bluuebunny/crossref_metadata_2025 huggingface dataset:
Knowledge-Based Framework for Validating Workflow Sequences
Authors: Piramuthu Selwyn
Published: August 2004

The increase in interest in representing business processes using workflow models necessitates considering means to improving workflow modeling process. This can be achieved through several different approaches; including improvement in the representation itself, better uncertainty handling, reactive as well as proactive means to handle dynamic changes in the workflow environment, among others. We present a method to validate workflow sequences using inductively constructed knowledge-base, and illustrate the proposed method using an example from the medical domain.
TIME-SHIFTS GENERALIZED MULTIRESOLUTION ANALYSIS OVER DYADIC-SCALING REDUCING SUBSPACES
Authors: LEVAN NHAN , KUBRUSLY CARLOS S.
Published: August 2004

A Generalized Multiresolution Analysis (GMRA) associated with a wavelet is a sequence of nested subspaces of the function space ℒ2(ℝ), with specific properties, and arranged in such a way that each of the subspaces corresponds to a scale 2mover all time-shifts n. These subspaces can be expressed in terms of a generating-wandering subspace — of the dyadic-scaling operator — spanned by orthonormal wavelet-functions — generated from the wavelet. In this paper we show that a GMRA can also be expressed in terms of subspaces for each time-shift n over all scales 2m. This is achieved by means of "elementary" reducing subspaces of the dyadic-scaling operator. Consequently, Time-Shifts GMRA associated with wavelets, as well as "sub-GMRA" associated with "sub-wavelets" will then be introduced.
JPEG2000 AND JPEG: A STATISTICAL APPROACH FOR LOSSILY COMPRESSED MEDICAL IMAGES QUALITY EVALUATION
Authors: OH TICK HUI , BESAR ROSLI
Published: August 2004

Image compression will always reduce the image fidelity, especially when the image is compressed at lower bit rates, which cannot be tolerated, especially in medical field. But compression is necessary due to the constraint of transmission bandwidth and the limited storage capacity. In this paper, the bad compression performance of the new JPEG2000 and the more conventional JPEG are studied. Besides, using the common objective measures such as Peak Signal-to-Noise Ratio (PSNR) and Root Mean Square Error (RMSE) as the standard quality measurements, we focus more on the statistical and frequency measures as the image characteristics evaluation. Four types of medical modalities are used: X-ray, Magnetic Resonance Imaging (MRI), Ultrasound and Computed Tomography (CT). From these various measurements, we found the general acceptance compression bit rate for each of the medical modalities.
WAVELET DIRECTIONAL HISTOGRAMS OF THE SPATIO-TEMPORAL TEMPLATES OF HUMAN GESTURES
Authors: SHARMA ARUN , KUMAR DINESH K. , KUMAR SANJAY , McLACHLAN NEIL
Published: August 2004

This paper evaluates the efficacy of directional information of wavelet multi-resolution decomposition to enhance histogram-based classification of human gestures. The gestures are represented by spatio-temporal templates. This template collapses spatial and temporal components of motion into a static gray scale image such that no explicit sequence matching or temporal analysis is required, and it reduces the dimensionality to represent motion. These templates are modified to be invariant to translation and scale. Two-dimensional, 3-level dyadic wavelet transforms have been applied on the template resulting in one lowpass sub-image and nine highpass directional sub-images. Histograms of wavelet coefficients at different scales are used for classification purposes. The experiments demonstrate that while the statistical properties of the template provide high level of classification accuracy, the global detail activity available in highpass decompositions significantly improve the classification accuracy.
A NEURAL NETWORK-WAVELET MODEL FOR GENERATING ARTIFICIAL ACCELEROGRAMS
Authors: SIRCA GENE F. , ADELI HOJJAT
Published: August 2004

In earthquake-resistant design of structures, for certain structural configurations and conditions, it is necessary to use accelerograms for dynamic analysis. Accelerograms are also needed to simulate the effects of earthquakes on a building structure in the laboratory. A new method of generating artificial earthquake accelerograms is presented through adroit integration of neural networks and wavelets. A counterpropagation (CPN) neural network model is developed for generating artificial accelerograms from any given design spectrum such as the International Building Code (IBC) design spectrum. Using the IBC design spectrum as network input means an accelerogram may be generated for any geographic location regardless of whether earthquake records exist for that particular location or not. In order to improve the efficiency of the model, the CPN network is modified with the addition of the wavelet transform as a data compression tool to create a new CPN-wavelet network. The proposed CPN-wavelet model is trained using 20 sets of accelerograms and tested with additional five sets of accelerograms available from the U.S. Geological Survey. Given the limited set of training data, the result is quite remarkable.
COMPRESSION OF SEGMENTED 3D SEISMIC DATA
Authors: ZHELUDEV VALERY A. , KOSLOFF DAN D. , RAGOZA EUGENE Y.
Published: August 2004

We present a preliminary investigation of compression of segmented 3D seismic volumes for the rendering purposes. Promising results are obtained on the base of 3D discrete cosine transforms followed by the SPIHT coding scheme. An accelerated version of the algorithm combines 1D discrete cosine transform in vertical direction with the 2D wavelet transform of horizontal slices. In this case the SPIHT scheme is used for coding the mixed sets of cosine-wavelet coefficients.
MONITORING MACHINING PROCESSES BASED ON DISCRETE WAVELET TRANSFORM AND STATISTICAL PROCESS CONTROL
Authors: LI XIAOLI , DU R.
Published: August 2004

This paper presents a new method to monitor machining processes based on a combination of discrete wavelet transform (DWT) and statistical process control (SPC), called a multi-scale statistical approach. First, DWT is applied to decompose the sensor signal onto different scales. Next, the detection limits are formed for each decomposed signal components, called the sub-signals, using Shewhart control charts. Finally, by inverse wavelet transform of the threshold crossing points of the sub-signals, malfunctions can be detected. Based on a test on the tool condition monitoring in turning using acoustic emission (AE) signal, it is shown that the new method is effective and robust.
EXPERIMENTAL STUDY OF TRANSLATION-INVARIANT DWT FACE FEATURE ESTIMATION
Authors: MA KUN , TANG XIAOOU
Published: August 2004

In this paper, we conduct a series of experiments to evaluate the translation invariant property of a set of discrete wavelet features in a face graph. Using local-area power spectrum estimation based on discrete wavelet transform, we compute a feature vector that possesses both efficient space-frequency structure and translation invariant properties.
THERMAL ENTANGLEMENT IN THE TWO-QUBIT HEISENBERG XYZ MODEL
Authors: RIGOLIN GUSTAVO
Published: August 2004

We study the entanglement of a two-qubit one-dimensional XYZ Heisenberg chain in thermal equilibrium at temperature T. We obtain an analytical expression for the concurrence of this system in terms of the parameters of the Hamiltonian and T. We show that depending on the relation among the coupling constants, it is possible to increase the amount of entanglement of the system by increasing its anisotropy. We also show numerically that for all sets of the coupling constants entanglement is a monotonically decreasing function of the temperature T, proving that we must have at least an external magnetic field in the z-direction to obtain a behavior where entanglement increases with T.
POPPER'S EXPERIMENT, COPENHAGEN INTERPRETATION AND NONLOCALITY
Authors: QURESHI TABISH
Published: August 2004

A thought experiment, proposed by Karl Popper, which has been experimentally realized recently, is critically examined. A basic flaw in Popper's argument which has also been prevailing in subsequent debates, is pointed out. It is shown that Popper's experiment can be understood easily within the Copenhagen interpretation of quantum mechanics. An alternate experiment, based on discrete variables, is proposed, which constitutes Popper's test in a clearer way. It refutes the argument of absence of nonlocality in quantum mechanics.
MINIMIZATION OF NONRESONANT EFFECTS IN A SCALABLE ISING SPIN QUANTUM COMPUTER
Authors: BERMAN G. P. , KAMENEV D. I. , TSIFRINOVICH V. I.
Published: August 2004

The errors caused by the transitions with large frequency offsets (nonresonant transitions) are calculated analytically for a scalable solid-state quantum computer based on a one-dimensional spin chain with Ising interactions between neighboring spins. Selective excitations of the spins are enabled by a uniform gradient of the external magnetic field. We calculate the probabilities of all unwanted nonresonant transitions associated with the flip of each spin with nonresonant frequency and with flips of two spins: one with resonant and one with nonresonant frequencies. It is shown that these errors oscillate with changing gradient of the external magnetic field. Choosing the optimal values of this gradient allows us to decrease these errors by 50%.
QUANTUM CIRCUITS FOR SINGLE-QUBIT MEASUREMENTS CORRESPONDING TO PLATONIC SOLIDS
Authors: DECKER THOMAS , JANZING DOMINIK , BETH THOMAS
Published: August 2004

Each platonic solid defines a single-qubit positive operator-valued measure (POVM) by interpreting its vertices as points on the Bloch sphere. We construct simple circuits for implementing these kinds of measurements and other simple types of symmetric POVMs on one qubit. Each implementation consists of a discrete Fourier transform and some elementary quantum operations followed by an orthogonal measurement in the computational basis.
MODELING FULL ADDER IN ISING SPIN QUANTUM COMPUTER WITH 1000 QUBITS USING QUANTUM MAPS
Authors: KAMENEV D. I. , BERMAN G. P. , KASSMAN R. B. , TSIFRINOVICH V. I.
Published: August 2004

The quantum adder is an essential attribute of a quantum computer, just as classical adder is needed for operation of a digital computer. We model the quantum full adder as a realistic complex algorithm on a large number of qubits in an Ising spin quantum computer. Our results are an important step toward effective modeling of the quantum modular adder which is needed for Shor's and other quantum algorithms. Our full adder has the following features. (i) The near-resonant transitions with small detunings are completely suppressed, which allows us to decrease errors by several orders of magnitude and to model a 1000-qubit full adder. (We add a 1000-bit number using 2001 spins.) (ii) We construct the full adder gates directly as sequences of radio-frequency pulses, rather than breaking them down into generalized logical gates, such as Control-Not and one qubit gates. This substantially reduces the number of pulses needed to implement the full adder. (The maximum number of pulses required to add one bit (F-gate) is 15.) (iii) Full adder is realized in a homogeneous spin chain. (iv) The phase error is minimized: the F-gates generate approximately the same phase for different states of the superposition. (v) Modeling of the full adder is performed using quantum maps instead of differential equations. This allows us to reduce the calculation time to a reasonable value.
FORMULATION OF A FAMILY OF SURE-SUCCESS QUANTUM SEARCH ALGORITHMS
Authors: HSIEH JIN-YUAN , LI CHE-MING , LIN JENN-SEN , CHUU DER-SAN
Published: August 2004

In this work, we consider a family of sure-success quantum algorithms, which is grouped into even and odd members for solving a generalized Grover search problem. We prove the matching conditions for both groups and give the corresponding formulae for evaluating the iterations or oracle calls required in the search computation. We also present how to adjust the phase angles in the generalized Grover operator to ensure the sure-success if minimal oracle calls are demanded in the search.
QUANTUM MECHANICS AND PATTERN RECOGNITION
Authors: CHAPLINE GEORGE
Published: August 2004

It has long been known that the Schrodinger equation provides a description of a certain kind of statistical Markov process. We show here that as a consequence, one can view quantum mechanics as an extension of the Helmholtz machine approach to pattern recognition. Not only does this observation throw new light on the relationship between quantum mechanics and computing theory, but it suggests that mathematical techniques developed for inverse scattering problems might provide an alternative to conventional pattern recognition algorithms.
POSITION AND MOMENTUM ENTANGLEMENT OF DIPOLE–DIPOLE INTERACTING ATOMS IN OPTICAL LATTICES: THE EINSTEIN–PODOLSKY–ROSEN PARADOX ON A LATTICE
Authors: OPATRNÝ TOMÁŠ , KOLÁŘ MICHAL , KURIZKI GERSHON , DEB BIMALENDU
Published: August 2004

We study a possible realization of the position- and momentum-correlated atomic pairs that are confined to adjacent sites of two mutually shifted optical lattices and are entangled via laser-induced dipole–dipole interactions. The Einstein–Podolsky–Rosen (EPR) "paradox"1 with translational variables is then modified by lattice-diffraction effects. This "paradox" can be verified to a high degree of accuracy in this scheme.
QUANTUM DECOYS
Authors: ARRIGHI PABLO
Published: August 2004

Alice communicates with words drawn uniformly amongst {|j>}j=1…n, the canonical orthonormal basis. Sometimes however, Alice interleaves quantum decoys [Formula: see text] between her messages. Such pairwise superpositions of possible words cannot be distinguished from the message words. Thus as malevolent Eve observes the quantum channel, she runs the risk of damaging the superpositions (by causing a collapse). At the receiving end honest Bob, whom we assume is warned of the quantum decoys' distribution, checks upon their integrity with a measurement. The present work establishes, in the case of individual attacks, the tradeoff between Eve's information gain (her chances, if a message word was sent, of guessing which) and the disturbance she induces (Bob's chances, if a quantum decoy was sent, to detect tampering). Whilst not directly applicable to secure channel protocols, quantum decoys seem a powerful primitive for constructing other n-dimensional quantum cryptographic applications. Moreover, the methods employed in this article should be of strong interest to anyone concerned with the old but fundamental problem of how much information may be gained about a system, versus how much this will disturb the system, in quantum mechanics.
COMMENT ON "ON THE ROLE OF LOCALITY CONDITION IN BELL'S THEOREM"
Authors: PATEREK TOMASZ
Published: August 2004

In his paper,1 Razmi derives a Bell-like inequality without imposing the locality condition. Then he shows violation of this inequality by certain quantum predictions. Here we point at a loophole in Razmi's proof, which invalidates his inequality.
Effect of Ni Ion Implantation on Corrosion Behavior of Zircaloy-4 in 0.5 M  H 2 SO 4
Authors: Peng D. Q. , Bai X. D. , Chen X. W. , Zhou Q. G. , Liu X. Y. , Yu R. H. , Deng P. Y.
Published: August 2004

In order to study the effect of nickel ion implantation on aqueous corrosion behavior, samples of Zircaloy-4 were implanted with nickel ions with fluences ranging from

1
×

10

16

to

5
×

10

17

ions
/

cm

2

using a metal vapor vacuum arc source operated at an extraction voltage of 40 kV. The valence states and depth distributions of elements in the surface of the samples were analyzed by X-ray photoelectron spectroscopy and Auger electron spectroscopy, respectively. Transmission electron microscopy was used to examine the microstructure of the nickel-implanted samples. The potentiodynamic polarization measurement was employed to evaluate the aqueous corrosion resistance of Zircaloy-4 in a 0.5 M

H

2

SO

4

solution. It was found that significant improvement was achieved in the aqueous corrosion resistance when the fluence is

1
×

10

16

Ni
/

cm

2

.

For fluences greater than

1
×

10

16

Ni
/

cm

2

,

the corrosion resistance of the implanted zirconium decreased compared with that of as-received Zircaloy-4; the higher the fluence, the worse the corrosion resistance. The mechanism of the corrosion behavior of the nickel-implanted Zircaloy-4 is discussed. © 2004 The Electrochemical Society. All rights reserved.
Excitatory convergence of periaqueductal gray and somatic afferents in the solitary tract nucleus: role for neurokinin 1 receptors
Authors: Boscan Pedro , Paton Julian F. R.
Published: September 2004

Our previous studies (Boscan P, Kasparov S, and Paton JF. Eur J Neurosci 16: 907–920, 2002) showed that activation of somatic afferents attenuated the baroreceptor reflex via neurokinin type 1 (NK1) and GABAA receptors within the nucleus of the solitary tract (NTS). The periaqueductal gray matter (PAG) can also depress baroreceptor reflex function and project to the NTS. In the present study, we have tested the possibility that the dorsolateral (dl)-PAG projects to the NTS neurons that also respond to somatic afferent input. In an in situ, arterially perfused, unanesthetized decerebrate rat preparation, somatic afferents (brachial plexus), cervical spinal cord, and dl-PAG were stimulated electrically, whereas NTS neurons were recorded extracellularly. From 45 NTS neurons excited by either brachial plexus or dl-PAG stimulation, 41 received convergence excitatory inputs from both afferents. Onset latency and evoked peak discharge frequency from brachial plexus afferents were 39.4 ± 4.7 ms and 10.7 ± 1.1 Hz, whereas this was 43.9 ± 6.4 ms and 7.9 ± 1 Hz, respectively, following dl-PAG stimulation. As revealed by using a paired pulse stimulation protocol, monosynaptic connections were found in 9 of 36 neurons tested from both spinal cord and dl-PAG. We tested NK1-receptor sensitivity in 38 neurons that received convergent inputs from brachial plexus/PAG. Fifteen neurons were sensitive to selective antagonism of NK1 receptors. CP-99994, the NK1 antagonist, failed to alter ongoing firing activity but reduced the evoked peak discharge frequency following stimulation of both brachial plexus (from 12.3 ± 1.8 to 7.2 ± 1.3 Hz; P < 0.01) and PAG (from 7.8 ± 1.5 to 4.5 ± 1 Hz; P < 0.01). We conclude that 1) somatic brachial and PAG afferents can converge onto single NTS neurons; 2) this convergence occurs via either direct or indirect pathways; and 3) NK1 receptors are activated by some of these inputs.
Both Sp1 and Smad participate in mediating TGF-β1-induced HGF receptor expression in renal epithelial cells
Authors: Zhang Xianghong , Yang Junwei , Li Yingjian , Liu Youhua
Published: September 2004

Hepatocyte growth factor (HGF) receptor is a transmembrane receptor tyrosine kinase encoded by the c-met protooncogene. In this study, we demonstrated that c-met expression was upregulated in the kidney after obstructive injury in mice. Because the pattern of c-met induction was closely correlated with transforming growth factor-β1 (TGF-β1) expression in vivo, we further investigated the regulation of c-met expression in renal tubular epithelial (HKC) cells by TGF-β1 in vitro. Real-time RT-PCR and Northern and Western blot analyses revealed that TGF-β1 significantly induced c-met expression in HKC cells, which primarily took place at the gene transcriptional level. Overexpression of inhibitory Smad7 completely abolished c-met induction, indicating its dependence on Smad signaling. Interestingly, TGF-β1-induced c-met expression was also contingent on a functional Sp1, as ablation of Sp1 binding with mithramycin A abrogated c-met induction in HKC cells. Transfection and sequence analysis identified a cis-acting TGF-β1-responsive region in the c-met promoter, in which resided a putative Smad-binding element (SBE) and an adjacent Sp1 site. TGF-β1 not only induced Smad binding to the SBE/Sp1 sites in the c-met promoter, but also enhanced the binding of Sp proteins. Furthermore, Sp1 could form a complex with Smads in a TGF-β1-dependent fashion. These results suggest a novel regulatory mechanism controlling c-met expression by TGF-β1 in renal epithelial cells, in which both Smad and Sp proteins participate and cooperate in activating c-met gene transcription.
X-ray powder diffraction analysis of a new palladium(II) amino acid complex
Authors: Corbi Pedro P. , Massabni Antonio C. , Costa-Neto Claudio M.
Published: August 2004

Powder X-ray diffraction data for a new palladium(II) amino acid complex, of composition PdC12H20N2O4S2, are presented in this paper. Orthorhombic cell parameters are: a=10.740 Å, b=19.999 Å, and c=5.2470 Å. © 2004 International Centre for Diffraction Data.
A crystal structure of ultra-dispersed form of polytetrafluoroethylene based on X-ray powder diffraction data
Authors: Bouznik V. M. , Kirik S. D. , Solovyov L. A. , Tsvetnikov A. K.
Published: August 2004

An X-Ray powder diffraction study of ultra-dispersed polytetrafluoroethylene was carried out. As well as a regular polytetrafluoroethylene the ultra-dispersed form contents a high proportion of the crystalline phase. The X-ray diffraction pattern could be described with two-dimensional hexagonal unit cell [a=5.685(1) Å, symmetry group p6mm]. Structural modeling with a continuous electron density approach as well as with a discrete disordered atoms distribution was accomplished. The model was refined using the Rietveld method. The structure is characterized by a spiral arrangement of polymers (CF2-)n along the z-axis with complete mutual disordering by rotational displacement around z, as well as a partial molecular translation along the z-axis. Molecular disordering results in a systematic absence of reflections with 1≠0 and as a sequence in two-dimensional unit cell effect. The presence of complete rotational disordering distinguishes the ultra-dispersed form of polytetrafluoroethylene from the standard one (fluoroplast-4), where only partial disordering is observed.
X-ray powder diffraction analysis of three two-component molecular crystals: 4-chloroanilinium and chloronitrobenzoic acids
Authors: Zhang Ming-Tao , Qiao Yuan-Yuan , Lin Shao-Fan , Yao Xin-Kan
Published: August 2004

The X-ray powder diffraction patterns for three two-component molecular crystals composed of 4-chloroanilinium and chloronitrobenzoic acids with different substituted positions are reported and discussed. © 2004 International Centre for Diffraction Data.
Synthesis and structural characterization of ASnFe(PO4)3 (A=Na2,Ca,Cd) phosphates with the Nasicon type structure
Authors: Aatiq Abderrahim
Published: August 2004

The crystal structures of ASnFe(PO4)3 (A=Na2, Ca, Cd) phases, obtained by conventional solid state reaction techniques at (950–1000 °C), were determined at room temperature from X-ray powder diffraction (XRD) using Rietveld analysis. The three materials exhibit the Nasicon-type structure (R3c space group, Z=6) with a random distribution of Sn(Fe) within the framework. Hexagonal cell parameters when A=Na2, Ca and Cd are: a=8.628(1) Å, c=22.151(2) Å; a=8.569(1) Å, c=22.037(2) Å and a=8.587(1) Å, c=21.653(2) Å, respectively. Structural refinements show a partial occupancy of M1 (Na(1)) and M2 (Na(2)) sites in Na2SnFe(PO4)3 leading to the cationic distribution [Na1.22□1.78]M2[Na0.78□0.22]M1SnFe(PO4)3. Ca2+ ions are distributed only in the M1 site of [□3]M2[Ca]M1SnFe(PO4)3. From XRD data, it is difficult to unambiguously distinguish between Cd2+ and Sn4+ ions in CdSnFe(PO4)3. Nevertheless the overall set of cation–anion distances within the Nasicon framework clearly shows that the cationic distribution can be illustrated by the [□3]M2[Cd]M1SnFe(PO4)3 crystallographic formula. Distortion within the [Sn(Fe)(PO4)3] frameworks, in ASnFe(PO4)3 (A=Na2,Ca,Cd) phases, is shown to be related to the M1 site size. © 2004 International Centre for Diffraction Data.
Structure and microstructure of gypsum and its relevance to Rietveld quantitative phase analyses
Authors: De la Torre Ángeles G. , López-Olmo María-Gema , Álvarez-Rua Carmen , García-Granda Santiago , Aranda Miguel. A. G.
Published: August 2004

Single crystals of gypsum were studied in a diffractometer equipped with a CCD two-dimensional detector. The microstructure of the crystal gave wide poorly shaped spots showing sometimes curved streaks around the spots, which made the integration process very difficult, yielding a low quality structure. The crystal structure and microstructure of gypsum has been studied by high-resolution synchrotron powder diffraction of a ground single crystal. The intensities in the synchrotron powder pattern can be reliably fitted although the peak shape displays anisotropic peak broadening. The Rietveld results for gypsum were a=6.522 91(3) Å, b=15.197 63(9) Å, c=6.522 91(3) Å, β=118.479(1)°, V=494.536(5) Å3and Z=4 (s.g. I2/c) with RWP=5.39% and RF=1.64%. We have also studied the influence of the structural description used for gypsum in a synchrotron Rietveld quantitative phase analysis of a standard mixture containing 50 wt % of CaSO4⋅2H2O and Al2O3. Finally, the effects of the type of preferred orientation correction for laboratory X-ray powder data are also discussed. ©2004 International Centre for Diffraction Data.
On the crystal structures of some nickel hexacyanoferrates (II,III)
Authors: Martínez-Garcia R. , Reguera E. , Balmaseda J. , Ramos G. , Yee-Madeira H.
Published: August 2004

The crystal structures of some nickel hexacyanoferrates (II, III), including mixed compositions containing Na+, K+ and Cs+, were resolved and refined from XRD powder patterns. Data from infrared, Mössbauer and adsorption techniques provided complementary structural information. The crystal structures of Ni3[Fe(CN)6]2⋅16H2O and NiCs2[Fe(CN)6] were refined in space group Fm3m. NiNa2[Fe(CN)6]⋅2H2O and NiK2[Fe(CN)6]⋅2H2O were found to be orthorhombic (space group Pmn21). This structure (Pmn21) results from a distortion around the alkali ion, which appears as a monohydrated interstitial species. On ionic exchange in an aqueous solution containing Cs+, the orthorhombic distortion disappears and the cubic cell is obtained. Cs+ is a large cation and space is not available for interstitial water molecules. This orthorhombic model is also supported by the Mössbauer spectra of the ferrous analogs, FeK2[Fe(CN)6]⋅xH2O and Fe[Pt(CN)6]. © 2004 International Centre for Diffraction Data.
Crystal structure of Sr2MgWO6 and Ba2SrWO6 determined by powder X-ray diffraction
Authors: Khalyavin D. D. , Senos A. M. R , Mantas P. Q.
Published: August 2004

The crystal structures of Sr2MgWO6 and Ba2SrWO6 compounds, studied by powder X-ray diffraction, were found to be distorted perovskites with a complete NaCl type ordering between Mg2+/W6+ and Sr2+/W6+ ions, respectively. The unit cells are characterized by the tetragonal (space group I4/m; a0a0a−) symmetry, with the parameters a=5.5849(10) Å and c=7.9455(10) Å, for Sr2MgWO6 and triclinic (space group F-1; a−b−b−) symmetry, with the parameters a=8.5409(10) Å, b=c=8.5860(10) Å, α=89.35(1)° and β=γ=90.31(1)°, for Ba2SrWO6. © 2004 International Centre for Diffraction Data.
X-ray powder diffraction investigations of phenol derivatives
Authors: Rafalska-Lasocha A. , Włodarczyk-Gajda B. , Grzywa M. , Lasocha W.
Published: August 2004

The X-ray powder diffraction patterns of three phenol derivatives—2-chlorophenol, 2,6-dichloro-4-nitrophenol, and 2,6-dichloro-phenoloindophenol tetrahydrate—were collected and the lattice parameters of these compounds were determined. The measurement for 2-chlorophenol was carried out at 250 K in a low-temperature chamber; this compound crystallizes in hexagonal system with a=1.59602(8) nm, c=0.59761(7) nm, space group P6 or P63/m. Investigated at room temperature, 2,6-dichloro-4-nitrophenol and 2,6-dichloro-phenoloindophenol tetrahydrate crystallize in the triclinic system with the unit cell parameters refined to a=0.8169(2) nm, b=1.6637(6) nm, c=0.7440(1) nm, α=96.6(3)°, β=116.19(2)°, γ=78.68°, and space group P-1(2), and a=0.7792(3) nm, b=1.2795(4) nm, c=0.7256(3) nm, α=91.17(5)°, β=96.93(4)°, γ=85.41(3)°, and space group P-1(2), respectively. © 2004 International Centre for Diffraction Data.
Monte Carlo indexing with McMaille
Authors: Le Bail A.
Published: August 2004

A Monte Carlo code for indexing powder diffraction patterns is presented. Cell parameters are generated randomly and tested against an idealized powder profile generated from the extracted d’s and I’s. Limits with this program in solving problems associated with zeropoint errors and impurity lines are examined. Most problems (V<2000 Å3, cell parameters <20 Å) are solved in less than 1–15 min if the symmetry is as low as monoclinic (with a >2 GHz processor); more time is needed for triclinic cases. Attempts are shown to be successful for the indexation of two-phase samples in simple cases (combining orthorhombic or higher symmetries). © 2004 International Centre for Diffraction Data.

Key words: powder diffraction, indexing, Monte Carlo
XRD and EXAFS studies of azomethynic copper metallochelates as models of blue copper proteins
Authors: Vlasenko V. G. , Shuvaev A. T. , Nivorozkin A. L. , Uraev A. I.
Published: August 2004

The structure of two biomimetic copper complexes bis[4-benzylaldimino-3-methyl-1-phenyl-5-thio (seleno)pyrazolato]copper(II)—36 32N6X2Cu (where X=S, Se) have been studied and X-ray patterns of these compounds have been prepared using the Rietveld refinement technique. Both complexes crystallized in a monoclinic lattice, space group-C2/c(15). The unit-cell parameters are a=28.917(3) Å; b=7.000(2) Å; c=17.550(4) Å; β=106.869(1) (1) for C36H32CuN6S2 and a=29.126(6) Å; b=7.042(4) Å; c=17.228(2) Å; β=105.587(2) for C36H32CuN6Se2. Analysis of the copper and selenium K-edge X-ray absorption spectra (EXAFS) of these complexes show that a copper atom is in pseudo-tetrahedric ligand environment N2X2 with typical Cu–N bonds (R=2.00–2.01 Å) and significantly different Cu–S and Cu–Se bonds (R=2.27 Å and R=2.41 Å, respectively) because of different sulfur and selenium ion radii. © 2004 International Centre for Diffraction Data.
Synthesis and Rietveld refinements of monoclinic Er2BaF8
Authors: Achary S. N. , Mathews M. D. , Tyagi A. K.
Published: August 2004

The compound Er2BaF8 is prepared by heating appropriate amounts of BaF2 and ErF3 at 900 °C for 18 h in a dry argon filled quartz ampoule. The polycrystalline sample obtained was characterized by a Rietveld refinement of the observed powder diffraction data. This compound crystallizes in a monoclinic lattice with unit cell parameters: a=6.9620(2), b=10.4960(3), c=4.2541(1) Å and β=99.685(1)°, V=306.14(1) Å3, Z=2, (space group C 2/m, No. 12). The structure analysis reveals the presence of one kind of Ba and Er atoms in the unit cell. There are three different kinds of fluorine atoms, namely F1, F2, and F3 in the ratio of 8:4:4. The Er atoms form a square-antiprism polyhedron with eight fluorine atoms, which share three of its edges to form a ring of six ErF8 polyhedra. The rings of ErF8 polyhedra are connected via two opposite corners along the c-axis of the unit cell. The voids formed within the rings are occupied by Ba atoms, which maintain a twelve-coordination polyhedron with the fluorine atoms. As per the Rietveld analysis, the F3 site may exist as a disordered state by shifting the fluorine atom from the two-fold axes. © 2004 International Centre for Diffraction Data.
Equations for quantifying Fe and K within the illite structure using X-ray powder diffraction
Authors: Kang Il Mo , Moon Hi-Soo , Song Yungoo , Kim Myung Hun
Published: August 2004

This study was performed to suggest convenient equations for quantifying Fe and K within the illite structure using relative intensities for the illite basal reflections. The 002/005 and 003/005 ratios were available for Fe and K quantifications, and equations could be derived as the following: CFe=(ln I002/005−1.807 ln I003/005+1.29)/(1.241 ln I003/005−3.843), CK=−(ln I002/005+0.121 ln I003/005−2.592)/(1.308 ln I003/005+1.984). The equations may obtain Fe and K contents within ca. ±0.05 atoms per half-unit cell, if incident radiation loss is minimized and basal reflection modification caused by expandable layers is eliminated. © 2004 International Centre for Diffraction Data.
Crystal structures of some manganese(II) and cadmium hexacyanoferrates (II,III) and structural transformations related to the sorption of Cesium
Authors: Martínez-García R. , Reguera E. , Rodriguez J. , Balmaseda J. , Roque J.
Published: August 2004

Mn2+and Cd2+form a family of isostructural hexacyanoferrates(II,III). Their crystal structures, including those of mixed compositions containing K+and Cs+as charge balance cations, were resolved and refined from XRD powder patterns. The crystal structures of M3[Fe(CN)6]2⋅xH2O and MCs2[Fe(CN)6] (where M=Mn, Cd) were refined in the space group Fm3m. The mixed salts, MK2[Fe(CN)6]⋅2H2O, were found to be orthorhombic (space group Pmn21). The orthorhombic structure results from a local distortion due to monohydrated potassium ions located in interstitial sites. On ionic exchange in an aqueous solution containing Cs+, the orthorhombic distortion disappears and the cubic cell is obtained. Cs+is a large ion, which practically fills the available interstitial voids stabilizing the cubic structure. In solutions of K+and Cs+the single salts, M2[Fe(CN)6]⋅8H2O (monoclinic P21/n) also transform, in this case liberating M2+ions and forming the corresponding mixed salts. An analogous but slow structural transformation was also observed in the anhydrous forms of these single salts. These structural transformations could be relevant to the use of these compounds as ion exchangers and particularly for the sorption of137Cs+from radioactive waste solutions. The XRD data were complemented with structural information from infrared (IR), Mössbauer and water vapor adsorption techniques. ©2004 International Centre for Diffraction Data.
X-ray and neutron Rietveld quantitative phase analysis of industrial Portland cement clinkers
Authors: Pritula O. , Smrčok Ľ. , Többens D. M. , Langer V.
Published: August 2004

Weight fractions of four dominant phases (C3S, C2S, C4AF, and C3A) present in five industrial clinkers were estimated by a series of neutron and X-ray Rietveld refinements. Calculated powder patterns were derived from the structural data for monoclinic and triclinic C3S, monoclinic C2S, orthorhombic C4AF, cubic C3A and MgO. Neutron diffraction data were collected with the high resolution E9 diffractometer (BENSC) using two different wavelengths, X-ray diffraction data with a high resolution transmission diffractometer. Elemental composition of the samples obtained by ESEM/EDX technique were in a good agreement with the data delivered by the producers. Convergence of the refinements was remarkably different for X-ray and for neutron data. Several refinements were not completed due to numerical instabilities. Neutron refinements were found to be more stable than X-ray, but there was not any notable difference in the final estimated phases’ compositions. Calculated absolute deviates of phases’ weight fractions were mostly within ±10%, which for the less abundant phases corresponded to relative deviations within ±50%. © 2004 International Centre for Diffraction Data.
Woldemar Mobitz and His 1924 Classification of Second-Degree Atrioventricular Block
Authors: Silverman Mark E. , Upshaw Charles B. , Lange Helmut W.
Published: August 2004

Woldemar Mobitz, an early 20th century German internist, analyzed arrhythmias by graphing the relationship of changing atrial rates and premature beats to AV conduction. Through an astute mathematical approach, he was able to classify second-degree atrioventricular block into 2 types, subsequently referred to as Mobitz type I (Wenckebach) and Mobitz type II (Hay). Type I AV block was most often due to digitalis and was reversible. There were no associated pathological findings. Type II AV block frequently progressed to complete AV block and was associated with seizures, death, and pathological findings.
Invasive Approaches to Treatment of Venous Thromboembolism
Authors: Augustinos Peter , Ouriel Kenneth
Published: August 2004

Deep vein thrombosis (DVT) occurs in one-quarter of a million individuals annually in the United States and results in significant disability from pulmonary embolism and chronic venous insufficiency, especially when the proximal iliofemoral is involved. Treatment has centered on early institution of adequate anticoagulation to prevent thrombus propagation and embolism, but anticoagulation alone does not always restore venous patency and many patients are left with venous outflow obstruction and valvular incompetence—the anatomic underpinnings of the postthrombotic syndrome. Various strategies have been used to restore patency of thrombosed veins, including open surgical thrombectomy, pharmacological thrombolysis, and percutaneous mechanical thrombectomy. Each modality has benefits and shortcomings. Surgical thrombectomy had previously been abandoned secondary to poor long-term results. More recently, with improved techniques and better patient selection, surgical thrombectomy has regained a therapeutic role in treating acute DVT in young patients with short segment occlusions. The advent of percutaneous techniques has allowed thrombolysis, percutaneous mechanical thrombectomy, and stenting to be used in conjunction with each other—allowing for better resolution of venous clot burden than when an individual modality is used alone. Practitioners who treat patients with DVT should be familiar with all the options available to restore venous patency, preserve valvular function, and thereby minimize the risk of late postthrombotic complications.
New Anticoagulants for Treatment of Venous Thromboembolism
Authors: Weitz Jeffrey I.
Published: August 2004

Treatment of venous thromboembolism (VTE) usually starts with concomitant administration of heparin or low-molecular-weight heparin (LMWH) and a vitamin K antagonist. The parenteral anticoagulant, which is given for at least 5 days, is stopped once the vitamin K antagonist produces a therapeutic level of anticoagulation. Although the introduction of LMWH has simplified the initial treatment of VTE, problems remain. LMWH must be given by daily subcutaneous (SC) injection and vitamin K antagonists require routine coagulation monitoring, which is inconvenient for patients and physicians. Recently, 3 new anticoagulants have been introduced in an attempt to overcome these limitations. These include fondaparinux and idraparinux, synthetic analogs of the pentasaccharide sequence that mediates the interaction of heparin and LMWH with antithrombin, and ximelagatran, an orally active inhibitor of thrombin. These agents produce a predictable anticoagulant response; thus, routine coagulation monitoring is unnecessary. Because they do not bind to platelets or platelet factor 4, fondaparinux and idraparinux do not cause heparin-induced thrombocytopenia (HIT). Unlike vitamin K antagonists, ximelagatran has a rapid onset of action, thereby obviating the need for concomitant administration of a parenteral anticoagulant when starting treatment. The lack of an antidote for these new agents is a drawback, particularly for idraparinux, which has a long half-life.
Long-Term Management of Patients After Venous Thromboembolism
Authors: Kearon Clive
Published: August 2004

Long-term treatment of venous thromboembolism (VTE) focuses mainly on the duration of anticoagulant therapy, usually with vitamin K (VK) antagonists. The duration of therapy should be individualized based on the risk of recurrent VTE if treatment were stopped and the risk of bleeding if treatment were continued. The risk of recurrence is low if thrombosis was provoked by a major reversible risk factor such as surgery; 3 months of treatment is usually adequate for such patients. The risk of recurrence is high if thrombosis was unprovoked (“idiopathic”) or associated with an irreversible risk factor such as cancer; anticoagulant treatment for at least 6 months, and often indefinitely, is indicated for such patients. Risk of recurrence is intermediate if thrombosis was associated with a minor transient risk factor; such patients can be treated for 3 to 6 months. Within each of these categories, presentation as pulmonary embolism, >1 previous VTE, an underlying malignancy, an antiphospholipid antibody, or selected hereditary thrombophilic states favor more prolonged therapy, whereas isolated distal deep vein thrombosis, high risk of bleeding, and patient preference favor shorter treatment. The optimal intensity of anticoagulant therapy with VK antagonists corresponds to a target international normalized ratio of 2.5 (range, 2.0 to 3.0). Long-term treatment with low-molecular-weight heparin is an alternative to VK-antagonist therapy and is usually preferable in patients with active cancer. Oral direct thrombin inhibitors also appear suitable for long-term prevention of recurrent VTE but await regulatory approval and comparison with VK antagonists.
Initial Treatment of Venous Thromboembolism
Authors: McRae Simon J. , Ginsberg Jeffrey S.
Published: August 2004

Adequate initial anticoagulant therapy of deep venous thrombosis (DVT) is required to prevent thrombus growth and pulmonary embolism (PE). Intravenous unfractionated heparin (UFH) is being replaced by low-molecular-weight heparin (LMWH) as the anticoagulant of choice for initial treatment of venous thromboembolism (VTE). Both agents are relatively safe and effective when used to treat VTE, with LMWH suitable for outpatient therapy because of improved bioavailability and more predictable anticoagulant response. Serious potential complications of heparin therapy, such as heparin-induced thrombocytopenia (HIT) and osteoporosis, seem less common with LMWH. The potential for fetal harm and changes in maternal physiology complicate the treatment of VTE during pregnancy. Although systemic thrombolysis is used in patients with massive PE and in some patients with proximal DVT, controversy persists with respect to appropriate patient selection for this intervention.
Increased circulating hematopoietic and endothelial progenitor cells in the early phase of acute myocardial infarction
Authors: Massa Margherita , Rosti Vittorio , Ferrario Maurizio , Campanelli Rita , Ramajoli Isabella , Rosso Roberta , De Ferrari Gaetano M. , Ferlini Marco , Goffredo Lucio , Bertoletti Alessandra , Klersy Catherine , Pecci Alessandro , Moratti Remigio , Tavazzi Luigi
Published: September 2004

Endothelial progenitor cell (EPC) mobilization has been reported following tissue damage, whereas no data are available regarding the mobilization of hematopoietic progenitor cells (HPCs). We performed the phenotypic and functional analysis of circulating CD34+ progenitor cells in patients with acute myocardial infarction (AMI), assessed from admission up to 60 days, in patients with stable angina pectoris (SA), and in healthy controls (CTRLs). In patients with AMI at admission (T0), the number of circulating CD34+ cells was higher (P < .001) than in CTRLs and became comparable with CTRLs within 60 days. Both the number of CD34+ cells coexpressing CD33, CD38, or CD117 and the number of HPCs was higher (P < .02 for all) in patients with AMI at T0 than in CTRLs, as was the number of hematopoietic colonies (P < .03). Patients with AMI (T0) had a significantly increased number of CD34+ vascular endothelial growth factor receptor 2–positive (VEGFR-2+) cells (P < .002) with respect to CTRLs, including CD34+ CD133+VEGFR-2+ and CD34+ CD117+VEGFR-2+ EPCs. The number of endothelial colonies was higher in patients with AMI (T0) than in CTRLs (P < .05). No significant difference was documented between patients with SA and CTRLs. Spontaneous mobilization of both HPCs and EPCs occurs within a few hours from the onset of AMI and is detectable until 2 months.
Treatment of Children and Adolescents With Stage II Testicular and Stages I and II Ovarian Malignant Germ Cell Tumors: A Pediatric Intergroup Study—Pediatric Oncology Group 9048 and Children's Cancer Group 8891
Authors: Rogers Paul C. , Olson Thomas A. , Cullen John W. , Billmire Deborah F. , Marina Neyssa , Rescorla Frederick , Davis Mary M. , London Wendy B. , Lauer Stephen J. , Giller Roger H. , Cushing Barbara
Published: August 2004

Purpose

To determine whether children with localized gonadal malignant germ cell tumors (MGCT) stage II testicular and stages I and II ovarian treated with four cycles of standard-dose cisplatin combined with etoposide and low-dose bleomycin (PEB) have an event-free survival (EFS) of at least 85% without significant toxicity.

Patients and Methods

Between May 1990 and July 1995, eligible pediatric patients with stage II or recurrent from stage I (as a stage II) testicular MGCT and stages I and II ovarian MGCT were enrolled onto this Pediatric Oncology Group and Children's Cancer Group study. PEB chemotherapy consisted of bleomycin 15 U/m2 on day 1, cisplatin 20 mg/m2/d on days 1 to 5, and etoposide 100 mg/m2/d on days 1 to 5. Patients received four cycles of therapy at 21-day intervals.

Results

Seventy-four patients with a median age of 10.5 years (range, 8.7 months to 16.7 years) were enrolled. Primary sites included: stage II testicular (n = 17), stage I ovarian (n = 41), and stage II ovarian MGCT (n = 16). Treatment with standard PEB resulted in 6-year EFS of 95% and overall survival (OS) of 95.7%. EFS and OS by primary site were as follows: stage II testicular, 100% and 100%; stage I ovarian, 95.1% and 95.1%; and stage II ovarian, 87.5% and 93.8%, respectively. Two patients died from recurrent disease, and one patient died of secondary acute myelocytic leukemia. Infrequent grade 3 to 4 hematologic toxicity was reported. No grade 3 to 4 renal, pulmonary, or ototoxicity was observed.

Conclusion

Combination chemotherapy with PEB results in excellent EFS and OS with minimal toxicity in children and adolescents with localized gonadal MGCT.
CNS Metastases in Breast Cancer
Authors: Lin Nancy U. , Bellon Jennifer R. , Winer Eric P.
Published: August 2004

As systemic therapy of metastatic breast cancer improves, CNS involvement is becoming a more widespread problem. This article summarizes the current knowledge regarding the incidence, clinical presentation, diagnosis, prognosis, and treatment of CNS metastases in patients with breast cancer. When available, studies specific to breast cancer are presented; in studies in which many solid tumors were evaluated together, the proportion of patients with breast cancer is noted. On the basis of data from randomized trials and retrospective series, neurosurgery and stereotactic radiosurgery (SRS) may prolong survival in patients with single brain metastases. The treatment of multiple metastases remains controversial, as does the routine use of whole-brain radiotherapy (WBRT) after either surgery or SRS. Although it is widely assumed that chemotherapy is of limited benefit, data from case series and case reports suggest otherwise. WBRT, neurosurgery, SRS, and medical therapy each have a role in the treatment of CNS metastases; however, neurologic symptoms frequently are not fully reversible, even with appropriate therapy. Studies specifically targeted toward this group of patients are needed.