bluuebunny/crossref_metadata_2025 huggingface dataset:
Low‐density lipoprotein receptor‐related protein 5 (LRP5) expression in human osteoarthritic chondrocytes
Authors: Papathanasiou Ioanna , Malizos Konstantinos N. , Tsezou Aspasia
Published: October 2009

The aim of this study was to investigate the activation of the Wnt/β‐catenin pathway in osteoarthritis and the role of low‐density lipoprotein receptor‐related protein 5 (LRP5) in human osteoarthritic chondrocytes. The influence of 1,25(OH)2D3 on the expression of the LRP5 gene in human chondrocytes was also assessed. Human cartilage was obtained from 11 patients with primary osteoarthritis (OA) undergoing total knee replacement surgery. Normal cartilage was obtained from five healthy individuals. Beta‐catenin and LRP5 mRNA levels were investigated using real‐time PCR and LRP5 protein expression using Western blot analysis. Furthermore, we evaluated the effect of 1,25(OH)2D3 on LRP5 mRNA expression levels in osteoarthritic chondrocytes. Blocking LRP5 expression was performed using small interfering RNA (siRNA) against LRP5, and subsequent MMP‐13 mRNA and protein levels were evaluated by real‐time PCR and Western blot analysis, respectively. We confirmed the activation of the Wnt/β‐catenin pathway in OA, as we observed significant up‐regulation of β‐catenin mRNA expression in osteoarthritic chondrocytes. We also observed that LRP5 mRNA and protein expression were significantly up‐regulated in osteoarthritic cartilage compared to normal cartilage, and LRP5 mRNA expression was further increased by vitamin D. Also, blocking LRP5 expression using siRNA against LRP5 resulted in a significant decrease in MMP‐13 mRNA and protein expressions. Our findings suggest the catabolic role of LRP5 is mediated by the Wnt/β‐catenin pathway in human osteoarthritis. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:348–353, 2010
Middle to Late Pleistocene palaeoenvironmental evolution of the southeastern Alpine Valeriano Creek succession (northeastern Italy)
Authors: Monegato Giovanni , Lowick Sally E. , Ravazzi Cesare , Banino Roberta , Donegana Marta , Preusser Frank
Published: October 2009

The Middle–Late Pleistocene alluvial and lacustrine succession of Valeriano Creek (southeastern Alpine foothills, 190 m a.s.l.) documents the environmental evolution of the piedmont plain before the onset of the Last Glacial Maximum (LGM). The sedimentary record was investigated by multidisciplinary stratigraphical and sedimentological studies coupled with petrographic and palaeobotanical analysis. A chronology has been provided by luminescence, radiocarbon dating and pollen biochronology. The succession developed at the valley mouth of a small catchment and is confined in the piedmont plain by the alluvial fans of major rivers. The oldest deposits were formed during a cold phase during the late Middle Pleistocene. This part of the piedmont plain was generally stable until Termination II, when it was trenched more than 15 m deep by watercourses. The infilling succession of the trench, mostly by low‐energy alluvial sediments interbedded with mire and peat deposits, documents, for the first time on the southern side of the Alps, the relationships between fluvial activity, vegetation and climate change at the foothills piedmont plain during late Marine Isotope Stage (MIS) 5. The stadial–interstadial climate forcing implies a local reorganisation of fluvial dynamics and of forest composition, although substantial plant cover persisted even during cooler stadials. In accordance with coeval alluvial and speleothem records from the northern side of the Alps, this environmental evolution supports a very restricted Alpine glaciation of the main fluvial catchments of the southeastern Alps during MIS 5a–d. Copyright © 2009 John Wiley & Sons, Ltd.
Pollen‐inferred palaeoclimate reconstruction in the Alps during the Lateglacial and the early Holocene: how to estimate the effect of elevation and local parameters
Authors: Ortu Elena , David Fernand , Peyron Odile
Published: October 2009

The modern analogue technique (MAT) was applied to six pollen sequences from the Belledonne Massif (northwestern French Alps) to estimate the effect of altitude and local parameters on pollen‐based climate reconstruction during the Lateglacial and the early Holocene. The six sites (Le Vivier (345 m a.s.l.), Les Etelles (700 m a.s.l.), La Coche (980 m a.s.l.), Montendry (1330 m a.s.l.), Le Grand Leyat (1660 m a.s.l.), La Gouille (1800 m a.s.l.)) are located in different vegetation belts (mixed deciduous woods, conifer woods, alpine pastures with maple). The main vegetation changes in the past are recorded at each site. The evolution of four climate parameters (coldest month temperature, warmest month temperature, mean annual temperature, annual precipitation) was quantitatively inferred from pollen data using MAT. The curves obtained were compared to the Les Etelles site, which was the least affected by non‐local pollen transport. The results show consistent trends for the climate parameters reconstructed at the different sites. However, the reconstruction does not indicate a decrease in temperature values related to the increasing elevation. Difficulties in reconstructing the altitudinal variations of climate parameters from pollen data during the periods studied are discussed and perspectives for improvement are considered. Copyright © 2009 John Wiley & Sons, Ltd.
Vibrational spectra and crystal structure of the di‐amino acid peptide cyclo(L‐Met‐L‐Met): comparison of experimental data and DFT calculations
Authors: Mendham Andrew P. , Potter Brian S. , Palmer Rex A. , Dines Trevor J. , Mitchell John C. , Withnall Robert , Chowdhry Babur Z.
Published: October 2009

Experimental Raman and FT‐IR spectra of solid‐state non‐deuterated and N‐deuterated samples of cyclo(L‐Met‐L‐Met) are reported and discussed. The Raman and FT‐IR results show characteristic amide I vibrations (Raman: 1649 cm−1, infrared: 1675 cm−1) for molecules exhibiting a cis amide conformation. A Raman band, assigned to the cis amide II vibrational mode, is observed at ∼1493 cm−1 but no IR band is observed in this region. Cyclo(L‐Met‐L‐Met) crystallises in the triclinic space group P1 with one molecule per unit cell. The overall shape of the diketopiperazine (DKP) ring displays a (slightly distorted) boat conformation. The crystal packing employs two strong hydrogen bonds, which traverse the entire crystal via translational repeats. B3‐LYP/cc‐pVDZ calculations of the structure of the molecule predict a boat conformation for the DKP ring, in agreement with the experimentally determined X‐ray structure. Copyright © 2009 John Wiley & Sons, Ltd.
Raman spectroscopic characterization of a thiophene‐based active material for resistive organic nonvolatile memories
Authors: Fazzi Daniele , Canesi Eleonora Valeria , Bertarelli Chiara , Castiglioni Chiara , Negri Fabrizia , Zerbi Giuseppe
Published: October 2009

A combined theoretical and experimental Raman study is presented on a diphenyl bithiophene molecule known as a good candidate for the development of organic nonvolatile memory devices. Spectroscopic markers suitable to distinguish the different stable conformers of the molecule have been predicted and detected. The combined analysis of theoretical and experimental Raman spectra recorded in solution indicates that at room temperature a dynamical equilibrium, characterized by interconversion between the two more stable conformers (namely trans and cis), takes place and that the more populated species is the cis form. Referring to the solid phase instead, Raman spectra of single‐crystal samples show the presence of the only trans conformer, as confirmed by X‐ray measurements. Finally, Raman spectra of thin films, as those used for the memory device, were collected; samples just deposited from solution and after few hours from the deposition were analyzed. Following the evolution of selective spectroscopic Raman markers, an isomerization process from the abundant cis (as‐deposited) to the totally trans (after few hours) conformer in the solid phase was detected. These results open the way to the identification of the molecular isomers present in the thin film of the memory cell and finally of the active molecular species involved in the switching mechanism of the operating device. Copyright © 2009 John Wiley & Sons, Ltd.
Surface‐enhanced Raman scattering (SERS) spectra of hemoglobin on nano silver film prepared by electrolysis method
Authors: Kang Yipu , Si Minzhen , Liu Renming , Qiao Shibao
Published: October 2009

Nano silver films were prepared by the electrolysis method. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to detect the morphology of the silver particles. The surface‐enhanced Raman scattering (SERS) spectra of the hemoglobin on nano silver film were recorded. It is seen from the SERS spectra that the nano silver films can enhance the Raman signals of the hemoglobin efficiently, and sodium citrate and phosphate buffered saline have no influence on the SERS spectra of hemoglobin. The electrolysis technique to fabricate this highly bioactive, stable, reusable, and low‐cost SERS substrate will be useful in the development of hemoglobin detection methods. Copyright © 2009 John Wiley & Sons, Ltd.
Spectroscopic investigations and computational study of 2‐[acetyl(4‐bromophenyl)carbamoyl]‐4‐chlorophenyl acetate
Authors: Panicker C. Yohannan , Varghese Hema Tresa , Mariamma K. C. , John Koshy , Mathew Samuel , Vinsova Jarmila , Van Alsenoy Christian , Mary Y. Sheena
Published: October 2009

The Fourier transform Raman (FT‐Raman) and Fourier transform infrared (FT‐IR) spectra of 2‐[acetyl(4‐bromophenyl)carbamoyl]‐4‐chlorophenyl acetate were studied. The vibrational wavenumbers were examined theoretically using the Gaussian03 set of quantum chemistry codes, and the normal modes were assigned by potential energy distribution (PED) calculations. The simultaneous Raman and infrared (IR) activations of the CO stretching mode in the carbamoyl moiety show a charge transfer interaction through a π‐conjugated path. From the optimized structure, it is clear that the hydrogen bonding decreases the double bond character of the CO bond and increases the double bond character of the CN bonds. The first hyperpolarizability and predicted IR intensities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar structures, which makes this compound an attractive object for future studies of nonlinear optics. Optimized geometrical parameters of the compound are in agreement with similar reported structures. Copyright © 2009 John Wiley & Sons, Ltd.
Raman investigations of rare‐earth arsenate single crystals
Authors: Barros G. , Santos C. C. , Ayala A. P. , Guedes I. , Boatner L. A. , Loong C.‐K.
Published: October 2009

Polarized Raman spectroscopy was used to investigate the room‐temperature phonon characteristics of a series of rare‐earth arsenate (REAsO4, RE = Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, and Lu) single crystals. The Raman data were interpreted in a systematic manner based on the known tetragonal zircon structure of these compounds, and assignments and correlations were made for the observed bands. We found that the wavenumbers of the internal modes of the AsO4 tetrahedron increased with increasing atomic number. This increase seems to be correlated to the contraction of the RE–O bond length. For three out of four lattice wavenumbers observed, this tendency was not nearly so marked as in the case of the internal mode wavenumber. Copyright © 2009 John Wiley & Sons, Ltd.
Application of LC‐NMR to analysis of carotenoids in foods
Authors: Tode Chisato , Maoka Takashi , Sugiura Makiko
Published: October 2009

LC‐NMR has been applied to componential analysis of carotenoids in several foods, specifically, tomato juice, palm oil, and satsuma mandarin orange juice. The crude carotenoids extracted with organic solvent from these foodstuffs were analyzed after simple pre‐processing. Three, four, and two kinds of carotenoids were identified for tomato juice, palm oil, and satsuma mandarin orange, respectively, primarily by comparing their NMR spectra with those of pure standard.
Deformation of oxide scales on Fe‐20Cr alloy under compressive stress
Authors: Zhou C. H. , Ma H. T. , Wang L.
Published: October 2009

The behavior of oxide scales on Fe‐20Cr alloy was investigated in constant load at 1173 K in air. The objective was to understand the effect of mechanical loading on the deformation of oxide scales. It was carried out mainly by comparison of surface morphologies of oxidized specimens observed by scanning electronic microscope (SEM). In all cases, the oxide scales formed on specimens without stress showed a flat surface. However, oxide scales formed on specimens after 20 h of oxidation under a stress of 8 MPa (strain 3.07%) showed slip band characteristics. Furthermore, for longer oxidation time up to 65 h, slip bands formed under a low stress of 2 MPa (strain 1.19%), and grain boundary sliding became the main surface feature for the specimens subjected to a stress of 5 MPa (strain 2.53%). Two typical deformation forms are illustrated in the work.
Electrochemical behavior of some copper alloys in sulfuric acid solutions
Authors: El‐Feky H. E. , Helal N. H. , Negem M. R.
Published: October 2009

In this article, the corrosion behavior of CuFe and CuAlFe was studied in H2SO4 solutions in the absence and presence of different concentrations of some inorganic additives, Na2MoO4, K2Cr2O7, KIO3, and Na2B4O7. The techniques of measurements used were open‐circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy. The polarization measurements indicated that the corrosion current, Icorr, of CuFe is less than that of CuAlFe. The investigated additives in H2SO4 shifted Ecorr to more positive values and increases Icorr. Impedance measurements indicated that Nyquist plots for CuFe may be regarded as a semi‐circle in early stages of immersion and tends to be a part of semi‐circle with elapse of time and a well‐defined inductive loop appears. In case of CuAlFe, the Nyquist plots tends to be semi‐circle or depressed semi‐circle. The values of Rp for CuFe are higher than those for CuAlFe. On the other hand, the values of Cdl for CuFe are lower than those obtained for CuAlFe. The presence of these additives in H2SO4 solutions decreases the values of polarization resistance (Rp) and increases the values of corrosion current density (Icorr) and capacitance of double layer (Cdl).
Experimental evaluation of high solid polyurethane coating in the presence of salt at high temperature
Authors: Rezaei F. , Sharif F. , Sarabi A. A. , Kasiriha S. M. , Rahmanian M. , Akbarinezhad E.
Published: October 2009

Ions' presence and high temperature affect the performance and service life of all types of coatings including pipeline coatings. Pipeline coatings are relatively thick and their evaluations are very time consuming. In this study, experiments on the thick coating samples (roughly 250 and 400 µm) of high solid polyurethane (HSPU) have been conducted to evaluate the effect of high temperature and presence of ions in the media, on the performance of coatings. The experiments were performed in two types of electrolytes, sodium chloride solution (3.5 wt% fraction) and distilled water, at two temperature levels of 25 and 75 °C, respectively. The coating performance was studied using electrochemical spectroscopy impedance (EIS) method. The results of experiments show that the presence of ions reduces the service life of the coating and higher temperature accelerates the degradation process further if oxygen is not limited.
Electrochemical study of stainless steels used in an oil company by electrochemical impedance
Authors: Boudinar Y. , Innal F. , Chadli H. , Belmokre K.
Published: October 2009

Localized corrosion is a serious problem for stainless steel exposed in a chloride solution. In this context, the present work concerns the study of electrochemical behavior of 316 (A and B) and 430 (C and D) stainless steels, where A and C are laboratory steels, while steels B and D were taken from heat exchangers tubes (after 10 years of operation). This study has addressed three different aqueous environments: (1) monoethanolamine (MEA) 15%, (2) natural seawater (NSW), and (3) NaCl 3%, using the technique of potentiodynamic polarization curve complemented by electrochemical impedance spectroscopy (EIS). The obtained experimental electrochemical parameters (Ecorr, Jcorr, Er, Cd, Rtc, and constant phase element) were used to compare the corrosion resistance of the tested steels. As a result, the nobility of these steels in NaCl 3% and in MEA 15% solutions is established in the following order: 316 (A) > 316 (B) > 430 (C) > 430 (D), where Er moves increasingly toward the positive direction, indicating a good protection against corrosion. In addition, the results show that the effect of the electrolyte (aggression) is characterized by increased corrosion potential and a decrease in the passivity domain for all samples. The hierarchy of the nobility of steels A and C in these electrolytes can be determined as follows: MEA 15% > NSW > NaCl 3%.
Electrochemical corrosion behaviour of a Ti‐IF steel and a SAE 1020 steel in a 0.5 M NaCl solution
Authors: Osório W. R. , Peixoto L. C. , Garcia A.
Published: October 2009

Investigations concerning the electrochemical corrosion behaviour of low carbon (LC) and ultra‐low carbon (ULC) steels are relatively scarce and limited. The present study aims to compare electrochemical impedance parameters and potentiodynamic polarization curves of an LC steel and an ULC Ti‐interstitial free (IF) steel evidencing the effects of carbon content and pearlite fraction on the electrochemical corrosion behaviour. Corrosion tests were carried out in a 0.5 M NaCl solution at 25 °C with a pH range between 6.5 and 6.8. It was found that the IF steel sample presents an electrochemical corrosion resistance, which is slightly higher than that of the LC steel sample.
Strength of spot‐welded steel sheets in corrosive environment
Authors: Mukhopadhyay G. , Bhattacharya S. , Ray K. K.
Published: October 2009

The load bearing capacity (LBC), often referred to as strength, of spot‐welded joints on as‐received and pre‐strained sheets of an interstitial free (IF) steel has been examined under 3.5% sodium chloride solution using tensile‐shear (TS) specimens. These tests have been carried out under three different test conditions: (i) after immersing the samples in the solution for various duration of time, (ii) at various slow strain rates by keeping the samples in solution, and (iii) at slow strain rate under in situ hydrogen charging. Analyses of the results infer that (i) increased duration of immersion of the samples in aggressive environment decreases their LBC but increases their extension corresponding to the maximum load (EML), (ii) slow strain rate tests in the solution indicate marginal decrease of LBC and EML of the spot‐welds, (iii) the LBC and EML of the spot‐welds of pre‐strained sheets decrease considerably with cathodic hydrogen charging while EML of the spot‐welded joints on the as‐received sheets is found to improve, and finally, (iv) the detrimental effect of corrosive environment increases with increased pre‐strain of the investigated sheets. These observations have been discussed together with post‐failure examinations of the broken fractured surfaces, which have assisted in understanding their failure mechanism.
Hollow fibre‐supported liquid membrane extraction and LC‐MS/MS detection for the analysis of heterocyclic amines in urine samples
Authors: Busquets Rosa , Jönsson Jan Åke , Frandsen Henrik , Puignou Lluís , Galceran Maria Teresa , Skog Kerstin
Published: October 2009

Heterocyclic amines (HCAs) are potent mutagens/carcinogens to which humans are frequently exposed through the consumption of cooked meat and fish food. The effect of normal intake of HCAs and their role in the aetiology of human cancer is unknown. To some extent, limitations of the existing analytical methods in monitoring the low levels of HCAs in biological samples have hindered obtaining conclusive results. In this study, a method for the analysis of HCAs in human urine has been studied to detect HCAs and metabolites at levels resulting from consumption of food cooked at ordinary conditions. The analytical method consisted of extraction and clean‐up by the novel technique liquid‐phase microextraction combined with LC‐MS/MS. The effect of pH during the extraction and hydrolysis step was examined. High sensitivity was achieved when the extraction was performed in raw urine adjusted to pH 5.5, 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine being detected from 2 pg/g urine, levels comparable with a normal exposure. Good reproducibility and repeatability was obtained for 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine and 2‐amino‐3,8‐dimethylimidazo[4,5‐f]quinoxaline, below 9% using isotopic dilution. The performance of the method on 9H‐pyrido[3,4‐b]indole, 2‐amino‐1‐methyl‐6‐(4′‐hydroxyphenyl)imidazo[4,5‐b]pyridine and 2‐amino‐1‐methyl‐6‐(5‐hydroxy)phenylimidazo[4,5‐b]pyridine was also studied.
Traffic flow continuum modeling by hypersingular boundary integral equations
Authors: Romero Luis M. , Benitez Francisco G.
Published: October 2009

The quantity of data necessary in order to study traffic in dense urban areas through a traffic network, and the large volume of information that is provided as a result, causes managerial difficulties for the said model. A study of this kind is expensive and complex, with many sources of error connected to each step carried out. A simplification like the continuous medium is a reasonable approximation and, for certain dimensions of the actual problem, may be an alternative to be kept in mind. The hypotheses of the continuous model introduce errors comparable to those associated with geometric inaccuracies in the transport network, with the grouping of hundreds of streets in one same type of link and therefore having the same functional characteristics, with the centralization of all journey departure points and destinations in discrete centroids and with the uncertainty produced by a huge origin/destination matrix that is quickly phased out, etc. In the course of this work, a new model for characterizing traffic in dense network cities as a continuous medium, the diffusion–advection model, is put forward. The model is approached by means of the boundary element method, which has the fundamental characteristic of only requiring the contour of the problem to be discretized, thereby reducing the complexity and need for information into one order versus other more widespread methods, such as finite differences and the finite element method. On the other hand, the boundary elements method tends to give a more complex mathematical formulation. In order to validate the proposed technique, three examples in their fullest form are resolved with a known analytic solution. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of metal oxides on intumescent flame‐retardant polypropylene
Authors: Wu Na , Yang Rongjie
Published: October 2009

Variable amounts of transition metal oxides (MO), such as MnO2, ZnO, Ni2O3, etc., were incorporated into blends of polypropylene (PP)/ammonium polyphosphate (APP)/dipentaerythritol (DPER) with the aim of studying and comparing their effects with main‐group MO on intumescent flame retardance (IFR). The PP/IFR/MO composites were prepared using a twin‐screw extruder, and the IFR behavior was evaluated through oxygen index and vertical burning tests. The progressive enhancement of flame retardancy has proved to be strongly associated with the interaction between APP and MO. With the aid of thermogravimetry (TG) analysis, Fourier transform infrared (FTIR) spectra and scanning electron microscopy, Ni2O3 has been shown to be the most effective among the aforementioned three MO. The flame‐retardant mechanism of the IFR system is also discussed in terms of catalytic charring, which relates to complex formation through the d‐orbitals of the transition metal elements. It is considered that the melt viscosity of a PP/APP/DPER blend containing Ni2O3 corresponds well to the gas release with increasing temperature. Copyright © 2009 John Wiley & Sons, Ltd.
Combining selected reaction monitoring with discovery proteomics in limited biological samples
Authors: Gupta Mukesh Kumar , Jung Jin Woo , Uhm Sang Jun , Lee Hookeun , Lee Hoon Taek , Kim Kwang Pyo
Published: October 2009

Simultaneous quantification of multiple proteins by selected reaction monitoring (SRM) has several applications in cell signaling studies including embryo proteomics. However, concerns have recently been raised over the specificity of SRM assays due to possible ion redundancy and/or sequence similarity of selected peptide with multiple non‐related proteins. In this Viewpoint article, we discuss some simple measures that can increase our confidence in the accuracy of SRM scans used in proteomic experiments. At least in embryonic samples from porcine species, these measures were found to be useful in validating MS‐identified differentially expressed proteins. Among the nine proteins analyzed by SRM assay, all the proteins that were found to be up‐ or down‐regulated in MS experiment were also faithfully up‐ or down‐regulated in SRM assay.
Synthesis and self‐assembly behavior of amphiphilic polypeptide‐based brush‐coil block copolymers
Authors: Cai Chunhua , Zhu Wenjie , Chen Tao , Lin Jiaping , Tian Xiaohui
Published: October 2009

Synthesis and self‐assembly behavior of a novel amphiphilic brush‐coil block copolymer bearing hydrophilic poly(ethylene glycol) segment and hydrophobic polypeptide brush segment were presented in this work. The poly(γ‐benzyl‐L‐glutamate) (PBLG) brush is synthesized through “grafting from” strategy by ring‐opening polymerization of γ‐benzyl‐L‐glutamate‐N‐carboxyanhydride (BLG‐NCA) initiated by the flanking terminal primary amino group of macroinitiator. The copolymers were characterized by 1H NMR, gel permeation chromatography, Fourier transform infrared, circular dichroism spectrum, and differential scanning calorimetry. The self‐assembly behavior of the brush‐coil block copolymers in aqueous solution was investigated by means of transmission electron microscopy, scanning electron microscopy, atomic force microscopy, and laser light scattering. Spherical micelles were observed when the length of PBLG brush is shorter. The aggregate morphology transforms to spindle‐like micelles and then to rod‐like micelles, as the length of polypeptide brush increases. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5967–5978, 2009
DNA binding to electropolymerized N‐substituted polypyrrole surfaces
Authors: Percec Simona , Skidd Gabriel , Zheng Ming
Published: October 2009

This study explores the use of N‐substituted polypyrroles as a route for localizing DNA molecules onto conducting surfaces. N‐substituted pyrrole monomers containing N‐hydroxysuccinimidyl groups for DNA binding reactions were synthesized. These monomers were electro‐copolymerized under different conditions on platinum or gold working electrodes in a three‐electrode/single compartment cell. Subsequent DNA reactions were performed by incubating the resulting polymer conductive films with amino‐substituted DNA sequences. In addition, the electro‐copolymerization reactions of pyrrole monomers were conducted on preselected electrode positions of the Molecular Nanosystems (MNS) wafers and the formation of conductive films was demonstrated. In these experiments, it was determined also that by controlling the electro‐copolymerization reactions, the conductive films can be restricted to grow on specific locations of the MNS wafer. This was achieved by electrically passivating the chosen electrodes with self‐assembled multilayers (SAM)s of alkane thiols. Hexadecane thiol (HDT) was found the most efficient in forming SAMs and in preventing the pyrrole electropolymerization. Various analytical techniques including AFM, IR, and cyclic voltammetry (CV) were used to characterize the monomers, the electropolymerized polymers, and the attachment of amine‐terminated DNA to polypyrrole copolymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6014–6024, 2009
Anhydrous state proton conduction in sulfonated bisphenol a polyetherimide with 1H‐1,2,4 triazole as proton solvent
Authors: Guhathakurta Soma , Min Kyonsuku
Published: October 2009

In this study, bisphenol A polyetherimide was sulfonated to various degrees (22, 48, and 62%) by trimethylsilylchlorosulfonate (TMSCS). Novel anhydrous proton conducting polyelectrolytes were prepared by the incorporation of 1H‐1,2,4‐triazole (Taz) as proton solvent in sulfonated polyetherimide (SPEI) matrix. The conductivity reached about 2 × 10–3 S/cm at 80 °C and 10–2 S/cm at 140 °C. The temperature dependence proton conductivity of the polyelectrolytes followed Arrhenius equation. The conductivity improved considerably at a temperature close to the triazole melting temperature in SPEI(X)H matrix. It was proposed that the high mobility of the triazolium ions (vehicle diffusion), in addition to structure diffusion, contribute to the high conductivity of these proton conducting electrolytes above the melting temperature of triazole. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2178–2187, 2009
Stable colloidal Co–Pd nanocatalysts for carbon nanotube growth
Authors: Berenguer A. , Cantoro M. , Golovko V. B. , Hofmann S. , Wirth C. T. , Johnson B. F. G. , Robertson John
Published: October 2009

The standard preparation method for catalysts for surface‐bound growth of carbon nanotubes (CNT) is to sputter or evaporate the metal catalyst (Fe, Co, and Ni) onto the surface. A lower cost method for large areas is to use liquid delivery. Colloids have the advantage of containing the catalyst in nanocluster form. Our previously developed colloidal catalysts were successful for growth but had limited shelf‐life due to oxidation and coagulation. Here, we develop an air‐stable colloidal catalyst with long shelf‐life of many months to years.
Oxide catalysts for carbon nanotube and few layer graphene formation
Authors: Rümmeli Mark H. , Schäffel Franziska , Bachmatiuk Alicja , Trotter Geoff , Adebimpe David , Simha‐Martynková Grazyna , Plachá Daniela , Rellinghaus Bernd , McCormick Paul G. , Borowiak‐Palen Ewa , Ayala P. , Pichler Thomas , Klingeler Rüdiger , Knupfer Martin , Büchner Bernd
Published: October 2009

Oxides are rapidly emerging as an exciting alternative to metal catalysts for carbon nanotubes (CNT) formation because they are more easily integrated in Si technology, are usually easily removed in purification steps and are cheap. In this contribution we highlight the potential of oxides to synthesise single walled carbon nanotubes (SWCNT) (via laser evaporation), multiwalled carbon nanotubes and few layer graphene (via thermal CVD).

magnified image

Schematic illustration of graphitic carbon grown from oxide step site to form a CNT (left image) or graphene layer (right image).
Taylor–Proudman columns in non‐hydrostatic divergent baroclinic and barotropic flows
Authors: de la Torre Juárez Manuel
Published: October 2009

The Taylor–Proudman theorem states that the velocity of slow, steady flow in a rotating incompressible fluid does not change along the direction of the rotation axis. This fundamental result has been invoked to explain blocking phenomena observed over topographic features in oceanic and atmospheric flows on Earth and atmospheric patterns observed in giant gas planets even in cases where the assumption of incompressibility fails. The possible existence of Taylor–Proudman columns is analyzed here for a less restrictive family of non‐hydrostatic divergent density‐stratified flows, including situations where the stratification gradient and rotation axis are not parallel. The results show that Taylor–Proudman‐like constraints are possible in baroclinic inviscid and viscous nonlinear flows of constant vorticity, Beltrami flows and low‐Rossby‐number flows. It is found that (1) the baroclinic term is moderated by a factor of the order of the Rossby number, (2) a conservation law can be found for baroclinic flows and (3) Taylor–Proudman columns will be eroded in viscous flows. One particular result stressed in this note is its interpretation in equatorial regions, where the rotation axis is perpendicular to the main stratification gradient, and it is argued that Taylor–Proudman columns could be difficult to discern with observational parameters from convective cells with only zonal and vertical transport. Copyright © 2009 Royal Meteorological Society
Characterization of the impact of geostationary clear‐sky radiances on wind analyses in a 4D‐Var context
Authors: Peubey C. , McNally A.P.
Published: October 2009

The impact of geostationary clear‐sky radiances (CSRs) on 4D‐Var wind analyses has been investigated by running a set of observing system experiments. Analysis scores have been calculated to measure the ability of individual satellite datasets to improve the wind analysis, starting from a no‐satellite baseline. In this context, the assimilation of CSRs from the two water‐vapour channels on Meteosat‐9 has been found to improve the wind analysis throughout the troposphere, with the strongest signal at 300 and 500 hPa. Indeed, for the Northern Hemisphere and the Tropics, the CSR impact at these levels exceeds that of the Meteosat‐9 atmospheric motion vectors (AMVs), the sampling of the latter in the assimilation being rather limited. Conversely, the impact of AMVs exceeds that of CSRs in the lower troposphere, where the latter provide very little direct information. This demonstrates the complementarity of the two datasets in the operational 4D‐Var wind analysis. The mechanisms through which the assimilation of CSRs can impact wind analyses have been isolated. The dominant effect is that of humidity‐tracer advection, by which the wind field is adjusted in order to fit observed humidity features via the minimization of the 4D‐Var cost function. Other mechanisms, such as balance constraints and the cycling of the forecast model that links the humidity and wind variables, have been found to play a minor role. The benefit of having frequent CSR images within the assimilation window has also been demonstrated. Copyright © 2009 Royal Meteorological Society
Balanced and unbalanced aspects of tropical cyclone intensification
Authors: Bui Hai Hoang , Smith Roger K. , Montgomery Michael T. , Peng Jiayi
Published: October 2009

We investigate the extent to which the azimuthally–averaged fields from a three‐dimensional, non‐hydrostatic, tropical cyclone model can be captured by axisymmetric balance theory. The secondary (overturning) circulation and balanced tendency for the primary circulation are obtained by solving a general form of the Sawyer–Eliassen equation with the diabatic heating, eddy heat fluxes and tangential momentum sources (eddy momentum fluxes, boundary‐layer friction and subgrid‐scale diffusion) diagnosed from the model. The occurrence of regions of weak symmetric instability at low levels and in the upper‐tropospheric outflow layer requires a regularization procedure so that the Sawyer–Eliassen equation remains elliptic. The balanced calculations presented capture a major fraction of the azimuthally–averaged secondary circulation of the three‐dimensional simulation except in the boundary layer, where the balanced assumption breaks down and where there is an inward agradient force. In particular, the balance theory is shown to significantly underestimate the low‐level radial inflow and therefore the maximum azimuthal‐mean tangential wind tendency. In the balance theory, the diabatic forcing associated with the eyewall convection accounts for a large fraction of the secondary circulation. The findings herein underscore both the utility of axisymmetric balance theory and also its limitations in describing the axisymmetric intensification physics of a tropical cyclone vortex. Copyright © 2009 Royal Meteorological Society
On the impact of high‐resolution, high‐frequency meteorological forcing on Denmark Strait ocean circulation
Authors: Haine T. W. N. , Zhang S. , Moore G. W. K. , Renfrew I. A.
Published: October 2009

This paper quantifies and discusses the impact of high‐resolution, high‐frequency atmospheric forcing on the ocean circulation in the vicinity of the Denmark Strait. The approach is to force a 2 km resolution regional ocean circulation model with atmospheric states from reanalysis products that have different spatial and temporal resolutions. We use the National Center for Environmental Prediction global reanalysis data (2.5° resolution, 6‐hourly output) and a specially configured regional atmospheric model (12 km resolution, hourly output). The focus is on the month‐long period in winter 2007 during the Greenland Flow Distortion Experiment. Diagnostics of upper‐ocean currents and mixing are sensitive to the small‐scale variability in the high‐resolution regional atmospheric model. The hydrographic state of the ocean model is insensitive over the month‐long experiments, however. Both sea ice and the fluxes of volume, heat, and freshwater across the east Greenland shelf break and through the Denmark Strait show a moderate response to the high‐resolution atmospheric forcing. The synoptic‐scale atmospheric state has a large role in controlling sea ice too, while internal ocean dynamics is the dominant factor controlling the flux diagnostics. It is the high spatial resolution, not the temporal resolution, that causes these effects, with O(10 km)‐scale features being most important. The sea‐level wind field is responsible, with the other atmospheric fields playing relatively minor roles. Copyright © 2009 Royal Meteorological Society
Analysis sensitivity calculation in an ensemble Kalman filter
Authors: Liu Junjie , Kalnay Eugenia , Miyoshi Takemasa , Cardinali Carla
Published: October 2009

Analysis sensitivity indicates the sensitivity of an analysis to the observations, which is complementary to the sensitivity of the analysis to the background. In this paper, we discuss a method to calculate this quantity in an Ensemble Kalman Filter (EnKF). The calculation procedure and the geometrical interpretation, which shows that the analysis sensitivity is proportional to the analysis error and anti‐correlated with the observation error, are experimentally verified with the Lorenz 40‐variable model. With the analysis sensitivity, the cross‐validation in its original formulation can be efficiently computed in EnKFs, and this property can be used in observational quality control.

Idealized experiments based on a simplified‐parametrization primitive equation global model show that the information content (the trace of the analysis sensitivity f any subset of observations) qualitatively agrees with the actual observation impact calculated from much more expensive data‐denial experiments, not only for the same type of dynamical variable, but also for different types of dynamical variables. Copyright © 2009 Royal Meteorological Society
An electropneumatic‐heated nebulizer for enhancing spray ionization in PhotoSpray atmospheric pressure photoionization sources for liquid chromatography/mass spectrometry
Authors: Robb Damon B. , Blades Michael W.
Published: October 2009

We introduce a novel electropneumatic‐heated nebulizer (EPn‐HN), incorporating an electrified internal pneumatic nebulizer, to enhance the yield of sprayed ions from PhotoSpray™ atmospheric pressure photoionization (APPI) sources for liquid chromatography/mass spectrometry (LC/MS). Spray ionization from the pneumatic‐heated nebulizers used in APPI sources provides a supplemental, complementary ionization method to be used for involatile and thermally labile compounds, otherwise intractable to APPI. Details of the construction and operation of the EPn‐HN device are provided. The performance of the EPn‐HN is demonstrated using two model compounds: substance P, a peptide used as a standard in studies of ion fragmentation mechanisms, and aztreonam, a thermally labile antibiotic. At the optimum voltage for spray ionization, improvements in sensitivity of two orders of magnitude are obtained relative to when the sprayer is grounded, the conventional case. Since both substance P and aztreonam cannot be detected using the APPI method alone, the results demonstrate how spray ionization from the EPn‐HN may be used to extend the range of compounds amenable to PhotoSpray sources. Copyright © 2009 John Wiley & Sons, Ltd.
Atmospheric‐pressure spin plasma jets processing of polymethylmethacrylate surface using experimental design methodology
Authors: Chen Tai‐Hung , Liu Chi‐Hung , Teng Jyh‐tong , Su Chun‐Hsien , Huang Chun , Sheu Han‐Lin , Lin Shermann
Published: October 2009

Atmospheric‐pressure spin plasma jets (APSPJs) have been developed to induce surface modifications on polymethylmethacrylate (PMMA). In this study, an experimental design methodology was used to investigate the influence of process parameters [such as radio frequency (RF) power, processing gap, and number of treatment cycles] on the characteristics of PMMA surface treated by APSPJs. It was observed from the atomic force microscope (AFM) and scanning electron microscope (SEM) results that the surface morphology of PMMA treated by direct plasma is much rougher than that treated by remote plasma. The direct plasma used in APSPJs processing created a substantial amount of nanostructure grains. Moreover, the measured XPS results showed that the O/C ratios of the PMMA surface were substantially increased and subsequently water contact angle decreased on direct plasma treatment. This decrease is due to an increase of oxygen‐containing functional groups on the PMMA surface by the APSPJs processing. From the statistical analysis, the RF power and the processing gap were found to play a major role in enhancing the hydrophilic properties of PMMA surface. In contrast, the number of treatment cycles played only a secondary role in this case. Finally, in this study the APSPJs processing was demonstrated to be an effective method for surface modification of PMMA by controlling processing parameters during the treatment process. Copyright © 2009 John Wiley & Sons, Ltd.
Direct detection of nicotine and cotinine in dusted latent fingermarks of smokers by using hydrophobic silica particles and MS
Authors: Benton Matthew , Rowell Frederick , Sundar Latha , Jan Ma
Published: October 2009

Sub‐micron sized hydrophobic silica particles doped with carbon black have been employed with latent fingermarks on glass and metal surfaces to develop a simple method for detecting nicotine and cotinine using surface assisted laser desorption/ionisation‐time of flight‐mass spectrometry (SALDI‐TOF‐MS) in positive ion reflectron mode. Dusting of surfaces enables location of marks for conventional identification of details but the particles also act as a laser desorption/ionisation enhancing agent (LDI) equivalent to a standard matrix enhancer 2,5‐dihydroxybenzoic acid used in matrix assisted LDI‐TOF‐MS (MALDI‐TOF‐MS). The method has been applied in the analysis of smokers' latent fingermarks on metal and glass surfaces. The metal surfaces were analysed following direct MS analysis of the pre‐dusted prints, while the glass surfaces were analysed following lifting using commercial tape, and then MS analysis of these pre‐dusted prints. In all cases of smokers, a major peak at m/z 163 (nicotine+1) and a less intense peak at m/z 161 (possibly anatabine+1) were found in the prints and in some cases additional peaks at 177 (cotinine+1) and 199 (possibly cotinine+Na) were observed. The presence of nicotine and cotinine in smokers' marks was confirmed using SALDI‐TOF‐MS‐MS following high energy collision‐induced dissociation when characteristic fragmentation patterns were observed for each compound. Copyright © 2009 John Wiley & Sons, Ltd.
Length Distribution of Single‐Walled Carbon Nanotubes in Aqueous Suspension Measured by Electrospray Differential Mobility Analysis
Authors: Pease Leonard F. , Tsai De‐Hao , Fagan Jeffery A. , Bauer Barry J. , Zangmeister Rebecca A. , Tarlov Michael J. , Zachariah Michael R.
Published: October 2009

The first characterization of the length distribution of single‐walled carbon nanotubes (SWCNT) dispersed in a liquid by electrospray differential mobility analysis (ES‐DMA) is presented. Although an understanding of geometric properties of SWCNTs, including length, diameter, aspect ratio, and chirality, is essential for commercial applications, rapid characterization of nanotube length distributions remains challenging. Here the use of ES‐DMA to obtain length distributions of DNA‐wrapped SWCNTs dispersed in aqueous solutions is demonstrated. Lengths measured by ES‐DMA compare favorably with those obtained from multiangle light scattering, dynamic light scattering, field flow fractionation with UV/vis detection, and atomic force microscopy, validating ES‐DMA as a technique to measure SWCNTs of <250 nm in length. The nanotubes are previously purified and dispersed by wrapping with oligomeric DNA in aqueous solution and centrifuging to remove bundles and amorphous carbon. These dispersions are particularly attractive due to their amenability to bulk processing, ease of storage, high concentration, compatibility with biological and high‐throughput manufacturing environments, and for their potential applications ranging from electronics and hydrogen‐storage vessels to anticancer agents.
SSRI antidepressants do not confound single photon emission computed tomography (SPECT) imaging studies using the α4β2 nicotinic acetylcholine receptor [123I]5‐I‐A85380 ligand: In vivo and in vitro evidence
Authors: Cavanagh Jonathan , Patterson James , Pimlott Sally , Wyper David , Dewar Deborah
Published: October 2009

Purpose: In clinical molecular imaging the interaction between antidepressant medication and SPECT ligands is a significant potential confound. This study measured nAChR availability, as determined by SPECT imaging, on and off selective serotonin reuptake inhibitors in first episode depressed patients. Methods: Five patients in their first episode of major depressive disorder (MDD) on a single SSRI underwent [123I]5‐I‐A85380‐ SPECT neuroimaging prior to stopping their medication and again 6 weeks following medication cessation. Autoradiography of post mortem brain tissue with [125I]5‐I‐A85380 in the presence or absence of four commonly prescribed antidepressants was also assessed. Results: SSRI antidepressants did not affect the relative binding availability of α4β2 nicotinic acetylcholine receptors for the [123I]5‐I‐A85380 ligand in vivo. Radioligand binding in vitro was unaffected by a single, high pharmacological concentration of antidepressants. Conclusion: SPECT imaging studies using [123I]5‐I‐A85380 to measure α4β2 nAChR availability in depressed patients are unlikely to be confounded to a major degree by concurrent antidepressant medication. Synapse 64:111–116, 2010. © 2009 Wiley‐Liss, Inc.