bluuebunny/crossref_metadata_2025 huggingface dataset:
Flux enhancement of radiation belt electrons during geomagnetic storms driven by coronal mass ejections and corotating interaction regions
Authors: Kataoka Ryuho , Miyoshi Yoshizumi
Published: September 2006

A meteorological view of solar wind structures is useful for probability prediction of the flux enhancement of radiation belt electrons. We report the averaged variations of the solar wind parameters and radiation belt electrons during isolated geomagnetic storms driven by coronal mass ejections (CMEs) and corotating interaction regions (CIRs), using a superposed epoch analysis centered on interplanetary shocks and stream interfaces, respectively, whose arrival times can be used as a precursor for the flux enhancement. A total of 49 CME‐ and 6 CIR‐associated storms with Dst < −100 nT are identified during solar cycle 23 from January 1996 to December 2004. In CME‐associated storms, the average flux recovers to the prestorm level about 2 days after a shock arrival. The occurrence probability of the >2 MeV electron flux alert with >103 pfu (pfu = particles cm−2 s−1 sr−1) at geosynchronous orbit 1 day after the shock is only 14% (7 of 49 events) and is smaller than the prestorm level, while the probability 4 days after the shock increases to 43% (21 of 49 events) and is larger than the prestorm level. In CIR‐associated storms, the average flux recovers to the prestorm level about 1 day after a stream interface arrival. The probability of an electron flux alert is 83% (5 of 6 events) 1 day after the stream interface arrival and remains at that level for at least the next 4 days.
Use of antifilarial IgG4‐ELISA to detect Brugia malayi infection in an endemic area of Malaysia
Authors: Rahmah N. , Khairul Anuar A. , Tengku Ariff R. H. , Zurainee M. N. , Noor A'shikin A. , Fadzillah A. , Maimunah A. , Ashraful Haq J.
Published: September 2006

Summary
objective  To evaluate the usefulness of antifilarial IgG4 antibody assay in detecting B. malayi infection in a filaria endemic area in Malaysia.methods  A sandwich ELISA using B. malayi soluble antigen was employed to detect antifilarial IgG4 antibodies in serum samples of 330 individuals who comprised 88 healthy individuals from nonendemic areas, 15 B. malayi microfilaraemic cases, 22 individuals with soil‐transmitted helminthiases, 9 elephantiasis cases and 196 residents from a B. malayi‐endemic area. An O.D. value of > 0.420 at serum dilution of 1:400 was used as the cut‐off point. This cut‐off point was obtained by taking the mean optical density (0.252 + 4 S.E.) of 36 negative sera which had O.D. values greater than 0.1 at serum dilution of 1: 400.results  All 15 microfilaraemic persons were positive for antifilarial IgG4 antibody. Non‐endemic normals, soil‐transmitted helminth infected persons and chronic elephantiasis cases were negative for antifilarial IgG4 antibody. Of the 196 individuals from the filaria endemic area, 37 (18.8%) demonstrated presence of antifilarial IgG4 antibodies; and only eight individuals (4.1%) were positive for microfilariae. All eight microfilaraemic individuals were also positive for antifilarial IgG4 antibodies.conclusion  Antifilarial IgG4‐ELISA could detect 4.6 times more positive cases than the microfilaria detection method. With appropriate cut‐off values that eliminate cross‐reactivities, this serological tool is very useful for Brugia malayi prevalence surveys and diagnosis.
New long trace profiler based on phase plate diffraction for optical metrology of SSRF
Authors: Zeng Danhua , Xiao Tiqiao , Du Guohao , Wen Li , Luo Hongxin , Xia Shaojian , Xu Hongjie
Published: September 2006

A long trace profiler LTP-1200, with a novel f-θ system based on phase plate diffraction and a scanning range up to 1200mm, has been developed at Shanghai Synchrotron Radiation Facility. The central dark line in the diffraction pattern generated by a π phase plate is taken as the positioning benchmark. A magnet levitated linear rail with very high accuracy is used. A granite bench is employed to reduce deformation due to self-gravity of the rail. The focused diffraction pattern is recorded with an area charge-coupled device. The generalized regression neural network algorithm is adopted to improve the beam positioning precision. The static stability of LTP-1200 in 5h is 0.14μrad, and the repeatability reaches 0.05μrad in a common laboratory without any special control of temperature, air turbulence, etc. Calibration tests were carried out with a high precision autocollimator and a standard spherical mirror, respectively. Results show the high performance and reliability of the LTP-1200.
Theoretical modeling of postionization fragmentation of rare-gas trimer cations
Authors: Janeček Ivan , Hrivňák Daniel , Kalus René , Gadéa Florent Xavier
Published: September 2006

The dynamics of ionic rare-gas trimers (Ar3+, Kr3+, and Xe3+) produced by a sudden ionization of neutral precursors is investigated theoretically with a hybrid classical-quantum method for solving the equations of motion governed by a Hamiltonian obtained from a previously tested diatomics-in-molecules model. Initial conditions are selected with Monte Carlo sampling. Two possibilities for generating the initial electronic state are considered: diabatic (local) and adiabatic (delocalized). The dynamics generally leads to fragmentation, producing either monomer ions or dimer ions in a relatively short time; however, a large number of long-lived metastable trimer ions are also seen in some cases. We have analyzed the dynamics with respect to the fraction of monomer ions produced, the distribution of the kinetic energy of the products, and the distribution of fragmentation times of the trimers. Initial diabatic ionization is associated with much faster fragmentation than adiabatic ionization. Spin-orbit coupling plays an important role in the fragmentation dynamics.
Time-convolutionless master equation for mesoscopic electron-phonon systems
Authors: Pereverzev Andrey , Bittner Eric R.
Published: September 2006

The time-convolutionless master equation for the electronic populations is derived for a generic electron-phonon Hamiltonian. The equation can be used in the regimes where the golden rule approach is not applicable. The equation is applied to study the electronic relaxation in several models with the finite number of normal modes. For such mesoscopic systems the relaxation behavior differs substantially from the simple exponential relaxation. In particular, the equation shows the appearance of the recurrence phenomena on a time scale determined by the slowest mode of the system. The formal results are quite general and can be used for a wide range of physical systems. Numerical results are presented for a two level system coupled to Ohmic and super-Ohmic baths, as well as for a model of charge-transfer dynamics between semiconducting organic polymers.
Flute instability growth on a magnetized plasma column
Authors: Rose D. V. , Genoni T. C. , Welch D. R. , Mehlhorn T. A. , Porter J. L. , Ditmire T.
Published: September 2006

The growth of the flute-type instability for a field-aligned plasma column immersed in a uniform magnetic field is studied. Particle-in-cell simulations are compared with a semi-analytic dispersion analysis of the drift cyclotron instability in cylindrical geometry with a Gaussian density profile in the radial direction. For the parameters considered here, the dispersion analysis gives a local maximum for the peak growth rates as a function of R∕ri, where R is the Gaussian characteristic radius and ri is the ion gyroradius. The electrostatic and electromagnetic particle-in-cell simulation results give azimuthal and radial mode numbers that are in reasonable agreement with the dispersion analysis. The electrostatic simulations give linear growth rates that are in good agreement with the dispersion analysis results, while the electromagnetic simulations yield growth rate trends that are similar to the dispersion analysis but that are not in quantitative agreement. These differences are ascribed to higher initial field fluctuation levels in the electromagnetic field solver. Overall, the simulations allow the examination of both the linear and nonlinear evolution of the instability in this physical system up to and beyond the point of wave energy saturation.
Low density of self-assembled InAs quantum dots grown by solid-source molecular beam epitaxy on InP(001)
Authors: Dupuy E. , Regreny P. , Robach Y. , Gendry M. , Chauvin N. , Tranvouez E. , Bremond G. , Bru-Chevallier C. , Patriarche G.
Published: September 2006

The authors report on a postgrowth method to obtain low density InAs∕InP(001) quantum dots by solid-source molecular beam epitaxy. They used an approach based on the ripening of the InAs sticks, which is triggered by the sample cooling under arsenic overpressure, before InP capping. Atomic force microscopy images show the evolution of InAs islands from sticks oriented along the [1-10] direction to dot-shaped islands with a density that can be reduced to about 2×109dots∕cm2. Macro- and microphotoluminescence reveal that these diluted InAs dots exhibit a strong spatial confinement and emit in the 1.55μm range.
Formation of CdTe nanostructures with dot, rod, and tetrapod shapes
Authors: Zhang Jia-Yu , Yu William W.
Published: September 2006

Colloidal dot-, rod-, and tetrapod-shaped CdTe nanocrystals (NCs) are obtained by varying the precursor concentration and the ligands. Both the dot- and rod-shaped NCs are of zinc-blende phase, whereas the tetrapod-shaped NCs are a mixture of zinc-blende and wurtzite structures. It is proposed that the concentration of stacking faults forming during NCs’ growth plays an important role in the geometry of CdTe NCs.
Coexistence of type-I and type-II band lineups in Cd(Te,Se)∕ZnSe quantum-dot structures
Authors: Toropov A. A. , Sedova I. V. , Lyublinskaya O. G. , Sorokin S. V. , Sitnikova A. A. , Ivanov S. V. , Bergman J. P. , Monemar B. , Donatini F. , Si Dang Le
Published: September 2006

The authors report on transmission electron microscopy, cathodoluminescence, and time resolved photoluminescence studies of thin Cd(Te,Se) layers in a ZnSe matrix, grown by molecular beam epitaxy. All observations confirm strain-induced self-assembly of quantum dots (QD’s), induced primarily by the 14% lattice mismatch between CdTe and ZnSe. The emission spectrum of the structure is the superposition of a relatively narrow luminescence line originating from CdSe-enriched type-I QD’s and a broad band attributed to the emission of an ultrathin ZnTeSe∕ZnSe layer with type-II band lineup, formed in between the QD’s.
Green top-emitting organic light emitting device with transparent Ba∕Ag bilayer cathode
Authors: Lee C. J. , Pode R. B. , Han J. I. , Moon D. G.
Published: September 2006

Using a vacuum thermal technique, semitransparent Ba∕Ag bilayer cathode has been fabricated for the top-emitting organic light emitting devices. In this work, optical transparency over 60% in the visible region and low sheet resistance of about 15Ω∕sq in the Ba (10nm)∕Ag (8nm) structure are reported. The surface and compositional morphologies of the cathode play a crucial role in determining the optical properties. Top-emitting organic light emitting device using this cathode has been fabricated and studied.
High quality ferromagnetic 0 and π Josephson tunnel junctions
Authors: Weides M. , Kemmler M. , Goldobin E. , Koelle D. , Kleiner R. , Kohlstedt H. , Buzdin A.
Published: September 2006

The authors fabricated high quality Nb∕Al2O3∕Ni0.6Cu0.4∕Nb superconductor-insulatorferromagnet-superconductor Josephson tunnel junctions. Depending on the thickness of the ferromagnetic Ni0.6Cu0.4 layer and on the ambient temperature, the junctions were in the 0 or π ground state. All junctions have homogeneous interfaces showing almost perfect Fraunhofer patterns. The Al2O3 tunnel barrier allows one to achieve rather low damping, which is desired for many experiments especially in the quantum domain. The McCumber parameter βc increases exponentially with decreasing temperature and reaches βc≈700 at T=2.11K. The critical current density in the π state was up to 5A∕cm2 at T=2.11K, resulting in a Josephson penetration depth λJ as low as 160μm. Experimentally determined junction parameters are well described by theory taking into account spin-flip scattering in the Ni0.6Cu0.4 layer and different transparencies of the interfaces.
Polarization of transverse modes in plasma crystals
Authors: Morfill G. E. , Yaroshenko V. V. , Thomas H. M.
Published: September 2006

The transverse dust-lattice (DL) modes can reveal elliptic (circular) polarization. The resulting vector of the particle displacement rotates around the “lattice strings” with the characteristic frequency of the transverse DL mode. Visualization of this effect could be a new useful tool for determining the main complex plasma parameters.
Fabrication of a graded-wavelength guided-mode resonance filter photonic crystal
Authors: Dobbs Dennis W. , Gershkovich Irena , Cunningham Brian T.
Published: September 2006

The authors report on the fabrication and characterization of a guided-mode resonance filter whose spectral reflectance features vary in a linear fashion as a function of position on the filter. This device was fabricated using nanoreplica molding in conjunction with a linearly graded TiO2 thin film deposition. The magnitude of gradation of the thin film was approximately 85nm over a distance of 26mm, which resulted in the spectral location of the primary reflection feature of the filter to be nearly linearly graded spanning a range of 798–909nm across the 26mm surface.
A variable immunoreceptor in a subpopulation of human neutrophils
Authors: Puellmann Kerstin , Kaminski Wolfgang E. , Vogel Mandy , Nebe C. Thomas , Schroeder Josef , Wolf Hans , Beham Alexander W.
Published: September 2006

Neutrophils are thought to rely solely on nonspecific immune mechanisms. Here we provide molecular biological, immunological, ultrastructural, and functional evidence for the presence of a T cell receptor (TCR)-based variable immunoreceptor in a 5–8% subpopulation of human neutrophils. We demonstrate that these peripheral blood neutrophils express variable and individual-specific TCRαβ repertoires and the RAG1/RAG2 recombinase complex. The proinflammatory cytokine granulocyte colony-stimulating factor regulates expression of the neutrophil immunoreceptor and RAG1/RAG2in vivo. Specific engagement of the neutrophil TCR complex protects from apoptosis and stimulates secretion of the neutrophil-activating chemokine IL-8. Our results, which also demonstrate the presence of the TCR in murine neutrophils, suggest the coexistence of a variable and an innate host defense system in mammalian neutrophils.
Recruitment of the
de novo
DNA methyltransferase Dnmt3a by Kaposi's sarcoma-associated herpesvirus LANA
Authors: Shamay Meir , Krithivas Anita , Zhang Jun , Hayward S. Diane
Published: September 2006

The Kaposi's sarcoma-associated herpesvirus LANA protein is expressed in all Kaposi's sarcoma-associated herpesvirus-infected cells, including the tumor cells of endemic and AIDS-associated Kaposi sarcoma, primary effusion lymphoma, and Castleman disease. LANA modulates cell gene expression, but the mechanisms of LANA-mediated transcriptional reprogramming are poorly understood. LANA-repressed cell genes were identified by using retroviral-transduced telomerase-immortalized microvascular endothelial cells. Transciptional repression of targeted genes was relieved by treatment with the methyltransferase inhibitor 5-aza-2′-deoxycytidine, suggesting a role for DNA methylation in repression. We found that LANA coprecipitated with DNA methyltransferases (Dnmts) and recruited endogenous DNA methyltransferase activity from the cell extract. LANA preferentially relocalized Dnmt3a from the nuclear matrix into the chromatin fraction. Further, LANA associated with repressed cellular promoters, recruited Dnmt3a to DNA, and facilitated
de novo
promoter methylation of a down-regulated gene, cadherin 13 (H-cadherin). The data provide an example of promoter-specific epigenetic DNA modification through viral protein recruitment of
de novo
Dnmt activity.
Vibrio choleraevirulence regulator-coordinated evasion of host immunity
Authors: Hsiao Ansel , Liu Zhi , Joelsson Adam , Zhu Jun
Published: September 2006

To successfully propagate and cause disease, pathogenic bacteria must modulate their transcriptional activities in response to pressures exerted by the host immune system, including secreted immunoglobulins such as secretory IgA (S-IgA), which can bind and agglutinate bacteria. Here, we present a previously undescribed flow cytometry-based screening method to identify bacterial genes expressedin vitroand repressed during infections ofVibrio cholerae, an aquatic Gram-negative bacterium responsible for the severe diarrheal disease cholera. We identified a type IV mannose-sensitive hemagglutinin (MSHA) pilus that is repressed specificallyin vivo. We showed that bacteria that failed to turn off MSHA biosynthesis were unable to colonize the intestines of infant mice in the presence of S-IgA. We also found thatV. choleraebound S-IgA in an MSHA-dependent and mannose-sensitive fashion and that binding of S-IgA prevented bacteria from penetrating mucus barriers and attaching to the surface of epithelial cells. The ability ofV. choleraeto evade the non-antigen-specific binding of S-IgA by down-regulating a surface adhesin represents a previously undescribed mechanism of immune evasion in pathogenic bacteria. In addition, we found that repression of MSHA was mediated by the key virulence transcription factor ToxT, indicating thatV. choleraeis able to coordinate both virulence gene activation and repression to evade host defenses and successfully colonize intestines.
Structure-Based Modulation of Inhibition of Return is Triggered by Object-Internal but not Occluding Shape Features
Authors: Reppa Irene , Charles Leek E.
Published: September 2006

When attention is oriented to an object it is inhibited from returning to the same object following a short delay. This inhibition-of-return (IOR) effect is modulated by an edge discontinuity presented between cue and target—an effect referred to as structure-based modulation of IOR. Here we examined two alternative accounts for the structure-based modulation effect. On one account the modulation is caused by the presence of any intervening feature between cue and target. On another account the modulation is caused by edge-bounded (i.e., closed) regions of space, on which space-based selection mechanisms operate. We presented cues and targets on unsegmented and internally or externally segmented rectangles to examine the two alternative accounts for the effect. Contrary to the predictions of the two alternative accounts, structure-based modulation of IOR was found with the internally but not with the externally segmented displays. This supports our hypothesis that object-based IOR arises from perceptually complete and internally structured object representations.
High-pressure neutron diffraction study of L-serine-I and L-serine-II, and the structure of L-serine-III at 8.1 GPa
Authors: Moggach Stephen A. , Marshall William G. , Parsons Simon
Published: September 2006

The hydrostatic compression of L-serine-d
7 has been studied to 8.1 GPa by neutron powder diffraction. Over the course of this pressure range the compound undergoes two phase transitions, the first between 4.6 and 5.2 GPa, yielding L-serine-II, and the second between 7.3 and 8.1 GPa, yielding L-serine-III. All three polymorphs are orthorhombic, P212121, and feature chains of serine molecules connected via head-to-tail ND...O hydrogen bonds formed between ammonium and carboxylate groups. The chains are linked into a ribbon by a second set of ND...O hydrogen bonds. The hydroxyl moieties are distributed along the outer edges of the ribbon and in phase I they connect the ribbons into a layer by chains of OD...OD hydrogen bonds. The layers are connected together by a third set of ND...O hydrogen bonds, forming R^3_4(14) rings with substantial voids at their centres. In the transition from phase I to II these voids begin to close up, but at the cost of breaking the OD...OD chains. The OD...OD hydrogen bonds are replaced by shorter OD...O hydrogen bonds to carboxylate groups. At 7.3 GPa the O...O distance in the OD...O hydrogen bonds measures only 2.516 (17) Å, which is short, and we propose that the phase transition to phase III that occurs between 7.3 and 8.1 GPa relieves the strain that has built up in this region of the structure. The hydroxyl D atom now bifurcates between the OD...O contact that had been present in phase II and a new OD...O contact formed to a carboxylate in another layer. Hirshfeld surface fingerprint plots show that D...D interactions become more numerous, while hydrogen bonds actually begin to lengthen in the transition from phase II to III.
Bond analyses of borates from the Inorganic Crystal Structure Database
Authors: Yu Daqiu , Xue Dongfeng
Published: September 2006

Various fundamental building blocks (FBBs) are observed in the crystallographic structures of oxoborates available in the Inorganic Crystal Structure Database, Version 1.3.3 (2004); the occurrence of borate groups with low complexity is dominant. Bond-valence parameters d
0 of B—O bonds in 758 oxoborates with various FBBs have been calculated using the bond-valence sum model. Some discrepancies in the d
0 values obviously occur if the detailed configurations of FBBs in borate crystals are considered; d
0 is sensitive to the chemical bonding structure of B atoms in the crystallographic framework. Moreover, d
0 values are affected by the existence of interstitial atoms and the substitution of other anionic groups. In addition, the d
0 parameters for B—N, B—S, B—P and B—F bonds are also calculated statistically. Some suitable d
0 data for various borate FBBs are recommended according to their particular configurations, especially for those with low complexity. On the basis of the proposed linear relationship between calculated nonlinear optical (NLO) coefficients of borates and the current d
0 values for various FBBs, it is found that the d
0 values may be regarded as a useful parameter for pre-investigating the NLO properties of borates, leading to an efficient structural evaluation and design of novel borates.
Specific twin junctions in doped zirconia
Authors: Morales F. M. , Rühle M.
Published: September 2006

The effect of different dopant cations on the phase transformations of the initially stabilized supersaturated tetragonal ZrO2 phase during various heat treatments has been studied. The obtained fraction of monoclinic grains develop twinned structures, but there is still a lack of information about the character of grain boundaries formed in doped monoclinic solid solutions. The inspection of particular selected-area electron diffraction patterns provides an alternative method with respect to high-resolution electron microscopy or electron back-scattered diffraction for characterizing different twin junctions in various doped zirconia systems. The classification of these special twins is based on the coincidence site lattice concept.
Structure and phase transition of the Se-rich variety of antimonpearceite, [(Ag,Cu)6(Sb,As)2(S,Se)7][Ag9Cu(S,Se)2Se2]
Authors: Evain Michel , Bindi Luca , Menchetti Silvio
Published: September 2006

The crystal structure of a Se-rich antimonpearceite has been solved and refined by means of X-ray diffraction data collected at temperatures above (room temperature) and below (120 K) an ionic conductivity-induced phase transition. Both structure arrangements consist of the stacking of [(Ag,Cu)6(Sb,As)2(S,Se)7]2−
A (A′) and [Ag9Cu(S,Se)2Se2]2+
B (B′) module layers in which Sb forms isolated SbS3 pyramids typically occurring in sulfosalts; copper links two S atoms in a linear coordination, and silver occupies sites with coordination ranging from quasi-linear to almost tetrahedral. In the ionic-conducting form, at room temperature, the silver d
10 ions are found in the B (B′) module layer along two-dimensional diffusion paths and their electron densities described by means of a combination of a Gram–Charlier development of the atomic displacement factors and a split-atom model. The structure resembles that of pearceite, except for the presence of both specific (Se) and mixed (S, Se) sites. In the low-temperature `ordered' phase at 120 K the silver d
10 ions of the B (B′) module layer are located in well defined sites with mixed S—Se coordination ranging from quasi-linear to almost tetrahedral. The structure is then similar to that of 222-pearceite but with major differences, specifically its cell metric, symmetry and local arrangement in the B (B′) module layer.
Order–disorder twinning model and stacking faults in α-NTO
Authors: Schwarzenbach Dieter , Kirschbaum Kristin , Pinkerton A. Alan
Published: September 2006

Crystals of the recently published [Bolotina, Kirschbaum & Pinkerton (2005). Acta Cryst. B61, 577–584] triclinic (P\overline1) structure of 5-nitro-2,4-dihydro-1,2,4-triazol-3-one (α-NTO) occur as fourfold twins. There are Z′ = 4 independent molecules per asymmetric unit. We show that the structure contains layers with 2-periodic layer-group symmetry p21/b 1 (1). This symmetry is lost through the stacking of the layers, which is a possible explanation for Z′ = 4. A layer can assume four different but equivalent positions with respect to its nearest neighbor. Twinning arises through stacking faults and is an instructive example of the application of order–disorder theory using local symmetry operations. The near-neighbor relations between molecules remain unchanged through all twin boundaries. The four structures with maximum degree of order, one of which is the observed one, and the family reflections common to all domains are identified. Rods of weak diffuse scattering confirm the stacking model.
On hydrogen bonding in 1,6-anhydro-β-D-glucopyranose (levoglucosan): X-ray and neutron diffraction and DFT study
Authors: Smrčok Ľubomír , Sládkovičová Mariana , Langer Vratislav , Wilson Chick C. , Koóš Miroslav
Published: September 2006

The geometry of hydrogen bonds in 1,6-anhydro-β-D-glucopyranose (levoglucosan) is accurately determined by refinement of time-of-flight neutron single-crystal diffraction data. Molecules of levoglucosan are held together by a hydrogen-bond array formed by a combination of strong O—H...O and supporting weaker C—H...O bonds. These are fully and accurately detailed by the neutron diffraction study. The strong hydrogen bonds link molecules in finite chains, with hydroxyl O atoms acting as both donors and acceptors of hydroxyl H atoms. A comparison of molecular and solid-state DFT calculations predicts red shifts of O—H and associated blue shifts of C—H stretching frequencies due to the formation of hydrogen bonds in this system.
Distribution of molecular pairs in Z′ = 2 structures
Authors: Collins Anna
Published: September 2006

The positions of pairs of independent molecules in Z′ = 2 structures have been surveyed for six of the most populated space groups for that class of structure. These results have been compared with the Z′ = 1 situation to reveal whether there are any fundamental differences in the construction of the asymmetric units in these cases. The results indicate that, broadly speaking, the packing of the molecular pairs in Z′ = 2 structures resembles that of single molecules in structures with Z′ = 1; this similarity may be chiefly attributed to the constraints imposed by the symmetry operators of the space group. However, there are key differences, which are particularly marked in the space groups with higher symmetry, that indicate that the asymmetric units in Z′ = 1 and Z′ = 2 structures are not directly comparable. In those cases where the positions of the pair centroids in Z′ = 2 structures are similar to the positions of molecular centroids for Z′ = 1 structures, it follows that the molecular centroids in Z′ = 2 structures must follow a different distribution. A different pattern is produced if the independent molecules in Z′ = 2 structures behave like the individual molecules in Z′ = 1 structures. These two scenarios combine to form the observed distributions of pair centroid positions.
First (3 + 2)-dimensional superspace approach to the structure of levyclaudite-(Sb), a member of the cylindrite-type minerals
Authors: Evain Michel , Petricek Vaclav , Moëlo Yves , Maurel Colette
Published: September 2006

The structure of synthetic levyclaudite-(Sb), approximately (Pb1 − y
Sb
y
S)1.357[Sn1 − x
(Cu2)
x
S2], has been determined by single-crystal X-ray diffraction on the basis of the (3 + 2)-dimensional superspace approach. This misfit-layer compound, of the cylindrite type, results from the combination of two heavily modulated triclinic Q and H subsystems with a common q wavevector and only one shared reciprocal axis (stacking direction). The Q pseudo-tetragonal layer, ∼(Pb0.70Sb0.30S), derived from the NaCl archetype, is positively charged; the H pseudo-hexagonal layer, ∼(Sn0.85Cu0.30S2), derived from the CdI2 archetype, is negatively charged, owing to the replacement of Sn4+ in an octahedral coordination by Cu+ pairs in an opposite triangular coordination. The analysis shows a strong transverse displacive modulation of the two layers, referred to as a `mondulation', correlated to a maximal Sb site occupation factor in the concavity of the Q layer undulation. The wavelength control of the `mondulation' obeys the vernier principle (14cQ
≅ 13cH
), which would correspond to an energy minimization through a charge transfer density modulation wave, common to all two-dimensional misfit-layer inorganic compounds.
Two-dimensional metal-organic frameworks containing linear dicarboxylates
Authors: Hawxwell Samuel M. , Adams Harry , Brammer Lee
Published: September 2006

The solvothermal synthesis of four two-dimensional metal-organic frameworks containing linear dicarboxylic acids as ligands for ZnII centres is described. Zn(BDC)(DMF) [(1) where BDC = benzene-1,4-dicarboxylic acid; DMF = N,N-dimethylformamide] adopts a common paddlewheel motif leading to a 44 grid network, whereas Zn3(BDC)3(EtOH)2 (2), Zn3(BDC)3(H2O)2·4DMF (3) and Zn3(BPDC)3(DMF)2·4DMF (4) each form networks with the relatively uncommon 36 topology based upon Zn3(O2CR)6 secondary building units. All contain coordinated solvent molecules, namely DMF [(1) and (4)], ethanol (2) or H2O (3). Comparison of structures (2) and (3) illustrates a clay-like flexibility in interplanar spacing which sheds light on the ability of the Zn3(BDC)3 framework to undergo desolvation and uptake of small solvent and gas molecules.
On concept formation in systematics
Authors: Rieppel Olivier
Published: September 2006

In his “Grundzüge einer Theorie der phylogenetischen Systematik”,Hennig (1950) cited three philosophers: the leading empiricist Rudolf Carnap, the conventionalist Hugo Dingler, and the somewhat more obscure empiricist Theodor Ziehen. David Hull characterized Hennig's “Grundzüge” as one long argument against idealistic morphology. It will here be argued that Hennig attacked idealistic morphology (synonymous with “systematic” morphology) for its mode of concept formation. Building on Carnap and Ziehen, who both looked back on Ernst Cassirer, Hennig argued that the “generic”, “thing” or “class” concept of traditional nomothetic science must be replaced with Cassirer's “relation concept.” According to Hennig, such “emancipation” of systematics from the Aristotelian “species” concept would also allow transcendence from the distinction of idiographic from nomothetic sciences, thus preserving the unity of science. However, the establishment of relations in the construction of a system of order presupposes entities that can be, or are, related. Relations presupposerelata, which in modern systematics are best conceptualized (at least at the supraspecific level) not as Aristotelian classes, nor as individuals as was argued by Hennig and Ziehen, but as tokens of natural kinds.

© The Willi Hennig Society 2006.
The risk of recurrent venous thromboembolism in pregnancy and puerperium without antithrombotic prophylaxis
Authors: Stefano Valerio De , Martinelli Ida , Rossi Elena , Battaglioli Tullia , Za Tommaso , Mannuccio Mannucci Pier , Leone Giuseppe
Published: September 2006

Whether or not pregnant women with a previous episode of venous thromboembolism (VTE) should receive antithrombotic prophylaxis is a matter of debate. In order to estimate the rate of recurrent deep venous thrombosis (DVT) or pulmonary embolism (PE) during pregnancy and puerperium we retrospectively investigated a cohort of 1104 women with previous VTE; after a single DVT or isolated PE, 88 of them became pregnant at least once without receiving antithrombotic prophylaxis. Overall, 155 pregnancies and 120 puerperium periods without prophylaxis were recorded. There were nine recurrences during pregnancy and 10 during puerperium, with a rate of 5·8% [95% confidence interval (CI) 3·0–10·6] and 8·3% (95%CI 4·5–14·6) respectively. In pregnancy, the rate of recurrence was 7·5% (95%CI 4·0–13·7) if the first VTE was unprovoked, related to pregnancy or to oral contraceptive use, whereas no recurrence occurred if the first VTE was related to other transient risk factors. In puerperium, the rate of recurrence was 15·5% (95%CI 7·7–28·7) in women with a pregnancy‐related first VTE, with a risk 3·9‐times higher than in the remaining women. Inherited thrombophilia was not associated with a statistically significant increase in risk of recurrence in pregnancy or in puerperium, yet the rate of recurrence in puerperium was 14·2% (95%CI 5·7–31·4) in overall carriers of factor V Leiden and 30% (95%CI 10·7–60·3) in carriers with a pregnancy‐related first VTE, with a risk 6·8 times higher than in women without thrombophilia and with a non pregnancy‐related first VTE.
Resolution of ambiguous low‐level positive quantitative polymerase chain reaction results in TEL‐AML1 positive ALL using a post‐PCR fluorescent oligoligation method*
Authors: Chen I‐Ming , Chakerian Artemis , Devidas Meenakshi , Borowitz Michael J. , Hunger Stephen P. , Willman Cheryl L. , Viswanatha David S.
Published: September 2006

The interpretation of low‐level or non‐reproducible amplification results in clinical quantitative polymerase chain reaction (Q‐PCR) assays can be difficult to definitively resolve. Concerning minimal residual disease detection in leukaemia, indeterminate low‐level results might create prognostic or therapeutic dilemmas. We evaluated low‐level, ambiguous Q‐PCR results in a study of paired diagnostic and end‐induction (day 29) TEL‐AML1 positive acute lymphoblastic leukaemia samples utilising a novel fluorescent primer ligation detection assay. The data presented here indicate that a significant number of low‐level apparent Q‐PCR positive results may be spurious or non‐specific in nature, requiring additional technical manoeuvres for confirmation of true positive cases.
[CO2]‐ and density‐dependent competition between grassland species
Authors: Van KLEUNEN MARK , ANDRE STEPHAN M. , SCHMID BERNHARD
Published: September 2006

The predicted ongoing increase of atmospheric carbon dioxide levels is considered to be one of the main threats to biodiversity due to potential changes in biotic interactions. We tested whether effects of intra‐ and interspecific planting density of the calcareous grassland perennialsBromus erectusandCarex flaccachange in response to elevated [CO2] (600 ppm) by using factorial combinations of seven densities (0, 1, 2, 4, 8, 16, 24 tillers per 8 × 8 cm2cell) of both species in plots with and without CO2enrichment. Although aboveground biomass ofC. flaccawas increased by 54% under elevated [CO2], the combined aboveground biomass of the whole stand was not significantly increased.C. flaccatended to produce more tillers under elevated [CO2] whileB. erectusproduced less tillers. The positive effect of [CO2] on the number of tillers ofC. flaccawas strongest at high intraspecific densities. On the other hand, the negative effect of [CO2] on the number of tillers ofB. erectuswas not present at intermediate intraspecific planting densities. Seed production ofC. flaccawas more than doubled under elevated [CO2], while seed production ofB. erectuswas not affected. Moreover, the mass per seed ofC. flaccawas increased by elevated [CO2] at intermediate interspecific planting densities while the mass per seed ofB. erectuswas decreased by elevated [CO2] at high interspecific planting densities. Our results show that the responses ofC. flaccaandB. erectusto elevated [CO2] depend in a complex way on initial planting densities of both species. In other words, competition between these two model species is both [CO2]‐ and density dependent. On average, however, the effects of [CO2] on the individual species indicate that the composition of calcareous grasslands is likely to change under elevated [CO2] in favor ofC. flacca.
Evaluation of the integrity of aseptic packages containing various filling products
Authors: Hsu Chuan‐Liang , Chang Ku‐Shang
Published: September 2006

The objective of this study was to investigate the integrity of aseptic aluminium laminate packages for different filling products after form‐fill‐seal processing using various testing methods. The integrity of the package was found to be influenced by the physical properties of filling product. When soyamilk (watery) was the filling product, the measured currents were lower than 10 μA for all of the packages subjected to electrolytic testing. If guava juice (high viscosity with high particulate content beverage) was the filling product, a total of 40% of tested packages showed escalation of current to greater than 1000 μA. This poor integrity was found to have resulted from compromise of the inner layer of packaging because of the particulate content of the juice. It was also demonstrated that the damage to the inner lining of the packages did not lead to the deterioration of the filling product by causing the development of penetrating micro holes. The cyclic voltammetry method is applicable to distinguish whether penetrating micro holes and damage have occurred in the plastic inner layer of a package.
HACCP effect on microbiological quality of minimally processed vegetables: a survey in six mass‐catering establishments
Authors: Kokkinakis Emmanuel N. , Fragkiadakis Georgios A.
Published: September 2006

Hazard analysis critical control points (HACCP) implementation effect in the microbiological quality of minimally processed vegetables was investigated, in mass‐catering establishments: two big hotels, two Universities and two major hospitals. Only one of each category had implemented HACCP and was purchasing vegetables produced with good agricultural practices (GAP). Samples from tomatoes in each food‐processing step; water, and personnel's hands were analysed microbiologically: totally, 240 tomatoes flora, 24 water and 60 personnel's hands samples. Tomatoes produced with GAP exhibited low microbial levels compared with conventional ones, while vegetable‐sanitation decreased microbial levels. Salads were safe in establishments applying HACCP methodology: Microbial‐level mean values (CFU g−1) of Escherichia coli was <20; total coliforms 3.67–3.88 log10; aerobic plate count 4.69–5.07 log10. The application of good manufacturing practices and good hygiene practices as parts of HACCP implementation, were found critical for the quality of the products. Based on actual results we present recommendations for a safer mass catering.
Effect of Calcium Lactate, 4‐Hexyl Resorcinol and Vacuum Packing on Physico‐chemical, Sensory and Microbiological Qualities of Minimally Processed Litchi (Litchi chinensis Sonn.)
Authors: Shah Narendra Singh , Nath Nirankar
Published: September 2006

Litchi (Litchi chinensis Sonn.) fruits are very susceptible to pericarp browning which adversely affects consumer acceptability even though the aril portion remains in excellent condition. Litchi arils (litchis) were treated with a solution containing 0–2% (w/v) calcium lactate (CL), 0–0.02% (w/v) 4‐hexyl resorcinol (4‐HR) and 1% potassium sorbate. The pH of solution was adjusted to 4.0 with citric acid. Treated litchis were packed in polystyrene trays, over‐wrapped with polypropylene film, vacuum‐packed (0, 47409.3, 94831.9 Pa) and stored at 4 ± 2 °C. Drip losses, pH, total soluble solids (TSS), sensory attributes and microbiological quality of stored samples were estimated. A four‐factor, three‐level experimental design (D6 Hokes design) with 19 experiments was chosen. Mathematical models were developed to analyse and predict the effect of CL, 4‐HR, in‐package vacuum and storage time on the responses. TSS, pH and sensory scores decreased significantly (P  0.01), whereas drip losses and microbial count increased significantly (P  0.01) with time. Drip loss was significantly (P  0.1) reduced by addition of CL. 4‐HR prevented browning and changes in colour score during storage were significantly less. Vacuum in packages exerted significant (P  0.01) effect over pH, TSS, sensory and microbiological qualities of minimally processed litchis.
Impact of patient‐reported outcome measures on routine practice: a structured review
Authors: Marshall Susan , Haywood Kirstie , Fitzpatrick Ray
Published: September 2006

Rationale, aims and objectives  Regular use of patient‐reported outcome measures (PROMs) by health care providers in their routine practice may help to improve the quality of care, but more evidence is needed before routine use of PROMs can be recommended. A structured review was undertaken to examine whether and how regular use of PROMs might improve routine practice.

Methods  A systematic search of Medline accessed through Webspirs Silverplatter was undertaken for the years 1976–2004. Controlled trials in English evaluating the impact of clinical use of PROMs on routine practice were included. Data regarding study design, characteristics of PROMs feedback, patient populations and study results were extracted by three reviewers.

Results  Feedback of PROMs results to health care providers appears to have a substantial impact on some processes of care, particularly on diagnosis of mental health conditions. However, the impact on patient health status is less consistent. Most of the published studies evaluated PROMs as a one‐off screening technology and measured only provider behaviours and patient health outcomes.

Conclusions  The pattern of results suggests a general lack of clarity in the field, especially regarding appropriate goals for PROMs and the mechanisms by which they might achieve them. To fully evaluate their role in routine practice, studies need to use PROMs that capture issues of importance to patients and to measure impacts relating to the patient–provider relationship and patient contributions to their well‐being. Until studies evaluate PROMs as a means facilitate patient‐centred care, their full potential in clinical practice will remain unknown.
Preventing paediatric admissions for respiratory disease: a qualitative analysis of the views of health care professionals
Authors: Maharaj Veena , Hsu Ronald , Beadman Anna
Published: September 2006

Rationale  The number of emergency paediatric admissions is increasing each year. The reasons for this are unclear but may include increasing demand from parents, changes in GP working patterns, and an increase in unnecessary admissions. Respiratory disease is the commonest diagnostic category for emergency admission in childhood.

Aims  To generate hypotheses for reduction in unnecessary admissions for respiratory disease by qualitative analysis of the views of health care professionals, to determine the proportion of preventable admissions as perceived by clinicians, and to assess the modified Paediatric Appropriateness Evaluation Protocol against clinicians judgements of appropriateness of admission.

Design  Eight health care professionals analysed clinical data from primary and secondary care for 94 cases that were admitted to an emergency assessment unit and received a hospital discharge diagnosis of respiratory disease. They assessed whether each admission was appropriate, whether it was preventable, and how it might have been prevented.

Results  A total of 31% of cases admitted to the assessment unit (29/94) were classified as preventable by the majority of professionals assessing the case. Provision of additional support, monitoring, and observation in the community was cited as a means of prevention in 33/94 cases. There was poor agreement between the modified PAEP and clinicians’ assessments of appropriateness of admission (kappa 0.1).

Conclusions  If the agreed views of these experienced doctors and nurses are correct, provision of additional services in the community could be an important means of preventing emergency admissions for respiratory disease. This hypothesis should be tested by further research including the views of families. The study provides further evidence that the modified PAEP may not be valid for use in UK practice. If inappropriate admission rates are to be used to measure effectiveness of services we need to develop an objective measure of appropriateness valid for use in the UK.
Use of a multidimensional assessment tool in a psychiatric adolescent care unit
Authors: Laget Jacques , Sofia Caroline , Bolognini Monique , Plancherel Bernard , Halfon Olivier , Stéphan Philippe
Published: September 2006

Aims  Adolescent mental health problems require treatment and care that are adapted to their needs. To evaluate this issue, it was decided to implement a multidimensional instrument focused on a global approach to adolescent social and behavioural functioning, combined with the ICD‐10 classification.

Methods  The combination of an assessment interview and a classification tool enabled the method to integrate the measurement of several domains of patient‐based outcome rather than focus on the measurement of symptoms. A group of 68 adolescents from an inpatient unit were compared with 67 adolescents from the general population.

Results  Results suggest that adolescents from the care unit adopt significantly riskier behaviour compared with adolescents from the control group. As expected, the main problems identified refer to the psychological and familial areas. A cluster analysis was performed and provided three different profiles: a group with externalizing disorders and two groups with internalizing disorders. On the basis of a structured interview it was possible to obtain information in a systematic way about the adolescents’ trajectory (delinquency, physical and sexual abuse, psychoactive substance use).

Conclusion  It was shown that treatment and care should not focus exclusively on mental health symptoms, but also upon physical, psychological and social aspects of the adolescent. A global approach helps in the consideration of the multitude of factors which must be taken into account when working with people with serious mental health problems and may help to turn the care unit’s activity more specifically towards the needs of these adolescents.
The basicoxal gland, a new exocrine structure in poneromorph ants (Hymenoptera, Formicidae)
Authors: Billen Johan , Ito Fuminori
Published: September 2006

The tegumental epithelium of the outer dorsolateral region in the proximal part of the coxae in the mid‐ and hindlegs of both workers and queens of the ants Odontomachus rixosus and O. simillimus is differentiated into a conspicuous and hitherto unknown exocrine gland. The glandular cells display a clear microvillar differentiation of their apical cell membrane, and are lined with the tegumental cuticle, which in this part contains crack‐like channels perpendicular to its surface, that carry the glandular secretions to the outside. Apical microvilli support the transport of substances, and contain an extension of tubular smooth endoplasmic reticulum in their centre. The function of the gland may be that of providing lubricant substances to the articulation region of the generally heavily sclerotized ponerine ant species. The gland is also found in several other ponerine and amblyoponine species, but not in the ectatommine species studied. The foreleg coxae lack a basicoxal gland in all species examined, which may be explained by the more limited articulation between the thorax and the coxae in the forelegs compared to the mid‐ and hindlegs.