bluuebunny/crossref_metadata_2025 huggingface dataset:
The application of terrestrial laser scanning to aeolian saltation cloud measurement and its response to changing surface moisture
Authors: Nield Joanna M. , Wiggs Giles F.S.
Published: November 2010

Saltation is the dominant form of aeolian transport of sand sized grains, yet its heterogeneous spatial and temporal distribution, and inherent feedback and interaction with the surface over which sand is transported, hinders large scale quantification. In this letter we present preliminary data on saltation cloud characteristics quantified using terrestrial laser scanning (TLS). These data, together with surface moisture and surface roughness patterns, elucidate the importance of saltation in the development of protodunes on a drying beach, and indicate the potential usefulness of TLS in examining aeolian processes in both beach and desert environments. Copyright © 2010 John Wiley & Sons, Ltd.
Evaluation of a humidity‐measuring instrument for the determination of water in spray‐dried flavour powders
Authors: Veazey Robert L. , Bockhorn Brian , Golding Robert , Wu Anna
Published: November 2010

Spray drying is a common technique for encapsulation of liquid and dry flavours. Control of the water content of spray‐dried flavour powders is critical for maintaining product quality and storage stability. Karl Fischer titration is the method of choice for confirming that the product meets specifications, but a simpler technique would be welcome in the quality control laboratory. We report here the results of an evaluation of a humidity‐measuring instrument, the Computrac® Vapor Pro®, for determining the water content of spray‐dried flavour powders. The instrument heats the sample to drive off moisture, which is measured with a water‐specific sensor. The influence of the oven temperature, sample size, purge time, and endpoint detection method were determined for our samples. The optimized Vapor Pro® measurements show excellent correlation (r2 = 0.9923, n = 51) with the reference Karl Fischer method over a range of 1.3% to 7.4% water, with comparable precision. The instrument is thus capable of replacing a Karl Fischer titrator for at‐line monitoring and QC evaluation of water in spray‐dried flavours.
Development of high intensity focused ultrasound simulator for large‐scale computing
Authors: Okita Kohei , Ono Kenji , Takagi Shu , Matsumoto Yoichiro
Published: November 2010

High intensity focused ultrasound (HIFU) has been developed as a noninvasive therapeutic option. HIFU simulations are required to support the development of the HIFU device as well as the realization of noninvasive treatments. In this study, an HIFU simulator is developed that uses voxel data constructed from computed tomography scan data on the living human body and signed distance function (SDF) data to represent the object. The HIFU simulator solves the conservation equations of mass and momentum for mixtures with the equation of state for each medium. The numerical method is the finite‐difference time‐domain method. A high‐order finite‐difference method based on Lagrange interpolation is implemented to reduce numerical phase error. This approach reproduces wave propagation to an nth order of accuracy. Representation of the sound source by volume fraction, which is obtained from the SDF using a smoothed Heaviside function, provides around 1.66th order of accuracy in the spherical wave problem. As a realistic application, transcranial HIFU therapy for a brain tumor is modeled, where tissue inhomogeneity causes not only displacement of the focal point but also diffusion of the focused ultrasound. Even in such cases, focus control using phase delays, which are pre‐computed based on the time‐reversal procedure, enables correct focal point targeting as well as improved ultrasound focusing. Copyright © 2010 John Wiley & Sons, Ltd.
Interfacial flow computations using adaptive Eulerian–Lagrangian method for spacecraft applications
Authors: Sim Jaeheon , Shyy Wei
Published: November 2010

Understanding the interfacial dynamics and fluid physics associated with the operation of spacecraft is important for scientific as well as engineering purposes. To help address the issues associated with moving boundaries, interfacial dynamics, and spatial‐temporal variations in time and length scales, a 3‐D adaptive Eulerian–Lagrangian method is extended and further developed. The stationary (Eulerian) Cartesian grid is adopted to resolve the fluid flow, and the marker‐based triangulated moving (Lagrangian) surface meshes are utilized to treat the phase boundary. The key concepts and numerical procedures, along with the selected interfacial flow problems are presented. Specifically, the liquid fuel draining dynamics in different flow regimes, and the liquid surface stability under vertically oscillating gravitational acceleration are investigated. Direct assessment of experimental measurement and scaling analysis is made to highlight the computational performance of the present approach as well as the key fluid physics influenced by the given flow parameters. Copyright © 2010 John Wiley & Sons, Ltd.
A high‐order upwind control‐volume method based on integrated RBFs for fluid‐flow problems
Authors: Mai‐Duy N. , Tran‐Cong T.
Published: November 2010

This paper is concerned with the development of a high‐order upwind conservative discretization method for the simulation of flows of a Newtonian fluid in two dimensions. The fluid‐flow domain is discretized using a Cartesian grid from which non‐overlapping rectangular control volumes are formed. Line integrals arising from the integration of the diffusion and convection terms over control volumes are evaluated using the middle‐point rule. One‐dimensional integrated radial basis function schemes using the multiquadric basis function are employed to represent the variations of the field variables along the grid lines. The convection term is effectively treated using an upwind scheme with the deferred‐correction strategy. Several highly non‐linear test problems governed by the Burgers and the Navier–Stokes equations are simulated, which show that the proposed technique is stable, accurate and converges well. Copyright © 2010 John Wiley & Sons, Ltd.
A Stokes model with cavitation for the numerical simulation of hydrodynamic lubrication
Authors: Nilsson B. , Hansbo P.
Published: November 2010

We present a cavitation model based on the Stokes equation and formulate adaptive finite element methods for its numerical solution. A posteriori error estimates and adaptive algorithms are derived, and numerical examples illustrating the theory are supplied, in particular with comparison to the simplified Reynolds model of lubrication. Copyright © 2010 John Wiley & Sons, Ltd.
Simulation of two‐phase flow with moving immersed boundaries
Authors: Holmvall M. , Lindström S. B. , Uesaka T.
Published: November 2010

A two‐dimensional multi‐phase model for immiscible binary fluid flow including moving immersed objects is presented. The fluid motion is described by the incompressible Navier–Stokes equation coupled with a phase‐field model based on van der Waals' free energy density and the Cahn–Hilliard equation. A new phase‐field boundary condition was implemented with minimization of the free energy in a direct way, to specifically improve the physical behavior of the contact line dynamics for moving immersed objects. Numerical stability and execution time were significantly improved by the use of the new boundary condition. Convergence toward the analytical solution was demonstrated for equilibrium contact angle, the Lucas–Washburn theory and Stefan's problem. The proposed model may be used for multi‐phase flow problems with moving boundaries of complex geometry, such as the penetration of fluid into a deformable, porous medium. Copyright © 2010 John Wiley & Sons, Ltd.
Wideband fast multipole boundary element method: Application to acoustic scattering from aerodynamic bodies
Authors: Wolf W. R. , Lele S. K.
Published: November 2010

A wideband adaptive multi‐level fast multipole method (MLFMM) is used to accelerate the matrix–vector products arising from a boundary element method (BEM) formulation which solves the Burton–Miller boundary integral equation (BIE). The wideband MLFMM presented here applies a plane wave expansion formulation with fast interpolation and filtering for calculations in the high‐frequency regime and a partial wave expansion formulation with rotation‐coaxial translation in the low‐frequency regime. The iterative solvers GMRES, Bi‐CGSTAB and CGS are tested and compared and a block diagonal preconditioner is used to improve the condition number of the BEM matrices and to accelerate the convergence of the iterative solvers. Details on the implementation of the formulations are described, including the treatment of singular integrals. Results for acoustic scattering from a wing plus engine nacelle configuration for a prescribed source in a subsonic uniform flow are presented for a broad range of frequencies in order to assess the implemented capability. Copyright © 2010 John Wiley & Sons, Ltd.
Fundamental validation of the finite volume particle method for 3D sloshing dynamics
Authors: Guo Lian Cheng , Zhang Shuai , Morita Koji , Fukuda Kenji
Published: November 2010

The use of the finite volume particle (FVP) method is validated for three‐dimensional sloshing dynamics with a free surface by comparing with results from experiments. In the first part, two typical sloshing experiments for a single liquid phase are simulated, and slosh characteristics that include the free surface behavior and hydrodynamic pressure are reported. Moreover, the influences of the circular wall geometry and spatial resolution in the simulation are studied in a sensitivity analysis. In the second part, two sloshing problems with solid bodies are simulated to preliminarily verify the applicability of the FVP method to three‐dimensional solid bodies' motion in liquid flow. Good agreement between simulations and corresponding experiments indicates that the present FVP method well reproduces three‐dimensional sloshing behavior. Copyright © 2010 John Wiley & Sons, Ltd.
Environmental fate of pyrethroids in urban and suburban stream sediments and the appropriateness of Hyalella azteca model in determining ecological risk
Authors: Palmquist Katherine , Fairbrother Anne , Salatas Johanna , Guiney Patrick D.
Published: November 2010

According to several recent studies using standard acute Hyalella azteca sediment bioassays, increased pyrethroid use in urban and suburban regions in California has resulted in the accumulation of toxic concentrations of pyrethroids in sediments of area streams and estuaries. However, a critical review of the literature indicates that this is likely an overestimation of environmental risk. Hyalella azteca is consistently the most susceptible organism to both aqueous and sediment-associated pyrethroid exposures when compared to a suite of other aquatic taxa. In some cases, H. azteca LC50 values are less than the community HC10 values, suggesting that the amphipod is an overly conservative model for community- or ecosystem-level impacts of sediment-associated pyrethroids. Further, as a model for responses of field populations of H. azteca, the laboratory bioassays considerably overestimate exposure, because the amphipod is more appropriately characterized as an epibenthic organism, not a true sediment dweller; H. azteca preferentially inhabit aquatic macrophytes, periphyton mats, and leaf litter, which drastically reduces their exposure to contaminated sediments. Sediment-bound pyrethroids are transported via downstream washing of fine particulates resulting in longer range transport but also more efficient sequestration of the chemical. In addition, site-specific variables such as sediment organic carbon content, grain size, temperature, and microbial activity alter pyrethroid bioavailability, degradation, and toxicity on a microhabitat scale. The type and source of the carbon in particular, influences the pyrethroid sequestering ability of sediments. The resulting irregular distribution of pyrethroids in stream sediments suggests that sufficient nonimpacted habitat may exist as refugia for resident sediment-dwelling organisms for rapid recolonization to occur. Given these factors, we argue that the amphipod model provides, at best, a screening level assessment of pyrethroid impacts and can correctly identify those sediments not toxic to benthic organisms but cannot accurately predict where sediments will be toxic. Integr Environ Assess Manag 2011;7:325–335. © 2011 SETAC
Synthesis of [13C5] and [carbonyl‐14C]‐5‐chlorofuran‐2‐carboxylic acid
Authors: Dorff Peter N. , Powell Mark E. , Elmore Charles S.
Published: November 2010

The inventory of labeled compounds and methods for their preparation are constantly growing, but still more building blocks of biologically relevant compounds need to be developed. Furans are frequently encountered in bioactive molecules, and a good synthesis of labeled furan is found in the literature. We required a relatively uncommon labeled furan, 5‐chloro‐2‐furoic acid, for investigative work labeled with C‐13 and C‐14. Carboxylation of the lithium anion of [13C4]furan with 13CO2 followed by chlorination using benzyltrimethylammonium dichloroiodate provided the target compound in modest yield and high purity. The same procedure was then repeated with unlabeled furan and 14CO2 to give [carbonyl‐14C]‐5‐chlorofuran‐2‐carboxylic acid. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis, radiolabeling and evaluation of a new positively charged 99mTc‐labeled fatty acid derivative for myocardial imaging
Authors: Mathur Anupam , Mallia Madhava B. , Sarma Haladhar D. , Banerjee Sharmila , Venkatesh Meera
Published: November 2010

123I‐labeled fatty acids and 18F‐FDG are used as metabolic markers for detecting myocardial abnormalities. However, a 99mTc‐based molecule may find wider application. In the present work, a new 99mTc‐labeled, uni‐positively charged, 16‐carbon fatty acid has been prepared and evaluated in normal Swiss mice. The results are then compared with the neutral analogue reported earlier.

A 16‐cysteinyl hexadecanoic acid conjugate was synthesized in a six‐step synthetic procedure starting with 16‐bromohexadecanoic acid. The ligand upon incubation with [99mTcN(PNP6)]2+ core formed the required positively charged complex in ∼85% yield. The complex, which was obtained as a mixture of syn‐anti isomers, was purified by HPLC and the major fraction was used for in vivo studies in Swiss mice. The biodistribution studies in Swiss mice showed initial uptake similar to 125I‐IPPA followed by rapid clearance from the myocardium till 10 min p.i. Thereafter, the rate of clearance was significantly decreased, an observation reported earlier for positively charged fatty acid complexes. In terms of absolute uptake, the positively charged complex performed better than the neutral analogue reported earlier. The positively charged fatty acid complexes, prepared using [99mTcN(PNP)]2+ core, seems to be better candidates for the development of myocardial metabolic tracers than their neutral counterparts. Copyright © 2010 John Wiley & Sons, Ltd.
Tree species diversity, species regeneration and biological productivity of seeded Acacia catechu Willd. In rehabilitated limestone mines in the North West Indian Himalayas
Authors: Raizada A. , Juyal G.P.
Published: November 2010

Degraded sites like mine spoils on hillslopes are characterized by poor soil physico‐chemical environments and instability. Reclamation of such areas using low cost bioengineering and vegetative methods were carried out in an abandoned limestone mine in the lower western Indian Himalayas and the impact of these measures on vegetation diversity, secondary succession and growth of seeded Acacia catechu Willd. after two decades of protection are reported in this paper. Results reveal that introduction of fast growing leguminous species affected species diversity and hampered the regeneration and growth of native vegetation, due to the dense shade of the over‐storey component. Species diversity (H') levels increased with the opening of the canopy at different elevations, with the highest diversity (1·624) being recorded on the hilltop with Acacia catechu and Wedlandia exserta dominating the area. Enumeration of various species in the growth stages indicated a large population in the pole stage followed by tree and sapling stage indicating scattered regeneration mostly by 1‐2 species. Tree associations in the lower, middle and upper reaches were of Leucaena leucocephala—A. catechu, A. catechu—Boehemeria rugulosa and A. catechu‐W. exserta, respectively. Seeded A. catechu plants now in the tree stage have attained an average height of 5·5 m and dbh of 10·44 cm with an average wood volume of 0·027 m3 in a period of 16–21 years. At current prices of heartwood (US $435 per m3) of A. catechu which is used in the manufacture of ‘kattha’, the investments made two decades ago (US$ 13043) in the rehabilitation of the limestone mine are fairly justified. Copyright © 2010 John Wiley & Sons, Ltd.
Self‐brazing aluminium clad steel
Authors: Ostafin M. , Balkenhol M. , Erlemeyer J. , Köhler M.
Published: November 2010

Aluminium clad steel strip FERAN®, produced by cold roll bonding, combines the forming and mechanical properties of low carbon, unalloyed deep drawing steel with the surface properties of Aluminium. Self‐brazing Aluminium clad steel is a material with the additional property that it can be brazed just like Aluminium brazing strip. The steel core provides for increased strength, especially at higher temperatures, and erosion resistance. Samples of self‐brazing Aluminium clad steel strip have been manufactured on a cladding pilot plant. Brazing tests with a NOCOLOK® fluxing agent at various temperatures and times were performed. The formed joints were investigated metallographically and by SEM/EDX.

Mittels Kaltwalzplattieren hergestelltes aluminiumplattiertes Stahlband FERAN® kombiniert die gute Umformbarkeit und die mechanischen Eigenschaften eines niedrig gekohlten unlegierten Stahls mit den Oberflächeneigenschaften von Aluminium. Selbstlötender aluminiumplattierter Stahl kann zudem analog zu lotplattiertem Aluminiumband hartgelötet werden. Der Stahlkern bringt dabei insbesondere verbesserte Erosionsbeständigkeit und Festigkeit bei erhöhten Temperaturen in den Verbund ein. Proben aus lotfähigem aluminiumplattierten Stahl wurden auf einem Technikums‐Plattiergerüst hergestellt und bei verschiedenen Temperaturen und Zeiten mit einem NOCOLOK® Flussmittel verlötet. Die Lötverbindungen wurden lichtmikroskopisch und mit REM/EDX untersucht.
Lichtbogenfügen umformbarer Stahl‐Aluminium‐Mischverbindungen
Authors: Reisgen U. , Stein L. , Steiners M. , Göttmann A.
Published: November 2010

In den letzten Jahren nahm das Fahrzeuggewicht aufgrund gesteigerter Anforderungen an Sicherheit und Komfort für die Insassen immer weiter zu. Um gleiche ober verbesserte Fahrleistungen zu erhalten, musste die Motorentechnik immer leistungsfähigere Verbrennungsmotoren liefern. Damit verbunden ist jedoch ein erhöhter Ausstoß von schädlichen Abgasen. Durch erhöhte Anforderungen an den Umweltschutz muss daher zukünftig das Fahrzeuggewicht wieder abgesenkt werden. Um dies zu realisieren sind neue Werkstoffkonzepte notwendig. Eine Möglichkeit stellt die Mischbauweise dar, bei der verschiedene Werkstoffe kombiniert werden. Dadurch können die werkstoffspezifischen Eigenschaften lokal optimiert ausgenutzt und eine der Beanspruchung angepasste Konstruktion realisiert werden. Die größte Bedeutung kommt dabei der Kombination von Stahl‐ und Aluminium zu. Da die Endkontur der Bauteile oft durch einen Umformprozess erzeugt wird, müssen neben ausreichender statischer Festigkeit auch Umformaspekte mit betrachtet werden. Durch die Entwicklung moderner, digital geregelter Lichtbogenprozesse in den letzten Jahren wurde ein prozesssicheres, reproduzierbares Fügen von Stahl‐Aluminium‐Mischverbindungen ermöglicht. Es wurden am Institut für Schweißtechnik und Fügetechnik (ISF) der RWTH Aachen University Untersuchungen zum Fügen von Stahl‐ mit Aluminium mit verschiedenen Lichtbogenprozessen durchgeführt. Dabei wird insbesondere die spätere Umformbarkeit der Verbindungen optimiert.

In recent years, the vehicle weight has been constantly increased due to particular requirements made on the passenger safety and comfort. For maintaining or even improving the road performance, engine manufacturers have been forced to supply increasingly more efficient combustion motors. However, increased exhaust emmission is a consequence. The requirements made on environmental protection, however, demand that the vehicle weight is reduced again in future. New material concepts will be required for the implementation. One possibility is the Multi‐Material construction where different materials are combined. Thus, the locally optimized exploitation of the material‐specific properties is guaranteed and a design which is appropriate to the type of duty is created. The combination of steel with aluminium has the highest relevance. Since the final contour of the components is often produced by a reforming process, also forming aspects must be taken into account, besides the consideration of sufficient static strength. The development of modern, digitally controlled arc welding processes has, in recent years, allowed for the reliable, reproducible joining of steel‐aluminium mixed compounds. Investigations about the joining of steel with aluminium, using different arc welding processes, are carried out in the Weldin and Joining Institute (ISF) RWTH Aachen University. Special attention is given to the possibility of later forming of the joints.
Determination of whole‐brain oxygen extraction fractions by fast measurement of blood T2 in the jugular vein
Authors: Qin Qin , Grgac Ksenija , van Zijl Peter C.M.
Published: November 2010

The oxygen extraction fraction of the brain reports on the balance between oxygen delivery and consumption and can be used to assess deviations in physiological homeostasis. This is relevant clinically as well as for calibrating blood oxygen level–dependent functional MRI responses. Oxygen extraction fraction is reflected in the arteriovenous difference in oxygen saturation fraction (Yv − Ya), which can be determined from venous T2 values when arterial oxygenation is known. A pulse sequence is presented that allows rapid measurement (<1 min) of blood T2s in the internal jugular vein. The technique combines slice‐saturation and blood inflow to attain high signal‐to‐noise ratio in blood and minimal contamination from tissue. The sequence is sensitized to T2 using a nonselective Carr‐Purcell‐Meiboom‐Gill T2 preparation directly after slice saturation. Fast scanning (pulse repetition time of about 2 sec) is possible by using a nonselective saturation directly after acquisition to rapidly achieve steady‐state longitudinal magnetization. The venous T2 (for 10 msec Carr‐Purcell‐Meiboom‐Gill interecho time) for normal volunteers was 62.4 ± 6.1 msec (n = 20). A calibration curve relating T2 to blood oxygenation was established using a blood perfusion phantom. Using this calibration, a whole‐brain oxygen extraction fraction of 0.37 ± 0.04 was determined (n = 20), in excellent agreement with literature values. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Simultaneously driven linear and nonlinear spatial encoding fields in MRI
Authors: Gallichan Daniel , Cocosco Chris. A. , Dewdney Andrew , Schultz Gerrit , Welz Anna , Hennig Jürgen , Zaitsev Maxim
Published: November 2010

Spatial encoding in MRI is conventionally achieved by the application of switchable linear encoding fields. The general concept of the recently introduced PatLoc (Parallel Imaging Technique using Localized Gradients) encoding is to use nonlinear fields to achieve spatial encoding. Relaxing the requirement that the encoding fields must be linear may lead to improved gradient performance or reduced peripheral nerve stimulation. In this work, a custom‐built insert coil capable of generating two independent quadratic encoding fields was driven with high‐performance amplifiers within a clinical MR system. In combination with the three linear encoding fields, the combined hardware is capable of independently manipulating five spatial encoding fields. With the linearz‐gradient used for slice‐selection, there remain four separate channels to encode a 2D‐image. To compare trajectories of such multidimensional encoding, the concept of a localk‐space is developed. Through simulations, reconstructions using six gradient‐encoding strategies were compared, including Cartesian encoding separately or simultaneously on both PatLoc and linear gradients as well as two versions of a radial‐based in/out trajectory. Corresponding experiments confirmed that such multidimensional encoding is practically achievable and demonstrated that the new radial‐based trajectory offers the PatLoc property of variable spatial resolution while maintaining finite resolution across the entire field‐of‐view. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.
Short‐echo, single‐shot, full‐intensity proton magnetic resonance spectroscopy for neurochemical profiling at 4 T: Validation in the cerebellum and brainstem
Authors: Öz Gülin , Tkáč Ivan
Published: November 2010

A short echo time (TE = 24 ms) semiadiabatic localization by adiabatic selective refocusing (LASER) sequence was designed and optimized for full‐intensity proton magnetic resonance spectroscopy (1H MRS) at 4 T. The sequence was combined with VAPOR water suppression and three‐dimensional outer volume suppression for improved localization and suppression of unwanted coherences. Artifact‐free, single‐shot spectra were obtained from the human brain with a spectral pattern almost identical to that obtained with an ultra‐short TE (TE = 5 ms) stimulated‐echo acquisition mode (STEAM) sequence as a result of the train of adiabatic refocusing pulses in semi‐LASER that reduce the apparent TE. Approximately 2‐fold higher signal intensity relative to STEAM was demonstrated in phantoms and the human brain. To test the performance of the sequence in clinically relevant brain regions with a volume coil, semi‐LASER spectra were acquired from three cerebellar and brainstem volumes of interest (VOIs) in 23 healthy subjects. Ultra‐short echo STEAM spectra were acquired from the same VOIs to compare neurochemical profiles obtained with semi‐LASER with those obtained with STEAM. Neurochemical profiles of the cerebellum and brainstem acquired by these two techniques were nearly identical, validating the accuracy of the metabolite concentrations obtained with semi‐LASER at the longer TE relative to STEAM. A high correlation between metabolite concentrations obtained by these two proton 1H MRS techniques indicated the sensitivity to detect intersubject variation in metabolite levels. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Ein Zwerg wird erwachsen
Authors: von Hagen Robin , Fischer Thomas , Mathur Sanjay
Published: November 2010

Innerhalb der Nanotechnik wendet die Nanochemie molekülchemische Synthesestrategien an, um neuartige Werkstoffe aufzubauen. So entstehen (metastabile) Phasen, Materialien und Strukturen, die auf rein thermodynamisch kontrollierten Reaktionswegen nicht zugänglich wären.
Actinoidenabtrennung aus hochradioaktiven Abfällen
Authors: Gompper Klaus , Geist Andreas , Geckeis Horst
Published: November 2010

P&T‐Verfahren verringern das Langzeitgefährdungspotenzial hochradioaktiver Abfälle. Partitioning (P) bezeichnet das Abtrennen langlebiger Radionuklide aus radioaktiven Abfällen, Transmutation (T) verwandelt diese Radionuklide durch Neutronenbestrahlung in stabile Spaltprodukte oder solche mit vergleichsweise kurzer Halbwertszeit.
Ein Spektrometer für die spektral aufgelöste Niederfeld‐NMR
Authors: Cudaj Markus , Guthausen Gisela , Kamlowski Andreas , Maier Diether , Hofe Thorsten , Wilhelm Manfred
Published: November 2010

Ein NMR‐Prototyp nutzt die 1H‐Spektroskopie bei 20 MHz und eröffnet neue Perspektiven für Reaktions‐ und Qualitätskontrolle.
Novel polyurethane networks based on hybrid inorganic/organic phosphazene‐containing nanotubes with surface active hydroxyl groups
Authors: Liu Wei , Zheng Yuanli , Li Jing , Liu Li , Huang Xiaobin , Zhang Jiawei , Kang Xiaoqi , Tang Xiaozhen
Published: November 2010

Recently, our group reported a novel preparation of poly(cyclotriphosphazene‐co‐4,4′‐sulfonyldiphenol) nanotubes (PZSNTs), which could be conveniently prepared in a one‐pot process at room temperature without any surfactant or other compatibilizing agent. PZSNTs were a new kind of phosphazene‐containing crosslinked polymers which attracted considerable interest for their outstanding biocompatibility, thermal stability, and flame‐retardant property. Moreover, PZSNTs which possessed inherent surface active hydroxyl groups could be directly used as a crosslinking agent to prepare polyurethane hybrid networks. PZSNTs were homogeneously dispersed in the polyurethane matrix. Tensile tests indicated that the nanocomposites were significantly reinforced by crosslinking of PZSNTs. The tensile strength was enhanced from 11.4 to 21.5 MPa while the elongation at break was almost invariable (460–430%). The storage moduli of the nanocomposites were significantly higher than that of the pure polyurethane. In terms of thermogravimetric analysis (TGA), the nanocomposites displayed an improved thermal stability. Copyright © 2010 John Wiley & Sons, Ltd.
Differentiated expression of somatostatin receptor subtypes in experimental models and clinical neuroblastoma
Authors: Georgantzi Kleopatra , Tsolakis Apostolos V. , Stridsberg Mats , Jakobson Åke , Christofferson Rolf , Janson Eva Tiensuu
Published: November 2010

Background

Neuroblastoma (NB) is a solid tumor of childhood originating from the adrenal medulla or sympathetic nervous system. Somatostatin (SS) is an important regulator of neural and neuroendocrine function, its actions being mediated through five specific membrane receptors. The aim of this study was to investigate the expression of the different somatostatin receptors (SSTRs) in NB tumor cells that may form targets for future therapeutic development.

Procedure

Tumor specimens from 11 children with stage II–IV disease were collected before and/or after chemotherapy. Experimental tumors derived from five human NB cell lines were grown subcutaneously in nude mice. Expression of SSRTs, the neuroendocrine marker chromogranin A (CgA) and SS was detected by immunohistochemistry using specific antibodies.

Results

SSTR2 was detected in 90%, SSTR5 in 79%, SSTR1 in 74%, SSTR3 in 68% whereas SSTR4 was expressed in 21% of the clinical tumors. The experimental tumors expressed SSTRs in a high but variable frequency. All clinical tumors showed immunoreactivity for CgA but not for SS.

Conclusion

The frequent expression of SSTRs indicates that treatment with unlabeled or radiolabeled SS analogs should be further explored in NB. Pediatr Blood Cancer 2011;56:584–589. © 2010 Wiley‐Liss, Inc.
Material characterization of graphite nanosheet composites
Authors: Lo Tzu‐Sen , Kuo Wen‐Shyong , Cheng Chia‐Ching
Published: November 2010

Three sets of expanded graphite‐filled polymers, having three different particle sizes, were reinforced with 1–5% by weight. The structural, mechanical, electrical, and thermal properties of these composites were studied and compared. After dispersion, the particles were reduced to nanometer size through exfoliation, sonication, and high‐shear strain rate mixing, which further breaks and delaminates them. In addition, scanning electron microscope characterizations were performed. The expanded graphite‐filled polymer material could be tailored to be high conducting. Compared with the pure polymer, the polymers filled with 5 wt% expanded graphite have seen a significant reduction in electrical resistivity by orders. The thermal expansion coefficient and water absorption for the weight containing 5 wt% expanded graphite has also been drastically improved, decreasing with the weight percentage of graphite content. Compression and impact tests were conducted. The influence of dispersion on the material behavior was studied. Some fracture modes associated with the layered microstructures of the graphite nanosheets were observed. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers
Proteomic analysis of male 4C germ cell proteins involved in mouse meiosis
Authors: Guo Xuejiang , Zhang Ping , Qi Yujuan , Chen Wen , Chen Xiangxiang , Zhou Zuomin , Sha Jiahao
Published: November 2010

Male meiosis is a specialized type of cell division that gives rise to sperm. Errors in this process can result in the generation of aneuploid gametes, which are associated with birth defects and infertility in humans. Until now, there has been a lack of a large‐scale identification of proteins involved in male meiosis in mammals. In this study, we report the high‐confidence identification of 3625 proteins in mouse male germ cells with 4C DNA content undergoing meiosis I. Of these, 397 were found to be testis specific. Bioinformatics analysis of the proteome led to the identification of 28 proteins known to be essential for male meiosis in mice. We also found 172 proteins that had yeast orthologs known to be essential for meiosis. Chromosome distribution analysis of the proteome showed underrepresentation of the identified proteins on the X chromosome, which may be due to meiotic sex chromosome inactivation. Characterization of the proteome of 4C germ cells from mouse testis provides an inventory of proteins, which is useful for understanding meiosis and the mechanisms of male infertility.
Subcellular proteomics revealed the epithelial–mesenchymal transition phenotype in lung cancer
Authors: Li Li‐Ping , Lu Chun‐ Hua , Chen Zhi‐Peng , Ge Feng , Wang Tong , Wang Wei , Xiao Chuan‐Le , Yin Xin‐Feng , Liu Langxia , He Jian‐Xing , He Qing‐Yu
Published: November 2010

Subcellular proteomics was used to compare the protein profiles between human lung adenocarcinoma A549 cells and human bronchial epithelial (HBE) cells. In total, 106 differential proteins were identified and the altered expression levels of partial identified proteins were confirmed by Western blot analysis. Importantly, pathway analysis and biological validation revealed epithelial–mesenchymal transition (EMT) phenotype shift in A549 cells as compared with HBE cells. The EMT phenotype of A549 cells can be increased by self‐producing TGF‐β1 and significantly decreased by silencing heterogeneous nuclear ribonucleoprotein (hnRNPK) expression. As EMT has been considered as an important event during malignant tumor progression and metastasis, investigating EMT and deciphering the related pathways may lead to more efficient strategies to fight lung cancer progression. By integrating the subcellular proteomic data with EMT‐related functional studies, we revealed new insights into the EMT progress of lung carcinogenesis, providing clues for further investigations on the discovery of potential therapeutic targets.
Exploring the use of dimethylsulfate for in vivo proteome footprinting
Authors: Moio Pasquale , Kulyyassov Arman , Vertut Damien , Camoin Luc , Ramankulov Erlan , Lipinski Marc , Ogryzko Vasily
Published: November 2010

Protein footprinting is a new methodology that is based on probing, typically with the use of MS, of reactivity of different amino acid residues to a modifying reagent. Data thus obtained allow one to make inferences about protein conformations and their intermolecular interactions. Most of the protein footprinting studies so far have been performed on individual proteins in vitro. We explore whether a similar approach is possible with the proteins inside of living cells, employing dimethylsulfate (DMS), a reagent widely used for the in vivo footprinting of nucleic acids. DMS can induce methylation of the lysine, histidine and glutamate residues on proteins. Using models of the histone H2B/H2AZ heterodimer assembled in vitro and from chromatin treated in vivo, we show that the methylation by deuterated DMS allows one to distinguish the accessibility of a particular residue in and out of the protein's environmental/structural context. The detection of changes in protein conformations or their interactions in vivo can provide a new approach to the identification of proteins involved in various intracellular pathways and help in the search for perspective drug targets and biomarkers of diseases.
Endothelin‐1‐ and isoproterenol‐induced differential protein expression and signaling pathway in HL‐1 cardiomyocytes
Authors: Hong Hye‐Min , Song Eun Joo , Oh Eulsik , Kabir Mohammad Humayun , Lee Cheolju , Yoo Young Sook
Published: November 2010

It is well known that the two chemical compounds endothelin‐1 (ET‐1) and isoproterenol (ISO) can individually induce cardiac hypertrophy through G protein‐coupled receptors in cardiomyocytes. However, the cardiac hypertrophy signaling pathway activated by ET‐1 and ISO is not well defined. Therefore, we investigated the protein expression profile and signaling transduction in HL‐l cardiomyocyte cells treated with ET‐1 and ISO. Following separation of the cell lysates by using 2‐DE and silver staining, we identified 16 protein spots that were differentially expressed as compared to the controls. Of these 16 spots, three changed only after treatment with ET‐1, whereas four changed only after treatment with ISO, suggesting that these two stimuli could induce different signaling pathways. In order to reveal the differences between ET‐1‐ and ISO‐induced signaling, we studied the different events that occur at each step of the signaling pathways, when selected biocomponents were blocked by inhibitors. Our results indicated that ET‐1 and ISO used different pathways for phosphorylation of glycogen synthase kinase‐3β (GSK3β). ET‐1 mainly used the mitogen‐activated protein kinase and phosphatidylinositol‐3‐kinase/AKT pathways to activate GSK3β, whereas under ISO stimulation, only the phosphatidylinositol‐3‐kinase/AKT pathway was required to trigger the GSK3β pathway. Furthermore, the strength of the GSK3β signal in ISO‐induced cardiac hypertrophy was stronger than that in ET‐1‐induced cardiac hypertrophy. We found that these two agonists brought about different changes in the protein expression of HL‐1 cardiomyocytes through distinct signaling pathways even though the destination of the two signaling pathways was the same.
Mapping the glycoxidation product Nε‐carboxymethyllysine in the milk proteome
Authors: Meyer Bianca , Al‐Diab Dima , Vollmer Gregor , Pischetsrieder Monika
Published: November 2010

Milk processing leads to severe protein damage caused by the formation of nonenzymatic posttranslational modifications (nePTMs), such as glycation and glycoxidation. As a result, the technological and nutritional function of milk proteins can be critically altered. The present study investigated the protein‐specific distribution of the glycoxidation product Nε‐carboxymethyllysine (CML) in the proteome of processed milk. For this purpose, raw milk and heated milk were separated by 1‐D or 2‐DE. The distribution of CML in the milk proteome was examined by immunoblotting. The changes in the protein composition that occurred during heating were monitored by Coomassie staining. Relative modification rates were measured for the major milk protein fractions after 30 and 60 min of heating at 120°C and normalized to the content of the respective protein fraction in the samples. The highest glycoxidation rates were detected in the high molecular weight aggregates that are generated during heating. The casein fraction and the whey protein β‐lactoglobulin were affected in a similar manner. The relevance of the results for industrial milk processing was confirmed by analyzing several commercial milk products accordingly. The presented approach allows nonenzymatic posttranslational modification mapping of the entire milk proteome.
Proteomic analysis of peripheral layers during wheat (Triticum aestivum L.) grain development
Authors: Tasleem‐Tahir Ayesha , Nadaud Isabelle , Girousse Christine , Martre Pierre , Marion Didier , Branlard Gérard
Published: November 2010

Grains of hexaploid wheat, Triticum aestivum (cv. Récital), were collected at 15 stages of development, from anthesis to physiological maturity, 0–700°C days (degree days after anthesis). Two hundred and seven proteins of grain peripheral layers (inner pericarp, hyaline, testa and aleurone layer) were identified by 2‐DE, MALDI‐TOF MS and data mining, then were classified in 16 different functional categories. Study of the protein expression over time allowed identification of five main profiles and four distinct phases of development. Composite expression curves indicated that there was a shift from metabolic processes, translation, transcription and ATP interconversion towards storage and defence processes. Protein synthesis, protein turnover, signal transduction, membrane transport and biosynthesis of secondary metabolites were the mediating functions of this shift. A picture of the dynamic processes taking place in peripheral layers during grain development was obtained in this study. It should further help in the construction of proteome reference maps for the developing peripheral layers.
Determination of in‐gel protein concentration by a ninhydrin‐based method
Authors: Kang Sung Ung , Lubec Gert
Published: November 2010

Until now quantification of proteins in gel‐based methods relies on the amount of protein loaded onto the gel. This does not, however, represent the amount of proteins in the gel and therefore determination of proteins within the gel is mandatory. A method to quantify proteins, both hydrophilic and hydrophobic, using in‐gel digestion with proteases, subsequent acid hydrolysis and the use of the ninhydrin reaction is herein presented.
Angular correlation for nuclear muon capture
Authors: Ciechanowicz S. , Oziewicz Z.
Published: November 2010

Formulae for the capture rates, gamma‐neutrino correlations, and angular distributions of recoil in muon capture processes Ji Jf by an unpolarized nucleus for Ji ≦ 3 and Jf ≦ 5/2, with and without change of parity of nuclear levels, are given explicitely in terms of the multipole amplitudes. Relation of helicity amplitudes for muonic atom decay to the multipole amplitudes and to amplitudes introduced by other authors is presented. The derivation is based on kinematics only, and the formulae are strictly valid for the muon capture by any nuclei.

The formulae are convenient for model calculations of partial transitions with realistic nuclear and muon wave functions and for the phenomenological analysis of a weak interaction.
Application of the method of collective coordinates the the quantisation of the two‐dimensional higgs model
Authors: Muller‐Kirsten H. J. W. , Wiedemann A.
Published: November 2010

A comprehensive analysis of the application of the method of collective coordinates to the two dimensional Higgs model is given. First the instanton solution is derived, and the geometry of configuration space, and the construction of Schrodinger wave functionals are discussed. It is then explicitly verified that the Goldstone mode is the projection of the vacuum state onto the generator of the broken symmetry. The elimination of this Goldstone mode by means of the unitary gauge condition is demonstrated to the the crucial point in the construction of a consistent perturbation procedure. The parameter of the broken symmetry group is then used as the collective coordinate for field configurations around a minimum of the interaction. Throughout, the discussion is sufficiently detailed in order to facilitate the application of the method to other fields.
The process of multi‐hadron production and the problem of colour confinement
Authors: Kalinkin B. N.
Published: November 2010

A new possibility of interpreting the multiple production characteristics is discussed based on the results obtained in a large number of papers. It is shown that assuming the mechanism of dynamic‐confinement of “colour”, one can consistently construct a model of multiple hadron production at high energies containing the thermodynamics mechanism as an essential element. This model accounts for the basic characteristics of this process in the hadron interactions, e+e−‐annihilation. deep inelastic lepton‐nucleon scattering and in the reactions followed by the production of particles with large transverse momenta as well.

It does not contradict the data on the multiple production in the interaction of hadrons and of nuclei with nuclei.
Theoretical study of solvent influence on the electronic absorption and emission spectra of kynurenine
Authors: Benassi Enrico , Sherin Peter S.
Published: November 2010

Neutral/zwitterionic form equilibrium, excited state wave functions, absorption and emission spectra of kynurenine (KN) in various solvents (water, methanol, ethanol, and dimethylsulfoxide) have been studied theoretically. The ground electronic state geometries have been optimized by density functional theory methods; the geometries of the first two singlets excited electronic states have been optimized using the CASSCF technique. The influence of the solvent was taken into account by the calculation of the solvation free energies using the Polarizable Continuum Model (PCM). The spectra of electronic absorption and fluorescence emission have been calculated by the CS‐INDO S‐CI and SDT‐CI methods [Momicchioli, Baraldi, and Bruni, Chem Phys, 1983, 82, 229]. The calculated data reproduce the experimental positions of maxima and the solvent‐induced shifts of the absorption and emission bands well. The energy gap between the two lowest excited states of KN increases from aprotic to protic solvents. This fact suggests that the “proximity effect” cannot be responsible for the ultrafast decay of KN fluorescence in protic solvents. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Classification of partially reflecting surfaces using photodetached electron spectrum
Authors: Afaq A. , Ahmad Iftikhar
Published: November 2010

Photodetachment spectra of H− near a partially reflecting surface is investigated by closed orbit theory. A reflection parameter K is introduced for the analysis of the photodetached‐electron spectrum. Factor K controls the spectra on the screen and strongly depends on the surface properties of a material. This parameter can effectively be used for the classification of surfaces using photodetachment microscopy. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010