bluuebunny/crossref_metadata_2025 huggingface dataset:
Ablation of TrkA function in the immune system causes B cell abnormalities
Authors: Coppola Vincenzo , Barrick Colleen A. , Southon Eileen A. , Celeste Arkady , Wang Kathryn , Chen Bei , Haddad El-Bdaoui , Yin Jian , Nussenzweig Andre , Subramaniam Arun , Tessarollo Lino
Published: September 2004

The nerve growth factor (NGF) receptor TrkA is widely expressed in non-neural tissues suggesting pleiotropic functions outside the nervous system. Based on pharmacological and immuno-depletion experiments, it has been hypothesized that NGF plays an important role in the normal development and function of the immune system. However, attempts to unravel these functions by conventional gene targeting in mice have been hampered by the early postnatal lethality caused by null mutations. We have developed a novel `reverse conditional' gene targeting strategy by which TrkA function is restored specifically in the nervous system. Mice lacking TrkA in non-neuronal tissues are viable and appear grossly normal. All major immune system cell populations are present in normal numbers and distributions. However, mutant mice have elevated serum levels of certain immunoglobulin classes and accumulate B1 cells with aging. These data, confirmed in a classical reconstitution model using embryonic fetal liver from TrkA-null mice, demonstrate that endogenous NGF modulates B cell development through TrkA in vivo. Furthermore, they demonstrate that many of the dramatic effects previously reported by pharmacological or immuno-depletion approaches do not reflect physiological developmental roles of TrkA in the immune system.
A null mutation ofHhexresults in abnormal cardiac development,defective vasculogenesis and elevated Vegfa levels
Authors: Hallaq Haifa , Pinter Emese , Enciso Josephine , McGrath James , Zeiss Caroline , Brueckner Martina , Madri Joseph , Jacobs Harris C. , Wilson Christine M. , Vasavada Hemaxi , Jiang Xiaobing , Bogue Clifford W.
Published: September 2004

The homeobox gene Hhex has recently been shown to be essential for normal liver, thyroid and forebrain development. Hhex–/– mice die by mid-gestation (E14.5) and the cause of their early demise remains unclear. Because Hhex is expressed in the developing blood islands at E7.0 in the endothelium of the developing vasculature and heart at E9.0-9.5, and in the ventral foregut endoderm at E8.5-9.0, it has been postulated to play a critical role in heart and vascular development. We show here, for the first time, that a null mutation of Hhex results in striking abnormalities of cardiac and vascular development which include: (1) defective vasculogenesis, (2)hypoplasia of the right ventricle, (3) overabundant endocardial cushions accompanied by ventricular septal defects, outflow tract abnormalities and atrio-ventricular (AV) valve dysplasia and (4) aberrant development of the compact myocardium. The dramatic enlargement of the endocardial cushions in the absence of Hhex is due to decreased apoptosis and dysregulated epithelial-mesenchymal transformation (EMT). Interestingly, vascular endothelial growth factor A (Vegfa) levels in the hearts of Hhex–/– mice were elevated as much as three-fold between E9.5 and E11.5, and treatment of cultured Hhex–/– AV explants with truncated soluble Vegfa receptor 1, sFlt-1, an inhibitor of Vegf signaling, completely abolished the excessive epithelial-mesenchymal transformation seen in the absence of Hhex. Therefore, Hhex expression in the ventral foregut endoderm and/or the endothelium is necessary for normal cardiovascular development in vivo, and one function of Hhex is to repress Vegfa levels during development.
New roles for FoxH1 in patterning the early embryo
Authors: Kofron Matt , Puck Helbert , Standley Henrietta , Wylie Chris , Old Robert , Whitman Malcolm , Heasman Janet
Published: September 2004

FoxH1 (Fast1) was first characterized as the transcriptional partner for Smad proteins. Together with Smad2/4, it forms the activin response factor(ARF) that binds to the Mix.2 promoter in Xenopus embryos. Foxh1 is expressed maternally in Xenopus. Depletion of maternal Foxh1 mRNA results in abnormalities of head and dorsal axis formation. We show that FoxH1 is required, together with XTcf3/β catenin,to activate the zygotic expression of the nodal gene, Xnr3 in a Smad2-independent manner. In contrast, maternal FoxH1 acts as an inhibitor of Xnr5 and 6 transcription, preventing their upregulation on the ventral side of the embryo, by the maternal T-box transcription factor VegT. We conclude that maternal FoxH1 has essential, context-dependent roles in regulating the pattern of zygotic gene expression in the early embryo.
The Lim homeobox geneLhx2is required for olfactory sensory neuron identity
Authors: Kolterud Åsa , Alenius Mattias , Carlsson Leif , Bohm Staffan
Published: September 2004

Progenitor cells in the mouse olfactory epithelium generate over a thousand subpopulations of neurons, each expressing a unique odorant receptor (OR)gene. This event is under the control of spatial cues, since neurons in different epithelial regions are restricted to express region-specific subsets of OR genes. We show that progenitors and neurons express the LIM-homeobox gene Lhx2 and that neurons in Lhx2-null mutant embryos do not diversify into subpopulations expressing different OR genes and other region-restricted genes such as Nqo1 and Ncam2. Lhx2-/- embryos have, however, a normal distribution of Mash1-positive and neurogenin 1-positive neuronal progenitors that leave the cell cycle, acquire pan-neuronal traits and form axon bundles. Increased cell death in combination with increased expression of the early differentiation marker Neurod1, as well as reduced expression of late differentiation markers (Gαolf and Omp), suggests that neuronal differentiation in the absence of Lhx2 is primarily inhibited at, or immediate prior to, onset of OR expression. Aberrant regional expression of early and late differentiation markers, taken together with unaltered region-restricted expression of the Msx1 homeobox gene in the progenitor cell layer of Lhx2-/- embryos, shows that Lhx2 function is not required for all aspects of regional specification of progenitors and neurons. Thus,these results indicate that a cell-autonomous function of Lhx2 is required for differentiation of progenitors into a heterogeneous population of individually and regionally specified mature olfactory sensory neurons.
Enhanced Fluorescence from Rhodamine B Intercalated into Hydrophobized Graphite Oxides Containing Perfluoroalkyl Chains
Authors: Matsuo Yoshiaki , Fukunaga Takahiro , Fukutsuka Tomokazu , Sugie Yosohiro
Published: October 2004

Fluorescence from Rhodamine B in hydrophobized graphite oxide was greatly enhanced by perfluoroalkyl chains, likely due to the lower radiationless quenching by low vibrational C–F bonds.
Temporal Emergence of Giant Vesicles Accompanied by Hydrolysis of Ammonium Amphiphiles with a Schiff-base Segment
Authors: Toyota Taro , Takakura Katsuto , Sugawara Tadashi
Published: October 2004

An aqueous dispersion of the ammonium amphiphile with a Schiff-base segment exhibited the formation and decomposition of giant vesicles with diameters of several micrometers 2–4 h after the preparation. The time course trace of the morphological changes of the self-aggregates by means of light microscopy, electron microscopy and 1H NMR revealed that the temporal emergence of the giant vesicles was dependent on the progress of hydrolysis of the Schiff-base segment.
Annie Cohen: pour une algérianité retrouvée
Authors: Bénayoun-Szmidt Yvette
Published: September 2004

Arrachée à son pays natal et exilée à Paris où elle vit depuis 1967, l’écrivaine judéo-algérienne Annie Cohen s’est frayée un chemin dans l’écriture. Dans ce processus visant une parfaite intégration
dans le nouveau pays d’accueil, ses premiers écrits traduisent clairement cette volonté de détachement de ses racines et de distanciation vis-à-vis de son pays d’origine. Soudainement, une rencontre avec un personnage mystérieux Le Marabout de
Blida la pousse à écrire sur son algérianité perdue. Cette rencontre qui se double d’un signe d’identité va autoriser La Parole du Sud qui permettra à l’écrivaine de se réconcilier avec le pays des ancêtres. Cette
pacification et cette affirmation de son identité judéo-algérienne deviennent une donnée fondamentale dans ses derniers romans.
Towards a comprehensive socio-cultural theory of the Jewish life-world in Morocco: The Jewish Traditional Marriage in Morocco
Authors: Elbaz Robert
Published: September 2004

For the Jewish traditional wedding in Morocco, like the wedding in any other sociocultural space, reflects and refracts the totality of all the practices that shape the life-world in all its complexity. For the Jewish wedding up to the middle of the twentieth century involved, aside
from all the ceremonies and customs that last approximately a week, the personal life of the Jew, his familial life, his social and communal life and, finally, the material/economic life - not the least of its important dimensions. Often the economic situation dictated the recurrence of this
or that ceremony, given that the material means, particularly in the small rural conglomerations (or in times and cases of economic hardship in the bigger communities as well) were sometimes quite limited
Bisphosphonates: Clinical Experience
Authors: Coleman Robert E.
Published: September 2004

Learning Objectives

After completing this course, the reader will be able to:

Explain the importance of bone disease in the common solid tumors of adulthood. Describe the pathophysiology of bone metastasis. List the specialized end points used in clinical trials assessing treatment of bone disease. Discuss the current standard for the treatment and prevention of bone complications that may arise in cancer and its treatment.

Access and take the CME test online and receive 1 hour of AMA PRA category 1 credit at CME.TheOncologist.com

Bone is a preferred site of metastasis for many solid tumors, and the complications associated with bone metastases can result in significant skeletal morbidity including severe bone pain, pathologic fracture, spinal cord compression, and hypercalcemia of malignancy (HCM). Bisphosphonates are the current standard of care for preventing skeletal complications associated with bone metastases. Clinical trials investigating the benefit of bisphosphonate therapy have used a composite end point defined as a skeletal-related event (SRE) or bone event, which typically includes pathologic fracture, spinal cord compression, radiation or surgery to bone, and HCM. Bisphosphonates have been shown to significantly reduce the incidence of these events in patients with bone metastases. Zoledronic acid (Zometa®; Novartis Pharmaceuticals Corp.; East Hanover, NJ), pamidronate (Aredia®; Novartis Pharmaceuticals Corp.), clodronate (Bonefos®; Anthra Pharmaceuticals; Princeton, NJ), and ibandronate (Bondronat®; Hoffmann-La Roche Inc.; Nutley, NJ) all have demonstrated efficacy superior to that of placebo in patients with breast cancer. Zoledronic acid is the only bisphosphonate that has been compared directly with pamidronate, and it was shown by multiple event analysis to be significantly more effective at reducing the risk of an SRE. In patients with prostate cancer, clodronate, etidronate (Didronel®; Procter and Gamble Pharmaceuticals, Inc.; Cincinnati, OH), and pamidronate have demonstrated transient palliation of bone pain. However, zoledronic acid is the only bisphosphonate to demonstrate both significant and sustained pain reduction and a significantly lower incidence and longer time to onset of SREs compared with placebo. Zoledronic acid is also the only bisphosphonate to demonstrate efficacy in patients with bone metastases from a variety of other solid tumors, including lung cancer and renal cell carcinoma. In conclusion, bisphosphonates effectively reduce skeletal complications in patients with bone metastases from breast cancer, and zoledronic acid has demonstrated the broadest clinical activity in patients with a wide variety of tumor types.
Safety of Intravenous and Oral Bisphosphonates and Compliance With Dosing Regimens
Authors: Conte PierFranco , Guarneri Valentina
Published: September 2004

Learning Objectives

After completing this course, the reader will be able to:

Describe the differences between oral and i.v. bisphosphonate therapy in terms of safety and side effects. Explain the renal effects of long-term i.v. bisphosphonate treatment. Discuss the importance of patient compliance in long-term disease management.

Access and take the CME test online and receive 1 hour of AMA PRA category 1 credit at CME.TheOncologist.com

Patients with advanced cancers—particularly breast and prostate cancers—are at high risk for bone metastasis, leading to accelerated bone resorption and clinically significant skeletal morbidity. Bisphosphonates are effective inhibitors of bone resorption and reduce the risk of skeletal complications in patients with bone metastases. The standard routes of administration for bisphosphonates used in clinical practice are either oral or i.v. infusion. Oral administration of bisphosphonates is complicated by poor bioavailability (generally <5%) and poor gastrointestinal tolerability. First-generation bisphosphonates, such as clodronate (Bonefos®; Anthra Pharmaceuticals; Princeton, NJ), must be administered at high oral doses (1,600–3,200 mg/day) to achieve therapeutic effects, which leads to poor tolerability and compliance with oral dosing regimens. Infusion of bisphosphonates is associated with dose- and infusion-rate-dependent effects on renal function. In particular, high bisphosphonate doses (e.g., 1,500 mg clodronate) can cause severe renal toxicity unless infused slowly over many hours. In contrast, the newer, more potent bisphosphonates effectively inhibit bone resorption at micromolar concentrations, and the small doses required can be administered via relatively short i.v. infusions without adversely affecting renal function. Zoledronic acid (Zometa®; Novartis Pharmaceuticals Corp.; East Hanover, NJ) is a new generation bisphosphonate, and the recommended dose of 4 mg can be safely infused over 15 minutes. The 90-mg dose of pamidronate (Aredia®; Novartis Pharmaceuticals Corp.) and the 6-mg dose of ibandronate (Bondronat®; Hoffmann-La Roche Inc.; Nutley, NJ) require 1- to 4-hour infusions. Intravenous bisphosphonates require less frequent dosing (once a month) and are generally well tolerated with long-term use in patients with bone metastases. Zoledronic acid has demonstrated the broadest clinical activity in patients with bone metastases.
Characterization of GABA Receptors
Authors: Enna S. J. , McCarson Kenneth E.
Published: September 2004

Described in this unit are ligand binding assays for GABAA, GABAB, and GABAC receptor recognition sites in brain tissue. These assays may also be used to determine the affinity of an unlabeled compound for the GABA binding sites. Not included in this unit are ligand binding assays for other components of the GABAA, receptor complex, such as the benzodiazepine or ion channel binding sites.
Electrophysiological Characterization of Recombinant and Native P2X Receptors
Authors: Niforatos Wende , Jarvis Michael F.
Published: September 2004

ATP acts as a fast neurotransmitter by activating a family of ligand‐gated ion channels, the P2X receptors. Functional homomeric P2X3 and heteromeric P2X2/3 receptors are highly localized on primary sensory afferent neurons that transmit nociceptive sensory information. Activation of these P2X3‐containing channels may provide a specific mechanism whereby ATP, released via synaptic transmission or by cellular injury, elicits pain. The experimental procedures described in this unit are useful for the electorphysiological characterization of P2X receptors. In addition, these protocols provide methods for the evaluation of ligands that interact with P2X receptors that are either natively expressed on excitable cells or cloned and expressed in heterologous cell systems. These methods are derived from standard electrophysiological principles and procedures that are applicable to a wide variety of ligand‐gated ion channels. Specific attention is given here to the reliable electrophysiological measurement of both quickly (P2X3) and more slowly (P2X2 and P2X2/3) desensitizing receptors.
DNASynthesis Without Base Protection
Authors: Sekine Mitsuo
Published: September 2004

DNA synthesis can be achieved by using O‐selective methods for internucleotide bond formation. This greatly simplifies the synthesis of oligodeoxyribonucleotides by eliminating the need for nucleobase protection and deprotection steps. This unit describes strategies that can be used for DNA synthesis without base protection. The discussion includes synthesis of phosphoramidite andH‐phosphonate monomers, solid‐phase assembly by the phosphoramidite andH‐phosphonate methods, and future prospects for DNA synthesis using N‐unprotected approaches.
Oligodeoxyribonucleotide Analogs Functionalized with Phosphonoacetate and Thiophosphonoacetate Diesters
Authors: Dellinger Douglas J. , Yamada Christina M. , Caruthers Marvin H.
Published: September 2004

Oligodeoxyribonucleotides with phosphonoacetate or thiophosphonoacetate internucleotide linkages can be made in high yield by solid‐phase synthesis and possess many advantages. They are highly stable to nucleases, water‐soluble, and anionic at neutral pH. They form stable duplexes with DNA and RNA, and stimulate RNase H degradation of complementary RNA. The preparation of the N,N‐(diisopropylamino)phosphinyl acetate monomers from standard protected nucleosides is described here, followed by the synthesis of phosphonoacetate and thiophosphonoate oligodeoxyribonucleotides, as well as chimeric oligomers that have these modified linkages in combination with natural or phosphorothioate linkages. Purification and characterization of these oligomers is also presented.
Derivatization of Glass and Polypropylene Surfaces
Authors: Beier Markus , Hoheisel Jörg D.
Published: September 2004

This unit describes the derivatization of solid support media, particularly glass and polypropylene, with a linker system by an iterative process that forms a dendrimeric structure, thereby increasing stepwise the loading capacity of the surface. The procedure permits the production of various types of linkers whose characteristics can be tailored to the requirements of the eventual applications. The specific modifications described here are used either for attaching prefabricated DNA oligonucleotides, PCR products, and peptide nucleic acid (PNA) oligomers, or for in situ synthesis of DNA microarrays.
Synthesis and Polymerase Incorporation of 5′‐Amino‐2′,5′‐Dideoxy‐5′‐N‐Triphosphate Nucleotides
Authors: Wolfe Jia Liu , Kawate Tomohiko
Published: September 2004

This unit presents synthetic procedures for the preparation of 5′‐amino‐2′,5′‐dideoxy analogs of adenosine, cytidine, guanosine, and thymidine, as well as corresponding 5′‐N‐triphosphate nucleotides, using commercially available reagents. The modified nucleosides are prepared in high yields from naturally occurring 2′‐deoxynucleosides using robust chemical reactions including tosylation, azide exchange, and the Staudinger reaction. Efficient conversion of these 5′‐amino nucleosides to corresponding 5′‐N‐triphosphate nucleotides is achieved through a one‐step reaction with trimetaphosphate in Tris‐buffered aqueous solution. The 5′‐amino modification renders these nucleoside and nucleotide analogs markedly increased reactivity, which is useful for a variety of biochemical, pharmaceutical, and genomic applications. Also included in this unit are protocols for polymerase incorporation of the 5′‐amino nucleotides, either partially or completely replacing their naturally occurring counterparts, and subsequent sequence‐specific cleavage at the modified nucleotides under mildly acidic conditions.
Actin‐Based Motility Assay
Authors: Le Clainche Christophe , Carlier Marie‐France
Published: September 2004

Actin‐based movement can be reconstituted by using microspheres functionalized with the enzymes N‐WASP or ActA, which use the Arp2/3 complex and actin to catalyze the formation of a branched actin filament network that is maintained in rapid turnover by three proteins (capping protein, profilin, and ADF). The particles continuously initiate filament assembly at their surface and are propelled, mimicking bacteria or the leading edge of motile cells. This biomimetic assay offers advantages over approaches based on living cells and cell extracts, because the physical‐chemical parameters are under control. The biomimetic motility assay offers the opportunity to test the function of proteins involved in signaling pathways or actin dynamics. It is a powerful tool to understand the physical mechanism of force production and has the potential to support high‐throughput screens for drugs, inhibitors of motility, or therapeutic agents in metastatic states in which motility is impaired.
Fluorescence Localization After Photobleaching (FLAP)
Authors: Dunn Graham A. , Holt Mark R. , Soong Daniel Y. H. , Gray Colin , Zicha Daniel
Published: September 2004

Fluorescence localization after photobleaching is a new method for localized photolabeling and subsequent tracking of specific molecules within living cells. The molecular species to be located carries two different fluorophores that can be imaged independently but simultaneously by fluorescence microscopy. For the method to work, these two fluorophores should be accurately colocalized throughout the cell so that their images are closely matched. One of the fluorophores (the target fluorophore) is then rapidly photobleached at a chosen location. The unbleached (reference) fluorophore remains colocalized with the target fluorophore; thus, the subsequent fate of the photobleached molecules can be revealed by processing simultaneously acquired digital images of the two fluorophores. Here we demonstrate the simplicity and effectiveness of the FLAP method in revealing both fast and slow molecular dynamics in living cells using a Zeiss LSM 510 laser scanning confocal microscope.
Searching the NCBI Databases Using Entrez
Authors: Baxevanis Andreas D.
Published: September 2004

One of the most widely‐used interfaces for the retrieval of information from biological databases is the NCBI Entrez system. Entrez capitalizes on the fact that there are pre‐existing, logical relationships between the individual entries found in numerous public databases. The existence of such natural connections, mostly biological in nature, argued for the development of a method through which all the information about a particular biological entity could be found without having to sequentially visit and query disparate databases. Two Basic Protocols describe simple, text‐based searches, illustrating the types of information that can be retrieved through the Entrez system. An Alternate Protocol builds upon the first Basic Protocol, using additional, built‐in features of the Entrez system, as well as providing alternative ways to issue the initial query. The Support Protocol reviews how to save frequently‐issued queries.
Analyzing and Visualizing Expression Data with Spotfire
Authors: Kaushal Deepak , Naeve Clayton W.
Published: September 2004

This unit assumes the reader is familiar with the Spotfire environment, has successfully installed Spotfire, and has uploaded and prepared data for analysis. It presents numerous methods for analyzing microarray data. Specifically, the first two protocols describe methods for identifying differentially expressed genes via the t‐test/ANOVA and the distinction calculation respectively. Another protocol discusses how to conduct a profile search. Additional protocols illustrate various clustering methods, such as hierarchical clustering, K‐means clustering, and principal components analysis. A protocol explaining coincidence testing allows the reader to compare the results from multiple clustering methods. Additional protocols demonstrate querying the Internet for information based on the microarray data, mathematically transforming data within Spotfire to generate new data columns, and exporting Spotfire visualizations.
Using the Reactome Database
Authors: Stein Lincoln D.
Published: September 2004

There is considerable interest in the bioinformatics community in creating pathway databases. The Reactome project (a collaboration between Cold Spring Harbor Laboratory and the European Bioinformatics Institute) is one such pathway database and collects structured information on all the biological pathways in the human. It is a curated collection of well‐documented molecular reactions that span the gamut from simple intermediate metabolism to complex cellular events. This information is supplemented with likely orthologous molecular reactions in mouse, rat, zebrafish, and other model organisms. This unit describes how to use the Reactome database to learn the steps of a biological pathway and see how one pathway interacts with another; navigate and browse through the Reactome database; identify the pathways in which a molecule of interest is involved; use the Pathfinder tool to search the database for possible connections within and between pathways.
Using Relational Databases for Improved Sequence Similarity Searching and Large‐Scale Genomic Analyses
Authors: Mackey Aaron J. , Pearson William R.
Published: September 2004

Relational databases are designed to integrate diverse types of information and manage large sets of search results, greatly simplifying genome‐scale analyses. Relational databases are essential for management and analysis of large‐scale sequence analyses, and can also be used to improve the statistical significance of similarity searches by focusing on subsets of sequence libraries most likely to contain homologs. This unit describes using relational databases to improve the efficiency of sequence similarity searching and to demonstrate various large‐scale genomic analyses of homology‐related data. This unit describes the installation and use of a simple protein sequence database, seqdb_demo, which is used as a basis for the other protocols. These include basic use of the database to generate a novel sequence library subset, how to extend and use seqdb_demo for the storage of sequence similarity search results and making use of various kinds of stored search results to address aspects of comparative genomic analysis.
Finding Protein Sequences Using PROWL
Authors: Beavis Ronald , Fenyö David
Published: September 2004

PROWL is a collection of tools for the identification of protein sequences, using input data derived from mass spectrometry. Experimental data from various types of mass spectrometers can be input directly into PROWL's component software. This unit presents protocols for several of the individual PROWL tools. Specifically, PepFrag allows for the analysis of a single spectrum derived from tandem mass spectrometry. GPM, on the other hand, provides for the analysis of multiple MS/MS spectra. An additional protocol introduces ProFound for analyzing a single spectrum of peptide mass fingerprinting data.
Preparation and characterization of poly(methyl methacrylate) grafted sago starch using potassium persulfate as redox initiator
Authors: Qudsieh Isam Y. M. , Fakhru'l‐Razi A. , Muyibi Suleyman A. , Ahmad Mansor B. , Rahman M. Z. Ab. , Zin Wan Yunus Wan Md
Published: September 2004

In this article, the graft copolymerization of methyl methacrylate (MMA) onto sago starch (AGU) was carried out in aqueous medium using potassium persulfate (PPS) under nitrogen gas atmosphere. The maximum percentage of grafting achieved was 90% under optimized conditions of reaction temperature, monomer, PPS, AGU, and reaction period corresponding to 50°C, 47 mmol, 1.82 mmol, 6.17 × 10−3 mol L−1, and 1.5 h, respectively. The grafting of MMA onto sago starch was confirmed by the differences in infrared spectroscopy. The viscosity measurement and the average molecular weight determination were estimated using Huggin's and Mark Houwink's equations, respectively. This material may have application as a biodegradable plastic. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1891–1897, 2004
Recycling of carbon/epoxy composites
Authors: Liu Yuyan , Meng Linghui , Huang Yudong , Du Jianjun
Published: September 2004

The recycling of carbon fibers from carbon/epoxy composites was attempted with a solvent method in nitric acid solutions. Gel permeation chromatography and gas chromatography/mass spectrometry showed that the epoxy resin could entirely decompose into low‐molecular‐weight compounds, and the main components of the dissoluble decomposed compounds were 2,4‐dinitrophenol and 2‐nitro‐4‐carboxylphenol. Electron probe microscopy showed no damage to the recycled carbon fibers. The single‐fiber tension strength loss of the recycled carbon fibers was 1.1% under the following conditions: a decomposition temperature of 90 °C, a nitric acid solution concentration of 8M, and a ratio of the sample weight to the nitric acid solution volume of 6 g:100 mL. Through orthogonal experimentation, the recycling conditions for the carbon/epoxy composites were examined. The best combination was a decomposition temperature of 90°C, a nitric acid solution concentration of 8M, and a ratio of the sample weight to the nitric acid solution volume of 4g:100 mL. This method could liquefy raw materials for rocket engine shells reinforced with carbon fibers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1912–1916, 2004
Cellulose acetate deacetylation in benzene/acetic acid/water systems
Authors: Olaru N. , Olaru Liliana
Published: September 2004

An unconventional system for cellulose acetate hydrolysis, consisting of homogeneous mixtures of benzene/acetic acid/water of different compositions, was investigated from the perspective of kinetics and also with respect to the degradation of the cellulosic chains during the process. It was observed that the decrease of the degree of substitution of the polymer occurs with higher reaction rate than that in the reference system, free of benzene, and depends on the composition of the reaction medium. A pseudo–first‐order kinetic law satisfactorily describes the deacetylation process performed in the presence of benzene. Also, the degradation of the polymeric chain during the process is dependent on the presence of the hydrocarbon and on the composition of the reaction system used. A lower degradation rate was found to characterize the first period of the process, compared with that produced in a benzene‐free system. These peculiarities were explained by the influence of benzene on the composition of solvent shell in the vicinity of macromolecules. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1965–1968, 2004
Block copolymers of unsaturated polyesters and functional elastomers
Authors: Cherian A. Benny , Thachil Eby Thomas
Published: September 2004

Block copolymers of unsaturated polyester were prepared by condensation polymerization of hydroxyl or carboxyl terminated liquid rubbers with maleic anhydride, phthalic anhydride, and propylene glycol. The condensate obtained was mixed with styrene monomer to get an unsaturated polyester resin formulation. In this study, copolymers of unsaturated polyesters with hydroxy terminated polybutadiene, carboxy terminated nitrile rubber, and hydroxy terminated natural rubber were prepared. Mechanical properties such as tensile strength, tensile modulus, elongation at break, toughness, impact strength, surface hardness, abrasion resistance, and water absorption were evaluated after the resin was cured in appropriate molds for comparison with the control resin. The fracture toughness and impact resistance of CTBN‐modified unsaturated polyester show substantial improvement by this copolymerization without seriously affecting any other property. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1956–1964, 2004
Softening of wood polymers induced by moisture studied by dynamic FTIR spectroscopy
Authors: Åkerholm Margaretha , Salmén Lennart
Published: September 2004

The softening of the wood polymers is very important in the utilization of wood fiber products. To better to understand how the hemicelluloses interact with the other wood polymers in the fiber ultrastructure and contribute to the mechanical properties of the wood, their softening inside the cell wall of pulp fibers was studied by dynamic FTIR spectroscopy under humid conditions. The two hemicelluloses of spruce, glucomannan and xylan, exhibited different softening behaviors indicating a different organization of the two hemicelluloses inside the cell wall. Lignin in mechanical pulp showed a more viscoelastic behavior already under dry conditions than the polysaccharides of the cell wall. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2032–2040, 2004
Water‐swellable hydrophobic porous copolymer resins based on divinylbenzene and acrylonitrile. II. Pore structure and adsorption behavior
Authors: Tang Xiaoshan , Wang Xunhua , Yan Jun
Published: September 2004

By using purified divinylbenzene (DVB, 98.8%) or technical DVB (79.3%), the hydrophobic, but water‐wettable or swellable porous copolymer resins based on DVB and acrylonitrile (AN) could be prepared with a wide range of pore structures under certain conditions. The specific surface area for the resulting AN/DVB resin, with an AN/DVB ratio of 40/60 (by mole), could reach a value of 704 m2/g, while such a resin is still water wettable or swellable by direct contact with water. The adsorption behavior of the AN/DVB resins was investigated by focusing on the comparison between the resins with and without prewetting, using caffeine and phenol as model adsorbates. Adsorption behavior of the AN/DVB resins, without prewetting, correlates well with the wetting ability of the resins in water, suggesting that a well water‐wettable hydrophobic porous AN/DVB resin could be directly applied, in a dry state, to the adsorption in an aqueous medium, almost without diminishing the ability of the resin to adsorb the solutes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2050–2056, 2004
The affective costs of overconfidence
Authors: McGraw A. Peter , Mellers Barbara A. , Ritov Ilana
Published: September 2004

Positive illusions, though often beneficial (Taylor & Brown, 1988), can diminish the pleasure of outcomes. This prediction follows from decision affect theory. We investigated this prediction by measuring the confidence that recreational basketball players felt while making shots and the pleasure they felt with subsequent outcomes. Results showed that most players were overconfident. Those who were more overconfident tended to experience less enjoyment with their outcomes. Using individual parameter estimates from decision affect theory, we estimated how each player would have felt if their self assessments had been accurate. For the vast majority, better calibration would have led to greater pleasure. In a second study, we randomly assigned players to a debiasing treatment condition or a control condition. Relative to the control players, debiased players were better calibrated and derived greater average pleasure from the task. Copyright © 2004 John Wiley & Sons, Ltd.
Serving emerging majority students
Authors: Laden Berta Vigil
Published: September 2004

This chapter presents an overview of the demographic shifts occurring in the United States and discusses the associated rapid increase in the number of community college students from diverse racial backgrounds. Profiles of two community colleges offer examples of timely responses to emerging majority students' academic, economic, and social needs.
The role of urban community colleges in educating diverse populations
Authors: Hagedorn Linda Serra
Published: September 2004

This chapter uses data from the Transfer and Retention of Urban Community College Students project to provide evidence of success among racially diverse students in the Los Angeles Community College District. Through interviews with student services personnel, it also describes the specific efforts that may be responsible for this success. In addition, it provides insight into the current and anticipated effects of severe budget cuts on minority student success initiatives.
Diversity in the two‐year college academic workforce
Authors: Jackson Jerlando F. L. , Phelps L. Allen
Published: September 2004

This chapter compares the racial and ethnic diversity among faculty and academic leaders with that of the student population in two‐year colleges. Using two national data sets, this study reveals that African American and Hispanic faculty and academic leaders remain underrepresented compared to the number of students of color attending the nation's two‐year colleges.
The Alliance for Equity in Higher Education
Authors: Merisotis Jamie P. , Goulian Katherine A.
Published: September 2004

This chapter describes the organization, operations, and goals of the Alliance for Equity in Higher Education, a national coalition of associations and institutions founded to serve the emerging majority of racially diverse college students.
Resources and information for serving minority populations
Authors: Sáenz Victor
Published: September 2004

This chapter summarizes useful and relevant resources and information on the topic of serving minority populations in community colleges, and presents information about several programs and services that have been successful in ensuring minority student success
Thermal Effects and Vibrational Corrections to Transition Metal NMR Chemical Shifts
Authors: Grigoleit Sonja , Bühl Michael
Published: September 2004

Both zero‐point and classical thermal effects on the chemical shift of transition metals have been calculated at appropriate levels of density functional theory for a number of complexes of titanium, vanadium, manganese and iron. The zero‐point effects were computed by applying a perturbational approach, whereas classical thermal effects were probed by Car–Parrinello molecular dynamics simulations. The systematic investigation shows that both procedures lead to a deshielding of the magnetic shielding constants evaluated at the GIAO‐B3 LYP level, which in general also leads to a downfield shift in the relative chemical shifts, δ. The effect is small for the titanium and vanadium complexes, where it is typically on the order of a few dozen ppm, and is larger for the manganese and iron complexes, where it can amount to several hundred ppm. Zero‐point corrections are usually smaller than the classical thermal effect. The pronounced downfield shift is due to the sensitivity of the shielding of the metal centre with regard to the metal–ligand bond length, which increase upon vibrational averaging. Both applied methods improve the accuracy of the chemical shifts in some cases, but not in general.
EPR Studies of Amine Radical Cations, Part 1: Thermal and Photoinduced Rearrangements of n‐Alkylamine Radical Cations to their Distonic Forms in Low‐Temperature Freon Matrices
Authors: Janovský I. , Knolle W. , Naumov S. , Williams F.
Published: September 2004

The thermal and photochemical transformations of primary amine radical cations (n‐propyl 1.+, n‐butyl 5.+) generated radiolytically in freon matrices have been investigated by using low‐temperature EPR spectroscopy. Assignment of the spectra was facilitated by parallel studies on the corresponding N,N‐dideuterioamines. The identifications were supported by quantum chemical calculations on the geometry, electronic structure, hyperfine splitting constants and energy levels of the observed transient radical species. The rapid generation of the primary species by a short exposure (1–2 min) to electron‐beam irradiation at 77 K allowed the thermal rearrangement of 1.+ to be monitored kinetically as a first‐order reaction at 125–140 K by the growth in the well‐resolved EPR signal of the distonic radical cation .CH2CH2CH2NH3+. By comparison, the formation of the corresponding .CH2CH2CH2CH2NH3+ species from 5.+ is considerably more facile and already occurs within the short irradiation time. These results directly verify the intramolecular hydrogen‐atom migration from carbon to nitrogen in these ionised amines, a reaction previously proposed to account for the fragmentation patterns observed in the mass spectrometry of these amines. The greater ease of the thermal rearrangement of 5.+ is in accordance with calculations on the barrier heights for these intramolecular 1,5‐ and 1,4‐hydrogen shifts, the lower barrier for the former being associated with minimisation of the ring strain in a six‐membered transition state. For 1.+, the 1,4‐hydrogen shift is also brought about directly at 77 K by exposure to ∼350 nm light, although there is also evidence for the 1,3‐hydrogen shift requiring a higher energy. A more surprising result is the photochemical formation of the H2CN. radical as a minor product under hard‐matrix conditions in which diffusion is minimal. It is suggested that this occurs as a consequence of the β‐fragmentation of 1.+ to the ethyl radical and the CH2NH2+ ion, followed by consecutive cage reactions of deprotonation and hydrogen transfer from the iminonium group. Additionally, secondary ion–molecule reactions were studied in CFCl2CF2Cl under matrix conditions that allow diffusion. The propane‐1‐iminyl radical CH3CH2CHN. was detected at high concentrations of the n‐propylamine substrate. Its formation is attributed to a modified reaction sequence in which 1.+ first undergoes a proton transfer within a cluster of amine molecules to yield the aminyl radical CH3CH2CH2N.H. A subsequent disproportionation of these radicals can then yield the propane‐1‐imine precursor CH3CH2CHNH, which is known to easily undergo hydrogen abstraction from the nitrogen atom. The corresponding butane‐1‐iminyl radical was also observed.
Total Synthesis of Salicylihalamides A and B
Authors: Herb Christian , Bayer Alexander , Maier Martin E.
Published: September 2004

The paper illustrates two efficient routes to macrolactone 19 containing a 3‐(para‐methoxybenzyloxy)propyl side chain at C‐15. The chiral center at C‐15 was introduced by a Noyori reduction of keto ester 5. The intermediate common to both routes, aldehyde 8, was prepared from keto ester 5. The subsequent chain extension utilized Evans aldol reactions. The first route leads to the alkene 14, which was used, after hydroboration, for a Suzuki cross‐coupling reaction with vinyl iodide 15. The derived seco acid 18 was converted into the macrolactone 19 by a Mitsunobu lactonization by using immobilized triphenylphosphine. Alternatively, an aldol reaction of 8 with the 4‐pentenoyl derivative 20 was used to prepare alkene 26. This building block led to ester 28, which could also be converted into macrolactone 19 by the classical ring‐closing metathesis. After conversion of the C‐15 side chain to the corresponding aldehyde, the enamide was introduced through hemiaminal formation and formal elimination of water. Separation of the double‐bond isomers and removal of the silyl protecting groups provided salicylihalamides A (E)‐1 and B (Z)‐1.
Emission trading regimes and incentives to participate in international climate agreements
Authors: Buchner Barbara , Carraro Carlo
Published: September 2004

This paper analyses whether different emission trading regimes provide different incentives to participate in a cooperative climate agreement. Different incentive structures are discussed for those countries, namely the US, Russia and China, that are most important in the climate negotiation process. Our analysis confirms the conjecture that, by appropriately designing the emission trading regime, it is possible to enhance the incentives to participate in a climate agreement. Therefore, participation and optimal policy should be jointly analysed. Moreover, our results show that the US, Russia and China have different most preferred climate coalitions and therefore adopt conflicting negotiation strategies. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
Usefulness of fluorine‐18 fluorodeoxyglucose positron emission tomography in patients with a residual structural abnormality after definitive treatment for squamous cell carcinoma of the head and neck
Authors: Ware Robert E. , Matthews Jane P. , Hicks Rodney J. , Porceddu Sandro , Hogg Annette , Rischin Danny , Corry June , Peters Lester J.
Published: September 2004

Background.

Residual structural abnormalities after definitive treatment of head and neck squamous cell carcinoma (HNSCC) are common and pose difficult management problems. The usefulness of fluorine‐18 fluorodeoxyglucose positron emission tomography (FDG PET) to supplement conventional evaluation with clinical and standard radiologic examination (CE) in such patients was assessed.

Methods.

Fifty‐three eligible patients were identified with residual structural abnormalities on CE. True disease extent could be validated in 46 patients. Patients had a median potential follow‐up of 55 months (range, 41–75 months) from the date of PET scan to the analysis closeout date.

Results.

PET had better diagnostic accuracy than CE (p = .0002) and induced management change in 21 patients (40%; 95% confidence interval [CI], 26%–54%), including avoidance of unnecessary planned surgery in 14 patients with negative PET. Appropriate management change was confirmed in 19 (95%) of 20 evaluable cases. Disease presence and extent assessment by PET were significant predictors of survival (p < .0001), whereas the extent of disease determined by CE was not.

Conclusion.

PET added significantly to the value of CE in restaging disease in patients with structural abnormalities after definitive treatment of HNSCC. Management decisions based on PET were appropriate in most patients. © 2004 Wiley Periodicals, Inc. Head Neck 26: 1008–1017, 2004
Dynamic mechanical analysis of viscoelastic functions in packable composite resins measured by torsional resonance
Authors: Papadogiannis Y. , Helvatjoglu‐Antoniades M. , Lakes R. S.
Published: September 2004

The objective of this study was to evaluate the viscoelastic functions of packable composite resins with the use of a resonant dynamic mechanical analysis technique in torsion. The materials tested were: Alert (Jeneric Pentron), Prodigy Condensable (Kerr Corporation), Surefil (Dentsply DeTrey), and Filtek P60 (3M Dental Products). Dynamic torsional loading was conducted in the frequency range from 1 to 150 Hz. Composite specimens were tested after storage in water at 37°C for 24 h. One group was thermal cycled for 3000 cycles with temperatures of 5–37–50°C. Measurements were taken at 21°C dry, and at 37 and 50°C wet. Storage modulus, loss tangent, and other viscoelastic parameters were determined from the amplitude/frequency curves. Data for storage modulus and loss tangent of the materials were analyzed by means of ANOVA and Student‐Newman‐Keuls test (α = 0.05). It was found that there were significant differences (P < 0.001) in storage modulus and loss tangent among the packable composites tested. The highest value of storage modulus, in measurements at 21°C, was for Alert (10.3 GPa), followed by Filtek P60 (9.31 GPa), Surefil (7.29 GPa), and Prodigy Condensable (6.74 GPa). There were significant differences (P < 0.001) in storage modulus and loss tangent among the four different conditions tested. Storage modulus decreased at higher temperatures, whereas the loss tangent increased. Thermal cycling increased storage modulus and decreased loss tangent. The results showed that both monomer and filler composition and filler loading of the materials significantly affect their viscoelastic functions, and the mechanical properties of the products cannot be characterized from the packability alone. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 327–335, 2004