bluuebunny/crossref_metadata_2025 huggingface dataset:
FAP‐1‐mediated activation of NF‐κB induces resistance of head and neck cancer to fas‐induced apoptosis
Authors: Wieckowski Eva , Atarashi Yoshinari , Stanson Joanna , Sato Taka‐Aki , Whiteside Theresa L.
Published: August 2006

Molecular mechanisms responsible for tumor resistance to apoptosis often involve the Fas/FasL pathway. While squamous cell carcinomas of the head and neck (SCCHN) express both Fas and FasL, their resistance to self‐induced apoptosis or apoptosis mediated by Fas agonistic antibody (CH‐11Ab) was independent of the level of Fas surface expression or the presence of soluble Fas in supernatants of primary or metastatic SCCHN cell lines. By in vitro immunoselection, using PCI‐15A cell line treated with successive cycles of CH‐11 Ab, Fas‐resistant sublines with the parental genotype were selected. Such sublines failed to cleave caspase‐8 upon Fas engagement and were resistant to CH‐11 Ab, although they remained sensitive to VP‐16 or staurosporin. In the presence of cycloheximide, the selected SCCHN sublines become susceptible to CH‐11 Ab, and showed cleavage of caspase‐8, suggesting that apoptosis resistance was mediated by an inhibitory protein(s) acting upstream of caspase‐8. Overexpression of Fas‐associated phosphatase 1 (FAP‐1), but not cellular FLICE‐inhibitory protein (cFLIP) in SCCHN sublines was documented by Western blots and RT‐PCR analyses. The FAP‐1+ selected sublines also downregulated cell surface Fas. A high phosphorylation level of IκBκ, NFκB activation and upregulation of Bcl‐2 expression were observed in the FAP‐1+ sublines. Treatment with the phosphatase inhibitor, orthovanadate, or silencing of FAP‐1 with siRNA abolished their resistance to apoptosis, suggesting that FAP‐1 phosphatase activity could be responsible for NF‐κB activation and resistance of SCCHN cells to Fas‐mediated apoptosis. J. Cell. Biochem. 100: 16–28, 2007. © 2006 Wiley‐Liss, Inc.
High affinity of anti‐GM1 antibodies is associated with disease onset in experimental neuropathy
Authors: Comín Romina , Yuki Nobuhiro , Lopez Pablo H.H. , Nores Gustavo A.
Published: August 2006

High antibody affinity has been proposed as a disease determinant factor in neuropathies associated with anti‐GM1 antibodies. An experimental model of Guillain‐Barré syndrome, induced by immunization of rabbits with bovine brain gangliosides or GM1, was described recently (Yuki et al. [2001] Ann. Neurol. 49:712–720). We searched plasma from these rabbits, taken at disease onset and 1 or 2 weeks prior to onset, for the presence of high‐affinity anti‐GM1 IgG antibodies. Affinity was estimated by soluble antigen binding inhibition. High‐affinity antibodies (binding inhibition by 10–9 M GM1) were detected at disease onset but not before. No such difference was found for other antibody parameters such as titer, fine specificity, and population distribution. These findings support the proposed role of high affinity as an important factor in disease induction by anti‐GM1 antibodies. © 2006 Wiley‐Liss, Inc.
NADPH oxidase inhibitor diphenyliodonium abolishes lipopolysaccharide‐induced down‐regulation of transferrin receptor expression in N2a and BV‐2 cells
Authors: Reis Katarina , Hälldin Jonas , Fernaeus Sandra , Pettersson Christina , Land Tiit
Published: August 2006

The activation of cellular inflammatory response is tightly linked to induced production of reactive oxygen species (ROS) and nitric oxide (NO), which in turn have been identified as important regulators of cellular iron metabolism. In the present study, we have used the microglia cell line BV‐2 and the neuroblastoma cell line N2a to study the regulatory effects of the microbial agent lipopolysaccharide (LPS) on the expression of the transferrin receptor (TfR) and ferritin in cell lines with different characteristics. The receptor mainly responsible for LPS recognition is the Toll‐like receptor 4 (TLR4) that triggers a variety of intracellular signalling cascades leading to the induction of transcription of target genes involved in the innate immune response. Among the pathways to be activated is the MAPK cascade leading to the activation of nuclear factor‐κB that induces transcription of a variety of genes, e.g., inducible nitric oxide synthase (iNOS). The TLR4‐mediated LPS response also induces the production of ROS through a mechanism(s) suggested to involve the activation of NADPH oxidase(s). This study shows that exposure of BV‐2 and N2a cells to LPS results in decreased TfR protein levels and increased H‐ferritin mRNA levels. The LPS down‐regulatory effect on TfR protein expression is abolished by the NADPH oxidase inhibitor diphenyliodonium (DPI) but is not affected by the free radical scavenger N‐acetyl‐L‐cysteine (NAC) or the iNOS inhibitor aminoguanidine (AG). The increased H‐ferritin mRNA levels in response to LPS are not affected by DPI, NAC, or AG. © 2006 Wiley‐Liss, Inc.
IL‐1β, an immediate early protein secreted by activated microglia, induces iNOS/NO in C6 astrocytoma cells through p38 MAPK and NF‐κB pathways
Authors: Kim Yun‐Jung , Hwang So‐Young , Oh Eok‐Soo , Oh Seikwan , Han Inn‐Oc
Published: August 2006

In the present study we sought to examine cell–cell interactions by investigating the effects of factors released by stimulated microglia on inducible nitric oxide (NO) synthase (iNOS) induction in astrocytoma cells. After examining the temporal profiles of proinflammatory molecules induced by lipopolysaccharide (LPS) stimulation in BV2 microglial cells, iNOS and IL‐1β were observed to be the first immediate‐response molecules. Removal of LPS after 3 hr stimulation abrogated NO release, whereas a full induction of IL‐1β was retained in BV2 cells. We observed consistently that conditioned medium (CM) from activated microglia resulted in the induction of iNOS in C6 cells, and IL‐1β was shown to be a key regulator of iNOS induction. An IL‐1β‐neutralizing antibody diminished NO induction. Incubation with recombinant IL‐1β stimulated NO release to a lesser extent compared to microglial CM; co‐treatment of LPS and IL‐1β had a potent, synergistic effect on NO release from C6 cells. Transient transfection with MEK kinase 1 (MEKK1) or nuclear factor‐kappa B (NF‐κB) expression plasmids induced iNOS, and IL‐1β further enhanced the MEKK1 response. Furthermore, IL‐1β‐mediated NO release from C6 cells was significantly suppressed by inhibition of p38 mitogen activated protein kinase (MAPK) or NF‐κB by specific chemical inhibitors. Both IL‐1β and MEKK1 stimulated p38 and JNK MAPKs, as well as the NF‐κB pathway, to induce iNOS in C6 cells. Microglia may represent an anti‐tumor response in the central nervous system, which is potentiated by the local secretion of immunomodulatory factors that in turn affects astrocytoma (glioma) cells. A better understanding of microglia–glioma or microglia–astrocyte interactions will help in the design of novel immune‐based therapies for brain tumors or neuronal diseases. © 2006 Wiley‐Liss, Inc.
Differential sensitivity of Desi (small‐seeded) and Kabuli (large‐seeded) chickpea genotypes to water stress during seed filling: effects on accumulation of seed reserves and yield
Authors: Nayyar Harsh , Kaur Satwinder , Singh Smita , Upadhyaya Hari D
Published: August 2006

Water stress during the reproductive phase, especially during seed development, is considered detrimental for chickpea yield. In the present study, the relative sensitivity of Desi and Kabuli chickpea types to water stress during seed filling was assessed in terms of effects on quantitative and qualitative aspects of seed yield. Leaves of both types experienced stress injury (evaluated as electrolyte leakage) to the same extent and possessed almost similar values of water potential at the end of 14 days of water stress. The stressed plants of Kabuli type lost more chlorophyll and had less photosynthesis than Desi type. At maturity, Desi type showed more diminution of vegetative dry matter due to stress over control than Kabuli type. On the other hand, Kabuli type showed a proportionally greater reduction in seed weight per plant, average seed weight, average seed size, number of pods (single‐ and double‐seeded) and harvest index. The stressed seeds of Kabuli type showed 48 and 46% reduction over control in starch and protein content compared with 25 and 40%, respectively in Desi type. The accumulation of soluble sugars was relatively greater due to stress in Kabuli (47%) than Desi type (23%). Fat and fiber content declined by 39 and 35% over control in Desi seeds because of stress whereas Kabuli type showed 46 and 67% decreases, respectively. Protein fractions, namely albumins, globulins, glutelins and prolamins, decreased in stressed seeds of Kabuli by 32, 40, 16 and 15% over control relative to 40, 48, 30 and 28%, respectively, in Kabuli type. The activities of sucrose synthase, invertase and soluble starch synthase were inhibited to a higher extent in Kabuli seeds than Desi seeds under stress. Kabuli seeds showed significantly more reduction in the accumulation of amino acids such as phenylalanine + tyrosine, tryptophan, valine, alanine and histidine and minerals (Ca, P, Fe) due to stress compared with Desi type. Copyright © 2006 Society of Chemical Industry
High‐performance liquid chromatographic enantioseparations on capillary columns containing crosslinked polysaccharide phenylcarbamate derivatives attached to monolithic silica
Authors: Chankvetadze Bezhan , Kubota Takateru , Ikai Tomoyuki , Yamamoto Chiyo , Kamigaito Masami , Tanaka Nobuo , Nakanishi Kazuki , Okamoto Yoshio
Published: August 2006

Monolithic capillary columns containing native silica gel were covalently modified with 3,5‐disubstituted phenylcarbamate derivatives of cellulose and amylose and applied for enantioseparations in capillary LC. The method previously used for covalent immobilization of polysaccharide phenylcarbamate derivatives onto the surface of microparticulate silica gel was successfully adapted for in situ modification of monolithic fused‐silica capillary columns. The effects of the nature of polysaccharide and the substituents, as well as of multiple covalent immobilization of polysaccharide derivative on chromatographic performance of capillary columns were studied. The capillary columns obtained using this technique are stable in all solvents commonly used in LC and exhibit promising enantiomer resolving ability.
Determination of anatoxin‐a in environmental water samples by solid‐phase microextraction and gas chromatography‐mass spectrometry
Authors: Rodríguez Vania , Yonamine Mauricio , Pinto Ernani
Published: August 2006

In the present work, a method was developed and optimized aiming at the determination of anatoxin‐a in environmental water samples. The method is based on the direct derivatization of the analyte by adding hexylchloroformate in the alkalinized sample (pH = 9.0). The derivatized anatoxin‐a was extracted by a solid‐phase microextraction (SPME) procedure, submersing a PDMS fiber in an amber vial for 20 min under magnetic stirring. GC‐MS was used to identify and quantify the analyte in the SIM mode. Norcocaine was used as internal standard. The following ions were chosen for SIM analyses (quantification ions in italics): anatoxin‐a: 191, 164, 293 and norcocaine: 195, 136, 168. The calibration curve showed linearity in the range of 2.5–200 ng/mL and the LOD was 2 ng/mL. This method of SPME and GC‐MS analysis can be readily utilized to monitor anatoxin‐a for water quality control.
Approaching the Proteoglycome: Molecular Interactions of Proteoglycans and Their Functional Output
Authors: Cattaruzza Sabrina , Perris Roberto
Published: August 2006

Summary: Through their diverse core protein modules and glycan/glycosaminoglycan moieties, proteoglycans may engage in numerous cellular and molecular interactions which are dispensable during embryogenesis, are essential for the maintenance of a healthy state and are prone to modulation in pathological conditions. Proteoglycan interactions may involve binding to other structural components of the ECM, to cell surface receptors, to membrane‐associated components, and to soluble signaling molecules, which through this interaction may become entrapped in the ECM or sequestered at the cell surface. Understanding of these multiple interplays is therefore of paramount importance and requires a detailed mapping through what we define as the proteoglycome.

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Fast frequency response analysis of large‐scale structures with non‐proportional damping
Authors: Kim Chang‐Wan , Bennighof J. K.
Published: August 2006

Modal frequency response analysis is an economical approach for large and complex structural systems since there is an enormous reduction in dimension from the finite element frequency response problem. However, when non‐proportional damping exists, the modal frequency response problem is expensive to solve at many frequencies because modal damping matrices are fully populated. This paper presents a new algorithm to solve the modal frequency response problem for large and complex structural systems with structural and viscous damping. The newly developed algorithm, fast frequency response analysis (FFRA) algorithm, solves the damped modal frequency response problem with O(m2) operations at each frequency. Then the FFRA algorithm is extended for solving a system of equations in optimization application with the modal correction approach, in which the mass, stiffness and damping matrices of a modified configuration differ from the original configuration. Numerical results show that the FFRA algorithm dramatically improves the performance of the modal frequency response analysis compared to conventional methods in industry while obtaining the same accuracy. Copyright © 2006 John Wiley & Sons, Ltd.
Phase‐field modelling of solidification microstructure formation using the discontinuous finite element method
Authors: Shu Y. , Ai X. , Li B. Q.
Published: August 2006

This paper presents a discontinuous Galerkin finite element computational methodology for solving the coupled phase‐field and heat diffusion equations to predict the microstructure evolution during solidification. The phase‐field modelling of microstructure formation is briefly discussed. The discontinuous Galerkin finite element formulation for the phase‐field model systems for solidification microstructure formation is described in detail. Numerical stability is performed using the Neumann method. The accuracy of the discontinuous model is verified by the analytic solution of a simple 1‐D solidification problem. Numerical calculations using the discontinuous finite element phase‐field model have been performed for simulating the complex 2‐D and 3‐D dendrite structures formed in supercooled melts and the results are compared well with those in literature using the finite difference methods. Parallel computing algorithm is presented and results show that the minimization of the intercommunication between microprocessors is the key to increase the effectiveness in parallel computing with the discontinuous finite element phase‐field model for solidification microstructure formation. Copyright © 2006 John Wiley & Sons, Ltd.
Application of hybrid Trefftz finite element method to non‐linear problems of minimal surface
Authors: Wang Hui , Qin Qing‐Hua , Arounsavat Detdexa
Published: August 2006

This investigation provides a hybrid Trefftz finite element approach for analysing minimal surface problems. The approach is based on combining Trefftz finite element formulation with radial basis functions (RBF) and the analogue equation method (AEM). In this method, use of the analogue equation approach avoids the difficulty of treating the non‐linear terms appearing in the soap bubble equation, making it possible to solve non‐linear problems with the Trefftz method. Global RBF is used to approximate the inhomogeneous term induced from non‐linear functions and other loading terms. Finally, some numerical experiments are implemented to verify the efficiency of this method. Copyright © 2006 John Wiley & Sons, Ltd.
Topology optimization of regions of Darcy and Stokes flow
Authors: Wiker Niclas , Klarbring Anders , Borrvall Thomas
Published: August 2006

This paper treats the topology optimization problem of obtaining an optimal layout of regions of Darcy and Stokes flow, where the objective is the total potential power functional representing average fluid pressure. It extends the work of Borrvall and Petersson, which concerned optimal layout of Stokes flow only. A generalization of Stokes' equations is derived and used as state constraints in the optimization problem. A proof of existence of solutions is provided, and it is seen that although the corresponding proof in Borrvall and Petersson does not need regularization, the present one does. It is also concluded that linear interpolations of state parameters will result in black and white (unfiltered) designs. The method is tested on an area‐to‐point flow problem of the type discussed by Bejan, where the influence of various parameters and numerical strategies on the design are studied. Copyright © 2006 John Wiley & Sons, Ltd.
Solution of periodic group circular hole problems by using the series expansion variational method
Authors: Chen Y. Z. , Lin X. Y.
Published: August 2006

This paper investigates the periodic group circular holes composed of infinite groups with numbering fromj= − ∞, …, −2, −1, 0, 1, 2, … toj= ∞ placed periodically in an infinite plate. The same loading condition and the same geometry are assumed for holes in all groups. The series expansion variational method (SEVM) is used for the solution of the periodic group circular hole problems. After using the SEVM, the boundary value problem is then reduced to an algebraic equation for the undetermined coefficients in the series expansion form, which is formulated on the central group. The influences on the central group from central group itself and many neighbouring groups are evaluated exactly. The influences on the central group from remote groups fromj= − ∞, −(M+ 2), −(M+ 1),M+ 1,M+ 2 toj= ∞ are approximately summed up into one term. This suggested technique is called the remainder estimation technique (RET) hereafter. It is proved from the computed results that the RET is very effective for the solution of the periodic group hole problems. Finally, several numerical examples are given and the interaction between the groups is addressed. Comparison between various sources of computation is presented. In the uniaxial tension iny‐direction, the stacking effect of the stacked groups is studied. Copyright © 2006 John Wiley & Sons, Ltd.
A wet‐road braking distance estimate utilizing the hydroplaning analysis of patterned tire
Authors: Cho J. R. , Lee H. W. , Yoo W. S.
Published: August 2006

A wet‐road braking distance estimate for the vehicles equipped with ABS (anti‐lock brake system) is presented in this paper. The entire speed interval at braking is divided into several uniform sub‐intervals, and the energy conservation law is applied to individual sub‐intervals to predict the intervalwise braking times and the resulting velocity profile at braking and the total braking distance. The proposed method is based on a numerical‐analytical approach such that the frictional energy loss of the patterned tire is computed by 3‐D hydroplaning analysis while the other at the disc pad is analytically derived. The operation of ABS is numerically implemented by controlling the tire angular velocity such that the preset tire slip ratio on the wet road is maintained. The tire hydroplaning is analysed by generally coupling an Eulerian finite volume method and an explicit Lagrangian finite element method. Illustrative numerical experiment is presented to support the validity of the proposed estimate. Copyright © 2006 John Wiley & Sons, Ltd.
Eigensolution for free vibration of planar frames by weighted graph symmetry
Authors: Kaveh A. , Dadfar B.
Published: August 2006

In this paper, the method recently developed for mass‐spring systems is generalized to include the free vibration of frames. Here, the inter‐relation for the mechanical properties of elements is established using weighted graphs, enabling the calculation of the eigenvalues involved. Using graph symmetry, the models are decomposed into submodels and healing processes are employed such that the union of the eigenvalues of the healed submodels results in the eigenvalues of the entire model. The present method is illustrated through many simple examples of different configurations. Copyright © 2006 John Wiley & Sons, Ltd.
An iterative regularization method for inverse phonon radiative transport problem in nanoscale thin films
Authors: Huang Cheng‐Hung , Chen Kuan‐Yu
Published: August 2006

An inverse phonon radiative transport problem with an alternative form of adjoint equation is solved in this study by using conjugate gradient method (CGM) to estimate the unknown boundary temperature distributions, based on the phonon intensity measurements. The CGM in dealing with the present integro‐differential governing equations is not as straightforward as for the normal differential equations; special treatments are needed to overcome the difficulties. Results obtained in this inverse analysis will be justified based on the numerical experiments where two different unknown temperature (or phonon intensity) distributions are to be determined. Finally, it is shown that accurate boundary temperatures can always be obtained with CGM. Copyright © 2006 John Wiley & Sons, Ltd.
Implementation of an exact finite reduction scheme for steady‐state reaction‐diffusion equations
Authors: Cardin Franco , Lovison Alberto , Putti Mario
Published: August 2006

In this paper we propose the numerical solution of a steady‐state reaction‐diffusion problem by means of application of a non‐local Lyapunov–Schmidt type reduction originally devised for field theory. A numerical algorithm is developed on the basis of the discretization of the differential operator by means of simple finite differences. The eigendecomposition of the resulting matrix is used to implement a discrete version of the reduction process. By the new algorithm the problem is decomposed into two coupled subproblems of different dimensions. A large subproblem is solved by means of a fixed point iteration completely controlled by the features of the original equation, and a second problem, with dimensions that can be made much smaller than the former, which inherits most of the non‐linear difficulties of the original system. The advantage of this approach is that sophisticated linearization strategies can be used to solve this small non‐linear system, at the expense of a partial eigendecomposition of the discretized linear differential operator. The proposed scheme is used for the solution of a simple non‐linear one‐dimensional problem. The applicability of the procedure is tested and experimental convergence estimates are consolidated. Numerical results are used to show the performance of the new algorithm. Copyright © 2006 John Wiley & Sons, Ltd.
An improved discrete Kirchhoff quadrilateral element based on third‐order zigzag theory for static analysis of composite and sandwich plates
Authors: Kapuria S. , Kulkarni S. D.
Published: August 2006

A new improved discrete Kirchhoff quadrilateral element based on the third‐order zigzag theory is developed for the static analysis of composite and sandwich plates. The element has seven degrees of freedom per node, namely, the three displacements, two rotations and two transverse shear strain components at the mid‐surface. The usual requirement of C1 continuity of interpolation functions of the deflection in the third‐order zigzag theory is circumvented by employing the improved discrete Kirchhoff constraint technique. The element is free from the shear locking. The finite element formulation and the computer program are validated by comparing the results for simply supported plate with the analytical Navier solution of the zigzag theory. Comparison of the present results with those using other available elements based on zigzag theories for composite and sandwich plates establishes the superiority of the present element in respect of simplicity, accuracy and computational efficiency. The accuracy of the zigzag theory is assessed by comparing the finite element results of the square all‐round clamped composite plates with the converged three‐dimensional finite element solution obtained using ABAQUS. The comparisons also establish the superiority of the zigzag theory over the smeared third‐order theory having the same number of degrees of freedom. Copyright © 2006 John Wiley & Sons, Ltd.
A minimal element distortion strategy for computational mesh dynamics
Authors: López Ezequiel J. , Nigro Norberto M. , Storti Mario A. , Toth Jorge A.
Published: August 2006

Mesh motion strategy is one of the key points in many fluid–structure interaction (FSI) problems. Due to the increasing application of FSI to solve the current challenging engineering problems, this topic has become of great interest. There are several different strategies to solve this problem, some of them use a discrete and lumped spring–mass system to propagate the boundary motion into the volume mesh, and many others use an elastostatic problem to deform the mesh. In all these strategies there is always risk of producing an invalid mesh, i.e. a mesh with some elements inverted. Normally this condition is irreversible and once an invalid mesh is obtained it is difficult to continue.

In this paper the mesh motion strategy is defined as an optimization problem. By its definition this strategy can be classified as a particular case of an elastostatic problem where the material constitutive law is defined in terms of the minimization of certain energy functional that takes into account the degree of element distortion. Some advantages of this strategy are its natural tendency to high quality meshes, its robustness and its straightforward extension to 3D problems. Several examples included in this paper show these capabilities.

Even though this strategy seems to be very robust it is not able to recover a valid mesh starting from an invalid one. This improvement is left for future work. Copyright © 2006 John Wiley & Sons, Ltd.
Does professional‐centred training improve consultation outcomes?
Authors: Parkin T , Barnard K , Cradock S , Pettman P , Skinner Tc
Published: August 2006

This study aimed to examine whether professional‐centred training improves consultation outcomes.

Using a pre‐ and post‐data collection design, immediately after consultations, professionals and patients completed a consultation review sheet which was coded for the level of agreement on issues discussed and decisions made. Patients also completed the Health Care Climate Questionnaire (HCCQ). Pre‐training results were fed back to the professionals to provide an objective measure of current practice. Training day one comprised 10 minutes' observation of videoed consultations of each professional in order to identify strengths and training needs. Each professional identified key areas of their consultation that they felt needed further development. Training day two centred on goal setting and negotiating agendas as these were identified as priority areas requiring more skills.

Data from 110 baseline and 73 follow‐up consultations were collected. The HCCQ showed no significant difference between baseline and follow up. Non‐parametric tests indicated that the level of agreement on decisions had improved (Mann‐Whitney U = 951; p = 0.002; χ2 = 3.67; df = 2; p = 0.026). The number of consultations where complete disagreement occurred between the patient and professional, on decisions made, reduced from 17% at baseline to 11% at follow up.

It was concluded that professional‐centred training can be effective in improving patients' perceptions of the consultation, and in increasing patient/professional agreement on recall of decisions made. Copyright © 2006 John Wiley & Sons, Ltd.
Mechanical properties and morphological behavior of calcium carbonate‐filled polypropylene in dynamic injection molding
Authors: Wang Quan , Qu Jinping
Published: August 2006

A custom‐made electromagnetic dynamic injection molding machine was adopted to study the mechanical properties and morphological behavior of calcium carbonate‐filled polypropylene (PP) in a dynamic injection molding process. The influence of vibration amplitude and frequency on the mechanical properties and morphological behavior of samples was investigated using tensile tests, notched Izod impact tests, differential scanning calorimetry, and scanning electronic microscopy. The tensile stress and the impact stress for all samples investigated were found to increase in a nonlinear manner with increasing vibration amplitude and frequency. The tensile stress reached a maximum value at about 8 Hz and 0.15 mm for neat PP and PP filled with 3, 20, and 30 wt% CaCO3. For PP filled with 40 wt% CaCO3, the tensile stress reached a maximum value at about 12 Hz and 0.2 mm. The impact stress reached a maximum value at about 12 Hz. From DSC experiments it was shown that the melting temperature slightly increased, but no new polymeric crystalline peak appeared under the vibration force field. The CaCO3 particles were diffused easily and distributed evenly in the PP melt under the vibration force field, so it is very useful in improving the quality of injection products. Copyright © 2006 Society of Chemical Industry
A measuring system for the fast simultaneous isotope ratio and elemental analysis of carbon, hydrogen, nitrogen and sulfur in food commodities and other biological material
Authors: Sieper Hans‐Peter , Kupka Hans‐Joachim , Williams Tony , Rossmann Andreas , Rummel Susanne , Tanz Nicole , Schmidt Hanns‐Ludwig
Published: August 2006

The isotope ratio of each of the light elements preserves individual information on the origin and history of organic natural compounds. Therefore, a multi‐element isotope ratio analysis is the most efficient means for the origin and authenticity assignment of food, and also for the solution of various problems in ecology, archaeology and criminology. Due to the extraordinary relative abundances of the elements hydrogen, carbon, nitrogen and sulfur in some biological material and to the need for individual sample preparations for H and S, their isotope ratio determination currently requires at least three independent procedures and approximately 1 h of work. We present here a system for the integrated elemental and isotope ratio analysis of all four elements in one sample within 20 min. The system consists of an elemental analyser coupled to an isotope ratio mass spectrometer with an inlet system for four reference gases (N2, CO2, H2 and SO2). The combustion gases are separated by reversible adsorption and determined by a thermoconductivity detector; H2O is reduced to H2. The analyser is able to combust samples with up to 100 mg of organic material, sufficient to analyse samples with even unusual elemental ratios, in one run. A comparison of the isotope ratios of samples of water, fruit juices, cheese and ethanol from wine, analysed by the four‐element analyser and by classical methods and systems, respectively, yielded excellent agreements. The sensitivity of the device for the isotope ratio measurement of C and N corresponds to that of other systems. It is less by a factor of four for H and by a factor of two for S, and the error ranges are identical to those of other systems. Copyright © 2006 John Wiley & Sons, Ltd.
Mass spectrometry study of hemoglobin‐oxaliplatin complexes in colorectal cancer patients and potential association with chemotherapeutic responses
Authors: Mandal Rupasri , Sawyer Michael B. , Li Xing‐Fang
Published: August 2006

Oxaliplatin is the most active platinum (Pt)‐containing anticancer drug for the treatment of advanced colorectal cancer. We report here the study of potential association of the levels of oxaliplatin‐protein complexes in 19 cancer patients with treatment efficacy using size‐exclusion high‐performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC/ICPMS) and nanoelectrospray ionization mass spectrometry (nanoESI‐MS) techniques. Blood samples from 19 colorectal cancer patients were collected at 1 and 48 h after the first infusion of oxaliplatin. HPLC/ICPMS quantification of the oxaliplatin‐protein complexes showed that the levels of Pt‐protein complexes in plasma samples at 48 h were reduced by approximately 50% compared to those at 1 h, whereas those in hemolysates did not change significantly. The concentrations of hemoglobin (Hb)‐oxaliplatin complexes determined by HPLC/ICPMS ranged from 3.1 to 8.7 µM. NanoESI‐MS analysis of the patient hemolysates showed three distinct mass spectral profiles of the Hb‐oxaliplatin complexes: (1) 1:1, (2) 1:1 with 1:2, and (3) multiple complexes of 1:1, 1:2, 1:3, and 1:4, corresponding to the Hb‐oxaliplatin complex concentrations determined by HPLC/ICPMS. Potential association of variables including Hb‐oxaliplatin complex concentrations with time to progress as the treatment efficacy indicator was analyzed using the Cox model. Multivariate analysis of the potential predictors showed that the statistically significant variables were Hb‐oxaliplatin complex concentration (p = 0.02), performance status (p = 0.02), baseline neutrophil count (p = 0.05), and the site of the primary cancer (colon vs. rectal, p = 0.01). The hazard ratio for the concentration of the Hb‐oxaliplatin complexes was 2.4, suggesting that the risk of cancer progression significantly increased with increasing of Hb‐oxaliplatin complexes in patients. These results demonstrate that the level of the Hb‐oxaliplatin complexes in erythrocytes is a potential biomarker for indicating inter‐patient variations in oxaliplatin treatment efficacy. Copyright © 2006 John Wiley & Sons, Ltd.
Determination of levetiracetam in human plasma by liquid chromatography/electrospray tandem mass spectrometry and its application to bioequivalence studies
Authors: Jain Deepak S. , Subbaiah Gunta , Sanyal Mallika , Pal Usha , Shrivastav Pranav S.
Published: August 2006

The first liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of levetiracetam, an antiepileptic drug, in human plasma is described. The plasma filtrate obtained after solid‐phase extraction (SPE), using a polymer‐based, hydrophilic‐lipophilic balanced (HLB) cartridge, was submitted directly to a short column LC/MS/MS assay. There was no significant matrix effect on the analysis. For validation of the method, the recovery of the free analytes was compared to that from an optimized extraction method, and the analyte stability was examined under conditions mimicking sample storage, handling, and analytical procedures. The extraction procedure yielded extremely clean extracts with a recovery of 79.95% and 89.02% for levetiracetam and the internal standard (IS), respectively. The intra‐assay and inter‐assay precision for the samples at the lower limit of quantitation (LLOQ) were 6.33 and 6.82%, respectively. The calibration curves were linear for the dynamic range of 0.5 to 50 µg/mL with a correlation coefficient r ≥ 0.9971. The intra‐assay accuracy at LLOQ, LQC, MQC, and HQC levels ranged from 81.60 to 95.40, 93.00 to 103.47, 95.97 to 104.09, and 91.15 to 95.18%, respectively, while the inter‐assay accuracy at LLOQ, LQC, MQC and HQC levels varied from 80.20 to 95.40, 88.53 to 107.53, 95.97 to 108.45, and 91.15 to 112.70%, respectively. The method is rugged and fast with a total instrumental run time of 2 min. The method was successfully applied for bioequivalence studies in human subject samples after oral administration of 1000 mg immediate release (IR) formulations. Copyright © 2006 John Wiley & Sons, Ltd.
Electron ionization mass spectra of 8‐aryl‐3,4‐dioxo‐2H,8H‐6,7‐dihydroimidazo[2,1‐c][1,2,4]triazines. Do they exhibit tautomerism in the gas phase?
Authors: Martiskainen Olli , Sztanke Krzysztof , Matosiuk Dariusz , Pihlaja Kalevi
Published: August 2006

The electron ionization mass spectra of the title compounds (1: a R = H, b 2‐CH3, c 4‐CH3, d 2,3‐diMe, e 2‐OCH3, f 4‐OCH3, g 2‐Cl, h 3‐Cl, i 4‐Cl, j 3,4‐diCl) were recorded at 70 eV to determine the effects of substituents and the possible keto‐enol tautomerism. The compounds showed several common fragment ions but also fragment ions which divided them into three classes, namely 1a–1d (parent compound and Me‐substituted derivatives), 1e and 1f (MeO‐substituted derivatives), and 1g–1j (Cl‐substituted derivatives). The presence of the HOCN+. ion as well as the exponential dependence of its total ion current in the case of p‐ and also 3‐Cl‐substituted compounds (1a, c, f, h–j) on the Hammett σ constants and the loss of CHO or one or two HOCN moieties can be somewhat easier explained by the presence of the enol form but as a whole the results support the predominance of the keto form, in parallel to the situation in solution. Copyright © 2006 John Wiley & Sons, Ltd.
The effect of growth rate on tissue‐diet isotopic spacing in rapidly growing animals. An experimental study with Atlantic salmon (Salmo salar)
Authors: Trueman Clive N. , McGill Rona A. R. , Guyard Philippe H.
Published: August 2006

The original article to which this Erratum refers was published in Rapid Commun. Mass Spectrom. 2005; 19: 3239–3247
Antiviral drugs for cytomegalovirus in transplant recipients: advantages of preemptive therapy
Authors: Singh Nina
Published: August 2006

Currently available, potent antiviral agents have proven highly effective for the prevention of CMV disease during the time that prophylaxis is employed. However, late‐onset CMV disease, occurring in 5–18% of the patients, has emerged as a significant complication in organ transplant recipients receiving prophylaxis. Complete suppression of the virus with long‐term use of a potent antiviral agent may be less conducive to antigen‐induced priming of host responses, which may explain why there is a greater likelihood of late‐onset CMV disease. On the other hand, allowing controlled low‐level viral replication, implicit in the strategy of preemptive therapy, may facilitate CMV‐specific immune reconstitution and have a mitigating effect on the risk of late‐onset CMV disease. Preemptive therapy with valganciclovir appears less likely to be associated with CMV disease, largely due to a lower incidence of late‐onset CMV disease. Emerging data, documenting that CMV disease in the era of prophylaxis with potent antiviral agents is an independent contributor to mortality, particularly infection‐associated mortality, stands to challenge the notion that prophylaxis is more likely to have a beneficial effect on CMV‐related secondary outcomes. Preemptive therapy is a more logical and theoretically more appealing approach for the prevention of CMV disease in transplant recipients. Published in 2006 by John Wiley & Sons, Ltd.
A comparative study of the risk of malignancy index and the ovarian crescent sign for the diagnosis of invasive ovarian cancer
Authors: Yazbek J. , Aslam N. , Tailor A. , Hillaby K. , Raju K. S. , Jurkovic D.
Published: August 2006

Objective

To compare the value of the risk of malignancy index (RMI) and the ovarian crescent sign (OCS) in the diagnosis of ovarian malignancy.

Methods

This was a prospective observational study of women with ultrasonographic diagnosis of an ovarian cyst. The RMI was calculated in all cases using a previously published formula (RMI = U (ultrasound score) × M (menopausal status) × serum CA125 (kU/L)). A value > 200 was considered to be diagnostic of ovarian cancer. The OCS was defined as a rim of visible healthy ovarian tissue in the ipsilateral ovary. Its absence was taken as being diagnostic of invasive cancer.

Results

A total of 106 consecutive women were included in the study, of whom 92 (86.8%) had a benign ovarian tumor, five (4.7%) had borderline lesions and nine (8.5%) had an invasive ovarian cancer. The absence of an OCS diagnosed invasive ovarian cancer with a sensitivity of 100% (95% CI, 70–100%), specificity of 93% (95% CI, 86–96%), positive predictive value (PPV) of 56%, negative predictive value (NPV) of 100% and positive likelihood ratio (LR+) of 13.86 (95% CI, 6.79–28.29). This compared favorably with a sensitivity of 89% (95% CI, 57–98%), specificity of 92% (95% CI, 85–96%), PPV of 50%, NPV of 99% and LR+ of 10.78 (95% CI, 5.34–21.77), which were achieved using RMI > 200 (P < 0.01).

Conclusions

The RMI and the OCS are useful tests for discriminating between invasive and non‐invasive ovarian tumors. The application of these tests in a sequential manner might improve the overall accuracy of ovarian cancer diagnosis. Copyright © 2006 ISUOG. Published by John Wiley & Sons, Ltd.
Chemischer Transport ternärer Oxide im System Ni/Mo/O – Experimente und Modellrechnungen
Authors: Steiner Udo , Reichelt Werner
Published: August 2006

Chemical Vapour Transport of Ternary Oxides in the System Ni/Mo/O – Experiments and Model Calculations

The chemical vapour transport behaviour of the phases in the Ni/Mo/O system has been investigated using Cl2 and Br2 as transport agents in a temperature gradient 1173 to 1073 K. Single crystals of Ni2Mo3O8, NiO and MoO2 have been obtained, while the deposited NiMoO4 crystals are destroyed during cooling down to room temperature due to a phase transition. Pure powders of the ternary compounds have been used as starting materials as well as mixtures of three coexisting phases. The observed transport behaviour is compared with results of thermo dynamical model calculations. The influences of source composition, transport agent and the moisture contents are described in detail.
[BeCl(12‐Krone‐4)][SbCl4]: Ein neuer kationischer Berylliumkomplex
Authors: Neumüller Bernhard , Dehnicke Kurt
Published: August 2006

[BeCl(12‐Crown‐4)][SbCl4]: A Novel Cationic Beryllium Complex

Beryllium chloride reacts in dichloromethane suspension in the presence of the equimolar amount of 12‐crown‐4 with antimony pentachloride exothermically to give [BeCl(12‐crown‐4)][SbCl4] (1), which is characterized by IR spectroscopy and by single crystal structure determination. Space group P21/c, Z = 8, lattice dimensions at 193 K: a = 1116.4(2), b = 1735.4(2), c = 1709.8(3) pm, β = 91.31(1)°, R1 = 0.0301. 1 contains cations [BeCl(12‐crown‐4)]+ with coordination number five at the beryllium atom, and polymeric anions $\rm [SbCl_{4}^{\phantom{\infty}-}]{\infty}$, forming zigzag chains along [001] with coordination number five at the antimony atoms, thus showing the steric effect of the lone pair.

1 can also be obtained by using the twofold amounts of 12‐crown‐4 and antimony pentachloride, however, accompanied by forming [SbCl3(12‐crown‐4)] (2). With respect to the wrong crystal structure determinations previously reported in the literature, we solved the X‐ray structure of 2 in the space group P21/c, Z = 4, lattice dimensions at 173 K: a = 1191.4(1), b = 783.7(1), c = 1489.7(2) pm, β = 90.83(1)°, R1 = 0.0243.
Element‐Element‐Bindungen. XI Kettenbildung bei kristallinen Dimethyldichalkogenanen
Authors: Mundt Otto , Becker Gerd , Baumgarten Jens , Riffel Heinz , Simon Arndt
Published: August 2006

Element‐Element Bonds. XI Chain Formation in Crystalline Dimethyldichalkogenanes

The structures of dimethyldichalkogenanes (H3C)2E2 liquid at room temperature have been determined by single‐crystal x‐ray diffraction {E = S, α‐form 1a, P21/c; Z = 4; a = 860.9(5); b = 648.0(4); c = 845.9(4) pm; β = 94.23(4)°; −141 ± 2 °C; β‐form 1b, P21/c; Z = 4; a = 518.3(3); b = 1445.6(10); c = 670.9(3) pm; β = 107.30(5)°; −141 ± 2 °C; E = Se, 2, Fdd2; Z = 16; a = 2236.6(5); b = 1759.0(9); c = 520.9(2) pm; −120 ± 2 °C; E = Te, 3, C2/c; Z = 4; a = 1260.8(4); b = 849.1(4); c = 561.0(3) pm; β = 107.04(6)°; −130 ± 2 °C}. As a remarkable result intermolecular E··E interactions indicated by the ratio Q = (E··E)/(E−E) increase gradually in strength when dimethyldisulfane with ordinary van der Waals contacts (1a, Q = 1.86; 1b, Q = 1.84) is compared with the selenium (2, Q = 1.54) and the tellurium derivatives (3, Q = 1.38). Taking these E··E contacts into account, an association of the binuclear molecules to pairs can be detected for polymorph 1b, whereas zigzag chains are encountered in the remaining crystal structures (1a, E−E··E = 95° and 174°; 2, 156° and 161°; 3, 151°). Additionally, by a careful inspection several crystal structures already published by other authors turn out to exhibit similar phenomena. Furthermore, the molecular packing modes of α‐dimethyldisulfane (1a) and elementary chlorine resemble each other, whereas the β‐polymorph 1b and the isotypic crystal structures of β‐dibromo‐ and dichlorodiselane as described by Kniep, Korte und Mootz constitute a pair of polytypoid stacking variants. A similar relationship could be established between the structures of dimethyldiselane (2) and the homologous ditellane 3. In comparison with numerous literature data the intermolecular interactions observed with these dimethyldichalkogenanes have to be classified as only weak.
Azidoaurates of the Alkali Metals
Authors: Afyon Semih , Höhn Peter , Armbrüster Marc , Baranov Alexey , Wagner Frank R. , Somer Mehmet , Kniep Rüdiger
Published: August 2006

Synthesis, crystal structure as well as IR‐ and Raman‐spectroscopic properties of the new ternary azidoaurates(III) A[Au(N3)4] (A = K, Rb, Cs) are reported. The translucent orange‐red compounds were prepared by reaction of the respective binary azides with HAuCl4 in aqueous solutions at room temperature. The crystal structures determined by single crystal X‐ray diffraction methods are monoclinic (C2/c (No. 15), K/Rb/Cs[Au(N3)4]: a = 1049.30(9) pm / 1033.93(10) pm / 1011.9(8) pm, b = 1047.52(8) pm / 1064.20(11) pm / 1093.8(8) pm, c = 776.97(7) pm / 809.79(8) pm / 858.4(6) pm, β = 91.220(5)° / 90.322(5)° / 92.72(5)°) and provide the first examples for azidoaurates with mono‐atomic cations. The unusual reduction of the lattice parameter a with increasing cation size in the isotypic series is discussed in detail. IR‐ and Raman‐spectroscopic measurements show strongly covalent gold‐nitrogen contacts, a bonding situation which is further supported by quantum chemical calculations and ELF‐analyses.
Synthese und Kristallstruktur von Na3[W3Cl13]
Authors: Weisser Martina , Tragl Sonja , Meyer H.‐Jürgen
Published: August 2006

Synthesis and Crystal Structure of Na3[W3Cl13]

A solid state reaction of tungsten(IV)chloride and sodium chloride yielded black plate‐like crystals of Na3[W3Cl13]. The structure of this compound was determined by single crystal X‐ray diffraction. Na3[W3Cl13] crystallizes in the monoclinic space group P 21/c with a = 9.093(1) Å, b = 23.851(4) Å, c = 9.155(1) Å, β = 120.26(1)°, and Z = 4. The crystal structure contains trigonal tungsten clusters ($\rm ({\bar d}_{w.w} = 2.737(1)\AA)$ = 2.737(1) Å) surrounded by chlorine atoms. The molecular [W3(μ3‐Cl)(μ‐Cl)3Cl9]3− cluster anions are forming layers parallel to the ac‐plane, sodium ions are located in and in between the layers.