bluuebunny/crossref_metadata_2025 huggingface dataset:
Grouping of hydrogen‐bond ability of pure solvents and their binary mixtures based on the similarity of their microscopic properties. Part 2
Authors: Pérez Adriana del C. , Mancini Pedro M.
Published: September 2008

The work presents a grouping scheme of some pure solvents (which are able to form hydrogen‐bonded complexes) and their binary mixtures on the basis of the similarity of their molecular‐microscopic properties. The solvatochromic parameters SPP, SA, and SB developed by Catalán et al. are selected as clustering variables. The Ward Method (WM) and the Group Average Method (GA) are applied as clustering procedures. The study pays particular attention to the microscopic solvent feature common to all solvents included in each cluster, describing the relevant solvating properties. It also contributes to a better understanding of the similarities and differences of the explored solvents. Copyright © 2008 John Wiley & Sons, Ltd.
Ab initio and DFT calculations on the gas phase elimination kinetics of 2,2‐diethoxy‐ethylamine and 2,2‐diethoxy‐N,N‐diethyl‐ethylamine
Authors: Mora José Ramón , Tosta María , Cordova Tania , Chuchani Gabriel
Published: September 2008

The mechanisms for the gas phase molecular elimination kinetics of 2,2‐diethoxy‐ethylamine and 2,2‐diethoxy‐N,N‐diethyl‐ethylamine were examined at MP2/6‐31G, B3LYP/6‐31G, B3LYP/6‐31G(d,p), MPW91PW91/6‐31G. MPW91PW91/6‐31G(d,p), PBEPBE/6‐31G, and PBEPBE/6‐31G(d,p) levels of theory. These elimination processes involve two parallel reactions. The first parallel reaction gives ethanol and the corresponding 2‐ethoxyethenamine. The latter compound further decomposes to ethylene, CO, and the corresponding amine. The second parallel reaction produces ethane and the corresponding ethyl ester of an α‐amino acid. Calculated thermodynamic and kinetic parameters from PBEPBE calculations were found to be in good agreement with the experimental values. The transition states of the parallel reactions are best described as four‐membered cyclic structures. The intermediate 2‐ethoxy‐ethenamine undergoes a consecutive elimination through a six‐membered cyclic transition state mechanism. Bond indexes and synchronicity (Sy) parameters are in agreement with concerted semi‐polar transition state structures. Copyright © 2008 John Wiley & Sons, Ltd.
Prediction Method for Specific Impulse Used as Performance Quantity for Explosives
Authors: Keshavarz Mohammad Hossein
Published: September 2008

A novel method is presented to estimate the prediction of the specific impulse of mostly ideal and less ideal compositions of explosives. It requires only elemental compositions and some structural parameters of pure and composite explosives. There is no need to use the heat of formation of the explosive, which is an essential input parameter to compute the specific impulse through complicated computer codes. Moreover, there is no need to use any assumed decomposition products to calculate the specific impulse. The new simple method gives good results for any CaHbNcOd explosives, even with complicated molecular structures, and their composite mixtures. The calculated specific impulse can also be used to estimate detonation pressures and velocities of pure and mixed explosives at specified loading densities.
Gene profiling and pathway analysis of neuroendocrine transdifferentiated prostate cancer cells
Authors: Mori Ryutaro , Xiong Shigang , Wang Qingcai , Tarabolous Chad , Shimada Hiroshi , Panteris Eleftherios , Danenberg Kathleen D. , Danenberg Peter V. , Pinski Jacek K.
Published: September 2008

BACKGROUND

Neuroendocrine (NE) cells are present in both normal prostate and prostate cancer. In addition, NE differentiation can be induced by various factors, such as IL‐6, in vitro and in vivo. However, the mechanism of this differentiation and the role of NE cells in prostate cancer are not well understood. In this study, we evaluated the gene expression and analyzed the pathways in prostate cancer cells exposed to various NE differentiation inducing factors in vitro.

METHODS

Gene expression signatures between control LNCaP cells and each treatment induced NE cell line were compared using Affymetrix GeneChip with network and pathway analysis.

RESULTS

All treatments were able to transdifferentiate LNCaP cells into NE phenotype as shown by morphology changes and NE marker measurements. Of the 54,675 oligonucleotide‐based probe sets in microarray, 44,975 were mapped into the Ingenuity Pathway Analysis database and were filtered according to the t‐test P value. At P < 0.002, the number of genes that were differentially expressed included 302 of the IL‐6 treated cells, 201 of genistein, 233 of epinephrine, and 191 of the charcoal stripped serum ones. A pooled data approach also showed 346 differentially expressed genes at the same P value. Gene ontology analysis showed that cancer‐related function had the highest significance.

CONCLUSIONS

Despite some overlap, each NE transdifferentiation inducing treatment was associated with a changed expression of a unique set of genes, and such gene profiling may help to elucidate the molecular mechanisms involved in NE transdifferentiation of prostate cancer cells. Prostate 69: 12–23, 2009. © 2008 Wiley–Liss, Inc.
Species‐specific insecticide resistance to imidacloprid and fipronil in the rice planthoppers Nilaparvata lugens and Sogatella furcifera in East and South‐east Asia
Authors: Matsumura Masaya , Takeuchi Hiroaki , Satoh Masaru , Sanada‐Morimura Sachiyo , Otuka Akira , Watanabe Tomonari , Van Thanh Dinh
Published: September 2008

BACKGROUND: In 2003 the development of insecticide resistance against neonicotinoids in the brown planthopper (BPH), Nilaparvata lugens (Stål) (Homoptera: Delphacidae), was first observed in Thailand and has since been found in other Asian countries such as Vietnam, China and Japan. However, the LD50 values of BPH and the whitebacked planthopper (WBPH), Sogatella furcifera (Horváth), against both neonicotinoid and phenylpyrazole insecticides have been poorly reported in many Asian countries.

RESULTS: The topical LD50 values for imidacloprid in the BPH populations collected from East Asia (Japan, China, Taiwan) and Vietnam in 2006 were 4.3–24.2 µg g−1 and were significantly higher than those collected from the Philippines (0.18–0.35 µg g−1). The BPH populations indicated a positive cross‐resistance between imidacloprid and thiamethoxam. Almost all the WBPH populations from Japan, Taiwan, China, Vietnam and the Philippines had extremely large LD50 values (19.7–239 µg g−1 or more) for fipronil, except for several populations from the Philippines and China.

CONCLUSION: Species‐specific changes in insecticide susceptibility were found in Asian rice planthoppers (i.e. BPH for imidacloprid and WBPH for fipronil). Insecticide resistance in BPH against imidacloprid occurred in East Asia and Indochina, but not in the Philippines. In contrast, insecticide resistance in WBPH against fipronil occurred widely in East and South‐east Asia. Copyright © 2008 Society of Chemical Industry
Application of MSM bulk material in a hybrid microactuator
Authors: Spasova B. , Ruffert C. , Wurz M. C. , Gatzen H. H.
Published: September 2008

Smart materials such as magnetic shape memory (MSM) metals allow to coming up with new actuators with a rather simple design. NiMnGa MSM material was applied for creating a hybrid microactuator. Two MSM stripes are mounted in a row. Thin‐film stators provide a magnetizing field causing a magnetic field induced strain (MFIS) in NiMnGa MSM stripes. However, the magnetic field is only used for elongating the stripes. The stripe subjected to strain is returning the other MSM stripe mechanically into its non‐strained state and vice versa. Compressing them to their non‐strained state is provided by mechanical means. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hot‐wire CVD of copper films on self‐assembled‐monolayers of MPTMS
Authors: Papadimitropoulos G. , Arapoyianni A. , Davazoglou D.
Published: September 2008

Self‐assembled monolayers (SAM's) of (3‐Mercaptopropyl)trimethoxysilane (MPTMS) were applied on Si (100) wafers covered either with low‐temperature silicon oxide (LTO) or with SiLK®. Cu films were subsequently chemically vapor deposited (CVD) on the MPTMS SAMs with a novel reactor equipped with a tungsten hot‐wire enabling the separate heating of the gas phase (hot‐wire CVD, HWCVD). CupraSelect®, which is the commercial name of hexafluoroacetylacetonate Cu(I) trimethylvinylsilane, was used as precursor for the deposition of Cu films and delivered in the reactor with the aid of a direct‐liquid injection system using ultra‐pure N2 as carrier gas. High quality Cu films were obtained on both LTO and SiLK®. The resistivities of HWCVD Cu films were found to be higher than those of thermally grown films. This is due possibly to the presence of impurities into the Cu films from the incomplete dissociation of the precursor and W impurities caused by the presence of the filament, which does not, however, degrade catastrophically the conductivity of Cu HWCVD films. The separate heating of the gas phase enhanced the deposition rate, which at filament temperature of 170 °C increases by a factor of approximately one and a half. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Enhanced95Zr diffusion in grain boundaries of nano‐crystalline ZrO2·9.5 mol% Y2O3
Authors: Drings Harald , Brossmann Ulrich , Carstanjen Heinz‐Dieter , Szökefalvi‐Nagy Ágnes , Noll Cornelia , Schaefer Hans‐Eckhardt
Published: September 2008

The95Zr cation self‐diffusivity in fully‐dense, nanocrystalline cubic ZrO2·9.5 mol% Y2O3(n‐YSZ, mean grain size 50 nm) has been studied by tracer self‐diffusion and precision‐grinding sectioning. In the temperature range of 897 °C to 937 °C the95Zr diffusion coefficient in grain boundaries was found to be about 7 orders of magnitude higher than in single crystals of similar composition. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stability of dislocation structures in copper towards stress relaxation investigated by high angular resolution 3D X‐ray diffraction
Authors: Jakobsen Bo , Poulsen Henning Friis , Lienert Ulrich , Bernier Joel , Gundlach Carsten , Pantleon Wolfgang
Published: September 2008

A 300 µm thick tensile specimen of OFHC copper is subjected to a tensile loading sequence and deformed to a maximal strain of 3.11%. Using the novel three‐dimensional X‐ray diffraction method ‘High angular resolution 3DXRD', the evolution of the microstructure within a deeply embedded grain is characterised in‐situ by the behaviour of individual subgrains. The loading sequence consists of three continuous deformation stages with strain rates of 1.1 × 10–6 s–1 and 3 × 10–2 s–1, in each case followed by a period of extended stress relaxation at fixed motor positions, as well as an unloading step. In contrast to the deformation stages, during each stress relaxation stage, number, size and orientation of subgrains are found to be constant, while a minor amount of clean‐up of the microstructure is observed as narrowing of the radial X‐ray diffraction line profile. The associated decrease in the width of the strain distribution indicates homogenization of the elastic strains present in the deformation structure. During reloading, the subgrain structure seemingly starts to develop further when the entire dislocation structure is deforming plastically. Upon unloading of the sample, the average backward strain of the subgrains increases. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth, evolution and photocatalytic activity of ZnO nano back‐tapered arrays
Authors: He Z. B. , Jiang Y. , Zhang W. J. , Zapien J. A. , Liu Y. , Zhang W. F. , Bello I.
Published: September 2008

Zinc oxide arrays of conical and hexagonal back‐tapered nanocolumns with well‐developed, flat and horizontal (0001) facets were synthesized on gold‐coated (100) silicon substrates by a thermal evaporation process. Evolution of these conical and back‐tapered structures was investigated by analysis of their morphological and chemical structures in different growth phases employing scanning electron microscopy, energy‐dispersive X‐ray spectroscopy and cathodoluminescence imaging. This study reveals that an ultrathin gold film predeposited on silicon is required to provide nucleation sites and form ZnO grains that progressively grow to vertical nanostructures. The growth process is assisted by carbon‐reduced zinc droplets deposited from the gas phase on the ZnO grains that evolve into back‐tapered nanocanonical and hexagonal columns. These nanostructures are shown to be effective in the degradation of organic dyes. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ammonium oxotrifluorotitanate: morphology control and conversion to anatase TiO2
Authors: Zhou Lei , O'Brien Paul
Published: September 2008

Uniform ammonium oxotrifluorotitanate (NH4TiOF3) mesocrystals were synthesized from an aqueous solution containing (NH4)2TiF6 and H3BO3 in presence of nonionic surfactant. Effects of various reaction conditions on the morphology of the NH4TiOF3 mesocrystals were examined by electron microscopy techniques. Results indicate that static solution, high surfactant concentration and low reaction temperature enhance the formation of uniform NH4TiOF3 mesocrystals with regular shapes. By sintering in atmosphere, the NH4TiOF3 mesocrystals were converted to anatase TiO2, which retain the original shapes of the NH4TiOF3 precursor due to similarities on their atom structures. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron momentum density in zinc oxide
Authors: Kothari R. K. , Sharma M. , Joshi K. B. , Sharma B. K.
Published: September 2008

The electron momentum density distribution in zinc oxide is reported. The momentum density distribution is determined experimentally through Compton profile measurement on polycrystalline ZnO by employing an annular 5Ci Am241 Compton spectrometer. Theoretical comparison is done through LCAO calculations under the hybrid scheme using CRYSTAL code. The calculated Compton profile is found to be in good agreement with the measurement. On the basis of equal‐valence‐electron‐density (EVED) profiles, partial covalent character of bonding is observed in ZnO. ZnO is found to be more ionic than the ZnS and ZnSe. The charge transfer mediated by p–d hybridization is predicted to be responsible for the partial covalent nature. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Elasticity, electronic structure, and dielectric property of cubic SrHfO3 from first‐principles
Authors: Hou Z. F.
Published: September 2008

Recently, SrHfO3 compound was proposed as a potential gate dielectric to fabricate metal–oxide–semiconductor field‐effect transistors (MOSFET) with equivalent oxide thickness (EOT) below 1 nm. Here we report the elasticity, electronic structure, and dielectric property of cubic SrHfO3 from first‐principle study based on the plane‐wave pseudopotential method within the local density approximation (LDA). The independent elastic constants of cubic SrHfO3 are derived from the derivative of total energy as a function of lattice strain. The elastic modulus is predicted from Voight‐Hill bounds. The Born effective charges, electronic dielectric tensors, long wavelength phonon frequencies, and LO–TO splitting of cubic SrHfO3 are computed by linear response with density functional perturbation theory (DFPT). The calculated lattice constant and bulk modulus of cubic SrHfO3 are in good agreement with the available experimental data and other theoretical results. Our results show cubic SrHfO3 is a ductile insulator with an indirect band gap of 3.74 eV (LDA value) and electric dielectric tensor of 4.43, Hf 5d states and O 2p states exhibit a strong hybridization, and cubic SrHfO3 can be mechanically stable. In addition, the phonon frequency of ‘soft mode' at zone‐center also agrees well with previous theoretical value. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two‐dimensional thermoelectric Seebeck coefficient of SrTiO3‐based superlattices
Authors: Ohta Hiromichi
Published: September 2008

This review provides the origin of the unusually large thermoelectric Seebeck coefficient |S | of a two‐dimensional electron gas confined within a unit cell layer thickness (∼0.4 nm) of a SrTi0.8Nb0.2O3 layer of artificial superlattices of SrTiO3/SrTi0.8Nb0.2O3 [H. Ohta et al., Nature Mater. 6, 129 (2007)]. The |S |2D values of the [(SrTiO3)17/(SrTi0.8Nb0.2O3)y ]20 superlattice increase proportional to y–0.5, and reach 290 μV K–1 (y = 1) at room temperature, which is ∼5 times larger than that of the SrTi0.8Nb0.2O3 bulk (|S |3D = 61 μV K–1), proving that the density of states in the ground state for SrTiO3 increases in inverse proportion to y. The critical barrier thickness for quantum electron confinement is also clarified to be 6.25 nm (16 unit cells of SrTiO3). Significant structural changes are not observed in the superlattice after annealing at 900 K in a vacuum. The value of |S |2D of the superlattice gradually increases with temperature and reaches 450 μV K–1 at 900 K, which is ∼3 times larger than that of bulk SrTi0.8Nb0.2O3. These observations provide clear evidence that the [(SrTiO3)17/(SrTi0.8Nb0.2O3)1]20 superlattice is stable and exhibits a giant |S | even at high temperature. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
H‐ and D‐related mid‐infrared absorption bands in Ga1–yIny As1–xNx epitaxial layers
Authors: Alt Hans Christian , Messerer Peter , Köhler Klaus , Riechert Henning
Published: September 2008

Epitaxially grown ternary and quaternary layers of GaAs based dilute nitrides have been exposed to H+ and D+ ion bombardment to investigate the interaction between hydrogen (deuterium) and nitrogen. Low‐temperature Fourier transform infrared absorption measurements reveal the formation of N–H (N–D) complexes by the appearance of high‐frequency absorption bands in the mid‐infrared due to vibrational modes of H(D). In thin layers, the transformation of isolated substi‐ tutional nitrogen, NAs, into complexes involving H (D) is complete, in thick (500–1000 nm) layers only partial. Analyses of the band intensities dependent on variations of the sample structure and parameters during ion irradiation challenge the model of a unique defect associated with the observed vibrational modes. A new model is proposed based on two different N–H (N–D) centers, each involving one H (D) atom. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of different substrates on the ionic conduction in LiCoO2/LiNbO3 thin‐film bi‐layers
Authors: Horopanitis E. E. , Perentzis G. , Papadimitriou L.
Published: September 2008

LiNbO3 thin films, deposited by e‐gun evaporation, show lithium deficiency, which is cured by “Li doping”. The “Li doping” of the films was achieved by preparing a structure of Li‐Nb‐O/Li/Li‐Nb‐O, which after annealing forms a homogenized LiNbO3 layer because of diffusion of Li in the two Li‐Nb‐O layers. The LiCoO2/LiNbO3 bi‐layers were prepared either on Stainless Steel/TiN or on Al2O3/Co/Pt substrates/ohmic‐contacts by depositing first either the cathode LiCoO2 or the electrolyte LiNbO3. The Nyquist plots of the AC impedance measurements of all structures showed that the interfaces prepared on Stainless‐Steel/TiN consisted of two semicircles. The structures deposited on Al2O3/Co/Pt showed a third semicircle, which is probably due to the roughness of the substrate. It is important that the ionic properties of the bi‐layers with the cathode material deposited first, a usual structure in a microbattery, are improved compared to the other structures. The quality of the LiNbO3 layer depends very much on the substrate. It can be evaluated from Arrhenius plots that the activation energy of this layer is considerably lower when the whole structure is deposited on Stainless Steel/TiN. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The properties of the nanometer thick Si/Ge films‐on‐insulator produced by Ge+ ion implantation and subsequent hydrogen transfer
Authors: Tyschenko I. E. , Voelskow M. , Cherkov A. G. , Popov V. P.
Published: September 2008

The behaviour of germanium implanted into the SiO2 layers in the vicinity of the bonding interface of silicon‐on‐insulator (SOI) structures has been studied. The enhanced segregation of the implanted Ge atoms at the Si/SiO2 bonding interface has been observed. Segregated Ge atoms form the layer, which is coherent with the silicon lattice. It is suggested that the formation of intermediate Ge layer is mediated by the occurrence of liquid Ge phase. The effect of Ge on the Hall mobility of holes in the 25 nm thick SOI layer was studied. An increase in the hole mobility by a factor of three was obtained in the SiGe‐on insulator structures in comparison with that measured in the respective Ge‐free SOI films. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of the size of self‐assembled individual quantum dots on their PL spectra
Authors: Zora A. , Simserides C. , Triberis G. P.
Published: September 2008

Based on an analytical expression for the photoluminescence (PL) intensity of individual quantum dots (QDs) in the linear regime, we investigate its dependence upon the size of self‐assembled InGaAs QDs. We prove that decreasing the QD size, the PL‐emission spectrum moves to higher energy, due to the confinement‐induced blue‐shift of the electronic levels and the redshift from the increased Coulomb interaction caused by the compression of the exciton radii. This shift is in agreement with experimental results. Moreover, we show that larger dots provide more intense PL spectra. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
RF MEMS status and perspectives
Authors: Coccetti Fabio , Peyrou David , Al Ahmad Mahmoud , Puyal Vincent , Pons Patrick , Aubert Hervé , Muller Alex , Dragoman Mircea , Plana Robert
Published: September 2008

The key challenges for the next generation of communication architectures are related to their ability to modify their properties in order to fit with different applications and environmental conditions. Among the emerging approaches targeting these miniaturized systems called “Smart Microsystems”, RF MEMS technology is considered as one of the most attractive and enabling solution. This paper will outline the main characteristics exhibited by RF MEMS technologies as well as the main technological process flow, the design and modelling methodologies that have to be implemented in order to meet the multi‐physics and multi‐scale challenge encountered in this field. The paper will continue with a major issue faced by RF MEMS related to reliability. Finally, the paper will finish with the presentation of innovative smart devices and systems that could be envisioned in the future. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Flexible WO3 based electrochromic displays using proton conducting solid electrolytes
Authors: Vasilopoulou M. , Botsialas A. , Argitis P. , Aspiotis G. , Papadimitropoulos G. , Davazoglou D.
Published: September 2008

All solid‐state flexible electrochromic displays were fabricated based on WO3 films deposited below 50 °C by heating a hot wire in a rough vacuum of the order of 1 Torr. Indium Tin Oxide (ITO) covered polyethylene tetraphthalate (PET) substrates and gel‐like organic electrolytes were used. These proton conductive electrolytes were based on poly(methyl methacrylate) (PMMA) into which a strong Brönsted phosphododecatungstic acid (H3PW12O40‐POM) was added at various concentrations. Transmittance measurements were recorded and it was found that all displays exhibited an intense, reversible electrochromic effect. The coloring voltage was found to depend strongly on the content in solids of the electrolyte, the POM's concentration and the basicity of the polymeric matrix. For devices polarized by voltage pulses it was found that the response time was of the order of 500 ms; coloration and bleaching times were comparable. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation of the electrical characteristics of MOS capacitors on strained‐silicon substrates
Authors: Kelaidis N. , Skarlatos D. , Tsamis C.
Published: September 2008

In this work, we analyze the electrical characteristics of MOS capacitors fabricated on strained silicon substrates using the commercial software Taurus/Synopsis. The effect of various parameters such as Germanium concentration in the Si1–xGex virtual substrate, thickness of the strained‐Silicon layer, oxide thickness, fixed charge and interface trapped charge on capacitance – voltage characteristics is examined. Experimental data are compared with simulation results. A strong influence of the s‐Si/SiGe heterostructure and its proximity to the s‐Si/SiO2 on the electrical characteristics of the system exists. Oxide charge inserted into simulation in order to fit experimental data shows an increase of charge with decreasing s‐Si thickness. The effect of interface traps on simulated C‐V characteristics is identical when traps are situated in the s‐Si/SiO2 or the s‐Si/SiGe interface. When increasing the thermal budget by increasing the post oxidation annealing time, the decrease of the hump phenomenon on the C‐V curves can be attributed to the Germanium diffusion, according to simulation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Towards electrically‐pumped microcavity polariton lasers
Authors: Tsintzos S. , Savvidis P. G. , Konstantinidis G. , Hatzopoulos Z. , Pelekanos N. T.
Published: September 2008

We present preliminary experimental results on a doped‐DBR microcavity diode sample, designed for electrically‐pumped operation at the elevated temperatures around 200 K. Low temperature reflectivity measurements as a function of incidence angle have shown clear evidence of polaritons in the strong coupling regime in this sample. Moreover, reflectivity spectra recorded at various temperatures between 185 and 217 K have demonstrated that the strong coupling regime persists at these elevated temperatures. Our results are very promising for the realization of polaritonic devices under electrical injection. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nanoimprint lithography and surface modification as prospective technologies for heterogeneous integration
Authors: Kehagias N. , Hu W. , Reboud V. , Lu N. , Dong B. , Chi L. , Fuchs H. , Genua A. , Alduncín J. A. , Pomposo J. A. , Mecerreyes D. , Sotomayor Torres C. M.
Published: September 2008

Nanoimprint lithography offers the possibility to pattern wafer‐scale surfaces with nm‐sized structures in polymers reaching the 10 nm lateral size. Printable polymers can be tailored to have a surface upon which molecules self‐assemble. Furthermore, the resulting surfaces may be heterogeneously structured with or without etching away parts of imprinted polymers, in order to provide a flexible platform for structured surfaces with functional materials. We review progress in these combined approaches and discuss three examples: (a) a process to modify printed surfaces in order to grow polymer brushes, (b) a technique to realise patterned surfaces with different emission colours by using a one‐step gas phase deposition of a single type of molecules on pre‐patterned solid substrates and (c) a general method suitable to pattern different conducting polymer species at the nanoscale range by combining nanoimprint lithography process and a lift‐off process. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micro‐ and nano‐particle manipulation by dielectrophoresis: devices for particle trapping and the influence of steric effects
Authors: Loucaides N. G. , Ramos A. , Georghiou G. E.
Published: September 2008

In this paper the concept of trapping biological nanoparticles, by utilizing Dielectrophoresis (DEP), is investigated in a system of parallel electrode arrays. The method is analyzed using a Smoluchowski equation that describes the time evolution of the concentration of the particles.

A modification is introduced in the Smoluchowski equation in order to take into account the finite particle dimensions and therefore constrain the maximum possible concentration to physically realistic limits. The results are finally compared with the non‐steric case and for different particle sizes of the steric model. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antifungal activity of alkanols againstZygosaccharomyces bailiiand their effects on fungal plasma membrane
Authors: Fujita Ken‐Ichi , Fujita Tomoko , Kubo Isao
Published: September 2008

A series of aliphatic primary alkanols from C6to C13were tested for antifungal activity against a food spoilage fungusZygosaccharomyces bailiiusing a broth dilution method and were compared for their effects againstSaccharomyces cerevisiaeandZ. rouxii. Decanol (C10) was found to be the most potent fungicide againstZ. bailiiat a minimum fungicidal concentration of 50 µg/ml (0.31 mM), whereas undecanol (C11) was found to be the most potent fungistatic at a minimum inhibitory concentration of 25 µg/ml (0.14 mM). The time‐kill curve study showed that decanol was fungicidal againstZ.bailiiat any growth stage. Octanol (C8) increased plasma membrane fluidity in the spheroplast cells ofS. cerevisiae. The primary antifungal action of alkanols comes from their ability to disrupt the native membrane‐associated function of integral proteins nonspecifically as nonionic surface‐active agents (surfactants). The antifungal activity of decanol againstZ. bailiiwas slightly enhanced in combination with anethole. Copyright © 2008 John Wiley & Sons, Ltd.
Resveratrol induces apoptosis and inhibits adipogenesis in 3T3‐L1 adipocytes
Authors: Rayalam Srujana , Yang Jeong‐Yeh , Ambati Suresh , Della‐Fera Mary Anne , Baile Clifton A.
Published: September 2008

Resveratrol, a phytoallexin, has recently been reported to slow aging by acting as a sirtuin activator. Resveratrol also has a wide range of pharmacological effects on adipocytes. In this study, we investigated the effects of resveratrol on adipogenesis and apoptosis using 3T3‐L1 cells. In mature adipocytes, 100 and 200 µM resveratrol decreased cell viability dose‐dependently by 23 ± 2.7%, and 75.3 ± 2.8% (p < 0.0001), respectively, after 48 h treatment, and 100 µM resveratrol increased apoptosis by 76 ± 8.7% (p < 0.0001). Resveratrol at 25 and 50 µM decreased lipid accumulation in maturing preadipocytes significantly by 43 ± 1.27% and 94.3 ± 0.3% (p < 0.0001) and decreased cell viability by 25 ± 1.3% and 70.4 ± 1.6% (p < 0.0001), respectively. In order to understand the anti‐adipogenic effects of resveratrol, maturing 3T3‐L1 preadipocytes were treated with 25 µM resveratrol and the change in the expression of several adipogenic transcription factors and enzymes was investigated using real‐time RT‐PCR. Resveratrol down‐regulated the expression of PPARγ, C/EBPα, SREBP‐1c, FAS, HSL, LPL and up‐regulated the expression of genes regulating mitochondrial activity (SIRT3, UCP1 and Mfn2). These results indicate that resveratrol may alter fat mass by directly affecting cell viability and adipogenesis in maturing preadipocytes and inducing apoptosis in adipocytes and thus may have applications for the treatment of obesity. Copyright © 2008 John Wiley & Sons, Ltd.
Evaluation of antioxidant, antinociceptive, and anti‐inflammatory activities of ethanol extracts fromAloe saponariaHaw.
Authors: Yoo Eun Ah , Kim Sung Dae , Lee Whi Min , Park Hwa Jin , Kim Sang Keun , Cho Jae Youl , Min Wongi , Rhee Man Hee
Published: September 2008

Aloe species are traditionally prescribed for hypertension, burning, and rheumatoid arthritis. To elucidate the mechanism of the antihypertensive and anti‐inflammatory activities of this herb, the ethanol fraction fromA. saponariaHaw. was evaluated for antioxidative activity using xanthine‐xanthine oxidase (XO) assay, 2,2‐Diphenyl‐lpicrylhydrazyl radical (DPPH) assay, lipopolysaccharide (LPS)‐induced nitric oxide (NO) production in RAW 264.7 cell, and antinociceptive activity using a tail‐flick assay and hind paw pressure assay in cisplatin‐treated hyperalgesic rats. The ethanol fraction displayed potent antioxidative activities in XO assay. In addition, ethanol fractions showed potent scavenging effects in DPPH assay. We next examined whether ethanol fractions showed anti‐inflammatory activities. Ethanol fractions significantly suppressed NO production from LPS‐activated RAW264.7 cells. As expected, ethanol fractions dose‐dependently inhibited the messenger RNA expression of inducible NO synthase (iNOS). Moreover, ethanol fractions potently suppressed the expression of cycloxygenase (COX)‐2 and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), which are stimulated by LPS in RAW264.7 cells. In addition, ethanol fractions significantly blocked cisplatin‐induced hyperalgesia using tail‐flick assay and hind paw pressure test in rats. Taken altogether, ethanol extracts of aloe may be useful as a functional food or as a drug against reactive oxygen species (ROS) mediated diseases. Copyright © 2008 John Wiley & Sons, Ltd.
Strontium isotope ratios (87Sr/86Sr) of tooth enamel: a comparison of solution and laser ablation multicollector inductively coupled plasma mass spectrometry methods
Authors: Copeland Sandi R. , Sponheimer Matt , le Roux Petrus J. , Grimes Vaughan , Lee‐Thorp Julia A. , de Ruiter Darryl J. , Richards Michael P.
Published: September 2008

Strontium isotope ratios (87Sr/86Sr) in tooth enamel provide a means to investigate migration and landscape use in humans and other animals. Established methods for measuring 87Sr/86Sr in teeth use bulk sampling (5–20 mg) and labor‐intensive elemental purification procedures before analysis by either thermal ionization mass spectrometry (TIMS) or multicollector inductively coupled plasma mass spectrometry (MC‐ICP‐MS). Another method for measuring 87Sr/86Sr is laser ablation MC‐ICP‐MS, but concerns have been expressed about its accuracy for measuring tooth enamel. In this study we test the precision and accuracy of the technique by analyzing 30 modern rodent teeth from the Sterkfontein Valley, South Africa by laser ablation MC‐ICP‐MS and solution MC‐ICP‐MS. The results show a mean difference in 87Sr/86Sr measured by laser ablation and by solution of 0.0003 ± 0.0002. This degree of precision is well within the margin necessary for investigating the potential geographic origins of humans or animals in many areas of the world. Because laser ablation is faster, less expensive, and less destructive than bulk sampling solution methods, it opens the possibility for conducting 87Sr/86Sr analyses of intra‐tooth samples and small and/or rare specimens such as micromammal and fossil teeth. Copyright © 2008 John Wiley & Sons, Ltd.
Reduction of in‐source collision‐induced dissociation and thermolysis of sulopenem prodrugs for quantitative liquid chromatography/electrospray ionization mass spectrometric analysis by promoting sodium adduct formation
Authors: Wujcik Chad E. , Kadar Eugene P.
Published: September 2008

Six chromatographically resolved sulopenem prodrugs were monitored for their potential to undergo both in‐source collision‐induced dissociation (CID) and thermolysis. Initial Q1 scans for each prodrug revealed the formation of intense [Prodrug2 + H]+, [Prodrug2 + Na]+, [Prodrug + Na]+, and [Sulopenem + Na]+ ions. Non‐adduct‐associated sulopenem ([Sulopenem + H]+) along with several additional lower mass ions were also observed. Product ion scans of [Prodrug3 + Na]+ showed the retention of the sodium adduct in the collision cell continuing down to opening of the β‐lactam ring. In‐source CID and temperature experiments were conducted under chromatographic conditions while monitoring several of the latter ion transitions (i.e., adducts, dimers and degradants/fragments) for a given prodrug. The resulting ion profiles indicated the regions of greatest stability for temperature and declustering potential (DP) that provided the highest signal intensity for each prodrug and minimized in‐source degradation. The heightened stability of adduct ions, relative to their appropriate counterpart (i.e., dimer to dimer adduct and prodrug to prodrug adduct ions), was observed under elevated temperature and DP conditions. The addition of 100 µM sodium to the mobile phase further enhanced the formation of these more stable adduct ions, yielding an optimal [Prodrug + Na]+ ion signal at temperatures from 400 to 600°C. A clinical liquid chromatography/tandem mass spectrometry (LC/MS/MS) assay for sulopenem prodrug PF‐04064900 in buffered whole blood was successfully validated using sodium‐fortified mobile phase and the [PF‐04064900 + Na]+ ion for quantitation. A conservative five‐fold increase in sensitivity from previously validated preclinical assays using the [PF‐04064900 + H]+ precursor ion was achieved. Copyright © 2008 John Wiley & Sons, Ltd.
Quantification of small molecules in plasma with direct analysis in real time tandem mass spectrometry, without sample preparation and liquid chromatographic separation
Authors: Zhao Yeping , Lam Michelle , Wu Danlin , Mak Rowena
Published: September 2008

Recently, a new ion source, Direct Analysis in Real Time (DART), has been introduced which allows direct biological sample introduction into a mass spectrometry (MS) system. The elimination of conventionally required sample preparation and separation by high‐performance liquid chromatography (HPLC) prior to MS analysis represents a remarkable opportunity to reduce assay turn‐around time, environmental impact and capital/manpower investment. This new technology initially was used in various qualitative applications to directly detect chemicals on solid surfaces, in liquids and gases. In this study, a DART source operating under ambient pressure with ground potential was installed onto a Sciex 4000 tandem mass spectrometer and employed in the sample analysis of plasma based on direct introduction into the DART‐MS/MS system. Reasonable precision and accuracy (%CV and %Error, both <10%) were achieved of a significant number of compounds tested in biological fluids. In addition, the limit of detection for 80% of the tested compounds reached 5 ng/mL or lower which is sufficient for pharmaceutical drug discovery support. Finally, experimental conditions that significantly impacted assay performance were investigated with respect to optimization and limitation. Because of its simplicity, fast data acquisition (3–5 s) and low cost, DART has the potential to significantly impact quantitative pharmaceutical analysis in biological matrices. Copyright © 2008 John Wiley & Sons, Ltd.
Determination of the fatty acyl profiles of phosphatidylethanolamines by tandem mass spectrometry of sodium adducts
Authors: Simões Cláudia , Simões Vanda , Reis Ana , Domingues Pedro , Domingues M. Rosário M.
Published: September 2008

Phosphatidylethanolamines (PEs) are one of the major constituents of cellular membranes, and, along with other phospholipid classes, have an essential role in the physiology of cells. Profiling of phospholipids in biological samples is currently done using mass spectrometry (MS). In this work we describe the MS fragmentation of sodium adducts of 2‐oleoyl‐1‐palmitoyl‐sn‐glycero‐3‐phosphatidylethanolamine (POPE) and 2‐linoleoyl‐1‐palmitoyl‐sn‐glycero‐3‐phosphatidylethanolamine (PLPE). This study was performed by electrospray ionization tandem mass spectrometry (ESI‐MS/MS) using three different instruments and also by matrix‐assisted laser desorption/ionization tandem mass spectrometry (MALDI‐MS/MS). All MS/MS spectra show product ions related to the polar head fragmentation and product ions related to the loss of acyl chains. In ESI‐MS/MS spectra, the product ions [M+Na‐R1COOH‐43]+ and [M+Na‐R2COOH‐43]+ show different relative abundance, as well as [M+Na‐R1COOH]+ and [M+Na‐R2COOH]+ product ions, allowing identification of both fatty acyl residues of PEs, and their specific location. MALDI‐MS/MS shows the same product ions reported before and other ions generated by charge‐remote fragmentation of the C3–C4 bond (γ‐cleavage) of fatty acyl residues combined with loss of 163 Da. These fragment ions, [M+Na‐(R2‐C2H3)‐163]+ and [M+Na‐(R1‐C2H3)‐163]+, show different relative abundances, and the product ion formed by the γ‐cleavage of sn‐2 is the most abundant. Overall, differences noted that are important for identification and location of fatty acyl residues in the glycerol backbone are: relative abundance between the product ions [M+Na‐R1COOH‐43]+ > [M+Na‐R2COOH‐43]+ in ESI‐MS/MS spectra; and relative abundance between the product ions [M+Na‐(R2‐C2H3)‐163]+ > [M+Na‐(R1‐C2H3)‐163]+ in MALDI‐MS/MS spectra. Copyright © 2008 John Wiley & Sons, Ltd.
Enrichment of low molecular weight serum proteins using acetonitrile precipitation for mass spectrometry based proteomic analysis
Authors: Kay Richard , Barton Chris , Ratcliffe Lucy , Matharoo‐Ball Balwir , Brown Pamela , Roberts Jane , Teale Phil , Creaser Colin
Published: September 2008

A rapid acetonitrile (ACN)‐based extraction method has been developed that reproducibly depletes high abundance and high molecular weight proteins from serum prior to mass spectrometric analysis. A nanoflow liquid chromatography/tandem mass spectrometry (nano‐LC/MS/MS) multiple reaction monitoring (MRM) method for 57 high to medium abundance serum proteins was used to characterise the ACN‐depleted fraction after tryptic digestion. Of the 57 targeted proteins 29 were detected and albumin, the most abundant protein in serum and plasma, was identified as the 20th most abundant protein in the extract. The combination of ACN depletion and one‐dimensional nano‐LC/MS/MS enabled the detection of the low abundance serum protein, insulin‐like growth factor‐I (IGF‐I), which has a serum concentration in the region of 100 ng/mL. One‐dimensional sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS‐PAGE) analysis of the depleted serum showed no bands corresponding to proteins of molecular mass over 75 kDa after extraction, demonstrating the efficiency of the method for the depletion of high molecular weight proteins. Total protein analysis of the ACN extracts showed that approximately 99.6% of all protein is removed from the serum. The ACN‐depletion strategy offers a viable alternative to the immunochemistry‐based protein‐depletion techniques commonly used for removing high abundance proteins from serum prior to MS‐based proteomic analyses. Copyright © 2008 John Wiley & Sons, Ltd.
GlycoMiner: a new software tool to elucidate glycopeptide composition
Authors: Ozohanics Oliver , Krenyacz Judit , Ludányi Krisztina , Pollreisz Ferenc , Vékey Károly , Drahos László
Published: September 2008

New computer software, GlycoMiner, has been developed to automatically identify tandem (MS/MS) spectra obtained in liquid chromatography/mass spectrometry (LC/MS) runs which correspond to N‐glycopeptides. The program complements conventional proteomics analysis, and can be used in a high‐throughput environment. The program interprets the spectra and determines the structure of the corresponding glycopeptides. GlycoMiner runs under Windows, can process spectra obtained on various instruments, and can be downloaded from our website (w3.chemres.hu/ms/glycominer). The algorithm works similarly to a human expert; evaluates the low mass oxonium ions; deduces oligosaccharide losses from the protonated molecule; and identifies the mass of the peptide residue. The program has been tested on tryptic digests of two glycopeptides: AGP (which has five different N‐glycosylation sites) and transferrin (with two N‐glycosylation sites). Results have been evaluated both manually and by GlycoMiner. Out of 3132 MS/MS spectra 338 were found to correspond to glycopeptides; identification by GlycoMiner showed a 0.1% false positive and 0.1% false negative rate. From these it was possible to identify 196 glycan structures manually; GlycoMiner correctly identified all of these, with no false positives. The rest were low quality spectra, not suitable for structure assignment. Copyright © 2008 John Wiley & Sons, Ltd.
Pre‐clinical remote telesurgery trial of a da Vinci telesurgery prototype
Authors: Nguan Christopher , Miller Brian , Patel Rajni , Luke Patrick PW , Schlachta Christopher M.
Published: September 2008

Background

The objective of this study was to perform a pre‐clinical remote telesurgery trial of a da Vinci® telesurgery prototype on a surgical‐grade virtual private network.

Methods

A da Vinci telesurgery‐enabled prototype was used to conduct surgical trials across a 17 MB/s bandwidth VPNe network spanning 2848 km round‐trip landline distance from London, Ontario, to Halifax, Nova Scotia, Canada. The outcomes measured during the trial were surgical times and quality of anastomoses.

Results

Network configuration resulted in observed latencies of 370 ms with 140 ms due to transport delay. The da Vinci telesurgery prototype performed well subjectively and average porcine pyeloplasty anastomotic times were 20.7 ± 4.7 min.

Conclusions

This work constitutes an early evaluation of the da Vinci telesurgery prototype for conceptually remote telesurgical operations. This study clearly demonstrated the feasibility of remote telesurgery using the da Vinci platform to perform a complex surgical task. Copyright © 2008 John Wiley & Sons, Ltd.
Overview of the vascular interventional robot
Authors: Da Liu , Zhang Dapeng , Wang Tianmiao
Published: September 2008

Background

Conventional vascular interventional surgery (VIS) is manually performed under fluoroscopic guidance, requiring lead protection for the surgeons. In order to reduce the X‐ray irradiation, the robot has been introduced to VIS in this study. The purpose of this article is to provide a comprehensive summary of the vascular interventional robot (VIR).

Methods

A retrospective review of the currently published literature on VIR is discussed. The overview details the key technologies of VIR.

Results

Surgeons operate the robot far away from the patient, so protecting themselves from X‐ray irradiation. The robot system carries out the VIS precisely and provides three‐dimensional visualization of vasculature that can be used for preoperative planning and intra‐operative navigation.

Conclusions

The use of the vascular interventional robot appears safe and feasible for vascular interventional surgery. VIR can offer radiation safety to surgeon and enhance surgical accuracy. Copyright © 2008 John Wiley & Sons, Ltd.
An integrated system for planning, navigation and robotic assistance for skull base surgery
Authors: Xia Tian , Baird Clint , Jallo George , Hayes Kathryn , Nakajima Nobuyuki , Hata Nobuhiko , Kazanzides Peter
Published: September 2008

Background

We developed an image‐guided robot system to provide mechanical assistance for skull base drilling, which is performed to gain access for some neurosurgical interventions, such as tumour resection. The motivation for introducing this robot was to improve safety by preventing the surgeon from accidentally damaging critical neurovascular structures during the drilling procedure.

Methods

We integrated a Stealthstation®navigation system, a NeuroMate®robotic arm with a six‐degree‐of‐freedom force sensor, and the 3D Slicer visualization software to allow the robotic arm to be used in a navigated, cooperatively‐controlled fashion by the surgeon. We employed virtual fixtures to constrain the motion of the robot‐held cutting tool, so that it remained in the safe zone that was defined on a preoperative CT scan.

Results

We performed experiments on both foam skull and cadaver heads. The results for foam blocks cut using different registrations yielded an average placement error of 0.6 mm and an average dimensional error of 0.6 mm. We drilled the posterior porus acusticus in three cadaver heads and concluded that the robot‐assisted procedure is clinically feasible and provides some ergonomic benefits, such as stabilizing the drill. We obtained postoperative CT scans of the cadaver heads to assess the accuracy and found that some bone outside the virtual fixture boundary was cut. The typical overcut was 1–2 mm, with a maximum overcut of about 3 mm.

Conclusions

The image‐guided cooperatively‐controlled robot system can improve the safety and ergonomics of skull base drilling by stabilizing the drill and enforcing virtual fixtures to protect critical neurovascular structures. The next step is to improve the accuracy so that the overcut can be reduced to a more clinically acceptable value of about 1 mm. Copyright © 2008 John Wiley & Sons, Ltd.