bluuebunny/crossref_metadata_2025 huggingface dataset:
Shape-invariant hypergeometric type operators with application to quantum mechanics
Authors: Cotfas Nicolae
Published: July 2006

A hypergeometric type equation satisfying certain conditions defines either a finite or an infinite system of orthogonal polynomials. The associated special functions are eigenfunctions of some shape-invariant operators. These operators can be analysed together and the mathematical formalism we use can be extended in order to define other shape-invariant operators. All the shape-invariant operators considered are directly related to Schrödinger-type equations.
Methoxyoxalamido Chemistry in the Synthesis of Tethered Phosphoramidites and Functionalized Oligonucleotides
Authors: Morocho Alan M. , Polushin Nikolai N.
Published: July 2006

A general approach to phosphoramidites tethered with single and multiple linkers through the use of methoxyoxalamido (MOX) chemistry is described. The approach utilizes readily available and inexpensive primary aliphatic amino alcohols and diamines to produce a rich and diverse variety of tethered phosphoramidites. Furthermore, the use of MOX chemistry in a modular fashion enables fairly rapid assembly of compound tethers. All novel phosphoramidites described have been successfully used in automated syntheses of 5′‐modified oligonucleotides.
Isolation of T‐Tubules from Skeletal Muscle
Authors: Zorzano Antonio , Camps Marta
Published: July 2006

The transverse tubules (T‐tubules) of mammalian cardiac and skeletal muscles are invaginations of the sarcolemma. They play a crucial role in excitation‐contraction coupling as well as in intracellular signaling and in regulation of glucose transport. The biochemical purification of T‐tubule membranes is a difficult task, and membrane fractions enriched in transverse tubules are usually contaminated with other cell‐surface and intracellular membranes. This unit includes methods that permit the isolation and purification of T‐tubules from skeletal muscle.
Radioactive Tracers
Authors: Chinkes David L.
Published: July 2006

This article is an overview of radioactive tracers technology. The general approaches for the synthesis of labeled compounds, such as organic chemical methods and biochemical techniques, are described. The factors affecting the stability of labeled compounds are discussed, along with methods of detection and quantitation of the commonly used radioactive isotopes. Considerations in the safe handling of radioactive tracers and regulatory issues related to working with radioactive materials are summarized. The uses and applications of labeled compounds in biomedical research, clinical practice, pharmaceutical development, gene analysis, and agricultural experiments are discussed.
Raman Scattering
Authors: Ewen Smith W.
Published: July 2006

Raman scattering involves the detection of inelastic light scattering resulting from molecular vibrations. Industrial applications of this technique are growing in areas such as process and quality control, materials characterization and reliability, biodetection and environmental and industrial hygiene monitoring. Small, as well as large samples of inorganic and organic compounds, biomolecules, polymers, films, and surfaces, may be investigated using Raman. Samples, which may be solid, gaseous, or liquid, are easily prepared and aqueous solutions may be examined. Instrumentation utilizes visible or near‐infrared laser sources, modern dispersive spectrographs or interferometers, fiber‐optic and/or microprobes, and highly sensitive detection systems.
Recycling, Rubber
Authors: P. Paul John ,   Updated by Staff
Published: July 2006

An overview of the uses for worn out scrap and reject rubber parts and articles, primarily tires, is presented. Uses and processing of worn out scrap and reject rubber include scrap rubber as a final source, pyrolysis of scrap rubber, depolymerization, rubber–asphalt modification, cryogenic pulverizing and mechanical tire shredding, rubber reclaiming, civil engineering, and tire retreading.

Scrap rubber as a fuel source (burning rubber, sometimes known as tire‐derived fuel) in cement kilns, electric utilities, pulp and paper mills, and dedicated tire‐to‐energy plants is discussed.

Processes for pyrolyzing rubber into oil and char are described, as are projects using rubber in asphalt and legislation being enacted to encourage the use of asphalt in rubber. Methods for cryogenically pulverizing and grinding tires are included. Methods of devulcanizing rubber using digesters, and heater or pan and reclaimator processes are presented. Uses of scrap rubber in civil engineering include erosion control retaining walls, fill material, athletic and playing surfaces, and in artificial reefs.
Sulfur
Authors:   Updated by Staff
Published: July 2006

The element sulfur is one of the most important raw materials of the chemical industry. Its unique characteristics, changes in its production, and methods for its mining and recovery are all described, as is the common terminology used in the industry for sulfur products. Environmental issues are presented. A discussion of the various uses for sulfur is presented, including agricultural applications, plastics and other synthetic products, paper products, paints, nonferrous metal production, petroleum refining, iron and steel production, soil and water treatment, animal nutrition, highway construction as an additive or rejuvenator for asphalt, sulfur concrete, sulfur polymer cement, coatings, mortar substitute, foams, and sulfur impregnation.
Technical Service
Authors: Reid, Austin H.
Published: July 2006

Technical service in the chemical industry is designed to provide timely and professional information and support to downstream customers regarding chemical products and their uses. Examples of the various tasks pertinent to contemporary technical service efforts are given; information on the structure of technical service organization, training of personnel, participation in technical societies, and trade associations are discussed. The part played by technical service, the product development function, and the uses of computer and other electronic technologies in technical service are included.
Salivary Gland Cancer
Authors: Garden Adam S.
Published: July 2006

Malignant salivary gland tumors are remarkable for their relative infrequency as compared to other solid tumors, and their wide diversity in histologic appearance, clinical presentation, and biologic behavior. By virtue of the slow growth rates of some of these tumors, posttreatment surveillance must continue for a decade or more in order to accrue reliable data regarding locoregional control and survival. Fortunately, useful prognostic information can be derived from assessment of clinical stage, and tumor histology.
Breast Cancer
Authors: Hayes Daniel F.
Published: July 2006

Breast cancer is a heterogeneous disease that exhibits a wide variety of clinical presentations, histologic types, and growth rates. Because of these variations, determining prognosis for an individual patient at the time of initial diagnosis requires careful assessment of multiple clinical and pathological parameters. This evaluation includes consideration of an expanding list of tumor‐ and patient‐related prognostic factors, which are especially important for decisions related to systemic treatment and predictions for overall survival.
Vulvar Cancer
Authors: Marsden Donald E. , Hacker Neville F.
Published: July 2006

Vulvar cancer is an uncommon malignancy accounting for approximately 4–5% of all gynecologic cancers. It used to be thought of as predominantly a disease of the elderly, although reports of young, reproductive‐age‐group women with this disease increasingly appear in the literature. The external location of the vulva should prompt early presentation, but traditionally significant delays in diagnosis have been associated with this cancer.

The past decade has seen a better understanding of the prognostic factors for vulvar cancer, which, in turn, has led to a more individualized approach to therapy. This has led to less aggressive surgery in the earlier stage of the disease with better cosmetic and functional results. It might be expected that, with the increasing life expectancy in many countries and the concomitant aging of the population, an increase in the number of cases being diagnosed would occur in the future.
Non‐Hodgkin Lymphomas
Authors: Gospodarowicz Mary K. , Crump Michael , Zucca Emanuele
Published: July 2006

The non‐Hodgkin's lymphomas (NHLs) are a diverse group of diseases with large variation in tumor biology and course of disease. The 1980s and 1990s brought a great increase in our knowledge of the biology of the immune system. Insights into the immunology and molecular genetics of NHL have led to the recognition of a number of new pathological entities, with unique natural histories. In addition, the clinical approach to patients with NHL has relied increasingly on aggregate assessment of prognostic factors, rather than single attributes such as disease stage, presence of extranodal involvement, presence of constitutional symptoms, or specific biochemical abnormalities. Furthermore, it is increasingly recognized that these biological attributes are surrogate measures of a tumor's growth and invasion potential, the host's response to the tumor, and the host's ability to tolerate treatment. A better understanding of the significance of molecular and immunological attributes of lymphoma will hopefully replace these clinical surrogates in refining NHL's prognosis and therapy more precisely in the future.
Leukemias
Authors: Disperati Patricia , Suarez‐Saiz Fernando J. , Khoury Haytham , Minden Mark D.
Published: July 2006

Leukemia, the malignant transformation of bone marrow blood‐forming cells, is not a single entity. Prior to any form of therapy, which would include antibiotics and transfusion, the leukemias were classified as acute or chronic. The acute leukemias were rapidly fatal, with individuals dying in days to weeks from the time of diagnosis. In contrast, individuals with chronic leukemias could live for many years without any therapy. With the recognition of the stem‐cell nature of blood formation and the identification of different lineages, it was possible to further subdivide the leukemias into those of the myeloid and lymphoid lineages; with the development of therapeutics, this distinction has proven to be important.
A study on the metalation of fluorinated phenyl benzyl ethers
Authors: Kliś Tomasz , Serwatowski Janusz , Wójcik Dominik
Published: July 2006

Lithiation of a series of aryl benzyl ethers containing fluorine atoms or CF group in the phenolic ring has been studied. It was found that the long‐distance inductive effect (two fluorine atoms in 2,6‐ or 2,3‐position to the oxygen) and the cooperation of the coordination and inductive effects (fluorine atom or CF group meta to oxygen atom) are the main factors directing ortholithiation. Dilithiation of aryl benzyl ethers by butyllithium is generally less effective, but in the presence of PMDTA occurs efficiently and gives compounds containing lithium atoms at the phenyl ring and in the benzylic position. 2,3‐Difluoro‐benzyloxybenzene was dilithiated using BuLi–PMDTA complex and the intermediate was trapped with Me3SiCl to give disilylated product in high yield. Copyright © 2006 John Wiley & Sons, Ltd.
The effect of environmental information on investment allocation decisions – an experimental study
Authors: Rikhardsson Pall , Holm Claus
Published: July 2006

This paper focuses on the use of environmental information in investment decision making. The research approach employed is based on an experiment where three groups of final year finance students were asked to allocate investment funds between two companies based on financial accounts and information material from these companies in which environmental information was included in varying degrees. The overall conclusion is that the qualitative environmental information affects short term allocation decisions, hence indicating a risk reduction potential of environmental information comparable to the classic interpretation of financial information.

The quantitative environmental information included in the experiment seems to mitigate rather than extend the directional effect of more environmental information. The evidence also seems to indicate that decision makers are not always aware which information categories affect their decision making. Hence, this has implications for how the potential value of environmental information is to be assessed. Finally, experimental studies as a methodology seem to be better suited to indicate actual effects of different types of information on decision making than attitude surveys. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Weak Attractive Interactions between Methylthio Groups and Electron‐Deficient Alkenes in peri‐Naphthalenes: A Competition with Conjugative Effects
Authors: O'Leary Jane , Wallis John D.
Published: July 2006

The solid‐state conformations of five peri‐disubstituted naphthalenes bearing a methylthio group and an electron‐deficient alkene indicate a weak attractive interaction between the functional groups in four cases in which out‐of‐plane displacements lead to a common orientation of the MeS⋅⋅⋅sp2‐C vector to the alkene bond. In some cases the interaction is not strong enough to outweigh the tendency of the alkene to conjugate with the aromatic ring, and in one case this optimisation of conjugation alone controls the molecular conformation. The methylthio group lies close to the aromatic plane in all but one example for which the plane of the sulfide group is presented to the alkene.
Alternating vector immunizations encoding pre‐erythrocytic malaria antigens enhance memory responses in a malaria endemic area
Authors: Bejon Philip , Kai Oscar K. , Mwacharo Jedidah , Keating Sheila , Lang Trudie , Gilbert Sarah C. , Peshu Norbert , Marsh Kevin , Hill Adrian V S
Published: July 2006

A heterologous prime‐boost strategy has been developed to potently induce T cell responses to pre‐erythrocytic malaria antigens. Efficacy in the field is likely to depend on both peak immunogenicity and the durability of responses. To improve both immunogenicity and durability of responses, 54 adult males from a malaria endemic area were immunized with different vaccination regimens, systematically varying antigenic insert and the number and sequence of component vaccinations. The component vaccinations were recombinant attenuated viruses, either fowlpox (FP) 9 or modified vaccinia virus Ankara (MVA). These were recombinant for either of two pre‐erythrocytic malaria antigens (multiple epitope‐thrombospondin‐related adhesion protein, ME‐TRAP, or circumsporozoite antigen (CS). ELISPOT assays were used to measure the effector and resting memory T cell responses. Sequence, antigen insert and number of vaccinations influenced immunogenicity, but the novel alternating vector immunizations generated the largest resting memory T cell populations. Effector responses were maintained at 84% of the peak response after 270 days. This durability of response is unprecedented. Classical prime‐boost vaccination responses were at 5% of the peak after 270 days. Vaccines administered by heterologous prime‐boost regimes are being developed for diverse pathogens and cancer. These data suggest these vaccines should also be administered by alternating vector regimens in clinical development.
Properties of alkyl esters base on castor oil
Authors: Cvengroš Ján , Paligová Jarmila , Cvengrošová Zuzana
Published: July 2006

Castor oil is a non‐traditional raw material for the preparation of methyl and ethyl esters of higher fatty acids as alternative fuels for diesel engines. Castor oil contains ricinoleic acid (12‐hydroxy octadecene acid) with a major share of about 90%. The article presents the parameters of castor oil‐based methyl esters (COME) and ethyl esters (COEE) defined by the standard EN 14 214. The densities of COME and COEE are higher than the limit defined by the standard EN 14 214. The viscosities are more than twice as high as the limit value. The cetane numbers are lower than defined by the standard EN 14 214. For the remaining parameters, COME and COEE meet, in principle, the standard EN 14 214. The presence of the free hydroxyl group has virtually no effect on the values of such parameters as carbon residue, filterability at low temperatures and oxidation stability, for which some influence was expected. The physicochemical parameters of the castor oil esters are discussed in comparison to the analogous esters of high‐oleic sunflower oil, which contain about 80% of oleic acid. Both the methyl and ethyl esters of high‐oleic sunflower oil meet the standard EN 14 214 in all prescribed parameters.
Multiple dysregulated pathways in nasopharyngeal carcinoma revealed by gene expression profiling
Authors: Shi Wei , Bastianutto Carlo , Li Anna , Perez‐Ordonez Bayardo , Ng Raymond , Chow Kan‐Yan , Zhang Wendy , Jurisica Igor , Lo Kwok‐Wai , Bayley Andrew , Kim John , O'Sullivan Brian , Siu Lillian , Chen Eric , Liu Fei‐Fei
Published: July 2006

Gene expression profiling was conducted using primary human nasopharyngeal carcinoma (NPC) biopsy samples to improve the understanding of the molecular pathways defining NPC and to identify novel potential therapeutic targets. RNA samples were extracted from 36 patients suspected to have NPC and hybridized onto the Affymetrix U133A chip. NPC was diagnosed in 19 patients, 11 had lymphoid hyperplasia (LH), and 6 were “normal” biopsies. Clinical stages for these NPC patients ranged from I–IV, including one M1. All NPC patients (except the M1) were treated with curative intent, which included radiotherapy alone (4 patients), or combined with chemotherapy (14 patients). Unsupervised clustering demonstrated a distinct NPC expression pattern, compared to normal biopsies. Subsequent Significance Analysis of Microarrays (SAM) derived from 14 NPC and 6 normal samples discovered 1,089 differentially regulated genes. Pathway analyses revealed novel insights into the mechanisms leading to NPC, whereby upregulation of NFκB2 and survivin play central roles in increasing resistance to apoptosis, and changes in integrin and WNT/β‐catenin signaling leading to uncontrolled proliferation. The role of survivin in resisting apoptosis in NPC was confirmed by RNA interference. Our data provide novel insights into the development and progression of NPC, and suggest survivin as a novel therapeutic target for NPC. © 2006 Wiley‐Liss, Inc.
Association of aberrant methylation of tumor suppressor genes with tumor aggressiveness and BRAF mutation in papillary thyroid cancer
Authors: Hu Shuiying , Liu Dingxie , Tufano Ralph P. , Carson Kathryn A. , Rosenbaum Eli , Cohen Yoram , Holt Elizabeth H. , Kiseljak‐Vassiliades Katja , Rhoden Kerry J. , Tolaney Sara , Condouris Stephen , Tallini Giovanni , Westra William H. , Umbricht Christopher B. , Zeiger Martha A. , Califano Joseph A. , Vasko Vasily , Xing Mingzhao
Published: July 2006

The role of aberrant tumor suppressor gene methylation in the aggressiveness of papillary thyroid cancer (PTC) has not been documented. By showing promoter methylation‐induced gene silencing in PTC‐derived cell lines, we first demonstrated the functional consequence of methylation of several recently identified tumor suppressor genes, including those for tissue inhibitor of metalloproteinase‐3 (TIMP3), SLC5A8, death‐associated protein kinase (DAPK) and retinoic acid receptor β2 (RARβ2). We then investigated the role of methylation of these genes in the aggressiveness of PTC by examining the relationship of their aberrant methylation to clinicopathological characteristics and BRAF mutation in 231 primary PTC tumors. Methylation of TIMP3, SLC5A8 and DAPK was significantly associated with several aggressive features of PTC, including extrathyroidal invasion, lymph node metastasis, multifocality and advanced tumor stages. Methylation of these genes was also significantly associated with BRAF mutation in PTC, either individually or collectively in various combinations. Methylation of these genes, either individually or collectively, occurred more frequently in more aggressive classical and tall‐cell PTC subtypes than in less aggressive follicular‐variant PTC, with the latter known to infrequently harbor BRAF mutation. Several other tumor suppressor genes investigated were not methylated. These results suggest that aberrant methylation and hence silencing of TIMP3, SLC5A8, DAPK and RARβ2, in association with BRAF mutation, may be an important step in PTC tumorigenesis and progression. © 2006 Wiley‐Liss, Inc.
Induction of p16INK4A mediated by β‐catenin in a TCF4‐independent manner: Implications for alterations in p16INK4A and pRb expression during trans‐differentiation of endometrial carcinoma cells
Authors: Saegusa Makoto , Hashimura Miki , Kuwata Takeshi , Hamano Mieko , Okayasu Isao
Published: July 2006

Excessive β‐catenin is considered to contribute to tumor progression by inducing transcription of cell cycle‐related genes such as cyclin D1 and c‐myc. In contrast, our recent studies demonstrated that β‐catenin could inhibit cell proliferation through activation of p14ARF/p53/p21WAF1 pathway during trans‐differentiation toward morular phenotype of endometrial carcinoma (Em Ca) cells. Here, we focused on associations with alterations in p16INK4A and pRb expression during this process. In clinical cases, p16INK4A immunoreactivity was found to frequently overlap with nuclear β‐catenin accumulation in small‐sized morules and surrounding glandular carcinomas (Sur‐Ca), demonstrating a significant positive correlation (r = 0.447, p < 0.0001) overall, while the immunoreactions showed stepwise decrease in enlarged morules, despite persistent accumulation of β‐catenin and p21WAF1 in nuclei. Immunoreactivity for both total pRb and its phosphorylated form was apparently decreased in all morules as compared to Sur‐Ca lesions, with a significantly positive correlation. In cell lines, transcriptional activation of p16INK4A promoter by active form β‐catenin, as well as p21WAF1, occurred through the region from −385 to −280 bp relative to the translation start site, in a TCF4‐independent manner. Moreover, cell proliferation was accompanied with phosphorylation of pRb and increased p16INK4A expression, while its inhibition by serum starvation caused decreased expression of total pRb but not p16INK4A, resulting in high relative amounts of the latter. These findings indicate that induction of p16INK4A mediated by nuclear β‐catenin and p21WAF1, along with loss of pRb expression, may be important for initial steps during trans‐differentiation of Em Ca cells. In addition, its down‐regulation is associated with progression of lesions. © 2006 Wiley‐Liss, Inc.
Nonattendance is still the main limitation for the effectiveness of screening for cervical cancer in the Netherlands
Authors: Bos Anita B. , Rebolj Matejka , Habbema J. Dik F. , van Ballegooijen Marjolein
Published: July 2006

Although mass screening for cervical cancer has been operational for more than 2 decades in the Netherlands, 700 women are still diagnosed with this cancer each year (9 per 100,000). We investigated these cases, in order to evaluate opportunities to further increase the effectiveness of the programme. We analyzed the screening history of women diagnosed with cervical cancer between 1994–1997 using the Dutch national pathology file that includes cervical cytology and histological results. More than half of the cases did not have previous preventive cervical smears, and another 30% had never been invited to the programme because of their age. In the future, we estimate that two thirds of all Dutch women with invasive cervical cancer will be unscreened or under‐screened, based on current screening participation of more than 70%. We conclude that increasing screening participation has much more potential for further reducing cervical cancer incidence than reducing the screening interval, increasing the age range or having a screening test with higher sensitivity. © 2006 Wiley‐Liss, Inc.
Gleason score, age and screening: Modeling dedifferentiation in prostate cancer
Authors: Draisma Gerrit , Postma Renske , Schröder Fritz H. , van der Kwast Theo H. , de Koning Harry J.
Published: July 2006

Tumor differentiation as measured by the Gleason score is highly predictive of the course of prostatic cancer after diagnosis. Since the introduction of the prostate‐specific antigen (PSA) test tumors are diagnosed with a favorable tumor stage and differentiation grade. Does screening with PSA just detect more tumors with favorable characteristics or is dedifferentiation actually being prevented by early detection and consequent treatment? The latter option implies that tumors dedifferentiate in the preclinical screen‐detectable phase. To model the natural history of prostate cancer, we analyzed the age‐specific distribution of clinical stage and Gleason score of 2,204 tumors diagnosed in the ERSPC‐Rotterdam trial. We fitted 2 MISCAN simulation models to the observed data: Model I where tumors dedifferentiate before becoming screen‐detectable and Model II where dedifferentiation occurs during the screen‐detectable preclinical phase. The hypothesis of dedifferentiation during the screen‐detectable phase was tested by a goodness of fit test of both models. In ERSPC‐Rotterdam, we observed a significantly more favorable distribution of Gleason scores in screen‐detected cancers compared to cancers found in the control arm, and in cancers detected in the second round compared to cancers detected in the first round of screening. Also, a significant association between Gleason score and age at diagnosis was found, most notably in cancers detected in the first round of screening. These findings were reproduced by Model II and less so by Model I, with a significant difference in goodness of fit between the 2 models (p< 0.001). This study provides epidemiological evidence of dedifferentiation as a major mechanism of progression in prostate cancer. Tumors dedifferentiate during the screen‐detectable phase and consequently screening with PSA and early treatment can possibly prevent dedifferentiation. © 2006 Wiley‐Liss, Inc.
Fast analysis in liquid chromatography using small particle size and high pressure
Authors: Nguyen Dao T.‐T. , Guillarme Davy , Rudaz Serge , Veuthey Jean‐Luc
Published: July 2006

In order to enhance chromatographic performances in terms of efficiency and rapidity, LC has recently evolved in the development of short columns packed with small particles (sub‐2 μm) working at high pressures (>400 bar). This approach has been described 30 years ago according to the fundamental chromatographic equations. However, systems and columns compatible with such high pressures have been introduced in the market in 2004 only. Advantages of small particles working at high pressure will be discussed in terms of sensitivity, efficiency, resolution, and analysis time. Potential problems encountered with high pressure in terms of frictional heating and solvent compressibility will also be discussed even if systems working at a maximum pressure of 1000 bar are not influenced by these parameters and give reliable and reproducible results. Several applications will highlight the potential and interest of this new technology.
Column selectivity for two‐dimensional liquid chromatography
Authors: Jandera Pavel
Published: July 2006

Selectivity of phase system is of primary concern when designing a 2‐D separation, as it affects the 2‐D system orthogonality and consequently the peak capacity controlling the number of peaks that can be separated in the available 2‐D retention space limited by the time of analysis. Possibilities for characterization of LC phase system selectivity with respect to different polar and nonpolar structural units are compared, with special attention to multidimensional samples with various types of repeat groups, such as homopolymers, (co)polymers, fatty acid esters with various acyl lengths and number and position of double bonds, etc. Possibilities of the 2‐D LC separations of these and other sample types, including pharmaceuticals, natural phenolic compounds, biopolymers, etc., using various combinations of separation modes are reviewed. Rules for design of comprehensive 2‐D LC×LC systems are discussed, with respect to mobile phase compatibility in the two systems and modulation techniques suppressing band broadening connected with the sample fraction transfer from the first to the second dimension. Pitfalls connected with online connection of normal‐phase and RP LC systems and their possible practical solutions are addressed and illustrated by practical examples.
Regioregular Poly[3‐(4‐alkoxyphenyl)thiophene]s: Evidence for a Two‐Step Aggregation Process
Authors: Koeckelberghs Guy , Cornelis David , Persoons André , Verbiest Thierry
Published: July 2006

Summary: A chiral, regioregular poly[3‐(4‐alkoxyphenyl)thiophene] has been prepared and studied. Films prepared by fast evaporation of the solvent, consist of random‐coils, while films prepared by slow evaporation are composed of chirally aggregated, coplanar strands. Heat treatment transforms the random‐coils into aggregated films via an intermediate state, which was characterized as chiral, coplanar, unaggregated polymer strands.

Overview of the possible aggregation processes.

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Overview of the possible aggregation processes.
Poly(diindenonaphthalene) and Poly(indenofluorene) – Tuning the Absorption Properties of Low Bandgap Cross‐Conjugated Polymers
Authors: Preis Eduard , Scherf Ullrich
Published: July 2006

Summary: Semiconducting polymers with moderate HOMO–LUMO energy gaps between 1.5 and 2.0 eV are of increasing attraction as donor components of bulk heterojunction‐type organic solar cells. The synthesis and characterization of a novel cross‐conjugated, aromatic polymer, poly(diindenonaphthalene) PDIN, with a HOMO‐LUMO gap of ca. 1.6 eV (λmax: 724 nm) in comparison to poly(indenofluorene) PIF, a previously described, structurally related polymer, is presented. The replacement of the central benzene ring of PIF by a naphthalene moiety in PDIN leads to an increase of the optical bandgap energy of ca. 0.16 eV.

Chemical structure of PIF and PDIN.

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Chemical structure of PIF and PDIN.
Novel Polyurethane Gels: The Effect of Structure on Gelation
Authors: Maiti Pralay , Radhakrishnan Ganga , Aruna Palanisamy , Ghosh Goutam
Published: July 2006

Novel polyurethane gels have been reported in common solvent like dimethyl formamide (DMF). Polyurethanes have been synthesized from diisocyanates, diols and rigid chain extenders. We have illustrated the influence of chemical structure of the chain extenders on gelation rate, thermal property and morphology of the gels in DMF. Gelation rate increases significantly with the rigidity of the chain extender. Introduction of more rigid chain extender molecules in polyurethane prepolymer enhanced the thermal stability of the pure polymer. On the contrary, the solvent retention power of the gels gradually decreases with increasing rigidity of chain extender presumably because of the poor dispersion/greater aggregation of the hard segments in the soft segment matrix. Morphology and formation of gelation have been discussed.
The measurement of marketing efficiency in the presence of spillovers: theory and evidence
Authors: Vardanyan Michael , Tremblay Victor J.
Published: July 2006

We develop a model of marketing efficiency based on a directional distance function that allows for marketing spillovers. A parametric model is used to test for spillovers from rival marketing and from a firm's marketing activity of its other related products. We then show how this information can be incorporated into a non‐parametric model and used to estimate marketing inefficiency. We apply brand level data from the US brewing industry to the non‐parametric model to determine the effectiveness of television, radio, and print advertising. We find that advertising spillovers are important in brewing and show that efficiency estimates are inaccurate when spillover effects are ignored. Our results also suggest that marketing efficiency may be an important component to firm success in brewing, a result that may apply to other consumer goods industries. Copyright © 2006 John Wiley & Sons, Ltd.
The effect of communication in incentive systems—an experimental study
Authors: Harbring Christine
Published: July 2006

In organizational theory, it is a widely accepted postulate that cooperation among subjects is enforceable. This assumption is essential for the evaluation of two frequently discussed incentive systems: team and tournament compensation. Whereas in team‐based pay systems cooperation is highly desired, cooperation in rank‐order tournaments—labeled as ‘collusion’—is regarded as one of the main drawbacks of relative performance evaluation. In this experimental study, two different communication technologies are introduced into both incentive environments. The results indicate that when only limited communication is permitted subjects tend to cheat on each other in the tournament rather than in the team setting. Interestingly, allowing subjects to exchange emails leads to a similarly stable cooperation in both incentive systems. Copyright © 2006 John Wiley & Sons, Ltd.
Immediate early gene (ZENK) responses to song in juvenile female and male zebra finches: Effects of rearing environment
Authors: Tomaszycki Michelle L. , Sluzas Emily M. , Sundberg Kristy A. , Newman Sarah W. , DeVoogd Timothy J.
Published: July 2006

Accurate song perception is likely to be as important for female songbirds as it is for male songbirds. Male zebra finches (Taeniopygia guttata) show differential ZENK expression to conspecific and heterospecific songs by day 30 posthatch in auditory perceptual brain regions such as the caudomedial nidopallium (NCM) and the caudomedial mesopallium (CMM). The current study examined ZENK expression in response to songs of different qualities at day 45 posthatch in both sexes. Normally reared juvenile zebra finches showed higher densities of immunopositive nuclei in both the dorsal and ventral areas of NCM and CMM (formerly cmHV), but not HA, a visual area, in response to normal song over untutored song or silence. Male and female patterns of ZENK expression did not differ. We next compared responses of birds reared without exposure to normal song (untutored) to those of normally reared birds. Untutored birds did not show higher responses to normal song than to untutored song in the three song perception areas. Furthermore, untutored birds of both sexes showed lower densities of immunopositive nuclei in all four areas than did normally reared birds. In addition, ZENK expression was greater in untutored females than in males in the dorsal portion of NCM and in CMM. Our findings suggest that at least some neural mechanisms of song perception are in place in socially reared female and male finches at an early age. Furthermore, early exposure to song tutors affects responses to song stimuli. © 2006 Wiley Periodicals, Inc. J Neurobiol 66: 1175–1182, 2006
A succession of anesthetic endpoints in the Drosophila brain
Authors: van Swinderen Bruno
Published: July 2006

General anesthetics abolish behavioral responsiveness in all animals, and in humans this is accompanied by loss of consciousness. Whether similar target mechanisms and behavioral endpoints exist across species remains controversial, although model organisms have been successfully used to study mechanisms of anesthesia. In Drosophila, a number of key mutants have been characterized as hypersensitive or resistant to general anesthetics by behavioral assays. In order to investigate general anesthesia in the Drosophila brain, local field potential (LFP) recordings were made during incremental exposures to isoflurane in wild‐type and mutant flies. As in higher animals, general anesthesia in flies was found to involve a succession of distinct endpoints. At low doses, isoflurane uncoupled brain activity from ongoing movement, followed by a sudden attenuation in neural correlates of perception. Average LFP activity in the brain was more gradually attenuated with higher doses, followed by loss of movement behavior. Among mutants, a strong correspondence was found between behavioral and LFP sensitivities, thereby suggesting that LFP phenotypes are proximal to the anesthetic's mechanism of action. Finally, genetic and pharmacological analysis revealed that anesthetic sensitivities in the fly brain are, like other arousal states, influenced by dopaminergic activity. These results suggest that volatile anesthetics such as isoflurane may target the same processes that sustain wakefulness and attention in the brain. LFP correlates of general anesthesia in Drosophila provide a powerful new approach to uncovering the nature of these processes. © 2006 Wiley Periodicals, Inc. J Neurobiol 66: 1195–1211, 2006
Negotiated representational mediators: How young children decide what to include in their science representations
Authors: Danish Joshua A. , Enyedy Noel
Published: July 2006

In this paper, we synthesize two bodies of work related to students' representational activities: the notions of meta‐representational competence and representation as a form of practice. We report on video analyses of kindergarten and first‐grade students as they create representations of pollination in a science classroom, as well as summarize results from interviews regarding the design choices that they made. Analysis of the semistructured pre‐ and postinterviews reveals that students attend to the content domain, local activity, and their personal preferences when evaluating representations. Analysis of video case studies that followed the students as they created their representations further reveals several key mediators of the students' representational activities, including other students, task constraints, the teacher, and local norms for what constituted a “good representation.” In addition, the data show that these norms shifted over time as new content was covered in the class, and were appropriated in interaction with other students. Finally, both sets of analyses reveal that students often face competing constraints when creating their representations, and resolve these constraints through a complex set of negotiations. © 2006 Wiley Periodicals, Inc.Sci Ed91:1–35, 2007
Greenland Ice Sheet History Since the Last Glaciation
Authors: Ten Brink Norman W. , Weidick Anker
Published: July 2006

The position of the Inland Ice margin during the late Wisconsin-Würm glaciation (ca. 15,000 yr BP) is probably marked by offshore banks (submarine moraines?) in the Davis Strait. The history of the Inland Ice since the late Wisconsin-Würm can be divided into four principal phases: (1) Relatively slow retreat from the offshore banks occurred at an average rate of approximately 1 km/100 yr until ca. 10,000 yr BP (Younger Dryas?) when the Taserqat moraine system was formed by a readvance. (2) At ca. 9500 yr BP, the rate of retreat increased markedly to about 3 km/100 yr, and although nearly 100 km of retreat occurred by ca. 6500 yr BP, it was punctuated by frequent regional reexpansions of the Inland Ice that formed extensive moraine systems at ca. 8800-8700 yr BP (Avatdleq-Sarfartôq moraines), 8400-8100 yr BP (Angujârtorfik-Fjord moraines), 7300 yr BP (Umîvît moraines), and 7200-6500 yr BP (Keglen-Mt, Keglen moraines). (3) Between 6500 and 700 yr BP, discontinous ice-margin deposits and ice-disintegration features were formed during retreat, which may have continued until the ice margin was near or behind its present position by ca. 6000 yr BP. Most of the discontinuous ice-margin deposits occur within 5–10 km of the present ice margin, and may have been formed by two main phases of readvance at ca. 4800-4000 yr BP and 2500-2000 yr BP. (4) Since a readvance at ca. 700 yr BP, the Inland Ice margin has undergone several minor retreats and readvances resulting in deposition of numerous closely spaced moraines within about 3 km of the present ice margin. The young moraines are difficult to correlate regionally, but several individual moraines have the following approximate ages: A.D. 1650, 1750, and 1880–1920.

Inland Ice fluctuations in West Greenland were very closely paralleled by Holocene glacial events in East Greenland and the eastern Canadian Arctic. Such similarity of glacier behavior over a large area strongly suggests that widespread climatic change was the direct cause of Holocene glacial fluctuations. Moreover, historical advances of the Inland Ice margin followed slight temperature decreases by no more than a few decades, and 18O data from Greenland ice cores show that slight temperature decreases occurred frequently throughout the Holocene. Therefore, we conclude that construction of the major Holocene moraine systems in West Greenland was caused by slight temperature decreases, which decreased rates of ablation and thereby produced practically immediate advances of the ice sheet margin, but did not necessarily affect the long-term equilibrium of the ice sheet.
An Anvilian (Early Pleistocene) Marine Fauna from Western Seward Peninsula, Alaska
Authors: Hopkins D.M. , Rowland R.W. , Echols R.E. , Valentine P.C.
Published: July 2006

Cover sediments of the York Terrace exposed near the California River, western Seward Peninsula, Alaska, yield mollusks, ostracodes, and foraminifera that lived during the Anvilian transgression of early Pleistocene age. The fossiliferous sediments lie at the inner edge of the York Terrace, a deformed wave-cut platform that extends eastward from Bering Strait along much of the southern coast of Seward Peninsula. The seaward margin is truncated by the little-deformed Lost River Terrace, carved during the Pelukian (Sangamonian) transgression. The early Pleistocene sediments seem to have been deposited between the first and second of four glaciations for which evidence can be found in the California River area.

The California River fauna includes several extinct species and several species now confined to areas as remote as the northwestern Pacific and north Atlantic. The fauna probably lived in water temperatures much like those of the present time but deeper water on the Bering Shelf is suggested.

The presence of an early Pleistocene fauna at the inner edge of the York Terrace at California River shows that the terrace was largely carved before and during early Pleistocene time. However, a marine fauna apparently of middle Pleistocene age is found on the York Terrace near Cassiterite Peak, and this seems to indicate that the terrace remained low until middle Pleistocene time. Uplift of the York Terrace probably was accompanied by uplift of Bering Strait. The strait may have been deeper, and there may have been no land bridge between the Seward Peninsula of Alaksa and the Chukotka Peninsula of Siberia during most of early and middle Pleistocene time.
Petrology and Origin of Stratified Scree in New Zealand
Authors: Harris Stuart A.
Published: July 2006

Stratified scree in the Porters Pass area of the South Island New Zealand consists of up to 30 m of alternating bands of angular gravel and gravelly silt. The gravel consists of frost-shattered bedrock, while the silt appears to have originated from weathered till that entered the area as loess. Every 10 m of stratified scree actually contains at least 5 m of loess. Glaciers left oversteepened slopes on which screes subsequently formed, probably during later nearby glacial advances. The more gently sloping land may have been covered in vegetation as dense as today, but every l0-118 yr, widespread destruction of the vegetation resulted in a marked period of loess deposition. Thus the stratified scree of Soons (1962) has a different origin to that postulated for the grezes litées of European workers.
Basal Temperatures in Polar Ice Sheets: A Qualitative Review
Authors: Hooke Roger LeB.
Published: July 2006

In recent years glacial geologists have become increasingly interested in the thermal regime at the bases of polar ice sheets, and have attempted to interpret certain Pleistocene glacial features in terms of this thermal regime. This effort has suffered from a lack of a reasonably comprehensive but qualitative review of factors controlling the temperature at the base of a polar glacier; this paper attempts to fill this void. Using the Laurentide Ice Sheet as an example, it is shown that under cold climatic conditions basal melting is likely to occur only beneath the lower part of the ablation area. If the climate is somewhat warmer, or if the accumulation rate is sufficiently low, basal melting may also occur beneath the accumulation area. The zone of greatest basal melt-water production is probably beneath the lower part of the ablation area.
Paleoclimatic Record of a Long Deep Sea Core from the Eastern Mediterranean
Authors: Cita Maria Bianca , Vergnaud-Grazzini Colette , Robert Christian , Chamley Hervé , Ciaranfi Neri , d'Onofrio Sara
Published: July 2006

A deep-sea core over 16 m long from the crestal area of the Mediterranean Ridge has been investigated with different techniques, including quantitative micropaleontology, stable isotopes (measured on the epipelagic speciesGlobigerinoides ruberand on the mesopelagic speciesGloborotalia inflata), and clay mineralogy. The resulting record of climatic fluctuations can be cross correlated to other Mediterranean cores by means of isochronous lithologies (tephra layers and sapropels). The climatic record of the Mediterranean is similar in character, phase, and chronology to the records investigated in the equatorial Pacific and in the Caribbean. Isotope stages 1 to 17 have been recognized. Cyclically repeated stagnant cycles resulting in sapropel deposition complicate both the isotopic and the faunal signal. The isotopic investigations reveal that the temperature change in the surface layers of the eastern Mediterranean was no greater than 8°C in the late “glacial” Pleistocene. The chronostratigraphic and biostratigraphic interpretation of Core KS09 indicate that the mean sedimentation rate was 2.4 cm/1000 years, a value very close to the 2.5 cm/1000 years calculated for the entire Quaternary section at DSDP Site 125, also located in the crestal area of the Mediterranean Ridge in the Ionian Basin. The base of KS09 is likely to be very close to the Brunhes/Matuyama boundary dated at 0.7 my.