bluuebunny/crossref_metadata_2025 huggingface dataset:
Two-photon absorption cross sections: An investigation of solvent effects. Theoretical studies on formaldehyde and water
Authors: Paterson Martin J. , Kongsted Jacob , Christiansen Ove , Mikkelsen Kurt V. , Nielsen Christian B.
Published: November 2006

The effects of a solvent on the two-photon absorption of microsolvated formaldehyde and liquid water have been studied using hybrid coupled-cluster/molecular mechanics (CC/MM) response theory. Both water and formaldehyde were considered solvated in water, where the solvent water molecules were described within the framework of molecular mechanics. Prior to the CC/MM calculations, molecular dynamics simulations were performed on the water/formaldehyde and water/water aggregates and many configurations were generated. By carrying out CC/MM response calculations on the individual configurations, it was possible to obtain statistically averaged results for both the excitation energies and two-photon absorption cross sections. For liquid water, the comparison between one- and two-photon absorption spectra is in good agreement with the experimental data available in the literature. In particular, the lowest energy transition occurring in the one-photon absorption spectrum of water only occurs with a relatively small strength in the two-photon absorption spectrum. This result is important for the interpretation of two-photon absorption data as these results show that in the absence of selection rules that determine which transitions are forbidden, the spectral profile of the two-photon absorption spectrum can be significantly different from the spectral profile of the one-photon absorption spectrum.
Obliquely propagating ion acoustic solitary waves in a dusty plasma in the presence of an external magnetic field
Authors: Maitra Sarit , Roychoudhury Rajkumar
Published: November 2006

The obliquely propagating nonlinear ion acoustic wave in a dusty plasma subjected to an external magnetic field is studied in the Sagdeev’s pseudopotential framework. The Sagdeev’s potential is derived in two cases, one of which assumes the quasineutrality condition and the other uses the Poisson equation instead. The respective ranges of parameters for which solitary waves exist in both the cases are studied in some detail numerically.
Electronic absorption spectrum of solid solutions of the system RbI–AgI–CsI
Authors: Yunakova O. N. , Miloslavsky V. K. , Kovalenko E. N.
Published: November 2006

The absorption spectrum in the region of the fundamental electronic bands are investigated in solid solutions of compounds in the system RbI–AgI–CsI, specifically, in the solid solutions Rb2−2xCs2xAgI3 in the concentration interval 0⩽x⩽1, RbxCs1−xAg2I3 for 0⩽x⩽0.9, and Rb1−xCsxAg4I5 for 0⩽x⩽0.2. In all cases a short-wavelength shift of the exciton bands and growth of the band gap Eg with increasing Cs+ concentration are observed. In RbxCs1−xAg2I3 an anomalous concentration dependence of the half-width of the exciton bands is observed, due to a tendency toward the formation of an ordered solid solution for x=0.5. A Cs+ impurity lowers the stability of the superionic conductor RbAg4I5 and promotes its decomposition into the compounds AgI and Rb2AgI3, but for x<0.2 it does not affect the temperatures of the phase transitions or the activation energy for Frenkel defects in the superionic state.
Computational probes of molecular motion in the Lewis-Wahnström model for ortho-terphenyl
Authors: Lombardo Thomas G. , Debenedetti Pablo G. , Stillinger Frank H.
Published: November 2006

We use molecular dynamics simulations to investigate translational and rotational diffusion in a rigid three-site model of the fragile glass former ortho-terphenyl, at 260K⩽T⩽346K and ambient pressure. An Einstein formulation of rotational motion is presented, which supplements the commonly used Debye model. The latter is shown to break down at supercooled temperatures as the mechanism of molecular reorientation changes from small random steps to large infrequent orientational jumps. We find that the model system exhibits non-Gaussian behavior in translational and rotational motion, which strengthens upon supercooling. Examination of particle mobility reveals spatially heterogeneous dynamics in translation and rotation, with a strong spatial correlation between translationally and rotationally mobile particles. Application of the Einstein formalism to the analysis of translation-rotation decoupling results in a trend opposite to that seen in conventional approaches based on the Debye formalism, namely, an enhancement in the effective rate of rotational motion relative to translation upon supercooling.
Electric field tunable ferrite-ferroelectric hybrid wave microwave resonators: Experiment and theory
Authors: Ustinov A. B. , Tiberkevich V. S. , Srinivasan G. , Slavin A. N. , Semenov A. A. , Karmanenko S. F. , Kalinikos B. A. , Mantese J. V. , Ramer R.
Published: November 2006

The electric field tuning characteristics of a combined microwave resonator based on ferrite-ferroelectric layered structure have been studied in a wide range of bias magnetic fields. The combined ferrite-ferroelectric resonator was composed of two rectangular resonators fabricated from a ceramic barium strontium titanate (BST) slab and a single-crystal yttrium iron garnet (YIG) film. The in-plane dimensions for the YIG and BST resonators were chosen to be equal in order to maximize the electromagnetic coupling between their main modes and reduce spurious influence of their higher order modes. A tuning range of 100MHz for the resonator frequency was realized at 5GHz through the variation of magnetic permeability and dielectric permittivity of the YIG-BST structure. A theory for the hybrid wave excitations, based on a coupled-mode approach, has been developed and provides good description of the data.
Magnetic state control of ferromagnetic nanodots by magnetic force microscopy probe
Authors: Chang Joonyeon , Mironov V. L. , Gribkov B. A. , Fraerman A. A. , Gusev S. A. , Vdovichev S. N.
Published: November 2006

We present the magnetic state control of individual ferromagnetic nanodots under inhomogeneous magnetic field induced by the probe of magnetic force microscope (MFM). Arrays of submicron sized elliptical ferromagnetic Co and FeCr dots with different sizes and periods were fabricated to demonstrate addressable manipulation of magnetization. MFM observations show the magnetization reversal and processes of local remagnetization of individual ferromagnetic nanodots subjected to magnetic change. Computer simulation of magnetization processes under inhomogeneous magnetic field induced by MFM probe was performed on the base of Landau-Lifshitz-Gilbert equation for magnetization.
Simulation of a carbon nanotube-based compliant parallel-guiding mechanism: A nanomechanical building block
Authors: Culpepper Martin L. , DiBiasio Christopher M. , Panas Robert M. , Magleby Spencer , Howell Larry L.
Published: November 2006

The authors report the behavior of a nanoscale parallel-guiding mechanism wherein the compliant components are single-walled carbon nanotubes. Parallel-guiding mechanisms are often the building blocks of macro- and microscale mechanical systems. The authors present results that provide insight into the performance of a parallel-guiding mechanism for nanoscale devices. The device exhibits a range over 75% of the device size, i.e., 5.5nm, when actuated with 6.4nN. Below 3.6nN, displacements are due to bulk elastic bending of the nanotubes. Above 5.2nN, displacements are governed by the hingelike bending of kinks in the nanotubes. van der Waals forces are shown to cause direction-dependent behavior.
Detection of electrical characteristics of DNA strands immobilized on self-assembled multilayer gold nanoparticles
Authors: Tsai Chien-Ying , Chang Tien-Li , Kuo Long-Sheng , Chen Ping-Hei
Published: November 2006

Electric detection of DNA in biosensors can be achieved by comparing the differences between the electrical characteristics of biosensors with various concentrations of DNA. This study shows significant electrical property differences between single-stranded DNA and double-stranded DNA by immobilizing DNA strands on biosensor’s self-assembled multilayer gold nanoparticles. The double-stranded DNA has lower electrical resistance than that of single-stranded DNA. These differences can be possibly utilized for DNA identification.
Base hydrolysis of acidopentaaminecobalt(III) ions and the question of common intermediates. Hydrolysis of some t-[Co(tren)(NH3)X]2+/3+ ions (X = NO3-, MeSO3-, Cl-, Me2SO, N3-)
Authors: Buckingham DA , Clark CR , Webley WS
Published: November 2006

The preparations, and
characterizations, of the complex cations t-[Co(tren)(NH3)X]2+/3+*
(X = NO3-, Me2SO, H2O, Cl-,
N3-) and p-[Co(tren)(NH3)X]2+/3+
(X = N3-, Cl-, H2O) are described.
Base hydrolysis of t-[Co(tren)(NH3)X]2+/3+ (X = MeSO3-,
Me2SO, NO3-, N3-) and of
p- [Co(tren)(NH3)N3]2+ follows the rate law kobs
= k[OH-] over the [OH-] range 1.0-10-4 mol dm-3
except for the 3+ ion t-[Co(tren)(NH3)Me2SO]3+
where some curvature is observed at [OH-] > 0.025 mol dm-3.
The products for the t-[Co(tren)(NH3)X]2+/3+ ions (X = Cl-,
NO3-, MeSO3-, Me2SO)
depend on X, and on the presence or absence of supporting electrolyte (1.0 mol
dm-3 NaClO4 or NaN3) varying from 12.1 %
retention of the t-configuration for X = NO3- in the
absence of electrolyte to c. 26% for X = Me2SO in 1.0 mol dm-3
NaN3. Significantly more retention is observed in the azido products
(75-80% t-[Co(tren)(NH3)N3]2+). The results
are interpreted in terms of important contributions to the mechanism from
pre-formed ion pairs.
Crystal structure of 3,3a',5,5'-tetra-t-butyl-2'-(3,5-di-t-butyl-4-hydroxyphenyl)-7'-[l -(3,5-di-t-butyl-4-hydroxypheny1)ethy1idene]-3a',4',7',7a'-tetrahydrospiro-[cyclohexa-2,5-diene-1,1 '-[1H]indene]-4,4'-dione
Authors: Hall SR , Raston CL , White AH
Published: November 2006

The crystal structure of
the title compound, C60H86O4, has been
determined at 295 K by single-crystal X-ray diffraction and refined by least
squares to a residual of 0.073 for 3399 'observed' reflections. Crystals are
monoclinic, P21/n, a 18.999(10), b 12.149(7), c 27.589(10) Ǻ,
β 107.32(6)°, Z 4. The compound is solvated with ether to the extent of
about two solvent molecules per unit cell.
The chemistry of lauren-1-ene. I. Nuclear magnetic resonance spectra and the course of osmic acid oxidation
Authors: Eaton PJ , Fawcett JM , Jogia MK , Weavers RT
Published: November 2006

Assignment
of the carbon and methyl proton magnetic resonances of lauren-1-ene (1) is
reported. The course of an unusual allylic oxidation involving osmic acid has
been confirmed.
Crystal structure of dunnione p-bromophenylhydrazone
Authors: Cooke RG , Raston CL , White AH
Published: November 2006

The crystal structure of
dunnione p-bromophenylhydrazone has been determined
by single-crystal X-ray diffraction methods at 295 K, the structure being
refined to a residual of 0.054 for 1429 'observed' reflections. Crystals are
triclinic, Pī, a 15.620(8), b 8.804(4), c
7.439(4) Ǻ, α 68.03(4), β 89.85(4), γ 77.44(4)°, Z 2. The
conjugation throughout the molecule is extensive and the crystal packing is
dominated by intermolecular charge-transfer interactions. Bonding in the
hydrazone moiety lies intermediate between those expected for hydrazone and azo
forms.
Molecular Cocrystals of Carboxylic Acids. XXI. The Role of Secondary Group Interactions in Adduct Formation Between 2-Aminopyrimidine and Substituted Benzoic Acids: the Crystal Structures of the Adducts With o-Phthalic Acid, o-Nitrobenzoic Acid, o-Aminobenzoic Acid and m-Aminobenzoic Acid
Authors: Smith G , Gentner JM , Lynch DE , Byriel KA , Kennard CHL
Published: November 2006

The crystalline adducts of 2-aminopyrimidine (2-ap) with a series of mainly ortho-substituted benzoic acids, o-phthalic acid ( opht ) [(2-ap)( opht )] (1), 2-nitrobenzoic acid (2-nba) [(2-ap)(2-bna)2] (2), 2-aminobenzoic acid (2-aba) [(2-aba) [(2-ap)(2-aba)2] (3) and 3-aminobenzoic acid (3-aba) [(2-ap)(3-aba)] (4) have been prepared and their hydrogen-bonding motifs characterized by using single-crystal X-ray diffraction. The role of substituent groups in secondary associations with cocrystal formation is considered for the 2-aminopyrimidine system.
Aplidites (A-G): Macrocyclic Orthonitrites From an Australian Tunicate, Aplidium sp.
Authors: Murray L , Lim TK , Currie G , Capon RJ
Published: November 2006

An Australian marine tunicate Aplidium sp. collected from the Great Australian Bight has been found to contain seven macrocyclic alkaloids, identified as the novel marine metabolites aplidites A-G (1)-(7). Each aplidite incorporates a hitherto undescribed orthonitrite functionality. Structures for the aplidites were secured by detailed spectroscopic analysis, derivatization and degradation.
Directing Bromination of Piperazine-2,5-diones
Authors: Badran TW , Chai CLL , Easton CJ , Harper JB , Page DM
Published: November 2006

From intermolecular and intramolecular competition experiments, it has been established that, by comparison with an N-methyl substituent, an N-acetyl group deactivates glycine residues in piperazine-2,5-diones towards free-radical bromination. Combined with the ease of introduction and removal of N-acetyl substituents, the deactivating effect provides a method for regiocontrolled functionalization of these compounds.
The Temperature and Potential Dependence of the Rate Constant for Electron Transfer at the Metal Redox Electrolyte Interface
Authors: Matthews D
Published: November 2006

The Gurney-Gerischer-Marcus (GGM) model is used to investigate the potential and temperature dependence of the rate constant for electron transfer at the interface between a metal and a redox electrolyte. In this model electron transfer is described in terms of nuclear configuration-potential energy diagrams, electronic configuration-potential energy diagrams, state distribution functions and rate constant distribution functions. The model of identical parabolas, which leads to Gaussian electron distribution functions, g(E), for the redox electrolyte, is used for the nuclear configuration diagrams. The rate constant distribution, k(E), is obtained from the overlap between occupied and unoccupied state distribution functions of the metal and redox electrolyte. Integration of k(E) over the vertical transition (Franck-Condon) energies, E, gives the rate constant, k, which is calculated as a function of the electrode potential and temperature for various values of the reorganization energy, λ. Differentiation of k with respect to potential returns g(E) for the redox electrolyte except for a small deviation which is due to the weak dependence on energy of the distribution of states in the metal. For high λ the variation of symmetry factor with potential is small and the Tafel plots do not show a significant decrease in rate at high overpotentials. For small λ the Tafel plots are strongly curved but do not go through a maximum at high overpotential; the Tafel plots tend to a limiting value with only a small decrease in rate constant at high overpotential. This result is reflected in the temperature dependence of the rate constant and in the dependence of the Arrhenius activation energy, Ea, on potential; Ea does not increase at high overpotentials. These results are due to the weak dependence on energy of the distribution function for a metal compared to a redox electrolyte and emphasize the advantages of using distribution functions to describe the kinetics of electron transfer.
Simultaneous removal of sperm plasma membrane and acrosome before intracytoplasmic sperm injection improves oocyte activation/embryonic development
Authors: Morozumi Kazuto , Shikano Tomohide , Miyazaki Shunichi , Yanagimachi Ryuzo
Published: November 2006

Direct injection of a single spermatozoon into an oocyte (ICSI) can produce apparently normal offspring. Although the production of normal offspring by ICSI has been successful in mice and humans, it has been less successful in many other species. The reason for this is not clear, but could be, in part, due to inconsistent activation of oocytes because of delayed disintegration of sperm plasma membrane within oocytes and incorporation of the acrosome containing a spectrum of hydrolyzing enzymes. In the mouse, the removal of sperm plasma membrane and acrosome was not a prerequisite to produce offspring by ICSI, but it resulted in earlier onset of oocyte activation and better embryonic development. The best result was obtained when spermatozoa were demembranated individually immediately before ICSI by using lysolecithin, a hydrolysis product of membrane phospholipids.
Influence of the processing route on microstructure and mechanical properties of the polycrystalline NiAl
Authors: DYMEK S. , WITCZAK Z. , DOLLAR M.
Published: November 2006

The influence of grain refinement on the mechanical properties of differently processed NiAl was presented. Five NiAl near‐stoichiometric alloys were investigated, three conventionally cast and two sintered from powders (fine‐grained powder made by mechanical alloying and nanopowder made by gas condensation). The mechanically alloyed and cast materials were hot extruded at different conditions to obtain diverse grain sizes. The nanomaterial was synthesized in inert gas condensation and then compacted at 1.4 GPa at 300 °C. It was shown that the ductility and strength can be directly controlled by appropriate texture and grain refinement.
New methods of track membrane treatment in the preparation of samples for further observation with scanning electron microscopy
Authors: ORELOVITCH O. L. , APEL P. YU. , SARTOWSKA B.
Published: November 2006

Track membranes are porous systems consisting of a polymer foil with thin channels (i.e. pores) piercing it from surface to surface. The creation of non‐cylindrical pores in a track membrane is important for the optimization of membrane characteristics, i.e. the highest productivity at the required selectivity. A new method of cleavage preparation (the irradiation of track membrane samples with accelerated electrons) for the observation of channel shapes directly in the membrane cross‐sections is presented. Diagrams showing the tensile and burst strengths as a function of the irradiation dose, and images of surfaces and cleavages of track membrane samples are presented in this work. The changes in the pore sizes and shapes along the channel were clearly seen. These results can be used for the optimization of track membrane production.
Chromosome arrangement and nuclear architecture but not centromeric sequences are conserved between Arabidopsis thaliana and Arabidopsis lyrata
Authors: Berr Alexandre , Pecinka Ales , Meister Armin , Kreth Gregor , Fuchs Jörg , Blattner Frank R. , Lysak Martin A. , Schubert Ingo
Published: November 2006

In contrast to the situation described for mammals and Drosophila, chromosome territory (CT) arrangement and somatic homologous pairing in interphase nuclei of Arabidopsis thaliana (n = 5) are predominantly random except for a more frequent association of the chromosomes bearing a homologous nucleolus organizer region. To find out whether this chromosome arrangement is also characteristic for other species of the genus Arabidopsis, we investigated Arabidopsis lyrata ssp. lyrata (n = 8), one of the closest relatives of A. thaliana. First, we determined the size of each chromosome and chromosome arm, the sequence type of centromeric repeats and their distribution between individual centromeres and the position of the 5S/45S rDNA arrays in A. lyrata. Then we demonstrated that CT arrangement, homologous pairing and sister chromatid alignment of distinct euchromatic and/or heterochromatic regions within A. lyrata interphase nuclei are similar to that in A. thaliana nuclei. Thus, the arrangement of interphase chromosomes appears to be conserved between both taxa that diverged about 5 million years ago. Since the chromosomes of A. lyrata resemble those of the presumed ancestral karyotype, a similar arrangement of interphase chromosomes is also to be expected for other closely related diploid species of the Brassicaceae family.
Deficiency of Arabidopsis thaliana frataxin alters activity of mitochondrial Fe–S proteins and induces oxidative stress
Authors: Busi Maria V. , Maliandi María V. , Valdez Hugo , Clemente Marina , Zabaleta Eduardo J. , Araya Alejandro , Gomez‐Casati Diego F.
Published: November 2006

Frataxin, a protein crucial for the biogenesis of mitochondria in different organisms, was recently identified in Arabidopsis thaliana. To investigate the role of frataxin in higher plants, we analyze two knock‐out and one knock‐down T‐DNA insertion mutants. The knock‐out mutants present an embryo‐lethal phenotype, indicating an essential role for frataxin. The knock‐down mutant has reduced frataxin mRNA and protein levels. This mutant also presents retarded growth, reduced fresh weight of fruits and reduced number of seeds per fruit. Surprisingly, transcription of aconitase and the Fe–S subunit of succinate dehydrogenase (SDH2‐1) are increased in mutant plants; however, the activity of these proteins is reduced, indicating a role for frataxin in Fe–S cluster assembly or insertion of Fe–S clusters into proteins. Mutant plants also have increased CO2 assimilation rates, exhibit increased formation of reactive oxygen species (ROS) and have increased levels of transcripts for proteins known to be involved in the ROS stress responses. These results indicate that frataxin is an essential protein in plants, required for full activity of mitochondrial Fe–S proteins and playing a protective role against oxidative damage.
Blatchford scoring system is a useful scoring system for detecting patients with upper gastrointestinal bleeding who do not need endoscopic intervention
Authors: Masaoka Tatsuhiro , Suzuki Hidekazu , Hori Shingo , Aikawa Naoki , Hibi Toshifumi
Published: November 2006

Background and Aim:  Several scoring systems have been devised to identify patients with upper gastrointestinal (UGI) bleeding who are at a high risk of adverse outcomes. We retrospectively evaluated the accuracy of the Blatchford scoring system for assessing the need for clinical intervention in cases of UGI bleeding admitted to the emergency department (ED).

Methods:  This was a retrospective study conducted on patients who underwent emergency GI endoscopy at the ED of our hospital. Those who needed blood transfusion, operative or endoscopic interventions to control the hemorrhage were classified into the ‘high risk’ group.

Results:  Of the 93 enrolled patients, 70 (75.3%) were classified into the high risk group. The Blatchford score was significantly higher in the high risk group than in the low risk group. When a cut‐off value of 2 was used, the sensitivity and specificity of the Blatchford scoring system were determined to be 100% and 13%, respectively. Thus, the Blatchford scoring system was deemed to be useful for distinguishing between the high risk group and the low risk group of patients with GI hemorrhage admitted to the ED.

Conclusion:  The Blatchford scoring system is accurate for identifying definitively low‐risk patients of GI hemorrhage, even prior to the performance of emergency UGI endoscopy at the ED.
Effects of switching from conventional antipsychotics to risperidone in Japanese patients with chronic schizophrenia
Authors: NAKANISHI SHINSUKE , KUNUGI HIROSHI , MURRAY ROBIN M. , NOJIMA SEIJI , OGAWA TOYOAKI , TAKAHASHI TOSHIHIKO
Published: November 2006

Abstract  Atypical antipsychotics are rapidly evolving to become the standard pharmacotherapy in schizophrenia; however, the trend of switching to such drugs is not necessarily progressing quickly in East Asia. This might be due to the scarcity of evidence for the efficacy of switching from conventional to atypical antipsychotics, which prompted the authors to examine effects of switching from conventional antipsychotics to an atypical drug, risperidone, in Japanese patients. Fifty patients with chronic schizophrenia completed the study in which combination therapy with other antipsychotics was allowed if monotherapy with risperidone was not tolerated. Symptoms were assessed with the brief psychiatric rating scale (BPRS). Switching to monotherapy was achieved in 34 patients (68%). The number of antipsychotics prescribed to each patient was reduced (from 2.1 to 1.4 drugs; P < 0.001) and the use of antiparkinsonian drugs decreased (P < 0.001). The mean BPRS score was also reduced 6 months after initiation of the switch (P < 0.001). Failure in switching to monotherapy was associated with higher dosage of antipsychotics at baseline. Switching from conventional antipsychotics to risperidone reduced schizophrenia symptoms, antiparkinsonian medication, and polypharmacy. However, a portion of patients, particularly those who receive an excessive dosage of antipsychotics, might not tolerate such switching.
Influence of contact pressure on fretting fatigue behaviour of AA 2014 alloy with dissimilar mating material
Authors: SADELER R.
Published: November 2006

The effect of contact pressure on the fretting fatigue behaviour of 2014 Al alloy which has been solution heat treated and age hardened (T6 heat treatment) with dissimilar mating materials, was investigated. The fretting fatigue configuration involved bridge‐type contact pads on a flat fatigue specimen. Specimens were made of 2014 Al alloy and bridge‐type pads were made AISI 4140 steel. All the fatigue tests were conducted at a rotational speed of 5000 rpm with a rotating bending fatigue machine (R=−1), using S–N curves to evaluate the fatigue and fretting fatigue properties. The fretting fatigue strength of the material subject to a T6 heat treatment condition at 1 × 107 cycles was dramatically reduced, as compared to that without fretting and with as‐cast. The fretting fatigue life exhibited a variable behaviour with an increase in the contact pressure. A scanning electron microscope was employed to observe the fretting scars and fracture surfaces of the specimens. This analysis showed that cracks originated at the contact surface and crack orientations were approximately ±56 ° from perpendicular to the loading direction.
‘JUMPS’ IN MACROECONOMIC MODELS: AN EXAMPLE WHEN EIGENVALUES ARE COMPLEX‐VALUED*
Authors: STEMP PETER J.
Published: November 2006

The dynamic properties of continuous‐time macroeconomic models are typically characterised by having a combination of stable and unstable eigenvalues. In a seminal paper, Blanchard and Kahn showed that, for linear models, in order to ensure a unique solution, the number of discontinuous or ‘jump’ variables must equal the number of unstable eigenvalues in the economy. Assuming no zero eigenvalues and that all eigenvalues are distinct, this also means that the number of predetermined variables, otherwise referred to as continuous or non‐ ‘jump’ variables, must equal the number of stable eigenvalues. In this paper, we investigate the application of the Blanchard and Kahn results and establish that these results also carry through for linear dynamical systems where some of the eigenvalues are complex‐valued. An example with just one complex conjugate pair of stable eigenvalues is presented. The Appendix contains a general n‐dimensional model.
Statistical Learning Within and Between Modalities
Authors: Conway Christopher M. , Christiansen Morten H.
Published: November 2006

When learners encode sequential patterns and generalize their knowledge to novel instances, are they relying on abstract or stimulus-specific representations? Research on artificial grammar learning (AGL) has shown transfer of learning from one stimulus set to another, and such findings have encouraged the view that statistical learning is mediated by abstract representations that are independent of the sense modality or perceptual features of the stimuli. Using a novel modification of the standard AGL paradigm, we obtained data to the contrary. These experiments pitted abstract processing against stimulus-specific learning. The findings show that statistical learning results in knowledge that is stimulus-specific rather than abstract. They show furthermore that learning can proceed in parallel for multiple input streams along separate perceptual dimensions or sense modalities. We conclude that learning sequential structure and generalizing to novel stimuli inherently involve learning mechanisms that are closely tied to the perceptual characteristics of the input.
High‐dose‐rate brachytherapy for intranasal tumours in dogs: results of a pilot study
Authors: Klueter S. , Krastel D. , Ludewig E. , Reischauer A. , Heinicke F. , Pohlmann S. , Wolf U. , Grevel V. , Hildebrandt G.
Published: November 2006

This prospective study describes the feasibility and toxicity of192Iridium high‐dose‐rate (HDR) brachytherapy as an alternative strategy for the treatment of canine intranasal tumours. Fifteen dogs with malignant intranasal tumours were treated twice weekly using a hypofractionated protocol with eight fractions, 5 Gy per fraction, resulting in a total dose of 40 Gy. Acute and chronic adverse side‐effects appeared to be rare. Only 7% of the acute side‐effects and 5% of the chronic were classified as severe (grade 3). Eight dogs showed clinical complete remission, and five dogs had partial remission, with a resolution of tumour‐related symptoms. Magnetic resonance imaging showed a reduced tumour mass in 12 cases. Median survival time was 17 months (range 4–48 months), with four dogs (three without disease) still alive. Median time to recurrence of these dogs was 14 months. In nine dogs, progression or recurrence of the tumour was the cause of death. This study suggests that HDR brachytherapy is feasible and well tolerated.
Usefulness of contrast‐enhanced ultrasonography with abdominal virtual ultrasonography in assessing therapeutic response in hepatocellular carcinoma treated with radiofrequency ablation
Authors: Kisaka Yoshiyasu , Hirooka Masasi , Kumagi Teru , Uehara Takahide , Hiasa Yoichi , Kumano Seishi , Tanaka Hiroaki , Michitaka Kojiro , Horiike Norio , Mochizuki Teruhito , Onji Morikazu
Published: November 2006

Abstract: Objective: Contrast‐enhanced computed tomography (CECT) is regarded as the gold standard for assessing the efficacy of radiofrequency ablation (RFA) against hepatocellular carcinoma (HCC). We evaluated the efficacy of virtual ultrasonography (VUS) with contrast‐enhanced ultrasonography (CEUS) vs. CECT for assessing the response to RFA.

Materials and methods: Study 1:
The therapeutic responses in 22 patients with 26 HCC nodules were assessed by CEUS with VUS as well as by CECT. The efficacy of treatment was based on whether the safety margin was greater than 5 mm after RFA.

Study 2: In seven patients with seven HCC nodules, the nodules were treated by RFA and the therapeutic efficacy was assessed by CEUS with VUS. The number of RFA sessions was assessed.

Results: Compared with CECT, CEUS with VUS had a specificity of 77%, a sensitivity of 91.6%, and an accuracy of 84%. When the therapeutic response to RFA was analyzed by CECT only, 1.86±0.69 assessments (mean) were required, while when response was assessed by CEUS with VUS, 1.14±0.38 CECT assessments were required (P=0.03).

Conclusion: CEUS with VUS is effective in assessing the therapeutic response to RFA of HCC. Moreover, the number of CECT scans required is reduced by this approach.
Liver regeneration in acute severe liver impairment: a clinicopathological correlation study
Authors: Katoonizadeh Aezam , Nevens Frederik , Verslype Chris , Pirenne Jacques , Roskams Tania
Published: November 2006

Abstract: Background: Although normally quiescent, the adult mammalian liver possesses a great capacity to regenerate after different types of injury. Major players in the regeneration process are mature residual cells, including hepatocytes, cholangiocytes and stromal cells. However, if the regenerative capacity of mature cells is impaired, hepatic progenitor cells (HPCs) are activated and expand into the liver parenchyma. Upon transit amplification, the progenitor cells generate new hepatocytes and biliary cells to restore liver homeostasis.

Aims/Methods: To study the relationship between different histopathological parameters as well as their correlations with clinical parameters and outcome, we examined liver specimens from 74 patients with acute or subacute severe liver impairment by immunohistochemistry for CK7/CK19 (evaluation of HPCs activation/differentiation), Mib1(Ki 67)/P21 (evaluation of proliferative activity/proliferation arrest of hepatocytes) and hematoxylin and eosin (evaluation of hepatocyte loss).

Results: Of the 74 patients, 32% survived without transplantation, 14% died without transplantation and 54% were transplanted. Our results show that a threshold of 50% loss of hepatocytes, associated with significant decrease in the proliferative activity of remaining mature hepatocytes, is needed for extensive hepatic progenitor cell activation. Such activation is a sign of disease severity and occurs early (within 1 week) in the disease course. However, development of intermediate hepatocytes, suggesting HPCs differentiation towards mature hepatocytes, takes at least 1 week's time. We found a positive correlation between histopathological parameters (percentage hepatocyte loss, number of proliferating hepatocytes and number of HPCs) and clinical parameters of liver impairment such as model for end stage liver diseases (MELD). Surviving patients compared with those who either died or were transplanted had significantly less hepatocyte loss, less HPCs activation and more mature hepatocyte proliferative activity. Hepatocyte proliferative activity and degree of hepatocyte loss were the most important independent histopathological parameters in predicting outcome.

Conclusion: Liver biopsy can provide important additional information in a patient with severe acute liver impairment.
Dyeing of nylon 6 fabric with a new bifunctional vinyl sulphone reactive disperse dye
Authors: Mousa A A , Youssef Y A , Farouk R , El‐Kharadly E A
Published: November 2006

A new bifunctional reactive disperse dye containing a temporarily anionic sulphatoethylsulphone and a nonionic disulphide bis(ethylsulphone) groups was synthesised and applied to nylon 6 fabric by the exhaust dyeing at a variety of pH and temperature conditions. A monofunctional reactive disperse dye containing only nonionic disulphide bis(ethylsulphone) group was also synthesised and its dyeing behaviour was compared with the bifunctional dye. The bifunctional reactive disperse dye exhibited high exhaustion and fixation values at pH 6 and 120 °C. The results also indicate that the combination of temporarily anionic and nonionic reactive groups of the bifunctional dye provided great enhancement in dyeing performance compared to that of the monofunctional dye. The dyes also showed very good levelling and fastness properties on nylon 6 fabric.
Mobilizing the Latino Youth Vote: Some Experimental Results*
Authors: Michelson Melissa R.
Published: November 2006

Objectives. The objectives of this article are to test whether Latino canvassers are more effective than non‐Latino canvassers at increasing voter turnout among young Latinos, and to test whether young Latinos are more receptive to a mobilization message that stresses ethnic group solidarity or one that emphasizes civic duty.

Methods. A randomized field experiment, conducted in Fresno, California in the fall of 2002, is the basis for the results reported here.

Results. Young Latino voters targeted by Latino canvassers are more likely to be contacted. However, once contacted, Latinos reached by non‐Latino canvassers are just as likely to turn out to vote as are those reached by non‐Latino canvassers. The mobilization effect is particularly strong among voters who have participated in at least one prior election.

Conclusions. The importance of using Latino canvassers to get out the Latino vote is confirmed, but should not be overemphasized. More importantly, this experiment demonstrates that door‐to‐door canvassing can have a substantively large and statistically significant effect on turnout among young Latinos, a demographic group often overlooked by parties and campaigns.
Serial Murder by Healthcare Professionals
Authors: Yorker Beatrice Crofts , Kizer Kenneth W. , Lampe Paula , Forrest A.R.W. , Lannan Jacquetta M. , Russell Donna A.
Published: November 2006

ABSTRACT: The prosecution of Charles Cullen, a nurse who killed at least 40 patients over a 16‐year period, highlights the need to better understand the phenomenon of serial murder by healthcare professionals. The authors conducted a LexisNexis® search which yielded 90 criminal prosecutions of healthcare providers that met inclusion criteria for serial murder of patients. In addition we reviewed epidemiologic studies, toxicology evidence, and court transcripts, to provide data on healthcare professionals who have been prosecuted between 1970 and 2006. Fifty‐four of the 90 have been convicted; 45 for serial murder, four for attempted murder, and five pled guilty to lesser charges. Twenty‐four more have been indicted and are either awaiting trial or the outcome has not been published. The other 12 prosecutions had a variety of legal outcomes. Injection was the main method used by healthcare killers followed by suffocation, poisoning, and tampering with equipment. Prosecutions were reported from 20 countries with 40% taking place in the United States. Nursing personnel comprised 86% of the healthcare providers prosecuted; physicians 12%, and 2% were allied health professionals. The number of patient deaths that resulted in a murder conviction is 317 and the number of suspicious patient deaths attributed to the 54 convicted caregivers is 2113. These numbers are disturbing and demand that systemic changes in tracking adverse patient incidents associated with presence of a specific healthcare provider be implemented. Hiring practices must shift away from preventing wrongful discharge or denial of employment lawsuits to protecting patients from employees who kill.
The expression of CD23 and CD40 in primary cutaneous B‐cell lymphomas
Authors: Magro Cynthia
Published: November 2006

Background:  CD23 expression in normal B lymphocytes is limited to autoreactive B cells, naïve B cells and mature B cells manifesting an activated phenotype. As a marker of hematologic dyscrasia/malignancy, expression of CD23 is associated with small lymphocytic lymphoma/chronic lymphocytic leukemia. An absence of CD23 expression within small lymphocytes is typically seen in marginal zone lymphoma and mantle cell lymphoma. Positive CD23 expression amidst neoplastic cells in primary cutaneous B‐cell lymphoma is not a reported phenomenon.

Methods:  This paper reports nine patients with cutaneous B‐cell lymphoma manifesting CD23 expression.

Results:  In seven of the nine cases CD23 expression was observed in the setting of recurrent disease, being present in both large and small lymphocytes. CD23 expression paralleled staining for CD40 in all but one case.

Conclusions:  A potential mechanism of CD23 upregulation may involve the anti‐apoptotic nuclear kappa beta CD40–CD40 ligand pathway. Neoplastic B cells manifesting CD23 expression could have a survival advantage, predisposing to recurrent disease and or oncogenic events permissive to disease progression.
Inflammatory Response to a Titanium Surface with Potential Bioactive Properties: An In Vitro Study
Authors: Göransson Anna , Gretzer Christina , Johansson Anna , Sul Young‐Taeg , Wennerberg Ann
Published: November 2006

Background:  The current hard tissue implants research aims to accelerate bone healing by designing surfaces that are bioactive. However, the role of the inflammatory response to these surfaces is so far incompletely described.

Purpose:  The aim of the study was to evaluate early inflammatory response in vitro to a potentially bioactive surface—an anodized surface with Mg ions incorporated (anodized/Mg)—and to compare it to a turned, a blasted, and an anodized surface.

Materials and Methods:  An interferometer was used for topographical characterizations. The disks were incubated with human mononuclear cells. Adherent cells were investigated with respect to number of cells, viability, differentiation, and cytokine production with and without lipopolysaccharide stimulation after 24 and 72 hours.

Results:  The number of adhered mononuclear cells differed significantly between the different modified surfaces, with the highest number on the anodized surface. However, there were no significant differences in cytokine production and differentiation between the different modified surfaces. The amount of anti‐inflammatory mediator interleukin‐10 remained over time, while the number of cells and pro‐inflammatory cytokine tumor necrosis factor‐α decreased. The cells were viable on all surfaces, respectively.

Conclusion:  The anodized surfaces with and without Mg ions showed an increased cell adherence, however, otherwise an inflammatory response similar to the turned and blasted surfaces. Furthermore, the potentially bioactive anodized/Mg surface showed a similar response to the TiUnite‐like anodized surface despite the former having a surface roughness of a smoother character.
Effect of H2 and Redox Condition on Biotic and Abiotic MTBE Transformation
Authors: Bradley P.M. , Chapelle F.H. , Landmeyer J.E.
Published: November 2006

Laboratory studies conducted with surface water sediment from a methyl tert‐butyl ether (MTBE)‐contaminated site in South Carolina demonstrated that, under methanogenic conditions, [U‐14C] MTBE was transformed to 14C tert‐butyl alcohol (TBA) with no measurable production of 14CO2. Production of TBA was not attributed to the activity of methanogenic microorganisms, however, because comparable transformation of [U‐14C] MTBE to 14C‐TBA also was observed in heat‐sterilized controls with dissolved H2 concentrations > 5 nM. The results suggest that the transformation of MTBE to TBA may be an abiotic process that is driven by biologically produced H2 under in situ conditions. In contrast, mineralization of [U‐14C] MTBE to 14CO2 was completely inhibited by heat sterilization and only observed in treatments characterized by dissolved H2 concentrations < 2 nM. These results suggest that the pathway of MTBE transformation is influenced by in situ H2 concentrations and that in situ H2 concentrations may be an useful indicator of MTBE transformation pathways in ground water systems.
‘This is like my comfort zone’: Senses of place and belonging within Oruāmo/Beachhaven, New Zealand
Authors: McCreanor Tim , Penney Liane , Jensen Victoria , Witten Karen , Kearns Robin , Barnes Helen Moewaka
Published: November 2006

Abstract:  This paper examines the culturally specific experiences of belonging within Oruāmo/Beachhaven, a suburb in North Shore City. In‐depth interviews with 32 caregivers of young children expose the fact that the ethnic groups represented – Māori, Samoan and Pākehā– vary in their uses and understandings of, as well as feelings for, residential neighbourhood. Examination of the themes of natural environment, social relations, continuity of residence, facilities, organisations and place transformation reveal that, while representatives of all groups had views on these matters, there was a variable degree of engagement with and priority afforded to these concerns.
The Dark Side of the NGF Family: Neurotrophins in Neoplasias
Authors: Krüttgen Alex , Schneider Imke , Weis Joachim
Published: November 2006

Although neurotrophins of the nerve growth factor (NGF) family are best known for their neurite outgrowth‐inducing and survival‐promoting effects on neuronal cells, these are actually pleiotropic growth factors acting physiologically on many different cell types of our body. As for many other growth factors, dysregulation of neurotrophin signal transduction is found in a number of tumors where they can accompany or contribute to malignant transformation. Interestingly, tropomyosin‐related kinase (Trk) receptor activation can either support or suppress tumor growth, depending on the tumor type. These same divergent responses have been observed with neurotrophins binding to the p75NTR neurotrophin receptor on tumor cells. This article summarizes the current knowledge on the role of neurotrophins and their receptors in malignancies, with special focus on tumors of neuropathological interest.
Elastic Stresses of Pressurized Cylinders With Hillside Nozzle
Authors: Wang H. F. , Sang Z. F. , Xue L. P. , Widera G. E. O.
Published: November 2006

The purpose of this work is to investigate the elastic stress and deformation of pressurized cylinders with a hillside nozzle. Two full-scale test models were designed and fabricated specially for the test. A 3D finite element numerical analysis was also performed. The elastic stress distribution, stress concentration range, deformation characteristics, and stress concentration factor were obtained. The elastic results show that the distinct stress concentration occurs on the hillside-nozzle intersection, and the intersection shrinks in the longitudinal section of cylinder, while a bulge appears in the transverse section. The range of stress concentration of the hillside-nozzle intersection in the transverse section of the cylinder is larger than that in the longitudinal section and the stress concentration factor declines with the increment of the angle β. The results will serve as the basis for developing a design guideline for pressurized cylinders with various angles of the hillside nozzle.
Microstructural differences in thin film ZnGa2O4:Mn phosphor produced by differences in sputtering gas pressure
Authors: Kim Joo Han , Holloway Paul H.
Published: November 2006

The authors report on the microstructural characteristics of sputter-deposited thin film ZnGa2O4:Mn phosphors, with an emphasis on the role of energetic particle bombardment. The thin film ZnGa2O4:Mn phosphors were deposited by radio frequency planar magnetron sputtering of a 2mol% Mn-doped ZnGa2O4 target in an Ar–O2 gas mixture at gas pressures ranging from 2to20mTorr. The growth rate of the ZnGa2O4:Mn films was decreased from 40to23Å∕min as the gas pressure was raised due to both increased gas-phase scattering as well as reduced target self-bias voltage. Owing to the thermalization of impinging energetic particles and the randomization in their incidence directions when arriving at the substrate, the ZnGa2O4:Mn films produced at an elevated gas pressure exhibited a porous composite microstructure in which larger columns consisted of bundles of smaller columns separated by voided boundaries. Energetic particle bombardment of the growing film surface at a low gas pressure yielded a densely packed zone-T-type microstructure due to porosity annihilation by knock-on processes and bombardment-enhanced adatom mobility. Atomic force microscopy and grazing incidence x-ray reflectivity data revealed that as the gas pressure was decreased from 20to2mTorr, the rms surface roughness of the deposited ZnGa2O4:Mn films was reduced from 4.95to1.23nm and the film density increased from 5.314to5.681g∕cm3, consistent with the postulated effects of energetic particle bombardment upon film microstructure.
An Atmospheric Pressure Ping-Pong “Ballometer”
Authors: Kazachkov Alexander , Kryuchkov Dmitriy , Willis Courtney , Moore John C.
Published: November 2006

Classroom experiments on atmospheric pressure focus largely on demonstrating its existence, often in a most impressive way. A series of amusing physics demonstrations is widely known and practiced by educators teaching the topic. However, measuring the value of atmospheric pressure (Patm) is generally done in a rather mundane way, simply by reading some commercially produced meter. Even though students building a 35-ft high water barometer1,2 is definitely instructive, as is the measurement of Patm with much smaller gas-filled devices,3,4 there exist hardly any physics lab exercises focused on the measurement of atmospheric pressure. This paper describes a modification of a well-known physics demonstration into an experiment that allows one to estimate atmospheric pressure quite accurately. Our simple and inexpensive apparatus can be used in lecture demonstrations or as a tool in an educational laboratory setting.