bluuebunny/crossref_metadata_2025 huggingface dataset:
An Approach for Retrieving Marine Boundary Layer Refractivity from GPS Occultation Data in the Presence of Superrefraction
Authors: Xie Feiqin , Syndergaard Stig , Kursinski E. Robert , Herman Benjamin M.
Published: January 2007

The global positioning system (GPS) radio occultation (RO) technique has demonstrated the ability to precisely probe earth’s atmosphere globally with high vertical resolution. However, the lowermost troposphere still presents some challenges for the technique. Over moist marine areas, especially in subtropical regions, a very large negative moisture gradient often exists across the thermal inversion capping the marine boundary layer (MBL), which frequently causes superrefraction (SR), or ducting. In the presence of SR, the reconstruction of refractivity from RO data becomes an ill-posed inverse problem. This study shows that one given RO bending angle profile is consistent with a continuum (an infinite number) of refractivity profiles. The standard Abel retrieval gives the minimum refractivity solution of the continuum and thus produces the largest negative bias, consistent with a negative bias often present in the retrieved refractivity profiles in the moist lower troposphere. By applying a simple linear parameterization of the refractivity structure within and just below the SR layer, an analytical relation between the Abel-retrieved refractivity and a continuum of solutions is derived. Combining the Abel retrieval and the analytical relation with some physical constraints, a novel approach is developed to reconstruct the vertical refractivity structure within and below the SR layer. Numerical simulation studies in this paper have demonstrated the great potential of the reconstruction method to provide a much-improved retrieval in the presence of SR, and the method should greatly enhance the ability to measure the MBL structure globally using the GPS RO technique.
Internalization of novel non-viral vector TAT-streptavidin into human cells
Authors: Rinne Johanna , Albarran Brian , Jylhävä Juulia , Ihalainen Teemu O , Kankaanpää Pasi , Hytönen Vesa P , Stayton Patrick S , Kulomaa Markku S , Vihinen-Ranta Maija
Published: January 2007

Background

The cell-penetrating peptide derived from the Human immunodeficiency virus-1 transactivator protein Tat possesses the capacity to promote the effective uptake of various cargo molecules across the plasma membrane in vitro and in vivo. The objective of this study was to characterize the uptake and delivery mechanisms of a novel streptavidin fusion construct, TAT47–57-streptavidin (TAT-SA, 60 kD). SA represents a potentially useful TAT-fusion partner due to its ability to perform as a versatile intracellular delivery vector for a wide array of biotinylated molecules or cargoes.

Results

By confocal and immunoelectron microscopy the majority of internalized TAT-SA was shown to accumulate in perinuclear vesicles in both cancer and non-cancer cell lines. The uptake studies in living cells with various fluorescent endocytic markers and inhibiting agents suggested that TAT-SA is internalized into cells efficiently, using both clathrin-mediated endocytosis and lipid-raft-mediated macropinocytosis. When endosomal release of TAT-SA was enhanced through the incorporation of a biotinylated, pH-responsive polymer poly(propylacrylic acid) (PPAA), nuclear localization of TAT-SA and TAT-SA bound to biotin was markedly improved. Additionally, no significant cytotoxicity was detected in the TAT-SA constructs.

Conclusion

This study demonstrates that TAT-SA-PPAA is a potential non-viral vector to be utilized in protein therapeutics to deliver biotinylated molecules both into cytoplasm and nucleus of human cells.
Lowering mechanical degradation of drag reducers in turbulent flow
Authors: Brostow Witold , Lobland Haley E. Hagg , Reddy Taruna , Singh Ram P. , White Leslie
Published: January 2007

Drag reduction (DR) agents are used in several ppm concentrations to accelerate significantly the flow through conduits in oil pipelines, oil well operations, flood water disposal, fire fighting, field irrigation, transport of suspensions and slurries, sewage systems, water heating and cooling systems, airplane tank filling, marine systems, and also in biomedical systems including blood flow. The drag reduction agents are typically high molecular mass polymers; in industrial applications they undergo mechanical degradation in turbulent flow. We provide an equation that describes quantitatively the degradation, thus predicting drag reduction as a function of time and of the concentration of the drag reduction agent. We report how grafting a polymer on the backbone of a different polymer affects the drag reduction efficacy. Our grafted polymer undergoes degradation by flow turbulence more slowly and also provides high levels of drag reduction efficacy at much lower concentrations than homopolymers do.
Uniformity, composition, and surface tension in solution deposited PbZrxTi1-xO3 films
Authors: Etin A. , Shter G.E. , Gelman V. , Grader G.S.
Published: January 2007

High quality, uniform PbZrxTi1-xO3(PZT) films were prepared on the 4 inch wafers by chemical solution deposition (CSD) of 1,3-propanediol precursors. Film uniformity was studied as a function of deposition conditions including spinning rates and co-solvents. Measurements of the surface tension and composition evolution during evaporation and spinning stages showed that the surface tension increases significantly when the co-solvent is nearly completely evaporated. The evaporation of the propanol co-solvent and volatile by-products occurs within the first 5 s of spinning giving rise to defects, whereas octanol is slowly evaporated during 60 s producing uniform coatings. Other co-solvents such as hexanol and pentanol produced uniform films as well. Therefore stabilization of the surface tension in the initial spinning stage is a key to prevent the defect formation. These findings facilitate the deposition of uniform PZT films over large substrates by a simple, scalable, and cost-effective process.
Effect of nickel addition on the exothermic reaction of titanium and boron carbide
Authors: Yang Y.F. , Wang H.Y. , Liang Y.H. , Zhao R.Y. , Jiang Q.C.
Published: January 2007

Exothermic reaction path of the Ni–Ti–B4C system in the differential thermal analysis apparatus proceeded in such a way that Ni initially reacted with B4C and Ti to form Ni–B compounds and Ti2Ni with heat release, respectively; subsequently, the formation of Ni–B eutectic liquid between Ni2B and Ni4B3, and the appearance of Ni–Ti eutectic liquid phase between Ti2Ni and Ti were followed, which enabled the diffusion of Ni, B, C, and Ti in solution to form Ni–Ti–B–C liquid more easily and quickly at a low temperature; finally, TiC and TiB2 were precipitated out of the liquid. The addition of Ni provided an easier route for reactant mass transfer and accelerated the occurrence of complete reaction.
Solvothermal synthesis of zirconia and yttria-stabilized zirconia nanocrystalline particles
Authors: Wang Xin M. , Xiao Ping
Published: January 2007

A solvothermal method was used to prepare zirconia and yttria-stabilized zirconia (YSZ) particles using zirconium hydroxide and yttrium hydroxide particles as precursors and ethanol or isopropanol as reaction media. The particle properties were characterized with x-ray diffractometry, scanning electron microscopy, transmission electron microscopy, thermal analysis, laser particle-size analysis, nitrogen adsorption (Brunauer–Emmett–Teller method) and Zeta potential analysis. Cubic/tetragonal ZrO2 and YSZ nanocrystals with crystallite size around 5 nm were obtained. The effect of different hydroxide precursors, attrition milling of hydroxide precursors, solvothermal processing conditions, and mineralizer was investigated and discussed by referring to the crystallization process of zirconium hydroxides.
Crystal orientation and surface morphology of face-centered-cubic metal thin films deposited upon single-crystal ceramic substrates using pulsed laser deposition
Authors: Francis Andrew J. , Salvador Paul A.
Published: January 2007

Cu, Pt, Ag, and Au were deposited on (100)-oriented ceramic substrates (SrTiO3, LaAlO3, and MgO). Over a wide range of temperatures (room temperature to 600 °C), Cu films were (100)-oriented and exhibited cube-on-cube epitaxy. Epitaxial Pt(100) films were obtained only at high temperature; oriented Pt(111) films were obtained at lower temperatures. Ag and Au were never obtained as purely (100)-oriented samples, although the amount of (100)-film increased with increasing temperature. Three-dimensional islands formed for all metals at higher temperatures, while flatter film surfaces developed at lower temperatures. At any given temperature, the surface roughness of films on SrTiO3(100) increased in the order Pt < Cu < Au < Ag. The variations in film structural characteristics are described well by considering the metals’ (i) surface/interfacial energies, (ii) surface energy anisotropies, and (iii) surface diffusion coefficients. Flat, epitaxial growth is promoted by low-energy interfaces, low surface energy anisotropies, and slow surface diffusion.
Electrical resistance of Sn–Ag–Cu ball grid array packages with Sn–Zn–Bi addition jointed at 240 °C
Authors: Shih Po-Cheng , Lin Kwang-Lung
Published: January 2007

Sn–8Zn–3Bi solder paste and Sn–3.2Ag–0.5Cu solder balls were reflowed simultaneously at 240 °C on Cu/Ni/Au metallized ball grid array substrates. The joints without Sn–Zn–Bi addition (only Sn–Ag–Cu) were studied as a control system. Electrical resistance was measured after multiple reflows and aging. The electrical resistance of the joint (R1) consisted of three parts: the solder bulk (Rsolder bulk, upper solder highly beyond the mask), interfacial solder/intermetallic compound (Rsolder/IMC), and the substrate (Rsubstrate).R1increased with reflows and aging time.Rsolder/IMC, rather thanRsolder bulkandRsubstrate, seemed to increase with reflows and aging time. The increase ofR1was ascribed to theRsolder/IMCrises.Rsubstratewas the major contribution toR1. HoweverRsolder/IMCdominated the increase ofR1with reflows and aging.R1of Sn–Zn–Bi/Sn–Ag–Cu samples were higher than that of Sn–Ag–Cu samples in various tests.
Synthesis of polystyrene-grafted carbon nanocapsules
Authors: Huang Hsuan-Ming , Tsai Hung-Chieh , Liu I-Chun , Tsiang Raymond Chien-Chao
Published: January 2007

A novel polymeric composite material, polystyrene (PS)-grafted carbon nanocapsules (CNCs), has been prepared. sec-butyllithium was first used to introduce negative charges on CNCs, and these CNC carbanions acted then as initiators for anionic polymerization of styrene. Based on a weight loss at the decomposition temperature of the butyl groups, the quantity of the butyls attached to the CNC surface was determined as 1.18 wt%, corresponding to 0.25 mol% initiator per mol of carbon atom on the CNC surface. Furthermore, the decomposition temperature of butylated CNCs was lower than that of the pristine CNCs by nearly 200 °C. The polystyrene content in our PS-grafted CNC sample was approximately 20%, and the molecular weight of the grafted PS on the surface of CNCs was calculated as 1200 gmol−1. Compared with the molecular weight of the ungrafted PS, the molecular weight of grafted PS was lower, thus indicating rates of initiation and/or propagation for CNC-bound carbanions lower than those of the free sec-butyllithium. The PS-grafted CNCs had good dispersion in toluene, tetrahydrofuran, cyclohexane, and other common organic solvents in which polystyrene was dissolvable and thus indicated good compatibility when further blended with other styrenic polymers. The PS-grafted CNCs were characterized and examined by Fourier transform infrared, thermogravimetric analysis, atomic force microscopy, differential scanning calorimetry, ultraviolet-visible spectroscopy, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. The electron microscopy images indicated that the PS-grafted CNCs were homogeneous composites containing uniform polymer/CNC ratios.
Effect of fullerene addition on thermoelectric properties ofn-type skutterudite compound
Authors: Itoh Takashi , Ishikawa Kenta , Okada Akira
Published: January 2007

Thermoelectric power generation is a promising method for harnessing waste thermal energy, especially in the temperature range between 500 and 800 K. It is necessary to improve the performance of thermoelectric materials for the realization of the power generation. Dispersion of nanoparticles such as fullerenes is expected to induce phonon scattering that decreases thermal conductivity of materials, and application to thermoelectric materials may lead to improved properties. In the present study, then-type Co0.92Ni0.08Sb2.96Te0.04thermoelectric compound was synthesized, and the thermoelectric properties were evaluated. Furthermore, the fullerene particles were sufficiently mixed with the thermoelectric compound powder by the mechanical grinding method, and influences of the fullerene additions to the compound were investigated. The dispersion of fullerene particles in then-type Co0.92Ni0.08Sb2.96Te0.04compound was conducted through the planetary ball milling method to disentangle agglomerates of the fullerene and to disperse the particles in the thermoelectric compound matrix. The thermal conductivity decreased with an increase in fullerene content, and the maximum in dimensionless figure of meritZTwas 0.62 at 800 K for 1 mass% fullerene addition. This was 28% higher than that of fullerene-free sample.
Serial alterations in digital hemodynamics and endothelin-1 immunoreactivity, platelet-neutrophil aggregation, and concentrations of nitric oxide, insulin, and glucose in blood obtained from horses following carbohydrate overload
Authors: Eades Susan C. , Stokes Ashley M. , Johnson Philip J. , LeBlanc Casey J. , Ganjam Venkataseshu K. , Buff Preston R. , Moore Rustin M.
Published: January 2007

Objective—To quantify changes in endothelium-derived factors and relate those changes to various aspects of digital hemodynamics during the prodromal stages of carbohydrate overload (CHO)-induced laminitis in horses.

Animals—20 adult horses without abnormalities of the digit.

Procedures—Digital and jugular venous blood samples were collected at 1-hour intervals (for assessment of endothelin-1 [ET-1] immunoreactivity and measurement of glucose, insulin, and nitric oxide [NO] concentrations) or 4-hour intervals (CBC and platelet-neutrophil aggregate assessment) for 8 hours or 16 hours after induction of CHO-associated laminitis in horses treated with an ET-1 antagonist. Effects of treatment, collection site, and time and the random effects of horse on each variable were analyzed by use of a repeated-measures model. Where treatment and collection site had no significant effect, data were combined.

Results—Compared with baseline values, CHO resulted in changes in several variables, including a significant increase from baseline in digital blood ET-like immunoreactivity at 11 hours; digital blood ET-like immunoreactivity was significantly greater than that in jugular venous blood at 8, 9, 11, and 12 hours. Digital and jugular venous blood concentrations of glucose increased from baseline significantly at 3, 4, and 5 hours; insulin concentration increased significantly at 5 hours; and the number of platelet-neutrophil aggregates increased significantly at 12 hours.

Conclusions and Clinical Relevance—In horses, concurrent increases in venous blood ET-1 immunoreactivity, insulin and glucose concentrations, and platelet-neutrophil aggregates support a role of endothelial dysfunction in the pathogenesis of CHO-induced laminitis.
Use of three-dimensional computed tomography for diagnosis and treatment planning for open-mouth jaw locking in a cat
Authors: Beam Rebekah C. , Kunz David A. , Cook Cristi R. , Carson Robert L. , Briscoe Phillip , Cook James L.
Published: January 2007

Case Description—A 2.5-year-old spayed female Persian cat was evaluated for acute inability to close its mouth.

Clinical Findings—A wry-mouth malocclusion was evident, and the right side of the mandible was longer than the left side. The right mandibular tooth row appeared to be lowered. The lower jaw was persistently maintained in an open position. The presumptive diagnosis was open-mouth jaw locking. Diagnostic imaging with computed tomography and 3-dimensional reconstruction was performed for definitive diagnosis and to achieve a better understanding of the lesions. Imaging revealed locking of the right ramus of the mandible, which was displaced ventrolaterally, causing the coronoid process to impinge on the right zygomatic arch.

Treatment and Outcome—A bilateral partial ostectomy of the rostroventral margins of the zygomatic arches with an autogenous fat graft implantation was performed. The cat recovered without complications and by the following morning was bright, alert, and responsive and eating canned cat food comfortably. One year after surgery, the owner reported that the cat had continued to function well, was eating normally, and had not had any observed locking episodes since surgery.

Clinical Relevance—Unlike radiographic imaging, computed tomography may be used to create 3-dimensional reconstructions of structures in cases of suspected open-mouth jaw locking; improve evaluation of the lesions; and improve decision-making and client education for diagnosis, treatment options, and prognosis.
Drag force of intermediate Reynolds number flow past mono‐ and bidisperse arrays of spheres
Authors: Beetstra R. , van der Hoef M. A. , Kuipers J. A. M.
Published: January 2007

Extensive lattice‐Boltzmann simulations were performed to obtain the drag force for random arrays of monodisperse and bidisperse spheres. For the monodisperse systems, 35 different combinations of the Reynolds number Re (up to Re = 1,000) and packing fraction ϕ were studied, whereas for the bidisperse systems we also varied the diameter ratio (from 1:1.5 to 1:4) and composition, which brings the total number of different systems that we considered to 150. For monodisperse systems, the data was found to be markedly different from the Ergun equation and consistent with a correlation, based on similar type of simulations up to Re = 120. For bidisperse systems, it was found that the correction of the monodisperse drag force for bidispersity, which was derived for the limit Re = 0, also applies for higher‐Reynolds numbers. On the basis of the data, a new drag law is suggested for general polydisperse systems, which is on average within 10% of the simulation data for Reynolds numbers up to 1,000, and diameter ratios up to 1:4. © 2007 American Institute of Chemical Engineers AIChE J, 2007.
The instructive redox behaviour of 4‐ferrocenylcatechol on nanocrystalline titanium dioxide electrodes
Authors: Maharaj Felicia J. D. , McDonagh Andrew M. , Colbran Stephen B.
Published: January 2007

An investigation into the redox behaviour of 4‐ferrocenylcatechol bound to nanocrystalline TiO2 electrodes identified a limitation to the use of catechol as an electron‐transfer facilitating anchoring group. 4‐Ferrocenylcatechol was adsorbed to transparent nanocrystalline TiO2 electrodes. UV–visible spectra of the modified electrode were recorded in an acetonitrile‐electrolyte solution. At an applied potential of + 0.45 mV (vs Ag/AgCl/Cl−) the ferrocenyl group oxidized to the ferrocenium cation and the catecholate group oxidized to the benzoquinone form. Subsequent application of a potential of 0 V reduced the ferrocenium to ferrocene but, owing to the irreversibility of the catechol oxidation in aprotic solvents, benzoquinone is not reduced to catecholate and subsequently desorbs and is lost due into solution. Electrochromic switching of the ferrocenyl electrochromophore on TiO2 with aprotic electrolyte is, therefore, irreversible. Copyright © 2006 John Wiley & Sons, Ltd.
Replicated alternatives and the role of confusion, chasing, and regret in decisions from experience
Authors: Ert Eyal , Erev Ido
Published: January 2007

The current paper explores choice among alternatives that can be classified into distinct classes. All the members of a particular class were ‘replicated alternatives’: they promised the same payoff distribution. Information to decision makers was limited to feedback concerning the realized (obtained and foregone) payoffs. Experiment 1 demonstrates that increasing the number of replicated alternatives creates confusion (which facilitates random choice) and changes the implications of the tendency to chase recent returns (i.e., select the alternative with the best recent outcomes). This effect, termed ‘confused chasing,’ facilitates risk seeking even when this behavior impairs expected earnings. Experiment 2 reveals that increasing the number of replicated alternatives can reduce (but does not eliminate) the tendency to underweight rare events. Experiment 3 shows that the relative importance of chasing and confusion is sensitive to the likelihood of realizing lower payoffs than the forgone payoffs. The main results are summarized with a simple model assuming that payoff sensitivity decreases with experienced regret. Copyright © 2006 John Wiley & Sons, Ltd.
Simple Bisthiocarbonohydrazones as Sensitive, Selective, Colorimetric, and Switch‐On Fluorescent Chemosensors for Fluoride Anions
Authors: Han Feng , Bao Yuhui , Yang Zhigang , Fyles Thomas M. , Zhao Jianzhang , Peng Xiaojun , Fan Jiangli , Wu Yunkou , Sun Shiguo
Published: January 2007

Bisthiocarbonohydrazones are found to be a class of sensitive, selective, ratiometric, and colorimetric chemosensors for anions such as fluoride (F−) or acetate (Ac−). The sensitivities, or the binding constants of the sensors with anions, were found to be strongly dependent on the substituents appended on the π‐conjugation framework, the delocalization bridge CHN, the aromatic moiety, and the hetero atom in the CX group (X=O, S) of the sensors. Single‐crystal structures and 1H NMR titration analysis shows that the CHN moiety is a hydrogen‐bond donor, and it is proposed that an additional CH⋅⋅⋅F hydrogen bond is formed for the sensors in the presence F−. A sensor bearing anthracenyl groups is demonstrated as a switch‐on fluorescent chemosensor for F− and Ac−. The recognition of F− in acetonitrile (MeCN) by a sensor with nitrophenyl substituents is tolerant to MeOH (MeCN/MeOH=10:1, v/v) and water (MeCN/H2O=30:1, v/v); at these solvent ratios the absorption intensity of the sensor–F− complex solution at maximal absorption wavelength was attenuated to half of the original value in pure MeCN.
Well‐Defined Cationic Alkyl– and Alkoxide–Aluminum Complexes and Their Reactivity with ε‐Caprolactone and Lactides
Authors: Dagorne Samuel , Le Bideau Franck , Welter Richard , Bellemin‐Laponnaz Stéphane , Maisse‐François Aline
Published: January 2007

We describe the synthesis, structure, and reactivity of low‐coordinate Al–alkyl and –alkoxide cationic complexes incorporating the sterically bulky aminophenolate bidentate ligand 6‐(CH2NMe2)‐2‐CPh3‐4‐Me‐C6H2O− (N,O). These complexes are derived from the ionization of neutral dialkyl Al complexes (N,O)AlR2 (1 a, R=Me; 1 b, R=iBu), readily obtained by alkane elimination between AlR3 and the corresponding aminophenol ligand, with the alkyl abstracting reagents B(C6F5)3 and [Ph3C][B(C6F5)4]. The reactions of 1 a,b with B(C6F5)3 yield complicated mixtures or decomposition products, however the ionization of the Al–diisobutyl derivative 1 b with [Ph3C][B(C6F5)4] affords a stable four‐coordinate AlPhBr cationic adduct [(N,O)Al(iBu)(PhBr)]+ (3+), as deduced from elemental analysis data. Complex 3+ readily coordinates Lewis bases such as THF to form the corresponding adduct [(N,O)Al(iBu)(thf)]+ (4+), and also rapidly chain‐transfers with 1‐hexene to yield the three‐coordinate Al–hexyl cation [(N,O)Alhexyl]+ (5+). Both cations 3+ and 5+ slowly dimerize to form unprecedented organoaluminum dications [(N,O)AlR+]2 (3′++, R=iBu; 5′++, R=hexyl) as deduced from X‐ray crystallographic analysis. Cation 3+ reacts quickly with iPrOH to form a stable Lewis acid/base adduct [(N,O)Al(iBu)(HOiPr)]+ (6+), which constitutes the first X‐ray characterized adduct between an Al–alkyl complex and a simple ROH. The AlROH proton in 6+ is readily abstracted by NMe2Ph to form the neutral isopropoxide Al complex [(N,O)Al(iBu)(OiPr)] (7). Upon reaction with THF, cation 6+ undergoes an intramolecular proton transfer to yield the ammonium AlTHF complex [(η1‐HN,O)Al(iBu)(OiPr)(thf)] (8 b+), in which the aminophenolate is η1‐coordinated to the Al center. Cation 8 b+ can then be converted to the desired Al–alkoxide derivative [(N,O)Al(OiPr)(thf)]+ (10+), by an intramolecular protonolysis reaction, as confirmed by X‐ray crystallography. The synthesized Al–alkyl cations form robust four‐coordinate adducts in the presence of cyclic esters such as ε‐caprolactone and (d,l)‐lactide, but no insertion chemistry occurs, illustrating the poor ability of the AlR+ moiety to ring‐open. In contrast, the Al–alkoxide cation 10+ polymerizes ε‐caprolactone in a controlled manner with excellent activity, but is inactive in the polymerization of (d,l)‐lactide and L‐lactide. Control experiments with L‐lactide show that cation 10+ ring‐opens L‐lactide to yield a robust five‐coordinated Allactate cation [(N,O)Al(η2‐L‐lactate‐OiPr)(thf)]+ (13+), derived from a monoinsertion of L‐lactide into the AlOiPr bond of 10+, that does not further react. Cation 13+ may be regarded as a structurally characterized close mimic of the initial intermediate in the ring opening polymerization (ROP), of lactides by [{LX}M(OR)(L)] (where LX−=bidentate monoanionic ligand and L=labile ligand) metal complex initiators.
Osmium(II) and Ruthenium(II) Arene Maltolato Complexes: Rapid Hydrolysis and Nucleobase Binding
Authors: Peacock Anna F. A. , Melchart Michael , Deeth Robert J. , Habtemariam Abraha , Parsons Simon , Sadler Peter J.
Published: January 2007

Density functional calculations show that aquation of [Os(η6‐arene)(XY)Cl]n+ complexes is more facile for complexes in which XY=an anionic O,O‐chelated ligand compared to a neutral N,N‐chelated ligand, and the mechanism more dissociative in character. The O,O‐chelated XY=maltolato (mal) [M(η6‐p‐cym)(mal)Cl] complexes, in which p‐cym=p‐cymene, M=OsII (1) and RuII (2), were synthesised and the X‐ray crystal structures of 1 and 2⋅2 H2O determined. Their hydrolysis rates were rapid (too fast to follow by NMR spectroscopy). The aqua adduct of the OsII complex 1 was 1.6 pKa units more acidic than that of the RuII complex 2. Dynamic NMR studies suggested that O,O‐chelate ring opening occurs on a millisecond timescale in coordinating proton‐donor solvents, and loss of chelated mal in aqueous solution led to the formation of the hydroxo‐bridged dimers [(η6‐p‐cym)M(μ‐OH)3M(η6‐p‐cym)]+. The proportion of this dimer in solutions of the OsII complex 1 increased with dilution and it predominated at micromolar concentrations, even in the presence of 0.1 M NaCl (conditions close to those used for cytotoxicity testing). Although 9‐ethylguanine (9‐EtG) binds rapidly to OsII in 1 and more strongly (log K=4.4) than to RuII in 2 (log K=3.9), the OsII adduct [Os(η6‐p‐cym)(mal)(9EtG)]+ was unstable with respect to formation of the hydroxo‐bridged dimer at micromolar concentrations. Such insights into the aqueous solution chemistry of metal–arene complexes under biologically relevant conditions will aid the rational design of organometallic anticancer agents.
Shape‐Controlled Synthesis and Self‐Assembly of Hexagonal Covellite (CuS) Nanoplatelets
Authors: Du Weimin , Qian Xuefeng , Ma Xiaodong , Gong Qiang , Cao Hongliang , Yin Jie
Published: January 2007

Single‐crystalline, hexagonal covellite (CuS) nanoplatelets were successfully synthesized through a facile, inexpensive, reproducible, and improved solvothermal process in toluene at 120 °C for 24 h with hexadecylamine as a capping agent and copper acetate and carbon disulfide as precursors. These nanoplatelets are about 26±1.5 nm in diameter and 8±1.2 nm thick, and have a tendency to self‐assemble into pillarlike nanostructures with face‐to‐face stacks, raftlike nanostructures with side‐by‐side arrays, and stratiform nanostructures with layer‐by‐layer self‐assembly. The crystal shape, morphology, and crystallographic orientation of the covellite obtained were investigated by means of XRD, TEM, and high‐resolution TEM, and a potential self‐assembly mechanism was proposed.
Recent Developments in the Metal‐Catalyzed Reactions of Metallocarbenoids from Propargylic Esters
Authors: Marco‐Contelles José , Soriano Elena
Published: January 2007

The transition‐metal‐catalyzed intramolecular cycloisomerization of propargylic carboxylates provides functionalized bicyclo[n.1.0]enol esters in a very diastereoselective manner and, depending on the structure, with partial or complete transfer of chirality from enantiomerically pure precursors. The subsequent methanolysis gives bicyclo[n.1.0] ketones, hence resulting in a very efficient two‐step protocol for the syntheses of α,β‐unsaturated cyclopropyl ketones, key intermediates for the preparation of natural products. The results from mechanistic computational studies suggest that they probably proceed through cyclopropyl metallocarbenoids, formed by endo‐cyclopropanation, that undergo a 1,2‐acyl migration. Finally, the potential of the intermolecular reaction and the related pentannulation of propargylic esters bearing pendant aromatic rings are also discussed.
Minimal cycle basis of graph products for the force method of frame analysis
Authors: Kaveh A. , Mirzaie R.
Published: January 2007

For an efficient force method of frame analysis, the formation of localized self‐equilibrating systems is an important issue. Such systems can be constructed on minimal cycle basis of the graph model of the structure. In this paper, algorithms are presented for the formation of minimal cycle bases of graph products corresponding to sparse cycle adjacency matrices, leading to the formation of highly sparse flexibility matrices. The algorithms presented employ concepts from three graph products namely Cartesian, strong Cartesian and lexicographic products. Though the formulation for the first two products exist, however, efficient implementations are made in this paper. The formulation for the generation of minimal cycle basis is extended to the lexicographic product. Copyright © 2007 John Wiley & Sons, Ltd.
Increased immunofluorescence sensitivity using 532 nm laser excitation
Authors: Perfetto Stephen P. , Roederer Mario
Published: January 2007

Objective:

We evaluated the use of a high power, diode pulsed solid‐state laser emitting 532 nm light for immunofluorescence applications. We compared the sensitivity and utility of this laser with the standard 488 nm excitation.

Methods:

A flow cytometer was equipped with both a 488 nm and a 532 nm laser; fluorescence emissions from each laser were collected using the same filters and the same detector system. Cells or compensation beads (e.g. latex beads coated with anti‐κ antibodies) were stained with monoclonal antibodies conjugated to phycoerythrin (PE) as well as the PE tandem dyes TRPE, Cy5PE, Cy5.5PE, and Cy7PE. The sensitivity of detection of these reagents as well as those in heavily compensated channels was quantified by measuring the spreading error for a primary detector into a secondary detector.

Results:

Measurement of the fluorescence emission of PE and PE‐tandem dyes was considerably more sensitive when using 532 nm excitation (150 mW) as compared with 488 nm excitation (20 mW). In addition, as the absolute number of photoelectrons collected was greater, there was less measurement‐error‐induced spread into the compensated channels. As an example, when comparing the spreading error of PE labeled cells into the TRPE detector, the green laser was found to be 15‐fold more sensitive as compared with the blue laser. In addition, the blue laser produced more autofluoresent signal from cells as compared with the green laser. Together, these advantages of the 532 nm excitation line provides for a significantly improved detection of immunofluorescence staining. Published 2007 Wiley‐Liss, Inc.
Robust design of communication systems: The case of expedited forwarding of voice traffic in differentiated services networks
Authors: Yoon Hyoup‐Sang , Yum Bong‐Jin
Published: January 2007

Design of experiments (DOE) is gaining acceptance in the community of telecommunication researchers, especially during the past several years. In this paper, a state‐of‐the‐art review on the use of DOE in the field of communication networks is presented, and the need for introducing a systematic robust design methodology to network simulations or testbed experiments is identified in ensuring robust behaviours of a network against uncontrollable sources of variation. Then, the Taguchi robust design methodology is applied for optimizing the expedited forwarding (EF) of voice traffic in a differentiated services network, and its step‐by‐step procedures are described in detail. The experimental data are collected using the ns‐2 simulator, and the SN ratio, a robustness measure, is analysed to determine an optimal design condition for each performance characteristic. The analysis results show that ‘type of queue scheduling schemes’ is a major control factor for ensuring robust behaviours of one‐way delay and jitter while ‘EF queue size’ is for throughput and loss rate. Finally, a compromised optimal design condition is identified using a desirability function approach adapted to multi‐characteristic robust design problems. Copyright © 2007 John Wiley & Sons, Ltd.
Performance evaluation and damage assessment of steel frame buildings under main shock–aftershock earthquake sequences
Authors: Li Quanwang , Ellingwood Bruce R.
Published: January 2007

Structures subjected to earthquake ground motions may be subjected to one or more aftershocks within a short period following the occurrence of the principal earthquake shock. Strong aftershocks have the potential to cause extensive structural damage, property losses and injuries to building occupants. This paper investigates the potential for aftershocks to cause additional damage to steel moment frame buildings, and provides a probabilistic description of structural damage states prior to and following those aftershocks. Statistics of structural response and damage states for steel frame buildings subjected to main shock–aftershock sequences are calculated using the enhanced uncoupled modal response history analysis (EUMRHA) method, a modification of an efficient and accurate method for predicting nonlinear response of frames. The frame connections are modelled by a moment–rotation relationship that takes brittle fracture of the connection welds into account. Damage accumulation is analysed in terms of a normalized ‘damage ratio’ and maximum inter‐storey drift. Simple probabilistic tools are proposed for purposes of rapid structural evaluation and condition assessment of damaged buildings. Copyright © 2007 John Wiley & Sons, Ltd.
The reflexive engineer: perceptions of integrated development
Authors: Robbins Peter T.
Published: January 2007

The professional ideology of engineers is said to be rooted in feelings of self‐importance and a belief in an ability to lead, based on qualities of technical expertise and rational decision‐making not held by the public at large. This paper outlines the views of another group of engineers, labelled ‘reflexive engineers’, having a much more integrated view of socio‐technical systems. Interviews were conducted with engineers working in the Global South in fields such as community water supply and sanitation. The paper aims to uncover how they make sense of the social and how they perceive factors shaping development practice. Copyright © 2007 John Wiley & Sons, Ltd.
Co‐evolutionary design for development: influences shaping engineering design and implementation in Nepal and the global village
Authors: Murcott Susan
Published: January 2007

This paper calls for a new generation of engineers, and the technologies they will invent and implement, to meet the basic human needs for security, broadly defined. The greatest threats to security for most people are not armed conflict but ‘common good’ social and environmental challenges. ‘Co‐evolutionary engineering design for development’ begins with a relationship among partners in the global village, informed by on‐the‐ground realities out of which culture/environment/location‐specific solutions emerge. This learning, iterative process among partners includes cooperation, local expertise, local resources and reliance on the global environment as a ‘lab’ for knowledge‐sharing and open‐source innovation. This article describes the conceptual framework of ‘co‐evolutionary design for development’ and takes the reader through the 10‐step cycle using, as a practical example, the design and implementation of an innovative arsenic and microbial remediation filter for households in rural Nepal. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of sodium adduct paeoniflorin, albiflorin and their derivatives by (+)ESI‐MSn, DFT calculations and computer‐aided mass spectrometry analysis program
Authors: Li Rui , Wang Xiaoling , Zhou Yan , Cai Min , Ding Lisheng
Published: January 2007

In order to analyze paeoniflorin, albiflorin and their derivatives (PADs) in Paeonia Lactiflora rapidly and effectively, (+)ESI‐MSn experiments were conducted, from which two diagnostic fragment patterns were acquired. Meanwhile, the dehydration ability of aglycones of PADs was obtained by calculating their activation energy using density functional theory, through which the unique dehydration phenomenon of benzoylalbiflorin, compared with benzoylpaeoniflorin, was interpreted. In addition, a computer‐aided mass spectrometry analysis program was developed to facilitate the analysis of the unknown compound by suggesting the possible structure of the analyte. Copyright © 2007 John Wiley & Sons, Ltd.
The Effect of Persistent TEMPO Radicals on the Gilch Polymerization
Authors: Wiesecke Jens , Rehahn Matthias
Published: January 2007

The mechanism of the Gilch polymerization leading to poly(p‐phenylene vinylenes) is still a matter of controversial discussion. Similar to some other research groups, we strongly favor a basically radical process. Moreover, we believe it is initiated by spontaneously formed diradicals. Here, we describe further experimental evidence which clearly supports the assumed initiation step: it is shown how the polymerization process is affected quantitatively when different amounts of 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (TEMPO) are added as a scavenger. In full agreement with our expectations, the chain growth is either retarded or completely prevented, depending on the respective molar ratio of monomer and scavenger.

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Pseudospectra, MUSIC, and dynamic wavelet neural network for damage detection of highrise buildings
Authors: Jiang Xiaomo , Adeli Hojjat
Published: January 2007

A non‐parametric system identification‐based model is presented for damage detection of highrise building structures subjected to seismic excitations using the dynamic fuzzy wavelet neural network (WNN) model developed by the authors. The model does not require complete measurements of the dynamic responses of the whole structure. A large structure is divided into a series of sub‐structures around a few pre‐selected floors where sensors are placed and measurements are made. The new model balances the global and local influences of the training data and incorporates the imprecision existing in the sensor data effectively, thus resulting in fast training convergence and high accuracy. A new damage evaluation method is proposed based on a power density spectrum method, called pseudospectrum. The multiple signal classification (MUSIC) method is employed to compute the pseudospectrum from the structural response time series. The methodology is validated using the data obtained for a 38‐storey concrete test model. The results demonstrate the effectiveness of the WNN model together with the pseudospectrum method for damage detection of highrise buildings based on a small amount of sensed data. Copyright © 2007 John Wiley & Sons, Ltd.
Tension membranes modelled by curvi‐linear bicubic splines
Authors: Brew J. S. , Lewis W. J.
Published: January 2007

One of the unique features of tension membrane structures (used as architectural roofing forms) is that their shape under tension has to be determined through an iterative, computational process, known as form‐finding. This paper describes the spline analysis approach, which makes use of general curvilinear co‐ordinates in Cartesian system, to model surface‐stretched tension membranes and inflatable structures. Surface‐stretched membranes are characterized by zero pressure difference between their outer and inner surfaces, while inflatable structures derive their shape and surface tension from the respective pressure differences. Examples presented in the paper include applications to both types of tension membranes and, for inflatable structures, include the case where the pressure difference is non‐uniform. The method can be applied to finding natural forms of shell structures. Copyright © 2007 John Wiley & Sons, Ltd.
Ageing and the brain
Authors: Esiri MM
Published: January 2007

In this review, the evidence for changes in the human brain with ageing at both the macroscopic and microscopic levels is summarized. Loss of neurons is now recognized to be more modest than initial studies suggested and only affects some neuron populations. Accompanying loss of neurons is some reduction in the size of remaining neurons. This reflects a reduced size of dendritic and axonal arborizations. Some of the likely causes of these changes, including free radical damage resulting from a high rate of oxidative metabolism in neurons, glycation and dysregulation of intracellular calcium homeostasis, are discussed. The roles of genes and environmental factors in causing and responding to ageing changes are explored. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Hallmarks of telomeres in ageing research
Authors: Shay JW , Wright WE
Published: January 2007

Telomeres are repetitive DNA sequences at the ends of linear chromosomes. Telomerase, a cellular reverse transcriptase, helps maintain telomere length in human stem cells, reproductive cells and cancer cells by adding TTAGGG repeats onto the telomeres. However, most normal human cells do not express telomerase and thus each time a cell divides some telomeric sequences are lost. When telomeres in a subset of cells become short (unprotected), cells enter an irreversible growth arrest state called replicative senescence. Cells in senescence produce a different constellation of proteins compared to normal quiescent cells. This may lead to a change in the homeostatic environment in a tissue‐specific manner. In most instances cells become senescent before they can become cancerous; thus, the initial growth arrest induced by short telomeres may be thought of as a potent anti‐cancer protection mechanism. When cells can be adequately cultured until they reach telomere‐based replicative senescence, introduction of the telomerase catalytic protein component (hTERT) into telomerase‐silent cells is sufficient to restore telomerase activity and extend cellular lifespan. Cells with introduced telomerase are not cancer cells, since they have not accumulated the other changes needed to become cancerous. This indicates that telomerase‐induced telomere length manipulations may have utility for tissue engineering and for dissecting the molecular mechanisms underlying genetic diseases, including cancer. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Ageing and hearing loss
Authors: Liu XZ , Yan D
Published: January 2007

Although many adults retain good hearing as they age, hearing loss associated with ageing is common among elderly persons. There are a number of pathophysiolological processes underlying age‐related changes to functional components in the inner ear. Genetic factors determine the ageing process but are under the influence of intrinsic and environmental factors. It is difficult to distinguish changes of normal ageing from those of other contributing factors. The effects of age‐related deafness can have significant physical, functional and mental health consequences. Although a deficit in hearing can be corrected to some degree by a hearing aid or other appropriate amplification devices, hearing‐related rehabilitative needs are much more than simply amplifying external sound. Only by better understanding the process of ageing and its effect on the auditory function can we better accommodate elderly people in our day‐to‐day interactions. We review here the structure and function of the inner ear, pathophysiology associated with age‐related hearing loss (ARHL), heritability, allelism and modifier genes of ARHL, and evaluate the genetic analyses for identification of genetic factors that are involved. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Renal ageing
Authors: Martin JE , Sheaff MT
Published: January 2007

The function of the kidney, as well as its morphology, changes markedly with age. The glomerular filtration rate falls progressively, independent of overt pathology. Glomerular, vascular and accompanying parenchymal changes occur and other disorders associated with ageing, such as diabetes and hypertension, have a stochastic deleterious effect on both form and function. Declining renal function with age has important implications, not only for individual homeostasis but also for the use of drug therapy and for the receipt and donation of organs for transplantation. Molecular mechanisms and cellular changes underlying some of the functional and structural changes associated with ageing are becoming clearer, as are some of the ways in which genetic background, age and disease can combine to produce functional damage. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The pathology of ageing: concepts and mechanisms
Authors: Martin JE , Sheaff MT
Published: January 2007

The rising numbers and proportion of aged individuals in the population is a global demographic trend. The diseases associated with ageing are becoming more prevalent, and the associated healthcare costs are having a significant economic impact in all countries. With these changes have come great advances in our understanding of the mechanisms of ageing. The mechanisms of cellular ageing at a genetic, protein and organelle level are becoming clearer, as are some of the more complex associations between environment and ageing. System ageing is also becoming better understood, and the potential biological advantages of ageing are being explored. Many of the advances in these fields are opening up the prospect of targeted therapeutic intervention for ageing and age related disease. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Pulsed Streamer Discharge Plasma over Ni/HZSM‐5 Catalysts for Methane Conversion to Aromatics at Atmospheric Pressure
Authors: Li Xiao‐Song , Shi Chuan , Xu Yong , Zhang Xiu‐Ling , Wang Kang‐Jun , Zhu Ai‐Min
Published: January 2007

A novel process consisting of a pulsed streamer discharge over Ni/HZSM‐5 catalysts for an oxygen‐free conversion of methane to aromatics is reported here. This plasma‐over‐catalyst process shows a significant synergetic effect on promoting methane conversion to aromatic products and high stability. Using this process at atmospheric pressure and a temperature of 573 K, significant amounts of aromatics have been obtained.

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