bluuebunny/crossref_metadata_2025 huggingface dataset:
Polymer Optical and Dielectric Properties through Vibrational Spectroscopy
Authors: Smith D. M. , Chughtai A. R.
Published: June 2007

Principles of the refraction and extinction of electromagnetic radiation incident upon homogeneous isotropic condensed phases are reviewed. The relationship between the complex refractive index,
n
(υ), and the absorption index,
k
(υ), through the Kramers–Kronig transform is shown as is the relationship of these optical constants to ɛ, the complex dielectric function. The basis of the determination of the optical constants n and k as a function of frequency for polymeric materials by infrared reflection‐absorption spectroscopy (IR‐RAS) is illustrated with examples as are other external reflection methods. Also discussed is the effect of absorber concentration on the IR‐RA spectra. Various methods for the measurement of optical constants and dielectric function of isotropic and anisotropic polymers covered are internal reflection techniques such as attenuated total reflectance (ATR), transmittance‐reflectance, transmission, and ellipsometry. The chapter concludes with comments on new spectroscopic techniques with potential application to the determination of optical constants of polymers.
Introduction to Vibrational Spectroscopy
Authors: Griffiths Peter R.
Published: June 2007

A summary of the basic theory of mid‐infrared, near‐infrared and Raman spectroscopy is given, including the concept of normal modes and fundamental, overtone, and combination bands. An introduction to vibration‐rotation spectroscopy of molecules in the vapor phase is then presented. The factors governing the intensity of bands in infrared and Raman spectra and the width of bands in condensed‐phase spectra and lines in vapor‐phase spectra are discussed. Finally, the effect of polarized light on oriented molecules is summarized.
Sampling Techniques and Fiber‐Optic Probes
Authors: Chalmers John M. , Griffiths Peter R.
Published: June 2007

The raw materials and development and commercial products of the pharmaceutical industry come in a wide and diverse range of forms. Sampling techniques for these must be representative and appropriately selected, particularly for solid‐state studies. In addition, process measurements require the use of specialized tools such as fibre‐optic probes. This chapter outlines the basic practices, principles and limitations underlying sample presentation methods for the vibrational spectroscopy techniques of near‐infrared (NIR), mid‐infrared, THz, and Raman spectroscopy. For NIR and mid‐infrared it covers both transmission and reflection techniques. The chapter also discusses sampling methods in relation to microspectroscopy and imaging. The chapter closes with discussions on fibre‐optic probes, fibre‐optic materials, and optical conduits and their uses with near‐infrared, mid‐infrared and Raman spectrometry.
Characterization and Optimization of Chemical Synthesis Using Real‐Time Vibrational Spectroscopy
Authors: Homsi Fadi , Barrett Paul , Wang Jian , Ferwerda Roel
Published: June 2007

For a long time, mid‐infrared and Raman spectroscopy have played an important role in the structure elucidation of organic compounds. However, only during the last 20 years, they became powerful technologies for understanding chemical reaction pathways and kinetics, and they are now an essential part of the Organic Chemist's Process Analytical Technology (PAT) toolbox. The technologies are utilized when researching reaction progress, kinetics, asymmetric and coordination chemistry, hydrogenation, reactive and green chemistry, and solution crystallization, which will all be discussed in detail. The chapter will be concluded with some of the new developments in this area.
The Analysis of Pharmaceutical Substances and Formulated Products by Vibrational Spectroscopy
Authors: Clark Don , Pysik Alexander
Published: June 2007

The sections in this article are

Introduction

Pharmacopoeial Considerations

Bulk Sample Analysis

Drug Substance Characterization

Functional Group Analysis

Hydrogen Bonding and Zwitterions

Polymorphism, Salts, Hydrates, and Solvates

Chirality

Methods to Probe Solid‐Phase Phenomena

Process Analytical Technology Applications

Formulation Analysis

Microscopic Sample Analysis

Drug Substance Characterization

Forensic Analysis

Conclusions

Acknowledgments
Pharmaceutical Applications of Chemical Mapping and Imaging
Authors: Clark Don , Henson Mark , LaPlant Fred , Šašić Slobodan , Zhang Lin
Published: June 2007

The sections in this article are

Introduction

The Technology and Rationale for Chemical Images

Sample‐Preparation Considerations for Chemical Mapping and Imaging

Chemical Mapping and Imaging Applications

Polymorph Analysis

Product Design and Development

Product Performance and Support

Chemical Image Production Using Chemometric Analysis

The Hyperspectral Cube and Chemical Images

Image Data Analysis

Data Preprocessing

Principal Component Analysis (

PCA

)

Ordinary Least Squares (
OLS
)

Partial Least Squares (

PLS

)

PLS

Quantitative Analysis

PLS

Classification

Analysis of Chemical Images

Conclusion

Acknowledgments
Terahertz Spectroscopy for Pharmaceutical Applications
Authors: Claybourn Mike , Yang Husheng , Gradinarsky Lubomir , Johansson Jonas , Folestad Staffan
Published: June 2007

The sections in this article are

Introduction

Absorption Spectroscopy in theTHzRegion

Instrumentation

Pharmaceutical Applications

Imaging Applications

Pharmaceutical Characterization Applications

Theoretical Modeling and Spectral Interpretation

Process Analysis
History, Trends and Prognostications
Authors: Griffiths Peter R. , Chalmers John M. , Pivonka Don E.
Published: June 2007

The development of mid‐infrared, near‐infrared and Raman spectrometers over the past 30 year is outlined and the way that these developments have impacted the analysis of pharmaceutical products is summarized. Fourier transform infrared (FT‐IR) spectrometers are almost one hundred times more sensitive than when they were introduced in 1969. The development of near‐infrared and Raman Spectrometers (both dispersive and Fourier transform) in the past 20 years has had an equal impact on pharmaceutical analysis. The rapid advances in the performance of personal computers have allowed some quite remarkable measurements that rely on complex chemometric algorithms to be made. Developments in accessories (such as attenuated total reflection accessories) and peripherals (such as infrared and Raman microscopes) has simplified the measurement of vibrational spectra. Finally, measurements that were completely unknown 25 years ago, such as hyperspectral imaging and vibrational circular dichroism spectrometry are also starting to have a large impact on pharmaceutical analysis.
Theory of Vibrational Spectroscopy of Polymers
Authors: Castiglioni Chiara
Published: June 2007

In this Chapter the theoretical basis for the modelling of vibrational spectra of polymers are illustrated. The different approaches suitable for the prediction of vibrational frequencies, infrared and Raman intensities are described with reference to the real case of a semi‐crystalline and of an amorphous polymeric material.

The theory underlying the calculation of phonon dispersion curves for a polymer showing regular conformation (treated as a 1‐D crystal) is reported and relationship between phonons of a polymer and normal modes of vibrations of its oligomers are discussed. The advantages resulting from a treatment based on valence coordinates and from the explicit use of the screw symmetry (for polymers with helical conformation) are shown.

Prediction of defect modes and its relevance in the structural characterisation of real samples is illustrated with examples.

A discussion about use and limitations of first principle approaches to the study of the vibrational spectra of polymers is reported, with reference to several studies that have appeared in the literature.
Depth Profiling of Polymers by Vibrational Spectroscopy
Authors: Fredericks Peter M.
Published: June 2007

Depth profiling has become an important application of the vibrational microspectroscopy of heterogeneous solid samples. This chapter discusses the experimental and theoretical aspects of depth profiling by both infrared and Raman spectroscopy. Various means, such as microtoming, exist to prepare the sample for analysis. Such methods are destructive but require only a small amount of sample. Infrared spectroscopy is restricted to destructive approaches, except for the ATR technique where limited depth profiling is possible using different internal reflection elements. Raman microspectroscopy can be used in the same way as IR and has the benefit of much better spatial resolution. However, if the Raman microspectrometer is operated in confocal mode it is also possible, without any sample preparation, for spectra to be collected from within the sample, a process known as “optical slicing”. While there have been some reports demonstrating the efficacy of this approach, there have also been warnings relating to the accuracy of the method. The latest experimental and theoretical studies are discussed in order to define the current state‐of‐the‐art in confocal Raman depth profiling.
Infrared Linear Dichroism of Polymers
Authors: Buffeteau Thierry , Pézolet Michel
Published: June 2007

The absorption of linearly polarized infrared radiation by oriented samples is sensitive to the state of polarization of the incident radiation. This phenomenon is known as the
infrared linear dichroism
(IRLD). The degree of optical anisotropy in oriented samples can be characterized by measuring two spectra using light polarized parallel and perpendicular to a reference direction. In this chapter, the theoretical expressions allowing the quantitative determination of molecular orientation from IRLD measurements for systems showing both uniaxial and biaxial symmetry of orientation are described. In addition, typical examples of the use of IRLD to determine the orientation of polymers are presented. These results were obtained from either static measurements or dynamic measurements using a rotating polarizer, a photoelastic modulator (PM‐IRLD) or ultrarapid scanning‐Fourier transform infrared (URS‐FTIR). The use of these techniques allows one to follow the kinetics of orientation over different timescales down to 40 min.
Vibrational Spectroscopy of Conducting Polymers: Theory and Perspective
Authors: Zerbi Giuseppe
Published: June 2007

The sections in this article are

Introduction

Why New Science and Innovative Technology with Polyconjugated Systems?

The World of π Electrons

The Theoretical Approach to Molecular Vibrations of Polyconjugated Molecules

Electron Phonon Coupling

AB
Initio Calculations

Polyacetylene

The Use of

IR

in the Case of Cis and Trans Pristine

PA

The Use of
R
aman Spectra of Polyenes and Trans

PA

Vibrational Spectroscopy of Doped and Photoexcited Trans

PA

Doping

Photoexcitation

From

PA

to Larger Systems: Polyaromatic Molecules

General Aspects

A Detailed Spectroscopic Analysis of Simple Linear Polyaromatic Chains

Doping

Photoexcitation

Photochromic Polymers

Molecular

NLO

Properties from Vibrational Spectra of Polyconjugated Molecules

What's Next? A New Window Opens

Acknowledgments
Synthesis functional poly(carbonate‐b‐ester) copolymers and micellar characterizations
Authors: Chiu Fang‐Chyou , Lai Chia‐Sheng , Lee Ren‐Shen
Published: June 2007

Functional poly(carbonate‐b‐ester)s were synthesized in buck by ring‐opening polymerization of the carbonate (TMC, MBC, or BMC) with tert‐butyl N‐(2‐hydroxyethyl) carbamate as an initiator, and then with ε‐CL (or ε‐BCL) comonomer. Subsequently, the PMMC‐b‐PCL with pendent carboxyl groups and the PTMC‐b‐PHCL with pendent hydroxyl groups were obtained by catalytic debenzylation. DSC analysis indicated that only one Tg at an intermediate temperature the Tgs of the two polymer blocks. A decrease Tg was observed when an increase contents of ε‐CL incorporated into the copolymers. In contrast, two increased Tms were observed with increasing PCL content. The block copolymers formed micelle in aqueous phase with critical micelle concentrations (cmcs) in the range of 2.23–14.6 mg/L and with the mean hydrodynamic diameters in the range of 100–280 nm, depending on the composition of copolymers. The drug entrapment efficiency and hydrolytic degradation behavior of micelle were also evaluated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Order from chaos: The poetics and pragmatics of scientific recordkeeping
Authors: Shankar Kalpana
Published: June 2007

Although the production of laboratory and field records is fundamental to the conduct of contemporary science, there has been little research into this topic in information studies. This article reports on a study in which, using ethnographic methods, the author studied recordkeeping as it is practiced in a basic research science laboratory. The process by which the record is created to reflect both personal need and professional norms is framed as a series of acts of selection, synthesis, and standardization. The article concludes with reflections on the role of deep understanding of scientific recordkeeping for other disciplines and the design of digital laboratory technologies.
Democratic theory in library information science: Toward an emendation
Authors: Buschman John
Published: June 2007

Despite quantities of popular rhetoric, democratic theory holds an aposiopetic place within library and information science (LIS) in both senses of that word: It is both in a stasis holding to basic ideas outlined 200 years ago and also a silence largely maintained. A review of a number of state‐of‐the‐literature reviews make the case that it has not been systematically explored or applied, and most LIS work elides the questions democratic theory raises. It is time to emend this and account for a relevant intellectual source which can more firmly ground LIS practice and research in normative terms. Toward that end, three productive wellsprings of democratic theory are reviewed: Jürgen Habermas, Sheldon Wolin, and those working on democratic education (Amy Gutmann, Richard Brosio, Maxine Greene). The article concludes with an outline of some possible LIS questions and approaches drawn from these democratic theorists.
Safeguarding young people from cyber pornography and cyber sexual predation: a major dilemma of the internet
Authors: Dombrowski Stefan C. , Gischlar Karen L. , Durst Theo
Published: June 2007

Over the past 20 years, the internet has provided an expedient mode of communication and access to a wealth of information. The internet is a valuable tool; however, it can also be detrimental to the wellbeing of children due to numerous online hazards. There is the potential for children to be abused via cyberspace through online sexual solicitation and access to pornography. Indeed, the internet is replete with inappropriate material, including pornography, chatrooms with adult themes and access to instant messaging wherein others could misrepresent themselves. Because children are actively utilizing the internet where unknown others can have access to them or where they can be exposed to inappropriate sexual materials, they require safeguarding and education in safe internet use. The purpose of this article is to provide a discussion of how to safeguard children from and educate them about online sexual solicitation and pornography. We contend that society needs an overall conceptual shift in its attitude towards young people's internet use. Copyright © 2007 John Wiley & Sons, Ltd.
Developing interprofessional relationships: tapping the potential of inter‐agency training
Authors: Glennie Sara
Published: June 2007

The creation of effective Local Safeguarding Children Boards in England and Wales is contingent upon the development of new interprofessional partnerships amongst practitioners, managers and strategic planners. Inter‐agency training will have a role to play in facilitating partnership development throughout an increasingly complex inter‐agency system. The following article reviews the recent history of inter‐agency training and the increasing clarity regarding its distinctive purpose. It highlights three theoretical frameworks that have been influential in the development of ideas about the most appropriate focus and process when working across organisational and professional boundaries. Finally, attention is drawn to an emerging consensus as to the core dimensions of effectiveness in interprofessional working relationships. Copyright © 2007 John Wiley & Sons, Ltd.
Face‐Selective [2]‐ and [3]Rotaxanes: Kinetic Control of the Threading Direction of Cyclodextrins
Authors: Oshikiri Tomoya , Takashima Yoshinori , Yamaguchi Hiroyasu , Harada Akira
Published: June 2007

New [2]‐ and [3]pseudorotaxanes containing α‐cyclodextrin (α‐CDs) molecules as rotors and alkyl pyridinium derivatives as axles were prepared by a slipping process. The inclusion behavior of these rotaxanes was investigated by using one‐ and two‐dimensional NMR spectroscopy. The methyl group at the 2‐position of the pyridinium moiety at the end of each axle molecule was found to control the rates of threading of the α‐CD onto the axle molecules. α‐CD can approach axle molecules from a particular direction to form inclusion complexes. Axle molecules that contain a 2‐methylpyridinium moiety at one end and a bulky stopper at the other end can regulate the direction of approach to give a [2]pseudorotaxane such as 2 b–α‐CD. A [3]pseudorotaxane in which two α‐CD molecules are arranged facing in the same direction at two stations of the tetracationic axle molecule was also obtained. These face‐selective behaviors are dominated by kinetic processes rather than thermodynamic processes.
Artificial Ditopic Arg‐Gly‐Asp (RGD) Receptors
Authors: Schmuck Carsten , Rupprecht Daniel , Junkers Matthias , Schrader Thomas
Published: June 2007

Covalent fusion of two artificial recognition motifs for arginine and aspartate resulted in a new class of ditopic RGD receptor molecules, 1–4. The two binding sites for the oppositely charged amino acid residues are linked by either flexible linkers of different length (in 1–3) or a rigid aromatic spacer (in 4). These spacers are shown to be critical for the complexation efficiency of the artificial hosts. If the linkers are too flexible, as in 1–3, an undesired intramolecular self‐association occurs within the host and competes with, and thereby weakens, substrate binding. The rigid aromatic linker in 4 prevents any intramolecular self‐association and hence efficient RGD binding is observed, even in buffered water (association constant of Ka≈3000 m−1). A further increase in hydrophobic contacts, as in host 16, can complement the specific Coulomb attractions, thereby leading to an even more stable complex (Ka=5000 m−1). The recognition events have been studied with NMR spectroscopy, UV/Vis spectroscopy, and fluorescence titrations.
An actin‐stabilizing peptide conjugate deduced from the major outer sheath protein of the bacterium Treponema denticola
Authors: Amin Mohsen , Grove David A. , Kapus András , Glogauer Michael , Ellen Richard P.
Published: June 2007

A synthetic peptide conjugated to bovine serum albumin, P34BSA, based on a 10‐mer in the deduced amino acid sequence of the major outer sheath protein of Treponema denticola, was found to stabilize actin filaments of fibroblasts. Pretreatment of cells with P34BSA inhibited the actin disruption induced by cytochalasin D and latrunculin B. P34BSA was taken up by the cells and localized among actin filaments. P34BSA bound actin from fibroblast lysates, and cell exposure to P34BSA led to the activation of RhoA, a key regulator of actin filament assembly in fibroblasts. Exposure of fibroblasts to P34BSA retarded their migration on a collagen substratum. P34BSA also inhibited chemotaxis of murine neutrophils. Our findings with a novel peptide conjugate imply that bacterial proteins known to perturb the cytoskeleton represent a rich source of molecular models upon which to design synthetic reagents for modulating actin‐dependent cellular functions. Cell Motil. Cytoskeleton 2007. © 2007 Wiley‐Liss, Inc.
The contributions of microtubule stability and dynamic instability to adenovirus nuclear localization efficiency
Authors: Warren James C. , Cassimeris Lynne
Published: June 2007

Adenoviruses (Ads) utilize host cell microtubules to traverse the intracellular space and reach the nucleus in a highly efficient manner. Previous studies have shown that Ad infection promotes the formation of stable, posttranslationally modified microtubules by a RhoA‐dependent mechanism. Ad infection also shifts key parameters of microtubule dynamic instability by a Rac1‐dependent mechanism, resulting in microtubules with lower catastrophe frequencies, persistent growth phases, and a bias toward net growth compared to microtubules in uninfected cells. Until now it was unclear whether changes in RhoGTPase activity or microtubule dynamics had a direct impact on the efficiency of Ad microtubule‐dependent nuclear localization. Here we have performed synchronous Ad infections and utilized confocal microscopy to analyze the individual contributions of RhoA activation, Rac1 activation, microtubule stability, dynamic behavior, and posttranslational modifications on Ad nuclear localization efficiency (NLE). We found that drug‐induced suppression of microtubule dynamics impaired Ad NLE by disrupting the radial organization of the microtubule array. When the microtubule array was maintained, the suppression or enhancement of microtubule turnover did not significantly affect Ad NLE. Furthermore, RhoA activation or the formation of acetylated microtubules did not enhance Ad NLE. In contrast, active Rac1 was required for efficient Ad nuclear localization. Because Rac1 mediates persistent growth of microtubules to the lamellar regions of cells, we propose that Ad‐induced activation of Rac1 enhances the ability of microtubules to “search and capture” incoming virus particles. Cell Motil. Cytoskeleton 2007. © 2007 Wiley‐Liss, Inc.
Performance of calibration standards for antigen quantitation with flow cytometry in chronic lymphocytic leukemia
Authors: Rossmann Eva D. , Lenkei Rodica , Lundin Jeanette , Mellstedt Håkan , Österborg Anders
Published: June 2007

Background:

The fluorescence intensities of CD3, CD4 on T cells and CD20, CD22 molecules on B cells were quantitatively measured on lymphocytes from chronic lymphocytic leukemia (CLL) patients and healthy donors.

Methods:

The performance of three different types of microbeads was compared, i.e. Quantum molecules of equivalent soluble fluorochrome (Q‐MESF), Quantum simply cellular (QSC), and QuantiBRITE™ (QB). As all PE‐conjugates had a F/P ratio of 1:1, the MESF units represented also the antibody binding capacity (ABC).

Results:

The ABCs of CD4 and CD20 antigens estimated with QSC (ABCQSC) were higher than those assigned with QB (ABCQB) with an average difference 49%. Higher numbers of antigenic sites were obtained with Q‐MESF than with QSC for CD20 antigen. On the contrary, CD4 antigenic sites numbers estimated with QSC were higher than those estimated with Q‐MESF. ABC values estimated with Quantum MESF PE (ABCQ‐MESF) were ∼15% higher than ABCQSC, whereas ABCQ‐MESF was ∼49% higher than ABCQB. Statistically significant correlations were found between the values obtained using various standards. The present study is the first to report down‐regulation of CD3 antigen on T cells from patients with CLL.

Conclusions:

This study emphasizes the relevance of quantitative measurement of fluorescence intensity by flow cytometry as a standardized approach to measure and interpret the expression of some CLL markers and reduce variability of results obtained at different sites in multi‐center clinical studies. © 2007 Clinical Cytometry Society
Impairment of dendritic cell function by excretory‐secretory products: A potential mechanism for nematode‐induced immunosuppression
Authors: Segura Mariela , Su Zhong , Piccirillo Ciriaco , Stevenson Mary M.
Published: June 2007

To determine whether helminth‐derived products modulate dendritic cell (DC) function, we investigated the effects of excretory‐secretory products (ES) and adult worm homogenate (AWH) derived from the gastrointestinal nematode Heligmosomoides polygyrus (Hp) on murine bone marrow‐derived DC (BMDC). Compared to the TLR9 ligand CpG, Hp‐derived products alone failed to induce DC activation. ES, but not AWH, inhibited BMDC cytokine and chemokine production and co‐stimulatory molecule expression (CD40, CD86 and MHC class II) induced by TLR ligation. TLR ligand‐independent, PMA‐induced DC activation was unaffected by ES. Recipients of ES‐treated BMDC pulsed with OVA had suppressed Ab responses in vivo, irrespective of the Th1 or Th2 isotype affiliation, compared to recipients of control OVA‐pulsed BMDC. Importantly, suppression occurred even in the presence of the potent type 1 adjuvant CpG. In contrast to untreated OVA‐pulsed BMDC, ES‐treated BMDC pulsed with OVA had reduced co‐stimulatory molecule and cytokine expression. CD4+CD25+Foxp3– T cells, which secreted high IL‐10 levels, were generated in co‐cultures of OT‐II OVA‐specific TCR‐transgenic CD4+ T cells and ES‐treated BMDC. These IL‐10‐secreting T cells suppressed effector CD4+ T cell proliferation and IFN‐γ production, the latter effect mediated by an IL‐10‐dependent mechanism. Together, these results demonstrate that nematode ES impaired DC function and suppressed both Th1 and Th2 adaptive immune responses possibly by inducing regulatory T cells.
Expansion and activation of CD4+CD25+ regulatory T cells in Heligmosomoides polygyrus infection
Authors: Finney Constance A. M. , Taylor Matthew D. , Wilson Mark S. , Maizels Rick M.
Published: June 2007

Regulatory T cell responses to infectious organisms influence not only immunity and immunopathology, but also responses to bystander antigens. Mice infected with the gastrointestinal nematode parasite Heligmosomoides polygyrus show an early Th2‐dominated immune response (days 7–14), but by day 28 a strongly regulatory profile is evident with antigen‐specific IL‐10 release and elevated frequency of CD4+ T cells bearing surface TGF‐β. CD4+CD25+ T cells from infected mice show enhanced capacity to block in vitro effector T cell proliferation. CD4+CD25+ cell numbers expand dramatically during infection, with parallel growth of both CD25+Foxp3+ and CD25+Foxp3– subsets. CTLA‐4 and glucocorticoid‐induced tolerance‐associated receptor, also associated with regulatory T cell function, become more prominent, due to both expanded CD25+ cell numbers and increased expression among the CD25– population. Both intensity and frequency of CD103 expression by CD4+ T cells rise significantly, with greatest expansion among CD25+Foxp3+ cells. While TGF‐β expression is observed among both CD25+Foxp3+ and CD25+Foxp3– subsets, it is the latter population which shows higher TGF‐β staining following infection. These data demonstrate in a chronic helminth infection that Foxp3+ regulatory T cells are stimulated, increasing CD103 expression in particular, but that significant changes occur to other populations including expansion of CD25+TGF‐β+Foxp3– cells, and induction of CTLA‐4 on CD25– non‐regulatory lymphocytes.
In Pursuit of an Acetylenedithiolate Synthesis
Authors: Seidel Wolfram W. , Meel Matthias J. , Schaffrath Markus , Pape Tania
Published: June 2007

Acetylene disulfides RSC2SR, which are furnished with typical thiol protection groups R, were synthesized, fully characterized, and tested with respect to the aimed cleavage of R. While the alkyne RSC2SR with R = C2H4SiMe3 is easily accessible, the corresponding disulfide with R = CPh3 can be prepared only with difficulties, and attempts to use the SiMe3 group lead to the isolation of a dithiacyclopentene derivative. The molecular structures of Ph3CSC2SCPh3 and Ph3CSC2H, which were investigated by X‐ray diffraction, show a remarkable combination of long and very short carbon–sulfur single bonds. However, removal of the trityl groups by sodium phenolate or methyllithium in THF led to intractable solutions. In contrast, removal of both trimethylsilylethyl groups in Me3SiC2H4SC2SC2H4SiMe3 with (Bu4N)F in THF proceeded smoothly, if benzyl bromide as the trapping agent is present. Hence, the successful transfer of the C2S22– synthon in solution was proven by isolation of BnSC2SBn.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Conformation of Trisialic Acid Lactone: NMR Spectroscopic Analysis and Molecular Dynamics Simulation
Authors: Chen Chien‐Sheng , Yu Yi‐Ping , Hsu Chun‐Hua , Wu Ying‐Ta , Zou Wei , Fang Jim‐Min , Wu Shih‐Hsiung
Published: June 2007

The conformation of the trisialic acid lactone α2,8‐(NeuAc)3 was analyzed by a combination of NMR spectroscopy, molecular modelling and molecular dynamic (MD) calculations. The interresidue NOEs provided 14 important distance restraints for the molecular simulation, and the final simulated structures showed a root mean square deviation of 0.78 for all superimposed structures. Because of the steric hindrance from the spirobicyclic δ‐lactone, the individual sialic acid pyranose rings are considered essential in the chair 5C2 conformation. In addition, lactone I close to the nonreducing end adopted a half‐chair A2HCB9 conformation, whereas lactone II, which is close to the reducing end adopted a skewed twist‐boat C2SC9 conformation. In the NMR solution structure and in the 1.0‐ns, in‐water MD calculation, the final simulated structures are in the exocyclic torsions (ω7, ω8) = (gauche–anti) surface of the energy adiabatic map, where the global minimum can be found. During the in‐water MD simulation, a slight fluctuation in the structure was observed, reflecting the steady conformation of the lactone and the middle residue of the trisaccharide. These data are consistent with a theoretical approach of polysialic acid (PSA) polylactone with torsions (ω7, ω8) = (65°, 175°) and (Φ, Ψ) = (75.8°, –112.4°). Thus, we conclude that the PSA polylactone is a right‐hand helix with a rotation angle, μ, of 240° and a repeating unit, n, of 1.5 residues. The structural properties of the PSA lactone discussed within this context differ from the helical epitope of G2+ PSA and may serve in future PSA‐related antigen designs. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Chiral Concave Imidazolinium Salts as Precursors to Chiral Concave N‐Heterocyclic Carbenes
Authors: Winkelmann Ole , Linder David , Lacour Jérôme , Näther Christian , Lüning Ulrich
Published: June 2007

Imidazolinium moieties have been incorporated into bimacrocycles to generate precursors for concave N‐heterocyclic carbenes (NHCs). By using one symmetrically substituted benzene bridgehead and one naphthalene bridgehead devoid of local C2‐symmetry, axially chiral concave imidazolinium ions have been obtained. Starting from 2,7‐dihydroxy‐1‐nitronaphthalene (7), the phenol groups have been transformed to 4‐pentenyl ethers 8, and the nitro group was then reduced to the corresponding amine 9. Next, 9 and a 2,6‐bis(alkenyloxy)aniline 10 were connected by an oxalic acid linker. After reduction of the diamide 13 to diamine 14, a bridge was installed with triethyl orthoformate to give a tetraalkenyl‐substituted imidazolinium salt 15. Ring‐closing metathesis of 15 followed by hydrogenation of the products 16 yielded the bimacrocyclic salts 17 in 9–18 % overall yield (based on 7), giving amounts up to >300 mg. The configurational stability of 17 was investigated by NMR using chiral enantiopure anions TRISPHAT 18 and BINPHAT 19 as stereodynamic probes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
N1–C4 β‐Lactam Bond Cleavage in the 2‐(Trimethylsilyl)thiazole Addition to β‐Lactam Aldehydes: Asymmetric Synthesis of Spiranic and Tertiary α‐Alkoxy‐γ‐keto Acid Derivatives
Authors: Alcaide Benito , Almendros Pedro , Redondo María C.
Published: June 2007

Starting substrates, enantiopure spiranic or 3‐substituted 3‐alkoxy‐4‐oxoazetidine‐2‐carbaldehydes, were prepared from (R)‐2,3‐O‐isopropylideneglyceraldehyde derived azetidine‐2,3‐diones by sequential Barbier‐type addition reactions followed by hydroxy functionalization and aldehyde unmasking. The reaction between the above β‐lactam aldehydes and 2‐(trimethylsilyl)thiazole (TMST) gave as major products conformationally constrained α‐alkoxy‐γ‐keto amides, which can be considered both as aldols as well as Passerini‐type products, by N1–C4 β‐lactam bond cleavage. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of Cyclic and Macrocyclic Ethers Using Metathesis Reactions of Alkenes and Alkynes
Authors: Groaz Elisabetta , Banti Donatella , North Michael
Published: June 2007

The metathesis transformations of cyclohexanes and cyclohexenes bearing allylic and/or propargylic ether substituents has been investigated. A range of products containing fused 6,8‐bicyclic ring systems resulting from alkene and/or enyne metatheses were obtained using first and second generation, well defined alkylidene ruthenium catalysts. However, the unstrained cyclohexene unit did not participate in any of these metathesis processes, even though doing so would have led to a thermodynamically more stable product. This contrasts with previous results on similar compounds and on the corresponding amino‐substituted cyclohexenes. The synthesis of dienes and dihydrofurans by metathesis processes involving the side chains of suitable cyclohexene ethers is also reported. When the unstrained cyclohexene unit was replaced by a norbornene group, the strained alkene did participate in a cascade of alkene and enyne metatheses. This chemistry was extended to alkyne metatheses of cyclohexene and norbornene esters, leading to 6,12‐fused cycloalkynes which would subsequently undergo further enyne and/or alkene metatheses. This culminated in the development of the first one‐pot metathesis process in which alkyne, enyne and alkene metathesis reactions initiated by two different catalysts all occur sequentially to form a 5,12‐fused bicyclic diene product. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
The effects of antidepressant medication adherence as well as psychosocial and clinical factors on depression outcome among older adults
Authors: Bosworth Hayden B. , Voils Corrine I. , Potter Guy G. , Steffens David C.
Published: June 2007

Objective

To examine the contribution of medication adherence to 12‐month depression scores in the context of other psychosocial and clinical predictors of depression in a sample of older adults treated for depression.

Methods

Secondary analysis of a prospective cohort study involving 241 older patients undergoing depression treatment using a standardized algorithm. Depression was measured at baseline and 12‐months post‐baseline. Baseline predictor variables included antidepressant adherence, barriers to antidepressant adherence, four domains of social support, basic and instrumental activities of daily living (BADLs and IADLs), and clinical factors including past history of depression and medical comorbidities.

Results

Nearly 28% of patients reported being nonadherent with their antidepressant medication. In bivariate analyses, greater antidepressant medication nonadherence, more medication barriers, poorer subjective social support, less non‐family interaction, greater BADL and IADL limitations, poor self‐rated health, higher baseline depression scores, and not having diabetes were related to higher 12‐month depression scores. In multivariable analyses, greater medication nonadherence, not having diabetes, poorer subjective social support, greater BADL limitations, and higher baseline depression scores were related to higher 12‐month depression scores.

Conclusion

Interventions should be directed toward improving antidepressant adherence and modifiable psychosocial variables. Copyright © 2007 John Wiley & Sons, Ltd.
Changes in the demand for private medical insurance following a shift in tax incentives
Authors: Rodríguez Marisol , Stoyanova Alexandrina
Published: June 2007

The 1998 Spanish reform of the Personal Income Tax eliminated the 15% deduction for private medical expenditures including payments on private health insurance (PHI) policies. To avoid an undesired increase in the demand for publicly funded health care, tax incentives to buy PHI were not completely removed but basically shifted from individual to group employer‐paid policies. In a unique fiscal experiment, at the same time that the tax relief for individually purchased policies was abolished, the government provided for tax allowances on policies taken out through employment. Using a bivariate probit model on data from National Health Surveys, we estimate the impact of said reform on the demand for PHI and the changes occurred within it. Our findings indicate that the total probability of buying PHI was not significantly affected by the reform. Indeed, the fall in the demand for individual policies (by 10% between 1997 and 2001) was offset by an increase in the demand for group employer‐paid ones. We also briefly discuss the welfare effects on the state budget, the industry and society at large. Copyright © 2007 John Wiley & Sons, Ltd.
Predictors of morbidity following free flap reconstruction for cancer of the head and neck
Authors: Clark Jonathan R. , McCluskey Stuart A. , Hall Francis , Lipa Joan , Neligan Peter , Brown Dale , Irish Jonathan , Gullane Patrick , Gilbert Ralph
Published: June 2007

Background

Free flap reconstruction of head and neck cancer defects is complex with many factors that influence perioperative complications. The aim was to determine if there was an association between perioperative variables and postoperative outcome.

Methods

We evaluated 185 patients undergoing free flap reconstruction following ablation of head and neck cancer between 1999 and 2001. Demographic, laboratory, surgical and anesthetic variables were analyzed using univariate and multivariable techniques.

Results

Ninety‐eight patients (53%) developed complications, of which 74 were considered major, giving a major morbidity rate of 40%. Predictors of major complications were increasing patient age, ASA class, and smoking. Predictors of medical complications were ASA class, smoking, age and crystalloid replacement. Predictors of surgical complications were tracheostomy, preoperative hemoglobin, and preoperative radiotherapy.

Conclusion

Patient age, comorbidity, smoking, preoperative hemoglobin, and perioperative fluid management are potential predictors of postoperative complications following free flap reconstruction for cancer of the head and neck. © 2007 Wiley Periodicals, Inc. Head Neck 2007
Hormonal response to buspirone is not impaired in major depression
Authors: Navinés Ricard , Gómez‐Gil Esther , Martín‐Santos Rocío , de Osaba María J. Martínez , Escolar Ginés , Gastó Cristóbal
Published: June 2007

It has been suggested that interactions between hypothalamic pituitary adrenal (HPA) axis and serotonin‐1A (5‐HT1A) receptor system are involved in the pathophysiology of major depression. Pharmacologic challenge test with 5‐HT1A receptor agonists is a useful approach to study the sensitivity of 5‐HT1A receptors in depressed patients and the interaction of these systems. A cross‐sectional case‐control study was designed to assess the effect of the 5‐HT1A receptor agonist, buspirone, on 5‐HT1A receptor function in 30 patients with major depression (DSM‐IV) and in 30 age‐ and sex‐matched healthy controls. Depressed patients showed a basal score in the Hamilton Rating Scale for Depression (HRSD) higher than 17. After the administration of a single oral dose of buspirone (30 mg), corticotrophin (ACTH), cortisol, and prolactin (PRL) peak response minus baseline (Δ) and area under the curve (AUC) were evaluated. No significant difference in the hormonal response between depressed patients and controls was observed. No correlation with the severity of depression (HRSD score) was found. These results indicate no consistent changes in the hormonal response to the 5‐HT1A agonist buspirone in depressed patients. Therefore, this study does not support the hypothesis of an altered postsynaptic 5‐HT1A receptor function in major depression. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of the impact of conservation measures on stream flow regime in catchments of the Loess Plateau, China
Authors: Mu Xingmin , Zhang Lu , McVicar Tim R. , Chille Basang , Gau Peng
Published: June 2007

Catchments in the Loess Plateau have been under the influence of human activities for centuries. In the last four decades, soil conservation measures have accelerated and intensified. These measures were designed to reduce soil erosion, improve agricultural productivity, and enhance environmental quality. It is important to evaluate the effects of these measures on hydrology in order to develop sustainable catchment management plans in the region. This study evaluated changes in stream flow data for four selected catchments in the Loess Plateau following large‐scale soil conservation measures. The non‐parametric Mann–Kendall test was used to identify trends in annual stream flow and the results showed significant downward trends in three of the four catchments. The Pettitt test indicated that a change point occurred in 1978 in these three catchments. Annual precipitation in all the catchments showed no significant trend during the period of record. Comparison of daily flow duration curves for two 20‐year periods (1957–1978) and (1979–2003) showed significant changes in stream flow regime. Reduction in most percentile flows varied between 20 and 45%, and the reduction in low flows was greatest. Overall, the reductions in daily flow were increasing with time, with significant changes occurring in the 1990s. However, it is not clear whether these catchments have seen the full effects of the soil conservation measures, so the results of this study might underestimate the final impact of soil conservation on stream flow regime. Copyright © 2007 John Wiley & Sons, Ltd.
Assessment of hydrological droughts for the Yellow River, China, using copulas
Authors: Shiau Jenq‐Tzong , Feng Song , Nadarajah Saralees
Published: June 2007

Droughts are one of the normal and recurrent climatic phenomena on Earth. However, recurring prolonged droughts have caused far‐reaching and diverse impacts because of water deficits. This study aims to investigate the hydrological droughts of the Yellow River in northern China. Since drought duration and drought severity exhibit significant correlation, a bivariate distribution is used to model the drought duration and severity jointly. However, drought duration and drought severity are often modelled by different distributions; the commonly used bivariate distributions cannot be applied. In this study, a copula is employed to construct the bivariate drought distribution. The copula is a function that links the univariate marginal distributions to form the bivariate distribution. The bivariate return periods are also established to explore the drought characteristics of the historically noticeable droughts. The results show that the return period of the drought that occurred in late 1920s to early 1930s is 105 years. The significant 1997 dry‐up phenomenon that occurred in the downstream Yellow River (resulting from the 1997–1998 drought) only has a return period of 4·4 years and is probably induced by two successive droughts and deteriorated by other factors, such as human activities. Copyright © 2007 John Wiley & Sons, Ltd.
Evidence of large rainfall partitioning patterns by banana and impact on surface runoff generation
Authors: Cattan Philippe , Bussière François , Nouvellon Alban
Published: June 2007

In this article the effect of redistribution of rainfall by banana on local water fluxes and the possible impact of these fluxes on surface runoff has been studied. First the water redistribution by a banana canopy at three development stages (vegetative, flowering, and bunch stage) was measured. The results showed a considerable stemflow, proportional to the leaf area index (LAI), which represented 18 to 26% of the incident rainfall volume according to the age of the crop. Consequently, the rainfall rate was 28‐fold higher at the plant collar for a fully developed banana canopy. For the throughfall, on average, the higher the LAI, the lower the mean throughfall. In addition, the spatial distribution of the throughfall varied according to the distance from the pseudostem. Notably, for the earlier stages, the area between the pseudostem and 0·5 m from it received weak throughfall. Secondly, simulations were carried out with a simple two‐compartment model simulating the total surface runoff volume. The simulations showed stemflow combined with the agronomical practice of furrowing has an effect on runoff compared to bare soil. A relative increase in surface runoff volume of three‐fold was encountered on a plot with a fully developed banana and a infiltration rate of 60 mm h−1. However, the absolute increase was only a few percentage of the incident rainfall volume, although it represented large water volumes given the tropical rains. These features must be taken into account for hydrological management of such systems. Copyright © 2007 John Wiley & Sons, Ltd.
Application of a coil‐type TDR probe for measuring the volumetric water content in weathered granitic bedrock
Authors: Katsura Shin'ya , Kosugi Ken'ichirou , Mizuyama Takahisa
Published: June 2007

As a first step toward describing water flow processes in bedrock, a coil‐type time domain reflectometry (TDR) probe capable of measuring volumetric water content, θ, in weathered bedrock at three depths was prepared. Because the coil‐type TDR probe is large in diameter (19 mm), it can be installed even in highly weathered bedrock more easily and appropriately than conventional TDR probes that consists of two or three rods of small diameter (5‐8 mm). The probe calibrations suggest that the values measured by the probe are very sensitive to changes in θ. Using the calibrated probe together with commercially available profile soil moisture sensors, the θ profile was monitored for 1 year. Even rainfall events with relatively small cumulative rainfall of 15 mm increased the bedrock θ, and the increments were comparable to those in the soil. After the end of the rainfall events, the bedrock θ displayed a more rapid drop than the soil, and varied little during the period of no rainfall. The water storage showed similar tendencies. These observations suggest that the bedrock θ is controlled by clearly distinguishable macropores and micropores within the bedrock. It is concluded that the coil‐type TDR probe is very effective in determining θ in weathered bedrock, and that bedrock, conventionally defined by conducting cone penetration tests and treated as impermeable, does conduct and hold substantial amounts of water, and therefore contribute greatly to hydrological processes in headwater catchments. Copyright © 2007 John Wiley & Sons, Ltd.
Children's understanding of modesty in front of peer and adult audiences
Authors: Watling Dawn , Banerjee Robin
Published: June 2007

Previous research has suggested that the understanding of modesty—downplaying one's achievements to evoke a positive social evaluation—develops in the primary school years. However, very little is known about how children's understanding of modesty is associated with social contextual factors, such as audience type. A sample of 92 children aged 8–11 years responded to hypothetical vignettes where the protagonist responded either modestly or immodestly to praise. The findings supported earlier indications of an increase with age in the understanding of modesty, and further found that modesty was judged as more appropriate for peer audiences than for adult audiences. No interactions between age group and audience type were observed. Children's increasing approval of modesty was associated with a tendency to justify their judgements by referring to concerns about social evaluation. Copyright © 2007 John Wiley & Sons, Ltd.