bluuebunny/crossref_metadata_2025 huggingface dataset:
Vergleichende Untersuchung raumakustischer Konzepte von Mehrpersonenbüros hinsichtlich Sprachverständlichkeit, Arbeitsgedächtnisleistung und Arbeitsbehaglichkeit durch Hörversuche
Authors: Schröder Elmar , Schanda Ulrich
Published: October 2007

Die vermehrt verwendete Betonkernaktivierung von Stahlbetondecken zur Kühlung und ggf. Beheizung von Mehrpersonenbüros schränkt die sonst übliche Ausführung einer schallabsorbierenden Decke stark ein. Das klassische Bürokonzept mit vollflächig schallabsorbierenden Decken und Stellwänden ist in diesen Fällen nicht mehr anwendbar. Alternativ zu diesem Stellwandkonzept wird in diesen Mehrpersonenbüros zunehmend ein sog. Trennwandkonzept umgesetzt. Dabei wird auf die Schallabsorption an der Decke vollständig verzichtet, aber dafür raumhohe, beidseitig hoch schallabsorbierende Stellwände ausgeführt. Ziel der vorliegenden Untersuchung war es, diese beiden Konzepte für Mehrpersonenbüros auf die Sprachverständlichkeit am Telefon, auf die Konzentrationsfähigkeit und auf die akustische Behaglichkeit am Arbeitsplatz zu vergleichen. Darüber hinaus wurde die Wirkung von tieffrequenten Absorbern untersucht. Zur Beurteilung der Bürokonzepte wurden Hörversuche durchgeführt. Hierzu wurden die raumakustischen Verhältnisse der Bürosituationen in realen Büroräumen mit Hilfe gemessener, binauraler Raumimpulsantworten auralisiert. Zum Vergleich wurde ein Mehrpersonenbüro ohne raumakustische Maßnahmen hinzugezogen. Mit diesem Verfahren sind unterschiedliche Bürosituationen direkt miteinander vergleichbar.
Valuing information and options: an experimental study
Authors: Delquié Philippe
Published: October 2007

Participants in four studies were faced with everyday‐life decision scenarios involving risk, such as purchasing an airline ticket whose price may change. They were asked to state their maximum willingness to pay (WTP) for resolving the uncertainty with either perfect information or an option. The two are strategically equivalent, therefore, should be valued in the same way. Across all experiments, individuals tend to value the option more than the information. In addition, the distributions of responses reveal frequent and gross violations of normative bounds. Contrary to normative predictions, no relationship is found between individuals' valuation of the gamble and their reported WTP for information or option. Furthermore, although participants pay attention to the probabilities of outcomes in valuing the gambles, they ignore the probabilities in valuing uncertainty resolution. Several reasoning heuristics that participants use to come up with a value of information are identified, and it appears that the Information and Option contexts tend to trigger different heuristics. Shift in reference point and regret are consistent with the Information–Option valuation discrepancy. Copyright © 2007 John Wiley & Sons, Ltd.
The recognition heuristic in memory‐based inference: is recognition a non‐compensatory cue?
Authors: Pachur Thorsten , Bröder Arndt , Marewski Julian N.
Published: October 2007

The recognition heuristic makes the strong claim that probabilistic inferences in which a recognized object is compared to an unrecognized one are made solely on the basis of whether the objects are recognized or not, ignoring all other available cues. This claim has been seriously challenged by a number of studies that have shown a clear effect of additional cue knowledge. In most of these studies, either recognition knowledge was acquired during the experiment, and/or additional cues were provided to participants. However, the recognition heuristic is more likely to be a tool for exploiting natural (rather than induced) recognition when inferences have to be made from memory. In our study on natural recognition and inferences from memory, around 85% of the inferences followed recognition information even when participants had learned three cues that contradicted recognition and when some of the contradictory cues were deemed more valid than recognition. Nevertheless, there were strong individual differences in the use of recognition. Whereas about half of the participants chose the recognized object regardless of the number of conflicting cues—suggestive of the hypothesized noncompensatory processing of recognition—the remaining participants were influenced by the additional knowledge. The former group of participants also tended to give higher estimates of recognition's validity. In addition, we found that the use of recognition for an inference may be affected by whether additional cue knowledge has been learned outside or within the experimental setting. Copyright © 2007 John Wiley & Sons, Ltd.
Probing the link between narcissism and gambling: the mediating role of judgment and decision‐making biases
Authors: Lakey Chad E. , Rose Paul , Campbell W. Keith , Goodie Adam S.
Published: October 2007

In this paper, three studies link narcissism to gambling in general, and gambling‐related problems in particular, and the predictive link is shown to be mediated by judgment and decision processes. In Study 1, we demonstrate that narcissism relates to greater self‐reported gambling frequency and gambling‐related monetary expenditures in two samples. We extend these initial findings in Study 2 by showing that narcissism predicts higher reports of gambling‐related pathology, as measured with a DSM‐IV‐based pathological gambling (PG) screen. Finally, we demonstrate in Study 3 that the link between gambling pathology and narcissism is partially mediated by narcissists' overconfidence, heightened risk acceptance, and myopic focus on reward, as measured by participants' behavioral performance on the Georgia Gambling Task (GGT) and Iowa Gambling Task (IGT). Discussion focuses on the empirical validation of the long‐assumed narcissism–gambling link, the decision processes that underlie this link, and relations between narcissists' self‐perceptions and their self‐defeating behavior, especially in risk‐relevant contexts. Copyright © 2007 John Wiley & Sons, Ltd.
Subjective valuation and asymmetrical motivational systems: implications of scope insensitivity for decision making
Authors: Desmeules Rémi , Bechara Antoine , Dubé Laurette
Published: October 2007

Studies using the Iowa Gambling Task have revealed individual differences in performance on the task. In this study, we tested the hypothesis that approach and avoidance motivations influence decision making through the process of subjective valuation. We examined the implications of a high sensitivity to gains or losses from two perspectives which we labeled scalar multiplication and valuation by feeling. Using two versions of the Iowa Gambling Task, we find evidence supporting the view that asymmetry in the systems regulating approach and avoidance leads to systematic biases that translate to differences in performance. Specifically, we find that high sensitivity in the Behavioral Activation System (BAS) translates to valuation by feeling and insensitivity to scope in the domain of gains, while high sensitivity in the Behavioral Inhibition System (BIS) translates to valuation by feeling and insensitivity to scope in the domain of losses. The basis for these findings is discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Getting scarred and winning lotteries: effects of exemplar cuing and statistical format on imagining low‐probability events
Authors: Newell Ben R. , Mitchell Chris J. , Hayes Brett K.
Published: October 2007

Three experiments tested the exemplar cuing and frequency format accounts of how the ‘imaginability’ of low‐probability events is enhanced. The experiments manipulated imaginability by varying the statistics used to describe negative (e.g. being scarred as a result of laser surgery) and positive (e.g. winning a lottery) low‐probability events. The results strongly supported the frequency format account, whereby imaginability is enhanced through the use of frequency formats for conveying statistical information (e.g. 20 out of 2000 as opposed to 0.01%). However, only limited support was found for exemplar cuing (EC) theory. Overall the results support the claim that the imaginability of outcomes plays a key role in thinking about low‐probability events, but question the mechanisms specified by EC theory for mediating such effects. Copyright © 2007 John Wiley & Sons, Ltd.
Ydj1 but not Sis1 stabilizes Hsp70 protein under prolonged stress in vitro
Authors: Tutar Lütfi , Tutar Yusuf
Published: November 2007

Yeast cytosol has two important co‐chaperons; Ydj1 and Sis1. Genetic experiments showed that Ydj1 is not essential for viability; however, cells lacking it grow very poorly at 30°C or unable to grow at extreme temperatures. On the other hand, Sis1 is an essential protein and apparently plays a functional role at assembly or disassembly of protein complexes. Stability experiments revealed that only Ydj1‐protected Hsp70 proteins can hydrolyze ATP under prolonged stress. © 2007 Wiley Periodicals, Inc. Biopolymers 89: 171–174, 2008.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Synergy between erythropoietin and stem cell factor during erythropoiesis can be quantitatively described without co‐signaling effects
Authors: Wang WeiJia , Horner Daniel N. , Chen Wen Li Kelly , Zandstra Peter W. , Audet Julie
Published: October 2007

Synergistic interactions between cytokines underlie developmental processes fundamental to tissue and cellular engineering. However, a mechanistic understanding of the cell‐specific and population‐mediated effects is often lacking. In this study, we have investigated the synergistic generation of erythroid cells in response to erythropoietin (EPO) and stem cell factor (SCF). We have used a quantitative approach to determine if the effects of EPO and SCF superpose in a supra‐additive fashion on the cell proliferation rate or on the death rate, suggesting a contribution from a joint cytokine effect (co‐signaling). Primary mouse bone marrow hematopoietic cells and the stem cell‐like FDCP‐mix cell line were used to investigate the effects of EPO and SCF (individually or in combination) on erythroid output. Carboxyfluorescein diacetate succinimidyl ester (CFSE)‐based cell‐division tracking and mathematical modeling were used to measure cell type‐specific proliferation and death rates. We observed a significant synergistic effect of EPO and SCF on the net generation of benzidine positive (erythroid) colony‐forming cells, CD71++ (early erythroblasts) cells and TER‐119+ (late erythroblasts and reticulocytes) cells in culture. When the observed increases in cell number were decomposed into proliferation and death rates, the cytokines were shown to act independently at different stages of erythroid development; SCF promoted the early proliferation of primitive cells, while EPO primarily promoted the survival of differentiating erythroid progenitor cells. Our analysis demonstrates that EPO and SCF have distinct and predominantly sequential effects on erythroid differentiation. This study emphasizes the necessity to separate proliferation rates from death rates to understand apparent cytokine synergies. Biotechnol. Bioeng. 2008;99: 1261–1272. © 2007 Wiley Periodicals, Inc.
Optimizing normoxic conditions in liver devices using enhanced gel matrices
Authors: Niu Mei , Clemens Mark G. , Coger Robin N.
Published: October 2007

For in vitro liver replacement devices, such as packed bed bioreactors, to maintain the essential functions of the liver, they must at least successfully support hepatocytes, the parenchymal cell of the liver. In vivo, the liver is a major consumer of oxygen. Hence it is unsurprising that the limited transport distance of oxygen (O2) governs the dimensions of the cellular space of engineered devices. Because cellular space capacity directly affects the device's performance, O2 transport is a critical issue in the scale up of bioreactor designs. In the current investigation, the microporosity of the extracellular matrix (ECM) has been modified to further improve O2 transport in packed bed devices beyond that previously reported in the literature. These improvements to the O2 enhancement technique enabled O2 transport distances of 481.7 ± 12.5 µm to be achieved under acellular conditions; and distances of 418.1 ± 6.0 µm to be attained in the presence of 1 million hepatocytes. Both values are significantly greater than the 170 µm baseline attained when 106 hepatocytes are packed within normal non‐enhanced ECM gels. The study's results also illustrate that the O2 enhancement technique has the added benefit of preventing regions of severe hypoxia and hyperoxia from developing within the cellular space. As such, enhanced ECM gels enable packed hepatocytes to maintain better hepatocellular metabolic status than is possible with normal non‐enhanced gels. Biotechnol. Bioeng. 2008;99: 1502–1512. © 2007 Wiley Periodicals, Inc.
Biomass‐supported palladium catalysts on Desulfovibrio desulfuricans and Rhodobacter sphaeroides
Authors: Redwood Mark D. , Deplanche Kevin , Baxter‐Plant Victoria S. , Macaskie Lynne E.
Published: October 2007

A Rhodobacter sphaeroides‐supported dried, ground palladium catalyst (“Rs‐Pd(0)”) was compared with a Desulfovibrio desulfuricans‐supported catalyst (“Dd‐Pd(0)”) and with unsupported palladium metal particles made by reduction under H2 (“Chem‐Pd(0)”). Cell surface‐located clusters of Pd(0) nanoparticles were detected on both D. desulfuricans and R. sphaeroides but the size and location of deposits differed among comparably loaded preparations. These differences may underlie the observation of different activities of Dd‐Pd(0) and Rs‐Pd(0) when compared with respect to their ability to promote hydrogen release from hypophosphite and to catalyze chloride release from chlorinated aromatic compounds. Dd‐Pd(0) was more effective in the reductive dehalogenation of polychlorinated biphenyls (PCBs), whereas Rs‐Pd(0) was more effective in the initial dehalogenation of pentachlorophenol (PCP) although the rate of chloride release from PCP was comparable with both preparations after 2 h. Biotechnol. Bioeng. 2008;99: 1045–1054. © 2007 Wiley Periodicals, Inc.
Stable immobilization of rat hepatocytes as hemispheroids onto collagen‐conjugated poly‐dimethylsiloxane (PDMS) surfaces: Importance of direct oxygenation through PDMS for both formation and function
Authors: Nishikawa Masaki , Yamamoto Takatoki , Kojima Nobuhiko , Kikuo Komori , Fujii Teruo , Sakai Yasuyuki
Published: October 2007

The highly oxygen‐permeable material, poly‐dimethylsiloxane (PDMS), has the potential to be applied to cell culture microdevices, but cell detachment from PDMS has been a major problem. In this study, we demonstrate that a combination of collagen covalently immobilized PDMS and an adequate oxygen supply enables the establishment of a stable, attached spheroid (hemispheroid) culture of rat hepatocytes. The bottom PDMS surfaces were first treated with oxygen plasma, then coupled with aminosilane followed by a photoreactive crosslinker, and they were finally reacted with a collagen solution. X‐ray photoelectron spectroscopy (XPS) and contact angle measurements showed that the covalent immobilization of collagen on the surface occurred only where the crosslinker had been introduced. On the collagen‐conjugated PDMS surface, rat hepatocytes organized themselves into hemispheroids and maintained the viability and a remarkably high albumin production at least for 2 weeks of culture. In contrast, hepatocytes on the other types of PDMS surfaces formed suspended spheroids that had low albumin production. In addition, we showed that blocking the oxygen supply through the bottom PDMS surface inhibited the formation of hemispheroids and the augmentation of hepatocellular function. These results show that appropriate surface modification of PDMS is a promising approach towards the development of liver tissue microdevices. Biotechnol. Bioeng. 2008;99: 1472–1481. © 2007 Wiley Periodicals, Inc.
A novel method for dissolution and stabilization of non‐mulberry silk gland protein fibroin using anionic surfactant sodium dodecyl sulfate
Authors: Mandal Biman B. , Kundu S. C.
Published: October 2007

The importance of silk protein has increased because of its potential use as a natural biopolymer for tissue engineering and biomedical applications. In this report we show a novel and ecofriendly method for dissolution of gland silk protein fibroin. Non‐mulberry silk fibroin from mature fifth instar larvae of Antheraea mylitta was found to be optimally soluble in 1% (w/v) anionic surfactant sodium dodecyl sulfate (SDS). Regenerated fibroin showed distinct bands of approximately 395 and 197 kDa on electrophoresis in non‐reducing and reducing conditions, respectively. Enhanced fibroin dissolution via internalization of hydrophobic amino groups inside a hydrophilic amino acid core in the form of micelles was observed. Prolonged storage stability without gelation of SDS‐extracted fibroin was seen. Atomic force microscopy showed micellar aggregation with mean micellar aggregation size of 8 nm. Circular dichroism spectroscopy revealed predominantly helical conformation due to surfactant addition with internal protein conformational changes as revealed by fluorescence spectroscopic studies. Biotechnol. Bioeng. 2008;99: 1482–1489. © 2007 Wiley Periodicals, Inc.
Sustainable decontamination of an actual‐site aged PCB‐polluted soil through a biosurfactant‐based washing followed by a photocatalytic treatment
Authors: Occulti Fabio , Roda Giovanni Camera , Berselli Sara , Fava Fabio
Published: October 2007

A two phases process consisting of a soya lecithin (SL)‐based soil washing process followed by the photocatalytic treatment of resulting effluents was developed and applied at the laboratory scale in the remediation of an actual‐site soil historically contaminated by 0.65 g/kg of polychlorinated biphenyls (PCBs). Triton X‐100 (TX) was employed in the same process as a control surfactant. SL and TX, both applied as 2.25 g/L aqueous solutions, displayed a comparable ability to remove PCBs from the soil. However, SL solution displayed a lower ecotoxicity, a lower ability to mobilize soil constituents and a higher soil detoxification capacity with respect to the TX one. The photocatalytic treatment resulted in marked depletions (from 50% to 70%) of total organic carbon (TOC) and PCBs initially occurring in the SL and TX contaminated effluents. Despite the ability of SL to adversely affect the rate of TOC and PCB photodegradation, higher PCB depletion and dechlorination yields along with lower increases of ecotoxicity were observed in SL‐containing effluents with respect to the TX ones at the end of 15 days of treatment. The two phases process developed and tested for the first time in this study seems to have the required features to become, after a proper optimization and scale up, a challenging procedure for the sustainable remediation of actual site, poorly biotreatable PCB‐contaminated soils. Biotechnol. Bioeng. 2008;99: 1525–1534. © 2007 Wiley Periodicals, Inc.
Efficient enzymatic acrylation through transesterification at controlled water activity
Authors: Nordblad Mathias , Adlercreutz Patrick
Published: October 2007

Enzymatic acrylation is a process of potentially strong interest to the chemical industry. Direct esterification involving acrylic acid is unfortunately rather slow, with inhibition phenomena appearing at high acid concentrations. In the present study the acrylation of 1‐octanol catalyzed by immobilized Candida antarctica lipase B (Novozym® 435) was shown to be as much as an order of magnitude faster when ethyl acrylate served as the donor of the acrylic group. Water activity is a key parameter for optimizing the rate of ester synthesis. The optimum water activity for the esterification of octanol by acrylic acid was found to be 0.75, that for its esterification by propionic acid to be 0.45 and the transesterification involving ethyl acrylate to be fastest at a water activity of 0.3. The reasons for these differences in optimum water activity are discussed in terms of enzyme specificity, substrate solvation, and mass transfer effects. Biotechnol. Bioeng. 2008;99: 1518–1524. © 2007 Wiley Periodicals, Inc.
Synthesis of 5‐(1,2,3‐Triazol‐4‐yl)‐2′‐deoxyuridines by a Click Chemistry Approach: Stacking of Triazoles in the Major Groove Gives Increased Nucleic Acid Duplex Stability
Authors: Kočalka Petr , Andersen Nicolai K. , Jensen Frank , Nielsen Poul
Published: October 2007

A general protocol for converting alkyl and aryl halides into azides and for converting these in situ into 1,4‐disubstituted triazoles was applied with 5‐ethynyl‐2′‐deoxyuridine. This afforded three modified 2′‐deoxyuridine analogues with either unsubstituted or 1‐phenyl‐/1‐benzyl‐substituted triazoles in their 5‐positions. Modelling demonstrates coplanarity of the two heteroaromatic rings, and UV spectroscopy showed the uracil pKa values to be almost unchanged. The three nucleosides were introduced into nonamer oligonucleotides by phosphoramidite chemistry. The heteroaromatic triazoles became positioned in the major grooves of the short dsDNA and DNA–RNA duplexes. While single modifications led to decreased duplex stability, the stacking of four consecutive modifications led to enhanced duplex stability, especially for DNA–RNA duplexes. The duplex structures were studied by CD spectroscopy and molecular dynamics simulations, which supported the conjecture that the duplex stabilizing effect is due to efficient stacking of the heteroaromatic triazoles.
Development of a Series of Cross‐Linking Agents that Effectively Stabilize α‐Helical Structures in Various Short Peptides
Authors: Fujimoto Kazuhisa , Kajino Masaoki , Inouye Masahiko
Published: October 2007

A series of cross‐linking agents of varying rigidity and length were designed to stabilize helical structures in short peptides and were then synthesized. The sequences of the short peptides employed in this study each include two X residues (X=Dap, Dab, Orn, and Lys) at the i/i+4, i/i+7, or i/i+11 positions to provide the sites for cross‐linking. These peptides were subjected to reaction with the synthesized cross‐linking agents, and the helical content of the resulting cross‐linked peptides were analyzed in detail by circular dichroism. For each of the peptide classes we found combinations with the cross‐linking agents suitable for the construction of stable helical structures up to >95 % helicity at 5 °C. Our method could also be applied to biologically related sequences seen in native proteins such as Rev.
Preparation and Study of New Poly‐8‐Hydroxyquinoline Chelators for an anti‐Alzheimer Strategy
Authors: Deraeve Céline , Boldron Christophe , Maraval Alexandrine , Mazarguil Honoré , Gornitzka Heinz , Vendier Laure , Pitié Marguerite , Meunier Bernard
Published: October 2007

Fourteen different ligands have been synthesized with two covalently linked 8‐hydroxyquinoline motifs that favor metal complexation. These bis‐chelators include different bridges at the C2 positions and different substituents to modulate their physicochemical properties. They can form metal complexes in a ratio of one ligand per metal ion with CuII and ZnII, two metal ions involved in the formation of amyloid aggregates of the toxic Aβ‐peptides in the Alzheimer disease. The apparent affinity of all bis‐8‐hydroxyquinoline ligands for CuII and ZnII are similar with logK ≈16 and logK ≈13 and are 10 000 times more efficient than for the corresponding 8‐hydroxyquinoline monomers. Their strong chelating capacities allow them to inhibit more efficiently than the corresponding monomers the precipitation of Aβ‐peptides induced by CuII and ZnII and also to inhibit the toxic formation of H2O2 due to copper complexes of Aβ. The best results were obtained with a one‐atom linker between the two quinoline units. X‐ray analyses of single‐crystals of CuII, ZnII or NiII complexes of 2,2′‐(2,2‐propanediyl)‐bis(8‐hydroxyquinoline), including a one‐atom linker, showed that all heteroatoms of the bis‐8‐hydroxyquinoline ligand chelate the same metal ion in a distorted square‐planar geometry. The CuII and ZnII complexes include a fifth axial ligand and are pentacoordinated.
Half‐Sandwich Rhodium (and Iridium) Complexes as Enantioselective Catalysts for the 1,3‐Dipolar Cycloaddition of 3,4‐Dihydroisoquinoline N‐Oxide to Methacrylonitrile
Authors: Carmona Daniel , Lamata M. Pilar , Viguri Fernando , Rodríguez Ricardo , Lahoz Fernando J. , Oro Luis A.
Published: October 2007

Cationic half‐sandwich complexes containing the [(η5‐C5Me5)M(Diphos*)] moiety (M=Rh, Ir; Diphos*=chiral diphosphine ligand) catalyze the cycloaddition of the nitrone 3,4‐dihydroisoquinoline N‐oxide (A) to methacrylonitrile (B) with excellent regio and endo selectivity and low‐to‐moderate enantioselectivity. The most active and selective catalyst, (SRh,RC)‐[(η5‐C5Me5)Rh{(R)‐Prophos)} (NC(Me)CCH2)](SbF6)2, has been isolated and fully characterized including the determination of the molecular structure by X‐ray diffraction. The R‐at‐metal epimers of the complexes [(η5‐C5Me5)M{(R)‐Prophos)}(NC(Me)CCH2)](SbF6)2 (M=Rh, Ir) isomerize to the corresponding S‐at‐metal diastereomers. The stoichiometric cycloaddition of A with B is catalyzed by diastereopure (SM,RC)‐[(η5‐C5Me5)M{(R)‐Prophos)}(NC(Me)CCH2)](SbF6)2 with perfect regio and endo selectivity and very good (up to 95 %) ee. The catalyst can be recycled up to nine times without significant loss of either activity or selectivity.
Geometric Formalism for DNA Quadruplex Folding
Authors: Webba da Silva Mateus
Published: October 2007

Understanding the control of self‐assembly and stereochemical properties of DNA higher order architectural folds is of fundamental importance in biology as well as biochemical technological applications. Guanine‐rich DNA sequences can form tetrahelical architectures termed quadruplexes. A formalism is presented describing the interdependency of a set of structural descriptors as a geometric basis for folding of unimolecular quadruplex topologies. It represents a standard for interpretation of structural characteristics of quadruplexes, and is comprehensive in explicitly harmonizing the results of published literature with a unified language. The formalism is a fundamental step towards prediction of unimolecular quadruplex folding topologies from primary sequence.
1,4‐Pentenyne as a Five‐Carbon Synthon for Efficient and Selective Syntheses of Natural Products Containing 2,4‐Dimethyl‐1‐penten‐1,5‐ylidene and Related Moieties by Means of Zr‐Catalyzed Carboalumination of Alkynes and Alkenes
Authors: Zhu Gangguo , Negishi Ei‐ichi
Published: October 2007

Two highly efficient protocols for enantioselective synthesis of 2,4‐dimethyl‐1‐penten‐1,5‐ylidene derivatives involve the combined use of the Zr‐catalyzed methylalumination of alkynes (ZMA) and the Zr‐catalyzed asymmetric carboalumination of alkenes (ZACA). The ZMA/ZACA protocol has been applied to the synthesis of a nafuredin intermediate 14 and a potential intermediate 18 for milbemycin β3, while the ZACA/ZMA protocol has been applied to the synthesis of a (−)‐bafilomycin A1 intermediate 25.
Antiproliferative Activity, Cell‐Cycle Dysregulation, and Cellular Differentiation: Salicyl‐ and Catechol‐Derived Acyclic 5‐Fluorouracil O,N‐Acetals against Breast Cancer Cells
Authors: Marchal Juan A. , Rodríguez‐Serrano Fernando , Caba Octavio , Aránega Antonia , Gallo Miguel A. , Espinosa Antonio , Campos Joaquín M.
Published: October 2007

Herein we report the preparation and biological activity of three compounds with the general formula 1‐[2‐(5‐substituted‐2‐hydroxybenzyloxy)‐1‐methoxyethyl]‐5‐fluorouracil. A catechol‐derived compound such as 1‐[3‐(2‐hydroxyphenoxy)‐1‐methoxypropyl]‐5‐fluorouracil and two salicyl‐derived compounds such as (Z)‐1‐[4‐(2‐hydroxyphenyl)‐1‐methoxybut‐3‐enyl]‐5‐fluorouracil [(Z)‐11] and its dihydrogenated derivative 1‐[4‐(2‐hydroxyphenyl)‐1‐methoxybutyl]‐5‐fluorouracil were prepared to complete the set of six O,N‐acetals. The most active compound against the MCF‐7 breast cancer cell line was (Z)‐11: IC50=9.40±0.64 μM. Differentiated breast cancer cells generate fat deposits in the cytoplasm. MCF‐7 cells treated with (Z)‐11 underwent an increase in lipid content relative to control cells after three days of treatment. Our results suggest that there may be significant potential advantages in the use of this new differentiating agent for the treatment of breast cancer.
Design and evaluation of a low field system for hyperpolarized 3‐He gas imaging of neonatal lungs
Authors: Krjukov E. , Fichele S. , Wild J.M. , Paley M.N.J.
Published: October 2007

3‐Helium can be optically pumped with laser light to produce exceptionally high nuclear polarization, which is independent of field strength. This increased polarization can allow imaging at low and ultra low field strengths, while still obtaining high signal‐to‐noise ratio. Low field magnets can be built for a fraction of the cost of high field clinical scanners and feature greatly reduced susceptibility artifact and less RF power requirement than higher field systems. Further advantage can be achieved by combination of hyperpolarized gas with parallel imaging methods. A particularly promising target for 3‐He imaging is the premature neonatal lung, where new ways to visualize impaired lung development would be very useful clinically. Overall safety is much improved operating at ultra low fields and there is good compatibility with standard neonatal physiological monitoring equipment. A six coil, open access resistive magnet operating at fields up to 0.015 T with unforced air cooling and sized to allow imaging of the neonatal lungs has been designed and built. A multi‐channel broadband spectrometer and software system has also been designed, constructed, and interfaced to the magnet. Both proton and hyperpolarized helium images have been acquired from test objects using the same four channel radiofrequency coil array, operating at a frequency of 450 kHz, by adjusting the magnetic field. The system is now in final preparation for studies of neonatal lungs in the Neonatal Intensive Care Unit. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 31B: 209–217, 2007
Modal analysis of a multilayered gradient coil insert in a 4‐T MRI scanner
Authors: Wang Fenglin , Mechefske Chris
Published: October 2007

In ultrahigh field strength Magnetic Resonance Imaging (MRI), the pulsed electrical currents passing through gradient coil windings cause powerful alternating forces that act on the gradient coil structure and create structural vibration and consequential acoustic noise (as high as 130 dB). The dynamic response of the gradient coil cylinder largely determines the acoustic noise generated in terms of frequency components, sound pressure levels (SPL), and the spatial distribution within the bore of the scanner. The objective of this article is to characterize the dynamic behavior of a real (multilayered) gradient coil insert in a 4‐T MRI scanner (from 200 to 3,000 Hz). The simply supported (assembly condition) and free–free (modal testing) condition are investigated in the dynamic analysis. In‐situ vibration testing, modal testing, and numerical analyses are applied to uncover the dynamic features. The results indicate that bending modes in combination with different specific free–free and simply supported radial mode shapes provide the fundamental characteristics of the dynamic behavior of the gradient coil cylinder in the frequency range tested. The change in dominant bending mode as a function of scanning input frequency was also studied. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 31B: 237–254, 2007
Design and performance of a DNP prepolarizer coupled to a rodent MRI scanner
Authors: Comment A. , van den Brandt B. , Uffmann K. , Kurdzesau F. , Jannin S. , Konter J.A. , Hautle P. , Wenckebach W.Th. , Gruetter R. , van der Klink J.J.
Published: October 2007

For most of the last forty years, the techniques of Dynamic Nuclear Polarization (DNP) have been confined to particle‐physics laboratories building polarized targets, but recently it has been shown that samples similar to a solid target can be transformed into room temperature liquid solutions while retaining a high nuclear polarization. This method of “hyperpolarization” is of interest in NMR/MRI/MRS. We describe a 3.35 T DNP/9.4 T MRI installation based on a continuous‐flow cryostat, using a standard wide‐bore low‐field NMR magnet as prepolarizer magnet and a widely available radical as polarizing agent. The interfacing to a rodent scanner requires that the infusion of the polarized solution in the animal be remotely controlled, because of limited access inside the magnet bore. Physiological constraints on the infusion rate can be a serious source of polarization loss, and the discussion of efficiency is therefore limited to that of the prepolarizer itself, i.e., the spin temperatures obtained in the solid state. To put our results in context, we summarize data obtained in targets with different types of radicals, and provide a short review of the DNP mechanisms needed in their discussion. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 31B: 255–269, 2007
Efficient method for parameter estimation of MRS signal using decimation and prior knowledge
Authors: Zeng Weiming
Published: October 2007

Magnetic resonance spectroscopy (MRS) signals are often characterized by a low signal‐to‐noise ratio and overlapping peaks. Under these circumstances simple signal processing methods are not adequate. Using the different decimated sequences of original MRS signal and prior knowledge of frequency differences and equal damping factors, an efficient parameter estimation method is presented in this article. The experimental results show that among three parameter estimation methods of HTLS, HTLSPK (Δfdeq) and the novel method, the last method obviously has the best performance with a lowest failure rate and a highest estimation accuracy. Even if some inaccuracy of prior knowledge is considered, the novel method also shows some advantages. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 31B: 270–277, 2007
Infinite time aggregation for the critical Patlak‐Keller‐Segel model in ℝ2
Authors: Blanchet Adrien , Carrillo José A. , Masmoudi Nader
Published: October 2007

We analyze the two‐dimensional parabolic‐elliptic Patlak‐Keller‐Segel model in the whole Euclidean space ℝ2. Under the hypotheses of integrable initial data with finite second moment and entropy, we first show local‐in‐time existence for any mass of “free‐energy solutions,” namely weak solutions with some free‐energy estimates. We also prove that the solution exists as long as the entropy is controlled from above. The main result of the paper is to show the global existence of free‐energy solutions with initial data as before for the critical mass 8π/χ. Actually, we prove that solutions blow up as a delta Dirac at the center of mass when t → ∞ when their second moment is kept constant at any time. Furthermore, all moments larger than 2 blowup as t → ∞ if initially bounded. © 2007 Wiley Periodicals, Inc.
WdCM: a workday calendar model for workflows in service grid environments
Authors: Liu Jianxun , Zhou Chunjie , Chen Jinjun
Published: November 2007

The time model for business cooperation across organizations and in business service grid has a special and important requirement, i.e. workday calendar model (WdCM). Workflow plays an important role in modelling business processes across multi‐enterprises or in service grid environments. However, current research in workflow time models does not pay sufficient attention to the differences in workday calendar between individual organizations. This paper aims to solve this problem by clarifying some basic concepts involved in the workday calendar models and presenting an XML‐based framework for workday calendar expressions, i.e. WdCM. Based on this WdCM, temporal constraints and the time optimization issue of workflow processes are investigated. Finally, a case study is analysed to demonstrate the feasibility of our workday calendar model. Copyright © 2007 John Wiley & Sons, Ltd.
Semantic patterns for user‐interactive question answering
Authors: Hao Tianyong , Hu Dawei , Wenyin Liu , Zeng Qingtian
Published: November 2007

A new type of semantic pattern is proposed in this paper, which can be used by users to post questions and answers in user‐interactive question answering (QA) systems. The necessary procedures of using semantic patterns in a QA system are also presented, which include question structure analysis, pattern matching, pattern generation, pattern classification and answer extraction. Both the manual creation method and the automatic generation method are proposed for patterns for different applications. A pattern instantiation level metrics is also presented for the predication of the quality of generated or learned patterns. We implemented a user interface for using the semantic pattern in our QA system, which allows users to effectively post and answer questions. Copyright © 2007 John Wiley & Sons, Ltd.
Detection of mycoplasmas in goat milk by flow cytometry
Authors: Assunção Patricia , Davey Hazel M. , Rosales Ruben S. , Antunes Nuno T. , de la Fe Christian , Ramirez Ana S. , de Galarreta Carlos M. Ruiz , Poveda Jose B.
Published: October 2007

The detection of mycoplasma in milk can be performed by either culture techniques or polymerase chain reaction (PCR) based methods. Although PCR can reduce the average diagnostic time to 5 h in comparison with the several days for the isolation of the agent, there is still a need to develop methods, which could give earlier results. For this purpose, we tested the ability of flow cytometry (FC) to detect mycoplasmas in milk samples. Milk samples inoculated with four different mycoplasmas, Mycoplasma agalactiae, Mycoplasma putrefaciens, Mycoplasma capricolum subsp. Capricolum, or Mycoplasma mycoides subsp. mycoides large‐colony type, known to cause contagious agalactia in goats, were stained with the DNA stain SYBR Green I and analyzed by FC. Three goat milk samples, from which mycoplasmas have been isolated in broth medium were also analyzed. All mycoplasmas were easily distinguished from debris of milk samples, but it was not possible to distinguish between the different mycoplasma species. In our conditions, the detection limit of the technique was of the order of 103–104 cells ml−1. Furthermore, mycoplasmas were also distinguished from Staphylococcus aureus. FC together with SYBR Green I was able to distinguish between mycoplasma cells and debris present in milk samples and gave results in 20–30 min. This is an important first step in developing a robust, routine flow cytometric method for the detection of mycoplasmas in milk samples. © 2007 International Society for Analytical Cytology
Hypertriglyceridaemic waist phenotype criteria and prevalent metabolic triad in women
Authors: Gazi Irene F. , Milionis Haralampos J. , Filippatos Theodosios D. , Tsimihodimos Vasilis , Kostapanos Michael S. , Doumas Michael , Tselepis Alexandros D. , Elisaf Moses
Published: October 2007

Background

To assess the metabolic profile and the prevalence of the metabolic triad (i.e. hyperinsulinaemia, hyperapobetalipoproteinaemia, and decreased low‐density lipoprotein particle size) in women characterized by the hypertriglyceridaemic waist (HTGW) phenotype and to identify cut‐off values for triglycerides and waist circumference, effectively discriminating women with the metabolic triad.

Methods

Two hundred and twenty‐eight female subjects without any history of vascular disease or diabetes mellitus attending an Outpatient Lipid Clinic setting at the University Hospital of Ioannina, Greece were studied.

Results

Currently available HTGW criteria for women were unable to detect any significant differences in the metabolic profile either in the pre‐ or post‐menopausal women, and proved similar in terms of sensitivity and specificity in identifying women with the metabolic triad. A cut‐off value of 1.26 mmol/L for triglycerides and 84.5 cm for waist circumference were determined by Receiver‐operating Curve evaluation. Women with both triglycerides and waist circumference above these thresholds had four‐fold higher odds of presenting with the metabolic triad compared with women with non‐HTGW phenotype.

Conclusions

A HTGW phenotype definition of 1.26 mmol/L for triglycerides and 84.5 cm for waist circumference may effectively identify Mediterranean women with the atherogenic metabolic triad. Whether these criteria are also associated with a higher incidence of vascular disease and/or new‐onset diabetes in women remains to be investigated. Copyright © 2007 John Wiley & Sons, Ltd.
Decreased in vivo oxidative stress and decreased platelet activation following metformin treatment in newly diagnosed type 2 diabetic subjects
Authors: Formoso Gloria , De Filippis Elena A. , Michetti Noemi , Di Fulvio Patrizia , Pandolfi Assunta , Bucciarelli Tonino , Ciabattoni Giovanni , Nicolucci Antonio , Davì Giovanni , Consoli Agostino
Published: October 2007

Background

In type 2 diabetes, metformin reduces cardiovascular risk beyond the effect of glycaemic control. Since oxidative stress and the consequent enhanced platelet activation contribute to accelerated atherosclerosis in diabetes, we hypothesized that metformin could reduce oxidative stress in this condition.

Methods

We randomized 26 newly diagnosed type 2 diabetic subjects to assume either metformin (M, n = 13) or gliclazide (G, n = 13) for 12 weeks. Drugs were titrated as needed to achieve good glycaemic control. Before and after treatment, we determined blood glucose, insulin, HbA1c, vitamin A and E levels and 8‐iso‐PGF2α and 11‐dehydro‐thromboxane B2 urinary excretion, an in vivo oxidative stress and a thromboxane‐dependent platelet activation marker, respectively.

Results

Notwithstanding a comparable improvement in metabolic control, 8‐iso‐PGF2α (M from 708 ± 32 to 589 ± 45 pg/mg cr, p < 0.001; G from 646 ± 80 to 665 ± 79, pg/mg cr, p = ns) and 11‐dehydro‐thromboxane B2 (M from 2190 ± 196 to 1753 ± 150 pg/mg cr, p < 0.05; G from 2048 ± 202 to 1923 ± 223, pg/mg cr, p = ns) urinary excretion decreased after metformin but not after gliclazide treatment. After metformin, vitamin A and E levels significantly increased while they remained unchanged after gliclazide.

Conclusions

These data suggest that metformin could improve oxidative stress, preserve antioxidant function and restrain platelet activation in type 2 diabetes. Copyright © 2007 John Wiley & Sons, Ltd.
Genetic screen for regulators of ind expression identifies shrew as encoding a novel twisted gastrulation‐like protein involved in Dpp signaling
Authors: Bonds Morgan , Sands Jennifer , Poulson Will , Harvey Canda , Von Ohlen Tonia
Published: October 2007

Initiation and refinement of expression of the Ind homeodomain protein in the Drosophila embryo is coordinately regulated by global dorsoventral patterning pathways Dorsal, Egfr, and Dpp, and well as by Vnd, which positions the ventral boundary of Ind. Therefore, we set out to look for novel regulators of dorsoventral patterning by screening the Exelixis deficiency collection for modified expression of Ind. Indeed, we found deficiencies that remove components of the known signaling pathways had altered or lost ind expression. These findings included deficiencies that remove screw, dpp, and egfr as well as deficiencies that remove ind itself. In addition, we found several deficiencies that had altered or loss of ind expression. We also observed phenotypes suggestive of dorsoventral patterning defects such as twisting during gastrulation, and defects associated with loss of dorsal specification. These include a pair of overlapping deficiencies that produced ventralized embryos. We find that transheterozygotes of these two deficiencies are also ventralized. There are seven genes common to both deficiencies, including CG11582, which encodes a twisted gastrulation‐like protein. These two deficiencies are also allelic with shrew mutations. Here, we present data supporting the conclusion that CG11582 is the gene affected in shrew mutants. Developmental Dynamics 236:3524–3531, 2007. © 2007 Wiley‐Liss, Inc.
Identification and expression of XRTN1‐A and XRTN1‐C in Xenopus laevis
Authors: Park Edmond Changkyun , Shim Sangwoo , Han Jin‐Kwan
Published: October 2007

Reticulon1, also known as neuroendocrine‐specific protein, belongs to the reticulon (RTN) family, whose members possess a conserved reticulon domain and are associated with the endoplasmic reticulum (ER) membrane. Here, we report cloning and expression of Xenopus homologues of Reticulon1‐A (XRTN1‐A) and ‐C (XRTN1‐C). XRTN1‐A and ‐C contain an open reading frame of 752 and 207 amino acids, respectively, each containing a conserved reticulon domain. Sequence analysis shows that XRTN1 proteins have an ER membrane retention signal and four putative membrane‐spanning domains. Reverse transcription‐polymerase chain reaction and whole‐mount in situ hybridization showed that XRTN1‐A is expressed in early neural precursors and differentiating neuronal populations, including the trigeminal placode, olfactory placode, lateral line placode, and otic vesicle. XRTN1‐C is expressed in the developing brain and spinal cord. We found that XRTN1‐C protein is localized to the ER of Xenopus and mammalian cells and the granules in neurites of primary neurons of the Xenopus spinal cord and rat hippocampus. We also showed that XRTN1‐C protein is detected in the heavy membrane fraction, which contains lysosomal and ER‐resident proteins, as well as in the nucleus and polysomal fractions of the Xenopus embryo. Finally, we showed that thyroid hormone specifically down‐regulates XRTN1‐A mRNA in the head of premetamorphic Xenopus tadpoles. Our work characterizes the intracellular roles of XRTN1 during Xenopus neural development. Developmental Dynamics 236:3545–3553, 2007. © 2007 Wiley‐Liss, Inc.
An olig2 reporter gene marks oligodendrocyte precursors in the postembryonic spinal cord of zebrafish
Authors: Park Hae‐Chul , Shin Jimann , Roberts Randolph K. , Appel Bruce
Published: October 2007

Continuous production of new neurons and glia in adult mammals occurs within specialized proliferation zones of the forebrain. Neural cell proliferation and neurogenesis is more widespread in adult amphibians, reptiles, and fish but the identity of neural stem cell populations in these organisms has not been fully described. We investigated expression of a reporter gene driven by olig2 regulatory DNA at postembryonic stages in zebrafish. We show that olig2 expression marks a discrete population of spinal cord radial glia in larvae and adults that divide continuously. olig2+ radial glia have hallmarks of stem cells and their divisions appear to be asymmetric, producing new oligodendrocytes but not neurons or astrocytes. Developmental Dynamics 236:3402–3407, 2007. © 2007 Wiley‐Liss, Inc.
1,3‐Dipolar Cycloadditions of N‐Benzyl‐2,3‐O‐isopropylidene‐D‐glyceraldehyde Nitrone to Methoxyallene – Control of Site‐ and Diastereoselectivity of Isoxazolidine Formation by Lewis Acids
Authors: Dugovič Branislav , Fišera Lubor , Reißig Hans‐Ulrich
Published: October 2007

The siteselectivity of cycloadditions of the D‐glyceraldehyde‐derived nitrone 1 and methoxyallene (2) is strongly influenced by Lewis acids. The uncatalyzed reaction results in the formation of isomeric isoxazolidines 3a–3d and 4a–4c, whereas in the presence of different Lewis acids exclusive formation of 4‐methylene‐substituted isoxazolidines 4a–4d is observed. Furthermore, the diastereofacial selectivity of the methoxyallene addition to nitrone 1 can be controlled, thus giving rise to both diastereomeric isoxazolidines 3,4′‐anti‐4 or 3,4′‐syn‐4, just by employing different Lewis acids. The redox ring‐opening of isoxazolidines 4 using Murahashi's protocol yields α‐methylene‐β‐amino acid esters 5a,b and 7a,b.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)