinguish between existing and new chemicals. The main responsibility was clearly placed on the authorities, building up trust among all stakeholders, including the public. The marketing of products was mainly dependent on their toxicity. The enforcement was strictly controlled which
generally led to substitutions of toxic substances with less toxic ones, especially in consumer products. However, maintaining a nation-specific regulation in today's global marketplace proved to be inappropriate. Therefore, in 2005 Switzerland adopted a new legislation largely harmonized
with the specific EU-Directives. REACH forces Switzerland once again to reconsider its legislation.
REACH: Its Potential Implications for the Insurance Industry
Authors: Blach Christine , Schmid Jürg , Strässle Karl
Published: December 2006

The REACH (Registration, Evaluation, Authorization on Chemicals) regulation will primarily affect the chemical industry, but it will also have an impact on industries that process chemicals, and also on the insurance industry. Of the risks a company faces some are managed within the
company, whereas others are transferred to insurance companies. REACH may now change the overall risk potential of a company and, as a consequence, this change may alter the portion of risk that is transferred to an insurer. REACH may lead to the identification of so far unknown hazardous
properties of chemical substances. Such new findings would increase the risk potential for all companies handling these substances and they could be the basis for new law suits. This could lead to additional exposure for the insurance industry, particularly with respect to liability. In the
long run, however, REACH should lead to safer products and, as a consequence, also to a reduction in the number of insurance claims and law suits. Therefore, any kind of risk reduction is to be welcomed by all stakeholders.
Developing Methods to Predict Chemical Fate and Effect Endpoints for Use Within REACH
Authors: Fenner Kathrin , Canonic Silvio , Escher Beate I. , Gasser Lukas , Spycher Simon , Tülp Holger C.
Published: December 2006

With the pending implementation of REACH, both old and new chemicals will have to be registered and chemical safety reports will have to be compiled. Depending on the yearly tonnages produced or imported, (eco-) toxicological and chemical fate data of varying degrees of detail will
have to be produced. It has been forecast that these new requirements will result in higher costs for registration and an increased need for animal testing. Some of this additional workload could be avoided by making use of in vitro or in silico prediction methods. At Eawag (Swiss
Federal Institute of Aquatic Science and Technology) several research groups are working on the development and validation of quantitative structure–activity relationships (QSARs) and related methods to predict ecotoxicological and fate endpoints, such as reactivities in or partitioning
between different environmental media, based on chemical structure or easily measurable physico-chemical properties. When developing such tools, special attention has to be paid to use only descriptors whose mechanistic significance for the modelled endpoint is well understood on a molecular
level. In this article four examples of our work in the field of compound fate and effect predictions will be presented: i) the measurement of compound descriptors for use in linear-free-energy relationships to predict partition coefficients between environmental media; ii) the development
of free-energy relationships for the prediction of indirect photolysis; iii) the evaluation of existing structure-biodegradability models to predict soil biodegradation half-lives; and iv) the application of mode-of-action-based test batteries to develop quantitative structure–activity
relationships to classify chemicals according to their modes of toxic action.
Prediction of Physicochemical Properties of Organic Compounds from 2D Molecular Structure – Fragment Methods vs. LFER Models
Authors: Schüürmann Gerrit , Ebert Ralf-Uwe , Kühne Ralph
Published: December 2006

A large number of models is available to predict physicochemical properties directly from the two-dimensional molecular structure. An alternative to conventional fragment methods is given by linear free-energy relationships (LFERs) employing Abraham parameters. The latter have a solid
mechanistic background, but a drawback in practice is the limited availability of Abraham parameters for substances of interest. As a consequence, more complex compounds typically require the estimation of Abraham parameters from the chemical structure. Comparative analysis of prediction methods
for Henry's law constant and sorption to soil organic matter shows that at present, fragment methods are superior to the LFER approach when employing calculated Abraham parameters. For the subset of typically more simple compounds with experimental Abraham parameters, the respective LFERs
are competitive to general-purpose fragment models. The discussion includes analyses of compound subsets without and with hydrogen bond functionalities, and of the impact of structural complexity on the model performance.
Will We Know More or Less about Chemical Risks under REACH?
Authors: Scheringer Martin , Böschen Stefan , Hungerbühler Konrad
Published: December 2006

After a brief overview of the history of the regulation of chemicals, we summarize problems with the current European chemicals legislation that have led to the development of the new European regulation, REACH (Registration, Evaluation and Authorization of CHemicals). Two key aspects
are (i) the problem of the large number of existing chemicals for which a practicable evaluation approach had to be found and (ii) the political intention to employ the precautionary principle as a guiding principle of the new regulation. The precautionary principle is related to the question
of how risk assessors can deal with the lack of data, uncertainty, and non-knowledge. A particular aspect of dealing with fundamental uncertainties in chemical risk assessment is the use of hazard indicators, in particular for the properties persistence, bioaccumulation, and toxicity (PBT
assessment). We analyze the way in which PBT assessments will have to be carried out under REACH. We estimate how many persistent chemicals might be expected among the existing chemicals and discuss uncertainties that impede the identification of these persistent chemicals. Our interpretation
of how hazard assessment approaches are implemented in REACH is that the scientific development of hazard assessment methods has not yet provided the practical tools needed for a more consistent and workable approach to PBT assessment under REACH.
A Bronze Medal for Switzerland at the 38th International Chemistry Olympiad 2006 in Korea
Authors: Hofstetter Dustin , Birbaum Karin
Published: December 2006

At the 2006 Chemistry Olympiad in Gyeongsan, South Korea, the Swiss students won a bronze medal.
Atom Probe Tomography II. The Precipitation in Al Base Alloys
Authors: De Geuser F. , Lefebvre W. , Auger P. , Danoix F. , Bigot A. , Blavette D.
Published: December 2006

This paper presents two illustrations of the study of phase separation in Al‐based alloys by means of tomographic atom probe. In an AlMgSi alloy, calculations of pair correlation functions have revealed that the nature of solute short range order differs from a pre‐aged specimen to a non‐pre‐aged specimen. This results in different responses to aged hardening treatments. Concerning Al3(Zr,Sc)‐type dispersoids observed in another Al‐based alloy, they are found to display a core‐shell structure wherein Zr is mainly present in the dispersoids periphery. This duplex structure is likely to explain the relative stability of Al3(Zr,Sc) dispersoids.
Crystallization of Highly Supercooled Silicate Melts
Authors: Roskosz M. , Toplis M. J. , Richet P.
Published: December 2006

Crystallization of liquids in the system CaO‐MgO‐Al2O3‐SiO2 at one atmosphere has been studied at temperatures between the glass transition (Tg) and the solidus. To determine the textures, compositions and unit‐cell parameters of the crystalline phases, the authors have characterized the experimental charges over a wide range of length scales by scanning and transmission electron microscopy, electron microprobe analyses, X‐ray diffraction, and Raman spectroscopy. With increasing temperature, crystals tend to reach the equilibrium composition, but the relative importance of thermodynamic and kinetic factors is a single function of T‐Tg, regardless of liquid composition. This feature is of considerable practical interest as it provides the possibility, not only to predict, but also to control the composition of the crystallizing phases.
Kinetic Monte Carlo Simulations of Precipitation
Authors: Clouet E. , Hin C. , Gendt D. , Nastar M. , Soisson F.
Published: December 2006

We present some recent applications of the atomistic diffusion model and of the kinetic Monte Carlo (KMC) algorithm to systems of industrial interest, i.e. Al‐Zr‐Sc and Fe‐Nb‐C alloys, or to model systems. These applications include study of homogeneous and heterogeneous precipitation as well as of phase transformation under irradiation. The KMC simulations are also used to test the main assumptions and limitations of more simple models and classical theories used in the industry, e.g. the classical nucleation theory.
Characterisation and Modelling of Non‐Isothermal Precipitation in Metallic Systems
Authors: Deschamps A. , Bley F. , Lae L. , Dumont M. , Perard F.
Published: December 2006

During the process of most age hardening metallic alloys, non‐isothermal precipitation plays a key role. The non‐isothermal nature of precipitation processes can be either imposed by constraints of the process route (e.g. precipitation during coiling of NbC in steels, or precipitation in weld heat affected zones), or it can be found as the optimal pathway to the desired properties (e.g. multi‐step heat treatments of aluminium alloys). The presented work addresses both on an experimental and on a modelling point of view some of these effects, both in aluminium alloys (the Al‐Zn‐Mg and Al‐Zr‐Sc systems) and in a Fe‐Cu alloy.
Atom Probe Tomography I. Early Stages of Precipitation of NbC and NbN in Ferritic Steels
Authors: Danoix F. , Bémont E. , Maugis P. , Blavette D.
Published: December 2006

The results reported in this paper give new information regarding the early stages of precipitation in model low niobium steels. It clearly appears that the kinetic paths for carbides and nitrides precipitation in the investigated model alloys are very different, more continuous in the case of carbides, and through GP zones formation in the case of nitrides.
Quantitative Phase Field Modeling of Precipitation Processes
Authors: Bronchard Q. , Le Bouar Y. , Finel A.
Published: December 2006

Phase Field modelling of microstructural evolution in alloys has already a long and successful history. One of the basics of the theory is the introduction of continuous fields (concentration, long‐range order parameters) that describe the local state of the alloy. These fields have a meaning only at a mesoscopic scale. One consequence is that we can treat much larger systems than with microscopic methods such as Monte Carlo or molecular dynamics simulations. The aim of this work is to precisely analyse the status of the mesoscopic free energy densities that are used in Phase Field theories and, simultaneously, to clarify the form that the Phase Field equations should adopt.
Platelet‐derived growth factor C plays a role in the branchial arch malformations induced by retinoic acid
Authors: Han Jing , Li Li , Zhang Zhaofeng , Xiao Ying , Lin Jiuxiang , Zheng Liping , Li Yong
Published: December 2006

BACKGROUND: All‐trans‐retinoic acid (RA) can produce branchial arch abnormalities in postimplantation rodent embryos cultured in vitro. Platelet‐derived growth factor C (PDGF‐C) was recently identified as a member of the PDGF ligand family. Many members of the PDGF family are essential for branchial arch morphogenesis and can be regulated by RA. The roles of PDGF‐C in branchial arch malformations induced by RA and possible mechanisms were investigated. METHODS: In whole embryo culture (WEC), mouse embryos were exposed to RA at 0, 0.1, 0.4, 1.0, or 10.0 μM, PDGF‐C at 25, 50, or 75 ng/mL, or PDGF‐C at 25, 50, or 75 ng/mL containing 0.4 μM RA. After 48 h of culture, mouse embryos were examined for dysmorphogenesis, and whole‐mount immunohistochemistry was applied to PDGF‐C. In explant cultures, explants were exposed to the same doses of RA and PDGF‐C as WEC. Semiquantitative RT‐PCR, zymography, and reverse zymography were used to evaluate the expressions and activities of matrix metalloproteinase (MMP)‐2, MMP‐14, and tissue inhibitor of metalloproteinase (TIMP)‐2. RESULTS: PDGF‐C was reduced by RA, and exogenous PDGF‐C rescued the branchial arch malformations induced by RA. Moreover, PDGF‐C prevented RA‐induced inhibition of the migratory ability of mesenchymal cells in the first branchial arch, by regulating the expressions of MMP‐2, MMP‐14, and TIPM‐2. CONCLUSIONS: Our results suggest that RA exposure reduces the expression of PDGF‐C. The branchial arch malformations resulting from fetal RA exposure are caused at least partially by loss of PDGF‐C and subsequent misregulations of the expressions of MMP‐2, MMP‐14, and TIMP‐2. Birth Defects Research (Part A), 2007. © 2006 Wiley‐Liss, Inc.
Patterns of severe abdominal wall defects: Insights into pathogenesis, delineation, and nomenclature
Authors: Vauthay Liliana , Mazzitelli Nancy , Rittler Monica
Published: December 2006

BACKGROUND: During the last decade, descriptions of malformation complexes involving an abdominal wall defect (AWD) have repeatedly appeared in the literature, and there has been frequent confusion regarding nomenclature, definitions, and delineations. The aims of this work were to evaluate possible embryological relationships among AWD cases, review the related nomenclature, identify patterns involving AWDs, and stress the importance of complete clinical descriptions. METHODS Cases diagnosed as AWD complexes were selected from live‐ and stillborn infants of the Hospital Materno Infantil ${\rm Ram\acute{\sigma}n}$ Sardá, Buenos Aires, and from the Laboratory of Perinatal Pathology, Buenos Aires, Argentina. They were sorted by the location of the AWD, the umbilical cord length, and the presence or absence of a persistent cloaca. The findings in 26 cases were described, according to proposed definitions. RESULTS: Three patterns could be identified: 1) the AWD involving the umbilical ring, a persistent or exstrophic cloaca, and a spinal cord anomaly; 2) the AWD extending laterally to the umbilical ring, severe unilateral limb defects, and same‐sided agenesis of abdominal organs; and 3) the AWD not involving the umbilical ring, clefts, exencephaly, and amputations. Furthermore, overlapping among these patterns was observed, and possible involved mechanisms are discussed. CONCLUSIONS: The observed overlapping among patterns suggested that malformation complexes involving AWDs might not be independent conditions but rather belong to a common and broader spectrum of anomalies. Complete clinical descriptions, the avoidance of synonyms and generalizations, and strictly defined inclusion criteria are proposed for a better understanding of pathogenetic pathways in, and relationships among, AWD complexes. Birth Defects Research (Part A), 2007. © 2006 Wiley‐Liss, Inc.
Formation of Fibril Structures in Polymerizable, Rod–Coil‐Oligomer‐Modified Epoxy Networks
Authors: Yu Yingfeng , Gao Zongyong , Zhan Guozhu , Li Liang , Li Shanjun , Gan Wenjun , Crivello James V.
Published: December 2006

This paper describes the in situ preparation of fibrils in epoxy networks in which the fibril‐like structures are cured polymerizable rod–coil oligomers. The epoxy‐terminated α,ω‐modified PEO oligomers, which are ABA rod–coil–rod oligomers with a poly(ethylene oxide) coil unit and two aromatic azomethine liquid‐crystalline rod units, were synthesized and then further blended with an epoxy precursor. Uniform nanoscale columnar structures were observed in the neat rod–coil oligomers as well as in the crosslinked liquid‐crystalline state. During the curing of the blends, the supramolecular nanoscale columnar structures of the rod–coil oligomers are transformed into polymeric fibrils where the epoxy functional end groups have co‐reacted with epoxy precursors to form a crosslinked network.
On the Nature of DNA‐Duplex Stability
Authors: Řezáč Jan , Hobza Pavel
Published: December 2006

The unwinding free energy of 128 DNA octamers was correlated with the sum of interaction energies among DNA bases and their solvation energies. The former energies were determined by using the recently developed density functional theory procedure augmented by London dispersion energy (RI‐DFT‐D) that provides accurate hydrogen‐bonding and stacking energies highly comparable with CCSD(T)/complete basis set limit benchmark data. Efficient tight‐binding DFT covering dispersion energy was also used and yielded satisfactory results. The latter method can be used for extended systems. The solvation energy was determined by using a C‐PCM continuum solvent at HF level calculations. Various models were adopted to correlate theoretical energies with experimental unwinding free energies. Unless all energy components (hydrogen‐bonding, intra‐ and interstrand‐stacking, and solvation energies) were included and weighted individually, no satisfactory correlation resulted. The most advanced model yielded very close correlation (RMSE=0.32 kcal mol−1) fully comparable with the entirely empirical correlation introduced in the original paper.3 Analysis of the theoretical results shows the importance of inter‐ and intramolecular stacking energies, and especially the latter term plays a key role in determining DNA‐duplex stabilization.
One‐Step Synthesis of Large‐Aspect‐Ratio Single‐Crystalline Gold Nanorods by Using CTPAB and CTBAB Surfactants
Authors: Kou Xiaoshan , Zhang Shuzhuo , Tsung Chia‐Kuang , Yang Zhi , Yeung Man Hau , Stucky Galen D. , Sun Lingdong , Wang Jianfang , Yan Chunhua
Published: December 2006

Gold nanorods were prepared in high yields by using a one‐step seed‐mediated process in aqueous cetyltripropylammonium bromide (CTPAB) and cetyltributylammonium bromide (CTBAB) solutions in the presence of silver nitrate. The diameters of the nanorods range from 3 to 11 nm, their lengths are in the range of 15 to 350 nm, and their aspect ratios are in the range of 2 to 70. The diameters of the Au nanorods obtained from one growth batch in CTPAB solutions decrease as their lengths increase, and their volumes decrease as the aspect ratios increase. The diameters of the Au nanorods obtained from one growth batch in CTBAB solutions first decrease and then slightly increase as their lengths increase, and their volumes increase as the aspect ratios increase. These Au nanorods are single‐crystalline and are seen to be oriented in either the [100] or [110] direction under transmission electron microscopy imaging, irrespective of their sizes. To the best of our knowledge, this is the first report of the preparation by using wet‐chemistry methods of single‐crystalline Au nanorods with aspect ratios larger than 15.
Reversible Immobilization and Direct Electron Transfer of Cytochrome c on a pH‐Sensitive Polymer Interface
Authors: Zhou Jianhua , Lu Xianbo , Hu Jianqiang , Li Jinghong
Published: December 2006

A pH‐sensitive polymer interface has been used as a matrix for reversible immobilization of cytochrome c (Cyt c) on an Au surface through a dip‐coating process. The pH‐sensitive behavior of the polymer brush interface has been demonstrated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The reversible immobilization and electron‐transfer properties of Cyt c have been investigated by in situ UV/Vis spectrophotometry and CV. The results have shown that the poly(acrylic acid) (PAA) brush acted as an excellent adsorption matrix and a good accelerant for the direct electron transfer of Cyt c, which gave redox peaks with a formal potential of 40 mV versus Ag/AgCl in pH 7.6 phosphate buffer solution. The average surface coverage of Cyt c on the PAA film was about 1.7×10−10 mol cm−2, indicating a multilayer of Cyt c. The electron‐transfer rate constant was calculated to be around 0.19 s−1 according to the CV experiments. The interface was subjected to in situ attenuated total internal reflection Fourier‐transform infrared (ATR‐FTIR) spectroscopic analysis, in order to further confirm the immobilization of Cyt c on the surface. This polymer–protein system may have potential applications in the design of biosensors, protein separation, interfacial engineering, biomimetics, and so on.
Tuning the Excited‐State Energy of the Organic Chromophore in Bichromophoric Systems Based on the RuII Complexes of Tridentate Ligands
Authors: Medlycott Elaine A. , Hanan Garry S. , Loiseau Frédérique , Campagna Sebastiano
Published: December 2006

A series of new heteroleptic and homoleptic RuII complexes containing variously substituted bis(pyridyl)triazine ligands has been prepared and their absorption spectra, redox behaviour and luminescence properties (both in fluid solution at room temperature and in a rigid matrix at 77 K) have been investigated. For some compounds, X‐ray structures have also been determined. The new bis(pyridyl)triazines incorporate additional chromophores, such as biphenyl, phenanthrene, anthracene and bromoanthracene derivatives, so the RuII species can be considered as multichromophoric species. The absorption spectra and redox properties of all the metal complexes have been assigned to features belonging to specific subunits, thus suggesting that these species can be regarded as multicomponent, supramolecular assemblies from an electronic coupling point of view. Whereas most of the complexes exhibit luminescence properties that can be attributed to metal‐to‐ligand charge‐transfer (MLCT) states involving the metal‐based subunit(s), the species containing the anthryl and, even more, the brominated anthryl chromophores exhibit complicated luminescence behaviour. For example, 2 d (the anthryl‐containing heteroleptic metal compound) exhibits MLCT emission at room temperature and emission from the anthracene triplet at 77 K; 2 e (the bromo‐substituted anthryl‐containing heteroleptic metal compound) exhibits anthryl‐based emission at 77 K and MLCT emission at room temperature, but with a prolonged lifetime, thus suggesting equilibration between two triplet states that belong to different chromophores. The equilibration regime between MLCT and aromatic hydrocarbon triplet states is therefore reached by suitable substitution on the organic chromophore.
Amphiphilic NO‐Donor Antioxidants
Authors: Chegaev Konstantin , Lazzarato Loretta , Rolando Barbara , Marini Elisabetta , Lopez Gloria V. , Bertinaria Massimo , Di Stilo Antonella , Fruttero Roberta , Gasco Alberto
Published: December 2006

Models of amphiphilic NO‐donor antioxidants 24–26 were designed and synthesized. The products were obtained by linking a lipophilic tail (C6, C8, C10) with a polar head constituted by the 2,6‐dimethoxyphenol antioxidant joined to the NO‐donor 3‐furoxancarboxamide substructure through a bridge containing a quaternary ammonium group. Compound 23, containing the shortest C2‐alkyl chain, was also studied as a reference. The antioxidant properties (TBARS and LDL oxidation assays) and the vasodilator properties of the compounds were studied in vitro. The ability of these products to interact with phospholipid vesicles was also investigated by NMR techniques. The results indicate that both activities are modulated by the ability of the compounds to accumulate on phospholipid layers.
Identical epidermal growth factor receptor mutations in adenocarcinomatous and squamous cell carcinomatous components of adenosquamous carcinoma of the lung
Authors: Kang Shin Myung , Kang Hyun Ju , Shin Ju Hye , Kim Hoguen , Shin Dong Hwan , Kim Se Kyu , Kim Joo‐Hang , Chung Kyung Young , Kim Sung Kyu , Chang Joon
Published: December 2006

BACKGROUND.

Adenosquamous carcinoma of the lung is composed of adenocarcinomatous and squamous cell carcinomatous components. The epidermal growth factor receptor (EGFR) mutations occur mostly in adenocarcinomas and rarely in squamous cell carcinoma of lung. Attempts to investigate the EGFR mutation status in each component of adenosquamous carcinoma and to characterize the patients according to mutation status may help to understand the histogenesis of adenosquamous carcinoma.

METHODS.

The mutation status of EGFR kinase domain from exon 18 to 21 was investigated in 25 Korean patients with adenosquamous carcinoma by polymerase chain reaction–single strand conformation polymorphism using the tissues of each component from the adenosquamous carcinoma tumor. Clinicopathologic characteristics of the patients according to the status of EGFR mutations were compared.

RESULTS.

EGFR mutations were identified in 11 (44%) patients: 9 mutations were in exon 19, 1 in exon 20, and 1 in exon 21. EGFR mutations were significantly more frequent (P = .005) in women (n = 8, 80%) than men (n = 3, 20%). Never‐smokers (n = 8, 62%) had EGFR mutations more commonly than smokers (n = 3, 25%; P = .111). Identical EGFR mutations in both components of adenosquamous carcinoma were confirmed by nucleotide sequencing.

CONCLUSIONS.

The frequency of EGFR mutation and clinicopathologic characteristics of the EGFR mutants in adenosquamous carcinoma are similar to those of Asian patients with adenocarcinomas. Identical EGFR mutations in both components suggest the possibility of monoclonality in the histogenesis of adenosquamous carcinoma. Cancer 2007;109:581–587. © 2006 American Cancer Society.
Cumulative cost pattern comparison of prostate cancer treatments
Authors: Wilson Leslie S. , Tesoro Ross , Elkin Eric P. , Sadetsky Natalia , Broering Jeanette M. , Latini David M. , DuChane Janeen , Mody Reema R. , Carroll Peter R.
Published: December 2006

BACKGROUND.

Studies that compare prostate cancer treatment costs show wide variation. None compare all contemporary treatment costs, and most focus on initial treatment costs. The authors compared healthcare utilization and cost patterns of prostate cancer treatments over a span of 5.5 years in 4553 newly diagnosed patients stratified by age and risk group.

METHODS.

Contemporary treatment and evaluation patterns for prostate cancer were identified by using CaPSURE, a national disease registry of men with prostate cancer that included ongoing clinical data collection from 31 academic and community urology practices and biennial patient‐reported outcome questionnaires that included demography, medical condition, comorbidity, risk measures, and healthcare utilization. Costs of outpatient visits, medications, and hospitalizations were applied from various national sources. Recurrent events analysis (MCF) accounted for left and right censorship. A mixed effects regression model with bootstrapping for skewed cost data quantified the relation between MCF cost, age, and risk.

RESULTS.

Prostate‐related costs in the first 6 months after treatment were $11,495, (from $2586 for watchful waiting (WW) to $24,204 for external beam radiation. After 6 months, average cost was only $3044. Annual cost is $7740, highest for androgen deprivation therapy ($12,590) and lowest for watch waiting ($5843). Risk and age were significantly related to initial treatment choice. Cumulative cost ($42,570) allowed a better estimate of treatment pattern costs.

CONCLUSIONS.

The cost burden of prostate cancer is high, but it varies by treatment type even when controlling for disease, age, and stage. Cumulative cost analysis allowed inclusion of adverse events and disease recurrence costs, making new cost comparisons evident among treatments. Cancer 2007;109:518–527. © 2006 American Cancer Society.
Underestimation of malignancy of breast core‐needle biopsy
Authors: Houssami Nehmat , Ciatto Stefano , Ellis Ian , Ambrogetti Daniela
Published: December 2006

BACKGROUND:

A review of the literature indicated variable underestimation rates for breast core‐needle biopsy (CNB) based on generally small series. In this article, the authors present precise estimates for overall underestimation and for categories of histologic underestimates (including categories that reflect contemporary classification) and examine the effect of lesion and sampling variables.

METHODS:

Among 4035 consecutive CNBs, the authors examined women whose CNB outcome represented a potential underestimate of malignancy (benign but of uncertain biologic or malignant potential or B3 and ductal carcinoma in situ [DCIS]). From 889 eligible women, all 758 women who had excision histology available were included.

RESULTS:

Overall underestimation of CNB was 27.7% (95% confidence interval [95% CI], 24.5–30.9%). The following category‐specific rates were used: B3 underestimates, 36.2% (95% CI, 30.6–41.8%); B3 underestimates (excluding atypical proliferations), 17.9% (95% CI, 10.8–24.9%); atypical ductal hyperplasia underestimates, 29.0% (95% CI, 21.4–36.6%; upgraded to DCIS) and 44.2% (95% CI, 36.0–52.5%; upgraded to DCIS or invasive cancer); and DCIS underestimates, 22.8% (95% CI, 19.0–26.5%). There was a significant trend toward greater underestimation of malignancy with increasing lesion size on imaging studies for overall underestimates (P = .00008), B3 underestimates (P = .009), and DCIS underestimates (P = .0007). Underestimation rates did not differ between masses (27.9%) and microcalcifications (27.6%; chi‐square statistic with 1 degree of freedom = 3.02; P = .98) and were significantly lower for vacuum‐assisted CNB (11‐gauge) than for automated CNB (14‐gauge; P = .001). Underestimation rates, when sampling microcalcifications, decreased with increasing number of cores collected, but this was mainly for DCIS underestimates.

CONCLUSIONS:

CNB results that were not definitely negative or were not positive for invasive cancer were associated with high rates of underestimation of disease and with target lesion size. Identifying imaging or sampling factors that affect underestimation rates of CNB may assist in reducing their occurrence and better predicting excision histology outcomes. Cancer 2007;109:496–501. © 2006 American Cancer Society.
Reaction Pathways Involved in the Mechanism of AlIII Chelation with Caffeic Acid: Catechol and Carboxylic Functions Competition
Authors: Lapouge Christine , Cornard Jean‐Paul
Published: December 2006

Density functional theory calculations on the AlIII–caffeic acid system are carried out to investigate the fixing mechanism of this metal ion to the two competing complexing sites in the ligand. This theoretical study was performed to explain the complex formation of 1:1 stoichiometry observed in aqueous medium at low pH values. Both complexation with the catechol and carboxylic functions are envisaged. The reaction pathways for the formation of these two chelates are calculated at the B3LYP/6‐31G** level of theory. The complexation on the more acidic group is relatively straightforward and shows the intermediate formation of a monodentate complex followed by a chelation process. The complexation reaction pathway with the catechol function is more sophisticated, and several pathways are explored. Once more, the formation of a monodentate complex is achieved and the most favorable pathway for chelation involves the successive steps: 1) coordination of AlIII on the oxygen atom of a hydroxyl group, 2) deprotonation of this hydroxyl group, 3) ring closure with the other oxygen atom, and 4) deprotonation of the second hydroxyl. From an energetic point of view, this second pathway is more favorable. Notably the energy barrier necessary to form the chelate is lower for the catechol function than that calculated for the carboxylic group. The results of this purely theoretical study are in complete agreement with spectroscopic investigations performed on this system.
Developing a framework for development: A discussion
Authors: Bateson Patrick , Hofer Myron , Oppenheim Ronald , Wiedenmayer Christoph
Published: December 2006

A multitude of scientific disciplines study the development of behavior. Their use of different methodological and conceptual approaches makes integration of findings difficult. In a symposium at the 38th Annual Meeting of the International Society for Developmental Psychobiology in Washington DC, the question was discussed if a general theory of development could unify the field. The three participants explain their views and discuss the possibility of a theoretical framework for development. © 2006 Wiley Periodicals, Inc. Dev Psychobiol 49: 77–86, 2007.
Characterization of offensive responses during the maturation of play‐fighting into aggression in male golden hamsters
Authors: Cervantes M. Catalina , Taravosh‐Lahn Kereshmeh , Wommack Joel C. , Delville Yvon
Published: December 2006

In hamsters, the maturation of aggression during puberty is associated with a gradual reduction of offensive responses. The purpose of this study was to analyze the changes during this decrease to provide an enhanced description of the behavior. During early puberty, play‐fighting is characterized by long and continuous contact duration throughout the encounter and repetitive attacks within bouts of agonistic interaction. By mid‐puberty, adult patterns of offensive behavior emerge. Contact time becomes shorter in duration and shifts to the beginning of the test, while attacks become less repetitive per bout. In late puberty, animals show an enhanced efficiency of behavior, as indicated by an increased percentage of attacks followed by bites. This study provides a better understanding of the development of aggression by characterizing the differences between juvenile play‐fighting and adult aggression and the process of the maturation of aggression. © 2006 Wiley Periodicals, Inc. Dev Psychobiol 49: 87–97, 2007.
Huddling by rat pups: Ontogeny of individual and group behavior
Authors: Alberts Jeffrey R.
Published: December 2006

A full account of behavioral development in rats must include the ontogeny of both individual and group behavior. Most of our accumulated knowledge, however, pertains to individual ontogenesis. Group behavior and its development are readily seen in the huddling behavior of rat pups. A rat huddle is an entity with characteristics and capabilities distinct from those of the individuals that comprise it. The huddle is a natural context for acquiring olfactory preferences for species odors. Olfactory learning in a huddle involves thermal and tactile stimulation from the mother's body but, surprisingly, not the rewards of suckling or of milk transfer. Although there is complete developmental continuity of huddling behavior, the sensory controls of huddling change dramatically during the first 2 weeks of postnatal life. Huddling behavior is initially controlled by thermal cues (“physiological huddling”) and then becomes dominated by olfactory stimuli (“filial huddling”). The complex group behavior of huddling was modeled successfully with computational methods. Group behavior emerges from individual interactions, guided entirely by rules of individual behavior (no rules for group behavior). Three simple rules of autonomous activity/inactivity can spawn the patterns of aggregon formation displayed by groups of 7‐day‐old pups, but not by 10‐day‐olds. The developmental change evident by Day 10 requires adding a rule by which each individual is affected by the activity state of adjacent pups. Group behavior responded to manipulations of central oxytocin on Day 10, but not on Day 7. © 2006 Wiley‐Periodicals, Inc. Dev Psychobiol 49: 22–32, 2007.