bluuebunny/crossref_metadata_2025 huggingface dataset:
Super-extremal processes and the argmax process
Authors: Resnick Sidney I. , Roy Rishin
Published: April 2006

In this paper, we develop the probabilistic foundations of the dynamic continuous choice problem. The underlying choice set is a compact metric space E such as the unit interval or the unit square. At each time point t, utilities for alternatives are given by a random function . To achieve a model of dynamic continuous choice, the theory of classical vector-valued extremal processes is extended to super-extremal processesY= {Yt, t > 0}. At any t > 0, Yt is a random upper semicontinuous function on a locally compact, separable, metric space E. General path properties of Y are discussed and it is shown that Y is Markov with state-space US(E). For each t > 0, Yt is associated.

For a compact metric E, we consider the argmax process M = {Mt, t > 0}, where . In the dynamic continuous choice application, the argmax process M represents the evolution of the set of random utility maximizing alternatives. M is a closed set-valued random process, and its path properties are investigated.
Principles for modelling financial markets
Authors: Platen Eckhard , Rebolledo Rolando
Published: April 2006

The paper introduces an approach focused towards the modelling of dynamics of financial markets. It is based on the three principles of market clearing, exclusion of instantaneous arbitrage and minimization of increase of arbitrage information. The last principle is equivalent to the minimization of the difference between the risk neutral and the real world probability measures. The application of these principles allows us to identify various market parameters, e.g. the risk-free rate of return. The approach is demonstrated on a simple financial market model, for which the dynamics of a virtual risk-free rate of return can be explicitly computed.
A note on the point processes of rare events
Authors: Hüsler J. , Schmidt M.
Published: April 2006

We discuss the limits of point processes which are generated by a triangular array of rare events. Such point processes are motivated by the exceedances of a high boundary by a random sequence since exceedances are rare events in this case. This application relates the problem to extreme value theory from where the method is used to treat the asymptotic approximation of these point processes. The presented general approach extends, unifies and clarifies some of the various conditions used in the extreme value theory.
Stochastic comparisons for fork-join queues with exponential processing times
Authors: Frostig Esther , Lehtonen Tapani
Published: April 2006

Consider a fork-join queue, where each job upon arrival splits into k tasks and each joins a separate queue that is attended by a single server. Service times are independent, exponentially distributed random variables. Server i works at rate , where μ is constant. We prove that the departure process becomes stochastically faster as the service rates become more homogeneous in the sense of stochastic majorization. Consequently, when all k servers work with equal rates the departure process is stochastically maximized.
A perpetuity and the M/M/∞ ranked server system
Authors: Preater J.
Published: April 2006

We relate the equilibrium size of an M/M/8 type queue having an intermittent arrival stream to a perpetuity, the solution of a random difference equation. One consequence is a classical result for ranked server systems, previously obtained by generating function methods.
Disulfide Conjugation of Peptides to Oligonucleotides and Their Analogs
Authors: Turner John J. , Williams Donna , Owen David , Gait Michael J.
Published: April 2006

Peptide conjugation of oligonucleotides and their analogs is being studied widely towards improving the delivery of oligonucleotides into cells. Amongst the many possible routes of conjugation, the disulfide linkage has proved to be the most popular. This reversible linkage may have advantages for cell delivery, since it is likely to be cleaved within cells, thus releasing the oligonucleotide cargo. It is straightforward to introduce thiol functionalities into both oligonucleotide and peptide components suitable for disulfide conjugation. However, severe difficulties have been encountered in carrying out conjugations between highly cationic peptides and negatively charged oligonucleotides because of aggregation and precipitation. Presented here are reliable protocols for disulfide conjugation that have been verified for both cationic and hydrophobic peptides as well as oligonucleotides containing deoxyribonucleosides, ribonucleosides, 2′‐O‐methylribonucleosides, locked nucleic acid (LNA) units, as well as phosphorothioate backbones. Also presented are reliable protocols for disulfide conjugation of peptide nucleic acids (PNAs) with peptides.
Using the Structure‐Function Linkage Database to Characterize Functional Domains in Enzymes
Authors: Brown Shoshana , Babbitt Patricia
Published: April 2006

The Structure‐Function Linkage Database (SFLD; http://sfld.rbvi.ucsf.edu/) is a Web‐accessible database designed to link enzyme sequence, structure, and functional information. This unit describes the protocols by which a user may query the database to predict the function of newly sequenced enzymes and to correct misannotated functional assignments for enzymes currently in public databases. It is especially useful in helping a user discriminate functional capabilities of a sequence that is only distantly related to characterized sequences in publicly available databases.
Using Pharmabase to Perform Pharmacological Analyses of Cell Function
Authors: Smith Peter J. S. , Remsen David
Published: April 2006

Pharmabase is designed to form a bridge between the molecular dimension of cell transport processes and the functional manipulation of the protein players. It has as its emphasis membrane transport and related pharmacology. Several search and navigation options are available, including membrane transport, disease, and a graphic interface arranged by pathway and cell type. The level of entry to the database can be tailored to the investigator's level of expertise. The final product of Pharmabase is a Compound Record detailing the use and targets of individual compounds. Navigation routes generally fall into hierarchical keys and are cross‐referenced. Pharmabase encourages input from its user community. It is maintained by the BioCurrents Research Center, an NIH resource funded through the National Center for Research Resources (NCRR).
Do surrogates describe patterns in marine macroalgal diversity in the Recherche Archipelago, temperate Australia?
Authors: Goldberg Nisse A. , Kendrick Gary A. , Walker Diana I.
Published: April 2006

Surrogates aim to predict species diversity and to minimize sampling effort. Here the value of surrogates for marine macroalgae is tested.

Higher taxonomic levels and dominant taxa were evaluated as surrogates for detecting patterns in macroalgal species diversity (derived from species‐level biomass data) in the Recherche Archipelago, Western Australia.

Data were stratified by two island groups (inshore and offshore), three depth intervals (<10 m, 10–20 m, >20 m), and two exposures to wave energy. Correlations between similarity matrices from surrogate and species diversity data matrices were analysed using a modified Spearman rank correlation (rs). The ability of surrogates to detect differences between exposures to wave energy was also investigated using analysis of similarity. Species diversity data were aggregated to higher taxonomic levels and were either fourth‐root or presence/absence (richness) transformed.

Species richness was the most consistent surrogate (rs‐values>0.69, P=0.001). Genus‐level richness was also strongly correlated to species diversity in the Recherche Archipelago, except in depths <10 m where patterns in diversity were characterized by species turnover.

At offshore islands in depths 10–20 m and >20 m, family‐ and order‐level biomass data were suitable surrogates owing to the abundance of Alariaceae (Order Laminariales) represented by a single genus and species. Surrogates using biomass data from the orders Laminariales, Ceramiales, Dictyotales and Fucales were also successful at offshore islands in middle to deeper depths.

At inshore islands in depths 10–20 m and >20 m, genera from the orders Gigartinales, Fucales and Ceramiales were strongly correlated to species biomass data.

Surrogates, like species richness, that were strongly correlated to species biomass data were also able to distinguish between exposures to wave energy, based on analysis of similarity tests.

Sampling effort would be reduced if collecting richness data in species‐rich macroalgal assemblages such as those found in temperate Australia.

Copyright © 2006 John Wiley & Sons, Ltd.
Altered thymocyte migration during experimental acute Trypanosoma cruzi infection: combined role of fibronectin and the chemokines CXCL12 and CCL4
Authors: Mendes‐da‐Cruz Daniella Arêas , Silva João Santana , Cotta‐de‐Almeida Vinícius , Savino Wilson
Published: April 2006

We previously showed migration disturbances in the thymus during experimental infection with Trypanosoma cruzi, the causative agent of Chagas disease. These changes were related to the enhanced expression of extracellular matrix ligands and receptors, leading to the escape of immature cells to the periphery. Here, we analyzed the expression and role of selected chemokines (CXCL12 and CCL4) and their receptors (CXCR4 and CCR5) in regulating thymocyte migration in conjunction with extracellular matrix during acute T. cruzi infection. We found increased chemokine deposition in the thymus of infected mice when compared to controls, accompanied by enhanced co‐localization with fibronectin as well as up‐regulated surface expression of CXCR4 and CCR5 in thymocytes. We also noticed altered thymocyte migration towards the chemokines analyzed. Such an enhancement was even more prominent when fibronectin was added as a haptotatic stimulus in combination with a given chemokine. Our findings suggest that thymocyte migration results from a combined action of chemokines and extracellular matrix (ECM), which can be altered during pathological conditions such as T. cruzi infection, and may be at the origin of the changes in the T cell repertoire seen in this pathological process.
Toward high sequence coverage of proteins in human breast cancer cells using on‐line monolith‐based HPLC‐ESI‐TOF MS compared to CE MS
Authors: Yoo Chul , Pal Manoj , Miller Fred R. , Barder Timothy J. , Huber Christian , Lubman David M.
Published: April 2006

A method is developed toward high sequence coverage of proteins isolated from human breast cancer MCF10 cell lines using a 2‐D liquid separations. Monolithic‐capillary columns prepared by copolymerizing styrene with divinylbenzene are used to achieve high‐resolution separation of peptides from protein digests. This separation is performed with minimal sample preparation directly from the 2‐D liquid fractionation of the cell lysate. The monolithic column separation is directly interfaced to ESI‐TOF MS to obtain a peptide map. The protein digests were also analyzed by MALDI‐TOF MS and an accurate Mr of the intact protein was obtained using an HPLC‐ESI‐TOF MS. The result is that these techniques provide complementary information where nearly complete sequence coverage of the protein is obtained and can be compared to the experimental Mr value. The high sequence coverage provides information on isoforms and other post‐translational modifications that would not be available from methods that result in low sequence coverage. The results from the use of monolithic columns are compared to that obtained by CE‐MS. The monolithic column separations provide a rugged and highly reproducible method for separating protein digests prior to MS analysis and is suited to confidently identify biomarkers associated with cancer progression.
Analysis of choline and atropine in hairy root cultures of Cannabis sativa L. by capillary electrophoresis‐electrospray mass spectrometry
Authors: Wahby Imane , Arráez‐Román David , Segura‐Carretero Antonio , Ligero Francisco , Caba Juan Manuel , Fernández‐Gutiérrez Alberto
Published: April 2006

We describe a capillary zone electrophoresis method coupled to electrospray ionization (ion trap) mass spectrometry (CZE‐ESI‐MS) for the identification and determination of choline and atropine compounds in hairy root extracts from Cannabis sativa L. Fused‐silica capillary and an alkaline solution of 20 mM ammonium acetate at pH 8.5 are used being the most suitable for the analysis of choline and atropine in less than 10 min. Under the optimized conditions, including CE and ESI‐MS parameters, the method resolved both compounds with very high sensitivity. The system exhibited good linear response in the range of 25–500 mg/L and 500–1000 μg/L for choline and atropine, respectively. The detection limit of choline was 18 mg/L and 320 μg/L for atropine. Finally, the developed method was applied to the analysis of these compounds in transgenic root cultures of Cannabis sativa L.
Laser‐deposited Ti‐Nb‐Zr‐Ta orthopedic alloys
Authors: Banerjee R. , Nag S. , Samuel S. , Fraser H.L.
Published: April 2006

The complex quaternary Ti‐35Nb‐7Zr‐5Ta orthopedic alloy has been successfully deposited from a powder feedstock consisting of a blend of elemental titanium, niobium, zirconium, and tantalum powders, using the laser engineered net‐shaping (LENS™) process. In the as laser‐deposited form, these alloys exhibit a substantially higher tensile strength as compared with more conventionally processed counterparts of similar composition, while maintaining excellent ductility and a low modulus. Furthermore, the as‐deposited alloys appear to exhibit a <001> texture, with a substantially large number of grains of the β phase aligning one of their <001> axes nearly normal to the substrate or parallel to the growth direction. The microstructure of the as‐deposited as well as tensile‐tested alloys have been characterized in detail using scanning electron microscopy (SEM), orientation microscopy (OM), and transmission electron microscopy (TEM). Formation of a high density of shear bands, possibly arising from slip localization due to precipitates of the ω phase in the β matrix, is clearly evident in the tensile‐tested sample. The enhanced tensile strength and low modulus in these laser‐deposited alloys coupled with the ability to form near‐net shape components makes LENS an attractive processing technology for orthopedic implants. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Comparison of conventional and highly crosslinked UHMWPE patellae evaluated by a new in vitro patellofemoral joint simulator
Authors: Burroughs Brian R. , Rubash Harry E. , Estok Daniel , Jasty Murali , Krevolin Janet , Muratoglu Orhun K.
Published: April 2006

A series of in vitro patella damage tests were developed using a knee simulator to investigate electron‐beam‐irradiated and ‐melted ultra‐high molecular weight polyethylene and conventional ultra‐high molecular weight polyethylene at the patellofemoral articulation. Three different simulations were created: (i) normal gait with optimal component alignment, (ii) stair climbing with optimal component alignment, and (iii) stair climbing with 4° of femoral component internal rotation to simulate a component malalignment condition. In the last two simulations, all patellae were artificially aged. In normal gait, the unaged conventional and highly crosslinked patellae demonstrated similar behavior. In both stair climbing tests, unlike the aged highly crosslinked components, the aged conventional patellae developed cracks by 2 million cycles. These results demonstrate the potential advantage of highly crosslinked polyethylene for the patella. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006
Performance of anaerobic reactors at low organic load subjected to sudden change in feed substrate types
Authors: Nain Mohd. Zulquer , Jawed Mohammad
Published: April 2006

Many researchers have studied the impact of stress/shock imposed due to change in environmental and operational conditions using the same feed substrate type on performances of anaerobic reactors. However, limited reports are available on performance of anaerobic reactors subjected to shock/stress conditions due to sudden change in feed substrate and hence the present work is directed towards this end. Three suspended growth batch reactors (R1, R2 and R3) were started up and operated at an organic loading rate of 1.40 kg COD m−3 d−1 with simple soluble feed substrate (i.e. jaggery) to obtain similar performance before application of shock. The shock was applied by suddenly changing feed substrate to reactors R2 (from jaggery to cerelac—a complex suspended type feed) and R3 (from jaggery to neutralized acetic acid) while keeping reactor R1 as the control. The immediate impact of sudden change in feed substrate was observed in reactor R3, which showed reduced gas production rate, while no visible impact on reactor R2 was observed for gas production rate. The performance of reactor R2 deteriorated marginally in respect of biogas production during the shock period. However, performance of reactor R3 deteriorated very much during the shock period: gas production ceased completely and indicated build‐up of high levels of volatile fatty acid. Lastly, reactors R2 and R3 were restored to jaggery feed substrate. Reactor R3 responded by producing biogas along with the other two reactors. It was observed that all three reactors started giving steady performance within 2 weeks of operation, which was similar to pre‐shock conditions. This study indicated that extreme caution is needed when there is a possibility of sudden stress/shock conditions due to complete change in feed substrate, even though all other operational and environmental parameters are planned to be maintained at pre‐shock conditions. Copyright © 2006 Society of Chemical Industry
Continuous bioremediation of phenol‐polluted air in an external loop airlift bioreactor with a packed bed
Authors: Nikakhtari Hossein , Hill Gordon A
Published: April 2006

An external loop airlift bioreactor with a small amount (99% porosity) of stainless steel mesh packing inserted in the riser section was used for bioremediation of a phenol‐polluted air stream. The packing enhanced volatile organic chemical and oxygen mass transfer rates and provided a large surface area for cell immobilization. Using a pure strain of Pseudomonas putida, fed‐batch and continuous runs at three different dilution rates were completed with phenol in the polluted air as the only source of growth substrate. 100% phenol removal was achieved at phenol loading rates up to 33 120 mg h−1 m−3 using only one‐third of the column, superior to any previously reported biodegradation rates of phenol‐polluted air with 100% efficiency. A mathematical model has been developed and is shown to accurately predict the transient and steady‐state data. Copyright © 2006 Society of Chemical Industry
The brand positioning and image of a religious organisation: an empirical analysis
Authors: Abreu Madalena
Published: April 2006

Brand positioning and image development are important topics for any religious organisation wishing to provide an effective service to the public. It follows that in a world with increasing religious options, the position strategy decision and the brand position statement are essential aspects of a fully responsive religious organisation. To investigate these issues the author presents the findings of a study that compared the brand position of a Catholic shrine in Portugal, i.e. the sanctuary of Fátima, with the image of the shrine as perceived by its pilgrims. The paper also attempts to offer a definition of religious marketing and explores some possible antecedents of effective brand positioning within this particular field.

Copyright © 2006 John Wiley & Sons, Ltd.
Outpatient drug safety: new steps in an old direction
Authors: Budnitz Daniel S. , Layde Peter M.
Published: April 2006

Iatrogenic injury from adverse drug events (ADEs) is a common and often preventable problem in modern medical practice. Attention to this problem has focused on the inpatient hospital setting and healthcare professionals. However, most medication is prescribed and used outside of hospitals and is managed by patients or lay caregivers in homes or workplaces. To address the public health problem of outpatient drug safety, interventions to prevent adverse events must recognize the central role of the patient in medication management and environmental factors specific to the outpatient setting. Lessons and techniques from the field of injury prevention should guide the development and implementation of safety interventions. First, Haddon's phase‐factor matrix can be used to help conceptualize outpatient drug safety interventions. Second, interventions to improve outpatient drug safety should be patient‐centered and extend beyond patient education to include engineering innovations and enforcement strategies. Third, the sustainability of active versus passive interventions should be considered when choosing safety interventions. Published in 2006 by John Wiley & Sons, Ltd.
Possible dysregulation of chaperon and metabolic proteins in cystic fibrosis bronchial tissue
Authors: Frischer Thomas , Myung Jae‐Kyung , Maurer Gerald , Eichler Irmgard , Szepfalusi Zsolt , Lubec Gert
Published: April 2006

Cystic fibrosis (CF) is an autosomal recessive disease due to mutations of the CF transmembrane conductance regulator gene. A systematic approach to generate a protein expressional pattern in CF bronchial tissue has not been performed so far. It was the aim of this hypothesis‐generating study to construct differential proteomes of bronchial biopsies in controls (n = 8) and CF patients (n = 9). Biopsies (pools of threeperpatient) were taken; proteins were extracted and run on 2‐DE with subsequent in‐gel digestion and mass spectrometrical identification and quantification of proteins using specific software. Three hundred sixty‐six protein spots were identified and compared between groups. Following an approach for multiple testing correction, the chaperone 75 kDa glucose‐regulated protein and ubiquinol–cytochrome c reductase complex core protein I and one form of nidogen, a pseudogene of aconitase 2, were increased in CF (p < 0.005). Aberrant protein levels may reflect molecular changes of CF as well as CF‐linked inflammation, infection and cellular stress response.
Identification of breast cancer metastasis‐associated proteins in an isogenic tumor metastasis model using two‐dimensional gel electrophoresis and liquid chromatography‐ion trap‐mass spectrometry
Authors: Li Da‐Qiang , Wang Lei , Fei Fei , Hou Yi‐Feng , Luo Jian‐Min , Wei‐Chen  , Zeng Rong , Wu Jiong , Lu Jin‐Song , Di Gen‐Hong , Ou Zhou‐Luo , Xia Qi‐Chang , Shen Zhen‐Zhou , Shao Zhi‐Min
Published: April 2006

To better understand the molecular mechanisms underlying breast cancer metastasis and search for potential markers for metastatic progression, we have developed a highly metastatic variant of human MDA‐MB‐435 breast cancer cell line through in vivo stepwise selection of pulmonary metastatic cells caused by parental MDA‐MB‐435 cells in the athymic mice. Comparative proteomic analysis using 2‐DE and LC‐IT‐MS revealed that 102 protein spots were reproducibly altered more than three‐fold between the selected variant and its parental counterpart. Eleven differentially expressed protein spots were identified with high confidence using SEQUEST with uninterpreted tandem mass raw data. Cathepsin D precursor, peroxiredoxin 6 (PDX6), heat shock protein 27 (HSP27), HSP60, tropomyosin 1 (TPM1), TPM2, TPM3, TPM4, 14‐3‐3 protein epsilon, and tumor protein D54 were up‐regulated in the highly metastatic variant, whereas alpha B‐crystalline (CRAB) was only detected in its parental counterpart. Differential expression was confirmed for four proteins including PDX6, CRAB, TPM4, and HSP60 by real‐time quantitative PCR and Western blotting analysis in our model. Immunohistochemical analysis in 80 breast cancer donors demonstrated a significant association of TPM4 (p = 0.002), HSP60 (p = 0.001), PDX6 (p = 0.002) but not CRAB (p = 0.113) staining with the presence of lymph node metastasis. In addition, TPM4 staining was also associated with clinical stage (p = 0.000), but no significant association was found between TPM4, PDX6, CRAB, and HSP60 expression and tumor size, hormone receptor, and HER‐2 status (p > 0.05). The functional implication of these identified proteins was also discussed. These proteomic data are valuable and informative for understanding breast cancer metastasis and searching for potential markers for metastatic progression.
Pseudomonas putida KT2440 responds specifically to chlorophenoxy herbicides and their initial metabolites
Authors: Benndorf Dirk , Thiersch Markus , Loffhagen Norbert , Kunath Christfried , Harms Hauke
Published: April 2006

Pseudomonas putida KT2440 is often used as a model to investigate toxicity mechanisms and adaptation to hazardous chemicals in bacteria. The objective of this paper was to test the impact of the chlorophenoxy herbicides 2,4‐dichlorophenoxyacetic acid (2,4‐D) and 2‐(2,4‐dichlorophenoxy)propanoic acid (DCPP) and their metabolites 2,4‐dichlorophenol (DCP) and 3,5‐dichlorocatechol (DCC), on protein expression patterns and physiological parameters. Both approaches showed that DCC has a different mode of action and induces different responses than DCPP, 2,4‐D and DCP. DCC was the most toxic compound and was active as an uncoupler of oxidative phosphorylation. It repressed the synthesis of ferric uptake regulator (Fur)‐dependent proteins, e.g. fumarase C and L‐ornithine N5‐oxygenase, which are involved in oxidative stress response and iron uptake. DCPP, 2,4‐D and DCP were less toxic than DCC. They disturbed oxidative phosphorylation to a lesser extent by a yet unknown mechanism. Furthermore, they repressed enzymes of energy‐consuming biosynthetic pathways and induced membrane transporters for organic substrates. A TolC homologue component of multidrug resistance transporters was found to be induced, which is probably involved in the removal of lipophilic compounds from membranes.
QM and QM/MM studies of selectivity in organic and bioorganic chemistry
Authors: Harvey Jeremy N. , Aggarwal Varinder K. , Bathelt Christine M. , Carreón‐Macedo José‐Luis , Gallagher Timothy , Holzmann Nicole , Mulholland Adrian J. , Robiette Raphaël
Published: April 2006

Electronic structure methods are used to explore the origin of selectivity in a number of organic, organometallic and bioorganic processes. Diastereoselectivity in reactions of sulfur and phosphorus ylides is shown to arise during a variety of different elementary steps, and is due to steric and electronic effects. Unusual rearranged products from Heck reaction of o‐bromo biphenyl derivatives are shown to result from an unusual electrophilic addition step. Predicting selectivity in oxidation of aromatic substrates by cytochrome P450 isoforms is a challenging problem, which can be tackled using hybrid QM/MM methods. Differences in the electronic structure of the Compound I active intermediates of different cytochrome P450 isoforms do not appear to be large enough to explain the different selectivity of these different isoforms. Copyright © 2006 John Wiley & Sons, Ltd.
Copolycarbonates of isosorbide and various diols
Authors: Chatti Saber , Kricheldorf Hans R. , Schwarz Gert
Published: April 2006

Isosorbide and equimolar amounts of various diols were polycondensed with diphosgene and pyridine. Bisphenol A, 3,3′‐dimethyl bisphenol A, bisphenol C, 1,3‐bis(4‐hydroxybenzoyloxy)propane, and 1,4‐cyclohexane diol were used as comonomers. The compositions were determined by 1H NMR spectroscopy; the random sequences were characterized by 13C NMR spectroscopy. For the high‐molar‐mass copolycarbonates of bisphenol A, 3,3′‐dimethyl bisphenol A, and bisphenol C, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry proved that the chain growth was mainly limited by cyclization. Copolycarbonates with alternating sequences were obtained by the polycondensation of bisphenol A with isosorbide bischloroformiate or from isosorbide and bisphenol A bischloroformiate. In these cases, large amounts of cyclic oligo‐ and polycarbonates were also formed. The glass‐transition temperatures were determined by differential scanning calorimetry measurements. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3616–3628, 2006
Competitive specific interactions in miscible blends of poly(hydroxyether terephthalate ester) and poly(4‐vinyl pyridine)
Authors: Liu Bingquan , Zhang Weian , Zheng Sixun , Guo Qipeng
Published: April 2006

The miscibility of poly(hydroxyether terephthalate ester) (PHETE) with poly(4‐vinyl pyridine) (P4VP) was established on the basis of thermal analysis. Differential scanning calorimetry showed that each blend displayed a single glass‐transition temperature (Tg), which is intermediate between those of the pure polymers and varies with the composition of blend. TheTg‐composition relationship can be well described with Kwei equation withk= 1 andq= −30.8 (K), suggesting the presence of the intermolecular specific interactions in the blend system. To investigate the intermolecular specific interactions in the blends, the model compounds such as 1,3‐diphenoxy‐2‐propanol, 4‐methyl pyridine, and ethyl benzoate were used to determine the equilibrium constants, according to Coleman and Painter model, to account for the association equilibriums of several structural moieties, using liquid Fourier transform infrared difference spectroscopy. In terms of the difference in the association equilibrium constant, it is proposed that there are the competitive specific interactions in the blends, which were confirmed by means of Fourier transform infrared spectroscopy of the blends. It is observed that upon adding P4VP to the system, the ester carbonyls of PHETE that were H‐bonded with the hydroxyl groups were released because of the formation of the stronger interchain association via the hydrogen bonding between the hydroxyls of PHETE and tertiary nitrogen atoms of P4VP. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1618–1626, 2006
Study of the possibility of realization of a spin valve on the basis of superconductor/ferromagnet multilayers
Authors: Garifullin I. A. , Tikhonov D. A. , Garif'yanov N. N. , Fattakhov M. Z. , Theis‐Bröhl K. , Westerholt K. , Sprungmann D. , Zabel H. , Brucas R. , Hjörvarsson B. , Tagirov L. R.
Published: April 2006

The ways of realization of two different schemes of a spin valve for the superconducting current on the basis of the superconductor/ferromagnet proximity effect are studied. First, we have studied the superconducting proximity effect in the thin film system Fe/Cr/V/Cr/Fe where the Cr layers play the role of screening layers between the superconducting V‐layer and the strongly pair breaking Fe‐layers. Besides the new results concerning the magnetic phase transitions in the Cr layers we found the upper limit of the thickness of the screening Cr layers for operation a spin valve based on the Fe/V/Fe trilayer. Second, we studied the superconducting spin valve effect of a V‐layer coupled to an antiferromagnetic [Fe/V]‐superlattice. The parallel upper critical magnetic field exhibits an anomalous temperature dependence up to the ferromagnetic saturation field of the superlattice, indicating that the superconducting transition temperature T c decreases when rotating the relative magnetization directions of the sublattice from antiparallel to parallel. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Investigating the structural properties of amyloid‐like fibrils formed in vitro from β2‐microglobulin using limited proteolysis and electrospray ionisation mass spectrometry
Authors: Myers Sarah L. , Thomson Neil H. , Radford Sheena E. , Ashcroft Alison E.
Published: April 2006

The protein β2‐microglobulin (β2m) aggregates to form classical amyloid fibrils in patients undergoing long‐term haemodialysis. Amyloid‐like fibrils with a cross‐β fold can also be formed from wild‐type β2m under acidic conditions in vitro. The morphology of such fibrils depends critically on the conditions used: incubation of β2m in low ionic strength buffers at pH 2.5 results in the formation of long (µm), straight fibrils while, at pH 3.6, short (<500 nm) fibrils form. At higher ionic strengths (0.2–0.4 M) at pH 1.5–3.6, the fibrils have a distinct curved and nodular morphology. To determine the conformational properties of β2m within in vitro fibrils of different morphologies, limited proteolysis of each fibril type using pepsin was performed and the resulting peptide fragments identified by tandem mass spectrometry. For comparison, the proteolytic degradation patterns of monomeric β2m and seven synthetic peptides spanning the entire sequence of the intact protein were similarly analysed. The results show that fibrils with different morphologies result in distinct digestion patterns. While the curved, worm‐like fibrils are relatively weakly protected from proteolysis, the long, straight fibrils formed at pH 2.5 at low ionic strength show only a single cut‐site at Val9, demonstrating that substantial refolding of the initially acid‐denatured and unprotected state of β2m occurs during assembly. The data demonstrate that the organisation of the polypeptide chain in fibrils with different morphological features differs considerably, despite the fact that the fibrils possess a common cross‐β architecture. Copyright © 2006 John Wiley & Sons, Ltd.
Signal improvement in elemental analyzer/continuous flow isotope ratio mass spectrometry for samples with low sulfur contents using a pre‐concentration technique for on‐line concentration adjustment
Authors: Fritzsche Florian , Tichomirowa Marion
Published: April 2006

Elemental analyzer/continuous flow isotope ratio mass spectrometry (EA/CF‐IRMS) has become a standard procedure for the determination of δ34S values. Common procedures are, however, frequently less than satisfactory for organic as well as for mineral samples with very low concentrations of sulfur (<2000 ppm). Here we present a method which employs cold trapping of SO2 to adjust the gas concentration for subsequent isotope signature determination. Analytical accuracy is comparable with common EA/CF‐IRMS analysis without trapping, showing a precision of better than ±0.4‰ in δ34S (1 SD). The virtual absence of memory effects was established by analyzing adjacent samples exhibiting a large difference in δ34S and by prolonged freezing of the carrier gas, yielding virtually no S concentration peak. The method was tested using less than 15% (6 µg) of the S required for a conventional isotope analysis at comparable signal intensity. Even smaller samples can be analyzed with high precision. This facilitates the on‐line δ34S determination in small biological and mineral samples, minimizing matrix effects in various materials including sandstone, soil, and plant samples. Copyright © 2006 John Wiley & Sons, Ltd.
Multivehicle path planning for nonline‐of‐sight communication
Authors: Schouwenaars Tom , Stubbs Andrew , Paduano James , Feron Eric
Published: April 2006

This paper presents a mathematical programming approach to online connectivity‐constrained trajectory planning for autonomous helicopters through cluttered environments. A lead vehicle must execute a certain mission whereby wireless line‐of‐sight communication to its ground station is lost. Relay helicopters are therefore introduced that must position themselves in such a way that indirect line‐of‐sight connectivity between the leader and the ground station is always maintained. This requires coordinated multivehicle trajectory optimization which is tackled online using centralized and distributed receding horizon planning strategies. The problem is formulated as a mixed‐integer linear program that accounts for the vehicle dynamics, obstacle and collision avoidance, and connectivity constraints. A centralized two‐helicopter mission is described for which simulation, hardware in the loop, and real‐time flight‐test results that show the online adaptability of the approach are presented. Simulations of distributed scenarios are given as well. © 2006 Wiley Periodicals, Inc.
Laser‐based, high repetition rate, ultrafast X‐ray source
Authors: Kutzner Jörg , Witte Henrik , Silies Martin , Haarlammert Thorben , Hüve Jana , Tsilimis Grigorios , Uschmann Ingo , Förster Eckhart , Zacharias Helmut
Published: April 2006

A compact, ultrashort, laser‐based hard X‐ray source particularly suited for high repetition rate laser systems (≥1 kHz) is presented. X rays in the keV energy range are generated efficiently with 30 fs laser pulses on different tape targets containing chromium and iron. Spectroscopic investigations showed that for the chromium as well as for the iron tapes, strong Kα and Kβ emission were observed in addition to a weak bremsstrahlung continuum. These tape targets are especially suited for applications in a transmission geometry, which provides significant advantages. The operation of the tape target was studied with repetition rates up to 10 kHz. With input pulses of 0.5 mJ and modest intensities in the low 1015 W/cm2 range, X‐ray Kα photon fluxes exceeding 6 × 109 photons/s were achieved, yielding conversion efficiencies of ηKα > 10−6. With a toroidally bent crystal the generated radiation was monochromatized and focused to a 85‐µm diameter spot demonstrating the ability of the source to act as a X‐ray point source, a pre‐requisite for an application in X‐ray microscopy. Copyright © 2006 John Wiley & Sons, Ltd.
Pool–dam structure based microfluidic devices for filtering tumor cells from blood mixtures
Authors: Chen Zaozao , Zhang Shengyou , Tang Zuming , Xiao Pengfeng , Guo Xiaoying , Lu Zuhong
Published: April 2006

In this paper, a microfilter device with a series of pool and dam structures was designed and fabricated. To evaluate the efficiency of the filter, physical models were established to describe the behaviors of different kind of cells in the microfilter device. In our physical model, both the physical size effect and the deformability of cells are considered. As the deformability of a cell depends largely on its excess surface area index (ESI), the ESI of the tumor SPC‐A‐1 cells was measured and found to be as 61.7–81%. From our measurements on red blood cells (RBCs) (44%) and white blood cells (WBCs) (84–137%), we have calculated the ultimate width of the dam gap structure to prohibit RBCs, WBCs, and tumor cells to be around 1.8 µm, 1.0–1.6 µm, and 3.7–4.4 µm, respectively. The experimental results showed that tumor cells (SPC‐A‐1) were successfully sorted from cell mixtures by the pool–dam structure filter under a pressure of 200 mm H2O, and that the separation efficiency reached 99.9%. Both theoretical and experimental analyses provided positive evidence for the physical isolation of cancer cells directly from the blood in real‐time through microfluidic structures. Copyright © 2006 John Wiley & Sons, Ltd.
Do different welfare states engender different policy preferences? Opinions on pension reforms in Eastern and Western Europe
Authors: VELLADICS KATALIN , HENKENS KÈNE , VAN DALEN HENDRIK P.
Published: April 2006

This article examines whether the different welfare states of the European Union member states engender different policy preferences and attitudes among the population. More specifically, it investigates variations in attitudes towards population ageing and pension reforms, and variations in people's retirement age preferences and expectations. It is shown that despite the different cultures and welfare traditions in the old and new member states, there are commonalities in people's value orientations and views about population ageing, not least that the vast majority are pessimistic about the consequences. In both Eastern and Western Europe, the most popular options for pensions reform are to raise taxes and to extend working life, and few favour reducing pension benefits. Despite these similarities, there are also marked attitudinal differences. Eastern Europeans rely more on their children for old-age care and are much more in favour of a pension structure in which benefits depend on the number of children. On personal expectations and preferences for retirement, it is shown that both Eastern and Western Europeans expect to retire from the labour market at an older age than the current actual retirement age.
Older people's views on how to finance increasing health-care costs
Authors: WERNTOFT ELISABET , RAHM HALLBERG INGALILL , ELMSTÅHL SÖLVE , EDBERG ANNA-KARIN
Published: April 2006

The aims of this paper are to investigate both older people's views about ways in which to finance health-care costs and their willingness to pay for treatment themselves, along with variations in these views by age and gender. The data are from the Good Ageing in Skåne (GAS) prospective longitudinal cohort study in Sweden, which involved medical examinations and a survey of living arrangements and socio-economic conditions. For the analysis reported in this paper, 930 GAS respondents aged 60–93 years were invited to participate in an additional structured interview, and 902 (97%) accepted. The sample was divided into the ‘young-old’ (aged 60–72 years), ‘old-old’ (78–84 years) and ‘oldest-old’ (87–93 years). It was found that the participants recommended increasing health-care funding by higher taxes and that they were willing to pay themselves for specific treatments, e.g. cosmetic surgery and medication to combat impotence and obesity. Many were also willing to pay privately for cataract surgery, to shorten the wait, although the respondent's financial circumstances associated with this willingness. Significantly more men than women, and of the ‘young-old’ than of the other two age groups, would pay for cataract surgery. The views of people aged 85 or more years differed from those of the young-old, e.g. significantly fewer believed that older people's health care received too little resource. Views about how to finance health care thus differed among the age groups and between men and women.
A multidimensional scale for the measurement of agreement with age stereotypes and the salience of age in social interaction
Authors: KRUSE ANDREAS , SCHMITT ERIC
Published: April 2006

This paper presents a new scale for the assessment of the salience of age in social interaction and of levels of agreement with four age stereotypical assertions, about the characteristics of people in the ‘third age’ and the ‘fourth age’, about older people's social roles and social participation, and about the problems for society produced by population ageing. The scale was constructed by testing the agreement of a national sample of 804 German respondents aged 41–84 years with over 60 item-statements in two pilot studies. The final scale has 24 items, and was tested using a stratified sample of 1,275 subjects aged 40–75 years. Five postulated subscales were confirmed using principal components analysis: ‘age salience’ in social interaction, old age as a time of ‘developmental gains and potentials of development’, old age as a time of ‘developmental losses and risks of development’, ‘the social downgrading of older people’, and believing that ‘older people are a burden on society’. For age stereotypes and age salience, no significant sex differences were found, but those aged 58–64 years held more optimistic views about old age and population ageing than both the younger and the older age groups (with no differences between the latter). Moreover, age stereotypes and age salience varied by several social-economic variables, particularly occupational status, the rate of unemployment in the region of residence, and being resident in the eastern or western part of Germany. No significant interactions between age group and sex were found for any of the five subscales.
Suicidal Behavior by Burns Among Adolescents in Kurdistan, Iran
Authors: Groohi Bahram , MacKay Rossignol Annette , Perez Barrero Sergio , Alaghehbandan Reza
Published: April 2006

The aim of this study was to identify the epidemiologic features and current etiological factors of suicidal behavior by burns among adolescents in Kurdistan, Iran. A prospective population-based study was carried out on patients with suicidal behaviors by burns requiring hospitalization among adolescents during 2000-2001 in Kurdistan, Iran. Sociodemographic and etiological factors were obtained through interviews with each patient or with family, relatives, or friends of the patient. Of 54 hospitalized burn patients aged 13-19 years, 40 (74.1%) patients were hospitalized because of suicidal behaviors by burns (6 males and 34 females). The incidence rate of these behaviors was 18.1 per 100,000 person-years (P-Y) and varied by gender (the incidence rates for females and males were 31.6 and 5.3 per 100,000 P-Y, respectively, p(2) = .000004). Most of the patients (60%) were single, 70% were homemakers, and 60% were either illiterate or had a low level of education. The most common precipitating factors for suicidal behaviors by burns were a quarrel with a family member or relative (47.5%) and marital conflict (17.5%). Most of the patients who were able to communicate regretted their suicidal behaviors (85.7%). Adolescents in Kurdistan are at higher risk of suicidal behaviors by burns compared to adolescents in other areas of Iran. Factors likely to be associated with suicidal behaviors by burns include lower socioeconomic status and family problems. These factors should be investigated further to better elucidate the etiology of these events. It also is necessary to implement prevention programs and strategies known to be effective to reduce the incidence of suicide in this region.
SOPRoxi
Authors: Scocco P. , Frasson A. , Costacurta A. , Pavan L.
Published: April 2006

In Italy, postvention models specifically designed for people surviving the suicide of a loved one are very scarce. The SOPRoxi project was developed to respond to this particular lack. By involving different professional and nonprofessional figures (GPs, mental health professionals, social workers, volunteers, etc), the SOPRoxi project aims to remove the stigma associated with this condition and to offer adequate, multifaceted help to survivors.