bluuebunny/crossref_metadata_2025 huggingface dataset:
Evanescent wave interference and the total transparency of a warm high-density plasma slab
Authors: Fourkal E. , Velchev I. , Ma C-M. , Smolyakov A.
Published: September 2006

It is shown that an overcritical density plasma slab can be totally transparent to a p-polarized obliquely incident electromagnetic wave. High transparency is achieved due to the interference of the evanescent waves in the subcritical region. The transmission coefficient has the resonant character due to the excitation of a plasma surface mode (plasmon-polariton). In a warm plasma case, the excitation of the propagating longitudinal (electrostatic) modes becomes possible. It is demonstrated that these longitudinal excitations facilitate the total transparency of an opaque plasma slab creating additional resonances in the transmission property of the system.
Fabricating artificial nanowells with tunable size and shape by using scanning tunneling microscopy
Authors: Li Shao-Chun , Jia Jin-Feng , Ma Xucun , Xue Qi-Kun , Han Yong , Liu Feng
Published: September 2006

The authors report a method of precisely fabricating the large-scale nanocrystals with well-defined shape and size. The (111) oriented Pb islands deposited on Si(111)-7×7 substrate were investigated with a manipulation technique based on scanning tunneling microscopy. By applying a series of voltage pulses on the as-grown islands, artificial center-full-hollowed or half-hollowed nanowells are created, and the thickness and shape can be precisely regulated via tuning the manipulation parameters. Artificial nanoarray patterns in micron scale are also constructed using this method.
Activation of Rho-associated coiled-coil protein kinase 1 (ROCK-1) by caspase-3 cleavage plays an essential role in cardiac myocyte apoptosis
Authors: Chang Jiang , Xie Min , Shah Viraj R. , Schneider Michael D. , Entman Mark L. , Wei Lei , Schwartz Robert J.
Published: September 2006

Rho-associated coiled-coil protein kinase 1 (ROCK-1) is a direct cleavage substrate of activated caspase-3, which is associated with heart failure. In the course of human heart failure, we found marked cleavage of ROCK-1 resulting in a 130-kDa subspecies, which was absent in normal hearts and in an equivalent cohort of patients with left ventricular assist devices. Murine cardiomyocytes treated with doxorubicin led to enhanced ROCK-1 cleavage and apoptosis, all of which was blocked by a caspase-3 inhibitor. In addition, a bitransgenic mouse model of severe cardiomyopathy, which overexpresses Gq protein and hematopoietic progenitor kinase-/germinal center kinase-like kinase, revealed the robust accumulation of the 130-kDa ROCK-1 cleaved fragment. This constitutively active ROCK-1 subspecies, when expressed in cardiomyocytes, led to caspase-3 activation, indicating a positive feed-forward regulatory loop. ROCK-1-dependent caspase-3 activation was coupled with the activation of PTEN and the subsequent inhibition of protein kinase B (Akt) activity, all of which was attenuated by siRNA directed against ROCK-1 expression. Similarly, ROCK-1-null mice (Rock-1−/−) showed a marked reduction in myocyte apoptosis associated with pressure overload. These data suggest an obligatory role for ROCK-1 cleavage in promoting apoptotic signals in myocardial hypertrophy and/or failure.
Combinations of biomarkers predictive of later life mortality
Authors: Gruenewald Tara L. , Seeman Teresa E. , Ryff Carol D. , Karlamangla Arun S. , Singer Burton H.
Published: September 2006

A wide range of biomarkers, reflecting activity in a number of biological systems (e.g., neuroendocrine, immune, cardiovascular, and metabolic), have been found to prospectively predict disability, morbidity, and mortality outcomes in older adult populations. Levels of these biomarkers, singly or in combination, may serve as an early warning system of risk for future adverse health outcomes. In the current investigation, 13 biomarkers were examined as predictors of mortality occurrence over a 12-year period in a sample of men and women (
n
= 1,189) 70–79 years of age at enrollment into the study. Biomarkers examined in analyses included markers of neuroendocrine functioning (epinephrine, norepinephrine, cortisol, and dehydroepiandrosterone), immune activity (C-reactive protein, fibrinogen, IL-6, and albumin), cardiovascular functioning (systolic and diastolic blood pressure), and metabolic activity [high-density lipoprotein (HDL) cholesterol, total to HDL cholesterol ratio, and glycosylated hemoglobin]. Recursive partitioning techniques were used to identify a set of pathways, composed of combinations of different biomarkers, that were associated with a high-risk of mortality over the 12-year period. Of the 13 biomarkers examined, almost all entered into one or more high-risk pathways although combinations of neuroendocrine and immune markers appeared frequently in high-risk male pathways, and systolic blood pressure was present in combination with other biomarkers in all high-risk female pathways. These findings illustrate the utility of recursive partitioning techniques in identifying biomarker combinations predictive of mortal outcomes in older adults, as well as the multiplicity of biological pathways to mortality in elderly populations.
Higher order Rab programming in phagolysosome biogenesis
Authors: Roberts Esteban A. , Chua Jennifer , Kyei George B. , Deretic Vojo
Published: September 2006

Phagosomes offer kinetically and morphologically tractable organelles to dissect the control of phagolysosome biogenesis by Rab GTPases. Model phagosomes harboring latex beads undergo a coordinated Rab5–Rab7 exchange, which is akin to the process of endosomal Rab conversion, the control mechanisms of which are unknown. In the process of blocking phagosomal maturation, the intracellular pathogen Mycobacterium tuberculosis prevents Rab7 acquisition, thus, providing a naturally occurring tool to study Rab conversion. We show that M. tuberculosis inhibition of Rab7 acquisition and arrest of phagosomal maturation depends on Rab22a. Four-dimensional microscopy revealed that phagosomes harboring live mycobacteria recruited and retained increasing amounts of Rab22a. Rab22a knockdown in macrophages via siRNA enhanced the maturation of phagosomes with live mycobacteria. Conversely, overexpression of the GTP-locked mutant Rab22aQ64L prevented maturation of phagosomes containing heat-killed mycobacteria, which normally progress into phagolysosomes. Moreover, Rab22a knockdown led to Rab7 acquisition by phagosomes harboring live mycobacteria. Our findings show that Rab22a defines the critical checkpoint for Rab7 conversion on phagosomes, allowing or disallowing organellar transition into a late endosomal compartment. M. tuberculosis parasitizes this process by actively recruiting and maintaining Rab22a on its phagosome, thus, preventing Rab7 acquisition and blocking phagolysosomal biogenesis.
Ca2+ and synaptotagmin VII–dependent delivery of lysosomal membrane to nascent phagosomes
Authors: Czibener Cecilia , Sherer Nathan M. , Becker Steven M. , Pypaert Marc , Hui Enfu , Chapman Edwin R. , Mothes Walther , Andrews Norma W.
Published: September 2006

Synaptotagmin (Syt) VII is a ubiquitously expressed member of the Syt family of Ca2+ sensors. It is present on lysosomes in several cell types, where it regulates Ca2+-dependent exocytosis. Because [Ca2+]i and exocytosis have been associated with phagocytosis, we investigated the phagocytic ability of macrophages from Syt VII−/− mice. Syt VII−/− macrophages phagocytose normally at low particle/cell ratios but show a progressive inhibition in particle uptake under high load conditions. Complementation with Syt VII rescues this phenotype, but only when functional Ca2+-binding sites are retained. Reinforcing a role for Syt VII in Ca2+-dependent phagocytosis, particle uptake in Syt VII−/− macrophages is significantly less dependent on [Ca2+]i. Syt VII is concentrated on peripheral domains of lysosomal compartments, from where it is recruited to nascent phagosomes. Syt VII recruitment is rapidly followed by the delivery of Lamp1 to phagosomes, a process that is inhibited in Syt VII−/− macrophages. Thus, Syt VII regulates the Ca2+-dependent mobilization of lysosomes as a supplemental source of membrane during phagocytosis.
PPARγ controls CD1d expression by turning on retinoic acid synthesis in developing human dendritic cells
Authors: Szatmari Istvan , Pap Attila , Rühl Ralph , Ma Jiang-Xing , Illarionov Petr A. , Besra Gurdyal S. , Rajnavolgyi Eva , Dezso Balazs , Nagy Laszlo
Published: September 2006

Dendritic cells (DCs) expressing CD1d, a molecule responsible for lipid antigen presentation, are capable of enhancing natural killer T (iNKT) cell proliferation. The signals controlling CD1 expression and lipid antigen presentation are poorly defined. We have shown previously that stimulation of the lipid-activated transcription factor, peroxisome proliferator-activated receptor (PPAR)γ, indirectly regulates CD1d expression. Here we demonstrate that PPARγ, turns on retinoic acid synthesis by inducing the expression of retinol and retinal metabolizing enzymes such as retinol dehydrogenase 10 and retinaldehyde dehydrogenase type 2 (RALDH2). PPARγ-regulated expression of these enzymes leads to an increase in the intracellular generation of all-trans retinoic acid (ATRA) from retinol. ATRA regulates gene expression via the activation of the retinoic acid receptor (RAR)α in human DCs, and RARα acutely regulates CD1d expression. The retinoic acid–induced elevated expression of CD1d is coupled to enhanced iNKT cell activation. Furthermore, in vivo relevant lipids such as oxidized low-density lipoprotein can also elicit retinoid signaling leading to CD1d up-regulation. These data show that regulation of retinoid metabolism and signaling is part of the PPARγ-controlled transcriptional events in DCs. The uncovered mechanisms allow the DCs to respond to altered lipid homeostasis by changing CD1 gene expression.
A cancer cell metalloprotease triad regulates the basement membrane transmigration program
Authors: Hotary Kevin , Li Xiao-Yan , Allen Edward , Stevens Susan L. , Weiss Stephen J.
Published: September 2006

Carcinoma cells initiate the metastatic cascade by inserting invasive pseudopodia through breaches in the basement membrane (BM), a specialized barrier of cross-linked, extracellular matrix macromolecules that underlies epithelial cells and ensheaths blood vessels. While BM invasion is the sine qua non of the malignant phenotype, the molecular programs that underlie this process remain undefined. To identify genes that direct BM remodeling and transmigration, we coupled high-resolution electron microscopy with an ex vivo model of invasion that phenocopies the major steps observed during the transition of carcinoma in situ to frank malignancy. Herein, a triad of membrane-anchored proteases, termed membrane type-1, type-2, and type-3 metalloproteinases, are identified as the triggering agents that independently confer cancer cells with the ability to proteolytically efface the BM scaffolding, initiate the assembly of invasive pseudopodia, and propagate transmigration. These studies characterize the first series of gene products capable of orchestrating the entire BM remodeling program that distinguishes the carcinomatous phenotype.
New monocyclic and acyclic hNK-2 antagonists retaining the β-turn feature. X-ray and molecular modelling studies
Authors: Altamura Maria , Dapporto Paolo , Fedi Valentina , Giolitti Alessandro , Guerri Annalisa , Guidi Antonio , Maggi Carlo Alberto , Paoli Paola , Rossi Patrizia
Published: September 2006

The human tachykinin NK-2 (hNK-2) receptor is considered a promising target for relevant pathologies at the respiratory, gastrointestinal and genitourinary level. With the aim of reducing the complexity of existing peptide antagonists, two series of hNK-2 receptor antagonists were designed, with the support of modelling, and synthesized. The X-ray structure determination of two compounds, each belonging to one of the two series, allowed the experimental validation of the initial rationale. In addition, it has been found that the two series share a β-turn structure, a key feature for binding the hNK-2 receptor.
Structural phase transition and hydrogen ordering of TlH2PO4 at low temperature
Authors: Oh I. H. , Merz M. , Mattauch S. , Heger G.
Published: September 2006

The crystal structure of TlH2PO4 (TDP) has been studied at low temperature. The lattice parameters were derived from high-resolution X-ray powder diffraction in the temperature range between 8 and 300 K. A detailed crystal structure analysis of the antiferroelectric low-temperature phase TDP-III has been performed based on neutron diffraction data measured at 210 K on a twinned crystal consisting of two domain states. The structure model in the triclinic space group P\bar 1 is characterized by a complete ordering of all the H atoms in the asymmetric O—H...O hydrogen bonds. The phase transition from the ferroelastic TDP-II to the antiferroelectric TDP-III phase at 229.5 ± 0.5 K is only slightly of first order and shows no detectable hysteresis effects. Its mechanism is driven by the hydrogen ordering between the partially ordered TDP-II state and the completely ordered TDP-III state. The polymorphism of TDP and the fully deuterated TlD2PO4 (DTDP) is presented in the form of group–subgroup relations between the different space groups.
Accurate bond-valence parameters for the Bi3+/Br− ion pair
Authors: Sidey Vasyl
Published: September 2006

Using a new calculation scheme, reliable and physically meaningful values of the bond-valence parameters (r
0 = 2.567 Å and b = 0.421 Å) have been deduced for the Bi3+/Br− ion pair from the molecular geometry and from the crystal structure of BiBr3.
Anisotropic displacement parameters for H atoms using an ONIOM approach
Authors: Whitten Andrew E. , Spackman Mark A.
Published: September 2006

X-ray diffraction data cannot provide anisotropic displacement parameters (ADPs) for H atoms, a major outstanding problem in charge-density analysis of molecular crystals. Although neutron diffraction experiments are the preferred source of this information, for a variety of reasons they are possible only for a minority of materials of interest. To date, approximate procedures combine rigid-body analysis of the molecular heavy-atom skeleton, based on ADPs derived from the X-ray data, with estimates of internal motion provided by spectroscopic data, analyses of neutron diffraction data on related compounds, or ab initio calculations on isolated molecules. Building on these efforts, an improved methodology is presented, incorporating information on internal vibrational motion from ab initio cluster calculations using the ONIOM approach implemented in GAUSSIAN03. The method is tested by comparing model H-atom ADPs with reference values, largely from neutron diffraction experiments, for a variety of molecular crystals: benzene, 1-methyluracil, α-glycine, xylitol and 2-methyl-4-nitroaniline. The results are impressive and, as the method is based on widely available software, and is in principle widely applicable, it offers considerable promise in future charge-density studies of molecular crystals.
Molecular versus crystal symmetry in tri-substituted triazine, benzene and isocyanurate derivatives
Authors: Chong Samantha Y. , Seaton Colin C. , Kariuki Benson M. , Tremayne Maryjane
Published: September 2006

The crystal structures of triethyl-1,3,5-triazine-2,4,6-tricarboxylate (I), triethyl-1,3,5-benzenetricarboxylate (II) and tris-2-hydroxyethyl isocyanurate (III) have been determined from conventional laboratory X-ray powder diffraction data using the differential evolution structure solution technique. The determination of these structures presented an unexpectedly wide variation in levels of difficulty, with only the determination of (III) being without complication. In the case of (I) structure solution resulted in a Rietveld refinement profile that was not ideal, but was subsequently rationalized by single-crystal diffraction as resulting from disorder. Refinement of structure (II) showed significant variation in side-chain conformation from the initial powder structure solution. Further investigation showed that the structure solution optimization had indeed been successful, and that preferred orientation had a dramatic effect on the structure-solution R-factor search surface. Despite the presence of identical side chains in (I) and (II), only the triazine-based system retains threefold molecular symmetry in the crystal structure. The lack of use of the heterocyclic N atom as a hydrogen-bond acceptor in this structure results in the formation of a similar non-centrosymmetric network to the benzene-based structure, but with overall three-dimensional centrosymmetry. The hydrogen-bonded layer structure of (III) is similar to that of other isocyanurate-based structures of this type.
Centrosymmetric and pseudo-centrosymmetric structures refined as non-centrosymmetric
Authors: Flack H. D. , Bernardinelli G. , Clemente D. A. , Linden A. , Spek A. L.
Published: September 2006

The behaviour of the Flack parameter for centrosymmetric and pseudo-centrosymmetric crystal structures based on crystal structures published as being non-centrosymmetric is presented. It is confirmed for centrosymmetric structures that the value obtained for the Flack parameter is critically dependent on the Friedel coverage of the intensity data, approaching 0.5 for a coverage of 100% and sticking near the starting value for a coverage of 0%. For pseudo-centrosymmetric structures, even those very close to being centrosymmetric, it is found that it is often possible to obtain significant values of the Flack parameter. A theoretical basis for this surprising result is established. It has also been possible to establish an a priori estimate of the standard uncertainty of the Flack parameter based only on the chemical composition of the compound and the wavelength of the radiation. The paper concludes with preliminary presentations of bias in the Flack parameter and of inconsistent chemical and crystallographic data.
Supercell and subcell description of the crystal structure of triammonium bis(O-phospho-L-serinate) trihydrate
Authors: Hołyńska Małgorzata , Bryndal Iwona , Lis Tadeusz
Published: September 2006

The X-ray diffraction pattern obtained for a crystal of triammonium bis(O-phospho-L-serinate) trihydrate at 100 K displays the presence of weak superstructure reflections with odd l indices. Omission of the superstructure reflections leads to orthorhombic Laue symmetry. The structure may be solved and refined in the space group P212121 as an average structure omitting the weak reflections. The model reveals the presence of O-phospho-L-serinate monoanions, ammonium cations and partly disordered water molecules. The structure solution for the whole data set could be obtained only in the space group P21. There are two monoanions and two dianions of O-phospho-L-serinate per asymmetric unit, as well as six ordered ammonium cations and six water molecules.
Superspace description of the homologous series Ga4Ti
m−4O2m−2 with the crystallographic shear structure based on that of rutile
Authors: Michiue Yuichi , Yamamoto Akiji , Tanaka Masahiko
Published: September 2006

A generalized approach is proposed for the structure description of the homologous series Ga4Ti
m−4O2m−2 with crystallographic shear (CS) structures based on that of rutile. A (3 + 1)-dimensional model for an ideal CS structure is built up in connection with the CS operation in three-dimensional space. Its structural parameters are determined by m, the shear plane and the shear vector. The Rietveld fitting of the X-ray diffraction profile of Ga4Ti13O32 (m = 17) was successfully carried out using the ideal CS structure as an initial model, where modulation functions of atomic positions are inherently discontinuous and sawtooth-like. The deviation of a real structure from the ideal one was described by a few additional Fourier terms. This method was confirmed to be efficient for reducing the number of structural parameters required in the refinement in comparison to the conventional three-dimensional description.
Stoichiometry-dependent structures: an X-ray and neutron single-crystal diffraction study of the effect of reaction stoichiometry on the crystalline products formed in the potassium–cyanurate system
Authors: Nichol Gary S. , Clegg William , Gutmann Matthias J. , Tooke Duncan M.
Published: September 2006

Reaction of cyanuric acid (C3H3N3O3; neutral form CYH3; anionic form CYH_2^-; dianionic form CYH2−) with K2CO3 or KOH in aqueous solution gave three different crystalline products, according to the reaction stoichiometry used. The structures of two products were easily determined by single-crystal X-ray diffraction: [K(CYH2)(H2O)], (1), of which the crystal structure is already known [Marsh, R. E. et al. (2002). Acta Cryst. B58, 62–77], and [K2(CYH)], (2), a highly symmetrical and dense structure. Further stoichiometric variation produced another new complex, (3), and reaction of Rb2CO3 with CYH3 yielded a further product, (4), which was found to be isostructural with (3). Determination of the structures of (3) and (4) by X-ray diffraction gave a result that was chemically unreasonable owing to a charge imbalance, with the asymmetric unit apparently containing 2− against 1.5+ (partial charges as the result of crystallographic mirror symmetry). A single-crystal neutron diffraction analysis carried out on a fully deuterated sample of (3) revealed the presence of a supercell, with the c axis doubled compared with the X-ray result. Subsequent refinement of the structure with this supercell showed that it is the result of just two D atoms breaking crystallographically imposed mirror symmetry, which is otherwise essentially observed by the rest of the structure. This minor deviation from pseudo-symmetry could not be identified by X-ray diffraction. Thus, single-crystal neutron diffraction data revealed that the true chemical formula of the structure of (3) [and presumably also of the isostructural (4) with Rb instead of K and H instead of D], is [K3(C3D2N3O3)3(C3D3N3O3)(D2O)4], the deuterated form of [K3(CYH2)3(CYH3)(H2O)4].
Commensurate (C6H14N2)2[Mo8O26]·4H2O and incommensurate (C6H14N2)2[Mo8O26]·4.66H2O: a structural versatility linked to solvent content
Authors: Evain Michel , Petricek Vaclav , Coué Violaine , Dessapt Rémi , Bujoli-Doeuff Martine , Jobic Stéphane
Published: September 2006

The syntheses and structure determinations by means of single-crystal X-ray diffraction of commensurate (C6H14N2)2[Mo8O26]·4H2O and incommensurate (C6H14N2)2[Mo8O26]·4.66H2O, two new organic–inorganic hybrid compounds based on polyoxomolybdates and differing in their solvent content, are reported. Given the important disorder observed in the latter compound, only a combination of non-harmonic waves, crenel functions and TLS tensors offered a good modelling of the structure. (C6H14N2)2[Mo8O26].nH2O results from the self-assembly of [Mo8O26]4− anionic chains, C6H14N2
2+ (H2DABCO2+) cations and water molecules. The [Mo8O26]4− chain is built from γ-[Mo8O28]8− octamolybdate clusters, connected to each other through corner sharing. In both compounds, the [Mo8O26]4− chains are separated, in a similar way, by the H2DABCO2+ subunits, acting as charge-compensating cations, and by the water molecules. The orientation of the H2DABCO2+ cations is shown to be different from what has been observed previously in monoclinic (H2DABCO)2[Mo8O26]·4H2O, and therefore to give a different network of hydrogen bonds.
Accurate molecular structures and hydrogen bonding in two polymorphs of ortho-acetamidobenzamide by single-crystal neutron diffraction
Authors: Leech Charlotte K. , Barnett Sarah A. , Shankland Kenneth , Gutmann Matthias , Wilson Chick C.
Published: September 2006

The structures of both known forms of the polymorphic material ortho-acetamidobenzamide, C9H10N2O2, have been determined by low-temperature neutron single-crystal diffraction. Neutron diffraction allows the full description of the H-atom positions in this molecular material, which is vital in benchmarking related crystal-structure predictions. Significant conformational differences are indicated by a number of the torsion angles involving H atoms when compared with previous X-ray studies. A comprehensive description of the hydrogen-bonding scheme in both polymorphs is given.
Modulated corrugations in the crystal structure of the superconductor CaAlSi
Authors: Sparta Karine M. , Müller Ralf , Merz Michael , Roth Georg , Adelmann Peter , Wolf Thomas
Published: September 2006

We report the crystal structure analyses of CaAlSi from single-crystal and powder X-ray diffraction and the existence of two commensurately modulated phases, a sixfold and a fivefold modulated structure. This polymorphism seems to be correlated to the thermal history of the sample. We describe both modulated structures using a three-dimensional and a (3 + 1)-dimensional formalism.
Exploration of the high-pressure behaviour of polycyclic aromatic hydrocarbons: naphthalene, phenanthrene and pyrene
Authors: Fabbiani Francesca P. A. , Allan David R. , Parsons Simon , Pulham Colin R.
Published: September 2006

The structural response of three members of the family of polycyclic aromatic hydrocarbons (PAHs) to high-pressure recrystallization from dichloromethane solutions is presented. Recrystallization of naphthalene in the 0.2–0.6 GPa pressure range does not result in the formation of a new polymorph. Furthermore, direct compression of a single crystal to 2.1 GPa does not result in a phase transition. A density decrease of 18.2% over the 0.0–2.1 GPa pressure range is observed and the principal effect of pressure is to `tighten' the herringbone structural motif and decrease the size of void regions. A new polymorph of pyrene, form III, has been crystallized at 0.3 and at 0.5 GPa. Structural investigation of this new polymorph by means of topological analysis and comparison of Hirshfeld surfaces and fingerprint plots shows that intermolecular interactions are substantially different from those found in the ambient-pressure structures, and do not fit a previously established packing model for PAHs. Similar discrepancies are found for the high-pressure polymorph of phenanthrene, which is here re-investigated in greater detail. The structures of these high-pressure polymorphs are dominated by π...π stacking with a limited contribution from C—H...π (peripheral) interactions. It is perhaps not surprising that high-pressure polymorphs deviate from a model that has been devised for ambient-pressure structures, and this may be a direct consequence of the ability of pressure to modify and combine intermolecular interactions in ways that are not usually found at ambient pressure. This is achieved by modifying the relative orientations of molecules and by encouraging the formation of denser structures in which molecules pack together more efficiently.
Isomeric N-(iodophenyl)nitrobenzamides form different three-dimensional framework structures
Authors: Wardell James L. , Low John N. , Skakle Janet M. S. , Glidewell Christopher
Published: September 2006

The isomeric N-(iodophenyl)nitrobenzamides, C13H9IN2O3, all form different three-dimensional framework structures. Molecules of N-(2-iodophenyl)-3-nitrobenzamide (II) are linked by a combination of N—H...O and C—H...O hydrogen bonds and a two-centre iodo...carbonyl interaction. The supramolecular structure of N-(2-iodophenyl)-4-nitrobenzamide (III) is built from one N—H...O and two C—H...O hydrogen bonds, but short I...O contacts are absent from the structure. In N-(3-iodophenyl)-2-nitrobenzamide (IV), which crystallizes with Z′ = 2 in space group P21, the structure contains two N—H...O hydrogen bonds, four C—H...O hydrogen bonds, two two-centre iodo...nitro interactions and an aromatic π...π stacking interaction. The structure of N-(3-iodophenyl)-3-nitrobenzamide (V) contains one N—H...O hydrogen bond and three C—H...O hydrogen bonds, together with a two-centre iodo...nitro interaction and an aromatic π...π stacking interaction, while in N-(3-iodophenyl)-4-nitrobenzamide (VI), the combination of one N—H...O hydrogen bond and two C—H...O hydrogen bonds is augmented not only by a two-centre iodo...nitro interaction and an aromatic π...π stacking interaction, but also by a dipolar carbonyl...carbonyl interaction. In the supramolecular structure of N-(4-iodophenyl)-4-nitrobenzamide (IX), which crystallizes with Z′ = 2 in space group P\overline 1, there are two N—H...O hydrogen bonds, four C—H...O hydrogen bonds and two three-centre iodo...nitro interactions.
Effect of 2% dorzolamide on retinal blood flow: a study on juvenile primary open‐angle glaucoma patients already receiving 0.5% timolol
Authors: Costagliola Ciro , Campa Claudio , Parmeggiani Francesco , Incorvaia Carlo , Perri Paolo , D’Angelo Sergio , Lamberti Giuseppe , Sebastiani Adolfo
Published: September 2006

Aim

To investigate whether dorzolamide modifies peripapillary retinal haemodynamics in juvenile primary open‐angle glaucoma (JPOAG) patients treated with timolol.

Methods

In 40 JPOAG subjects, before and after dorzolamide coadministration with timolol, the following examinations were achieved: intraocular pressure (IOP), blood pressure (BP), ocular perfusion pressure (OPP), heart rate (HR), visual field and retinal flowmetry.

Results

Adjunctive therapy with dorzolamide induced the following modifications: IOP reduction [1.75 mmHg, 95% confidence interval (CI) 1.23, 2.26; P < 0.05], OPP increase (5.09 mmHg, 95% CI 2.97, 7.20; P < 0.02) and retinal blood flow improvement (35.0 arbitrary units, 95% CI 12.20, 57.80; P < 0.03). BP, HR and visual field indices did not change.

Conclusions

Dorzolamide, in association or in fixed combination with timolol, significantly improves retinal blood flow in JPOAG patients.
Current status of haploidentical stem cell transplantation
Authors: Dey Bimalangshu R. , Spitzer Thomas R.
Published: September 2006

Haploidentical stem cell transplantation is an alternative transplant strategy for patients without an human leucocyte antigen‐matched donor. The historical experience with haploidentical stem cell transplantation has been characterised by the immunological consequences of crossing a major histocompatibility barrier, namely graft‐versus‐host disease (GVHD), graft rejection and impaired immune reconstitution. Ex vivo T‐cell depletion of the graft may reduce the risk of GVHD, but at the expense of a higher risk of engraftment failure and relapse of the underlying malignancy. Myeloablative transplant strategies using vigorously T‐cell‐depleted ‘megadose’ stem cells appear to have improved the outcomes of selected patients with acute leukaemia. Non‐myeloablative stem cell transplantation strategies, in which mixed chimaerism as a platform for adoptive cellular immunotherapy is intentionally induced, show promise for limiting GVHD and lessening transplant‐related mortality. Future approaches, based on promising preclinical and early clinical observations, may include selective allodepletion of the graft, and manipulation of the cellular environment post‐transplant using selected cellular populations or immunomodulatory soluble factors.
Freeman–Sheldon syndrome: a case report
Authors: CORRIGAN L. A. , DUNCAN C. A. , GREGG T. A.
Published: September 2006

Summary.  Background.  Freeman‐Sheldon Syndrome is a rare craniofacial syndrome that has not been described in the dental literature to date. The main feature of relevance is severe microstomia, which limits access for routine dental care.

Case Report.  Dental treatment was carried out successfully under local anaesthetic for a young child with Freeman‐Sheldon syndrome. A novel coloured compomer material was helpful in the management of the case.

Conclusion.  The importance of early referral of children with rare craniofacial anomalies to Specialist Paediatric Dental services is highlighted.
The use of theatre time for paediatric dentistry under general anaesthesia
Authors: FOLEY JENNIFER , SOLDANI FRANCESCA
Published: September 2006

Objective.  The aim of this paper was to determine the use of theatre time for all procedures performed under general anaesthetic on a paediatric dental list.

Methods.  A prospective study of paediatric dental general anaesthetic procedures was undertaken at Ninewells Hospital and Medical School, NHS Tayside, Dundee, UK. Data were collected prospectively for 71 operating lists over a 3‐year period from April 2003 to March 2006. Both operator status and the procedure being undertaken were recorded. In addition, pre‐anaesthetic, anaesthetic, operating and disconnection times were recorded.

Results.  Of the 71 lists examined, 61 either finished early or on time, with a median unused time of 32.50 min (interquartile range = 19.50, 50.00 min), whilst 10 lists finished late with a median overrun time of 30.50 min (interquartile range = 9.25, 45.50 min). Comparing lists which finished late with those which were completed within time, the median pre‐anaesthetic time was significantly longer (Mann–Whitney U‐test, W = 20.05, P = 0.048). Overall, the theatre was in use for 78.22% of time combining pre‐anaesthetic, anaesthetic, operating and disconnection times; hence, there was poor time utilization of theatre for 21.78% of the total theatre time.

Conclusions.  Overall, 85.9% of theatre sessions for dental procedures under general anaesthetic in children finished early or on time. Where lists finished late, the duration of the pre‐anaesthetic time appeared to be the significant factor.
Multiple supernumerary teeth in the maxillary canine and mandibular premolar regions: a case in the postpermanent dentition
Authors: SASAKI HIDEKAZU , FUNAO JUNKO , MORINAGA HIDEKI , NAKANO KAZUHIKO , OOSHIMA TAKASHI
Published: September 2006

Background.  A supernumerary tooth is an extra tooth above the normal number, of which approximately 90% occur in the premaxillary region and show rudimentary forms of crown morphology. Most cases occur singly, with bilateral occurrence in the maxillary canine regions very rare in children with no other associated diseases or syndromes.

Case report.  A case of a 14‐year‐old boy with bilateral supernumerary teeth with normal crown shapes in both the maxillary canine and mandibular premolar regions. The supernumerary teeth in the maxilla were diagnosed at 12.2 years of age and in the mandible at 14.1 years of age.

Conclusion.  Four supernumerary teeth in the maxillary and mandibular canine‐premolar region is a rare finding.
Sharing specialist skills for diabetes in an inner city: A comparison of two primary care organisations over 4 years
Authors: Mohiddin Abdu , Naithani Smriti , Robotham Dan , Ajakaiye Olubukola , Costa Dominic , Carey Steve , Jones Richard H. , Gulliford Martin C.
Published: September 2006

Objective  To evaluate the effects of organizational change and sharing of specialist skills and information technology for diabetes in two primary care groups (PCGs) over 4 years.

Methods  In PCG‐A, an intervention comprised dedicated specialist sessions in primary care, clinical guidelines, educational meetings for professionals and a shared diabetes electronic patient record (EPR). Comparison was made with the neighbouring PCG‐B as control. In intervention and control PCGs, practice development work was undertaken for a new contract for family doctors. Data were collected for clinical measures, practice organizational characteristics and professional and patient views.

Results  Data were analysed for 26 general practices including 17 in PCG‐A and nine in PCG‐B. The median practice‐specific proportions of patients with HbA1c recorded annually increased in both areas: PCG‐A from median 65% to 77%, while PCG‐B from 53% to 84%. For cholesterol recording, PCG‐A increased from 50% to 76%, and PCG‐B from 56% to 80%. Organizational changes in both PCGs included the establishment of recall systems, dedicated clinics and educational sessions for patients. In both PCGs, practices performing poorly at baseline showed the greatest improvements in organization and clinical practice. Primary care professionals’ satisfaction with access and communication with diabetes specialist doctors and nurses increased, more so in the intervention PCG. Only 16% of primary care professional respondents used the diabetes EPR at least monthly. Patient satisfaction and knowledge did not change.

Conclusions  Improvements in practices’ organizational arrangements were associated with improvements in clinical care in both PCGs. Sharing specialist skills in one PCG was associated with increased professional satisfaction but no net improvement in clinical measures. A shared diabetes EPR is unlikely to be used, unless integrated with practice information systems.
Remarks on the morphology and biology of Cleigastra apicalis (Meigen, 1826) (Diptera, Scathophagidae)
Authors: Grochowska Maria
Published: September 2006

The egg, second‐ and third‐instar larvae and puparium of Cleigastra apicalis are described for the first time. All pre‐imaginal stages are found on stems of the common reed affected by flies of the genera Lipara and Platycephala and the butterfly Arenostola phragmitidis. The larvae feed on dead plant and animal tissue and the excreta of other insects that live inside the stems of the common reed. Exceptionally they will scrape living plant tissue. The pupa is the overwintering stage.
Ultrastructure of the spermatozoon of Myrmecocichla formicivora (Vieillot, 1881) and Philetairus socius (Latham, 1790) (Aves; Passeriformes), with a new interpretation of the passeridan acrosome
Authors: Jamieson Barrie G. M. , Hodgson Alan , Spottiswoode Claire N.
Published: September 2006

Passerine spermatozoa exhibit apomorphies that distinguish them from non‐passerine neognaths and palaeognaths. The acrosome is longer than the nucleus (excepting the suboscines, most Corvida, and a few Passerida). A perforatorium and endonuclear canals are absent. The proximal centriole is absent (except in the suboscines). The distal centriole is secondarily short, contrasting with its elongate condition in palaeognaths and Galloanserae. In the Passerida a single mitochondrial strand winds extensively along the axoneme (restricted to the anterior axoneme in suboscines and Corvida). A fibrous, or amorphous, periaxonemal sheath, seen in palaeognaths and many non‐passerines, respectively, is absent. The acrosome in Myrmecocichla formicivora and Philetairus socius is bipartite: an acrosome core is surmounted by an acrosome crest; the core is ensheathed by a layer which is a posterior extension of the crest. The acrosome helix is a lateral extension of the crest and the crest layer with (Myrmecocichla) or without (Philetairus) protrusion of material of the acrosome core into it. In M. formicivora, as in other muscicapoids, a fibrous helix is intertwined with at least the more proximal region of the mitochondrial helix. The fibrous helix is absent at maturity in Philetairus and other described passeroid spermatozoa with the possible exception of Passer italiae. In Philetairus a granular helix precedes the mitochondrial helix.
Spermiogenesis and spermatozoa ultrastructure in Salminus and Brycon, two primitive genera in Characidae (Teleostei: Ostariophysi: Characiformes)
Authors: Veríssimo‐Silveira R. , Gusmão‐Pompiani P. , Vicentini C. A. , Quagio‐Grassiotto I.
Published: September 2006

In Salminus, spermiogenesis is cystic and gives origin to a type I aquasperm. Spermatid differentiation is characterized by chromatin condensed into thick fibres, nuclear rotation, nuclear fossa formation, cytoplasmic channel formation, mitochondrial fusion producing long and ramified mitochondria, and the presence of several membranous concentric rings around the plasma membrane that encircles the cytoplasmic channel. In Salminus and Brycon, spermatozoa are very similar. They exhibit a spherical nucleus and chromatin condensed into fibre clusters, and a deep nuclear fossa. They show a long midpiece with few elongate mitochondria at the initial region and a cytoplasmic channel completely encircled by one or two membranous concentric rings. The flagellar axis is perpendicular to the nucleus and exhibits the classic axoneme (9 + 2). The very strong similarity observed between Salminus and Brycon spermatozoa supports the hypothesis that these subfamilies are likely to have a monophyletic origin.
Can Productivity Growth Explain the NAIRU? Long‐Run Evidence from Britain, 1871–1999
Authors: HATTON TIMOTHY J.
Published: September 2006

This paper investigates the effect of productivity growth on the non‐accelerating inflation rate of unemployment (NAIRU) over the long run, using historically consistent time series for the UK from 1871 to 1999. A two‐equation model of unemployment and wage‐setting that incorporates productivity effects is estimated over the whole period, allowing for shifts associated with changes in labour market institutions. The results indicate that faster productivity growth reduces the NAIRU, but that this goes only part of the way towards explaining wide swings in average unemployment across the decades.
Policy Variability, Productive Spending and Growth
Authors: VARVARIGOS DIMITRIOS
Published: September 2006

In this paper I present two models with policy variability arising from randomness in the provision of productive public spending. In the first model, public spending enters as an input in output production. In this case I find that the relationship between policy variability and growth depends critically on the technological parameters of the production function. In the second model, public spending enters as an input in the education sector of the economy. In this case I find that policy variability retards growth as individuals respond to increased uncertainty by actually reducing rather than increasing their investment in human capital.
South Asian transnational marriages in comparative perspective
Authors: CHARSLEY KATHARINE , SHAW ALISON
Published: September 2006

AbstractThis issue on South Asian transnational marriages brings diverse practices and networks into detailed ethnographic focus. Gender and agency are key themes explored in the collection, as well as the potential and actual transformation of gendered status resulting from marrying a migrant or joining a spouse overseas. The introduction identifies some common threads. Several articles challenge the assumption of wives' passivity in arranged marriages or in their joining husbands overseas, while one highlights the less‐documented experiences of men who migrate to join wives working abroad. The collection also offers insights into the cultural and emotional reasons for such marriages, complementing analyses that stress strategic motivations, and noting the emotional consequences of separation and new household formations for the experiences of marriage and parenthood. Marriage emerges as an important means of producing and transforming transnational networks, while marriage practices and dynamics are themselves transformed in the process.
Interpersonal Processes of Care Survey: Patient‐Reported Measures for Diverse Groups
Authors: Stewart Anita L. , Nápoles‐Springer Anna M. , Gregorich Steven E. , Santoyo‐Olsson Jasmine
Published: September 2006

Objective. To create a patient‐reported, multidimensional physician/patient interpersonal processes of care (IPC) instrument appropriate for patients from diverse racial/ethnic groups that allows reliable, valid, and unbiased comparisons across these groups.

Data Source/Data Collection. Data were collected by telephone interview. The survey was administered in English and Spanish to adult general medicine patients, stratified by race/ethnicity and language (African Americans, English‐speaking Latinos, Spanish‐speaking Latinos, non‐Latino whites) (N=1,664).

Study Design/Methods. In this cross‐sectional study, items were designed to be appropriate for diverse ethnic groups based on focus groups, our prior framework, literature, and cognitive interviews. Multitrait scaling and confirmatory factor analysis were used to examine measurement invariance; we identified scales that allowed meaningful quantitative comparisons across four race/ethnic/language groups.

Principal Findings. The final instrument assesses several subdomains of communication, patient‐centered decision making, and interpersonal style. It includes 29 items representing 12 first‐order and seven second‐order factors with equivalent meaning (metric invariance) across groups; 18 items (seven factors) allowed unbiased mean comparison across groups (scalar invariance). Final scales exhibited moderate to high reliability.

Conclusions. The IPC survey can be used to describe disparities in interpersonal care, predict patient outcomes, and examine outcomes of quality improvement efforts to reduce health care disparities.
Liquidity and Credit Risk
Authors: ERICSSON JAN , RENAULT OLIVIER
Published: September 2006

We develop a structural bond valuation model to simultaneously capture liquidity and credit risk. Our model implies that renegotiation in financial distress is influenced by the illiquidity of the market for distressed debt. As default becomes more likely, the components of bond yield spreads attributable to illiquidity increase. When we consider finite maturity debt, we find decreasing and convex term structures of liquidity spreads. Using bond price data spanning 15 years, we find evidence of a positive correlation between the illiquidity and default components of yield spreads as well as support for downward‐sloping term structures of liquidity spreads.
Effects of seasonality and migratory prey on body condition of Cichla species in a tropical floodplain river
Authors: Hoeinghaus D.J. , Winemiller K.O. , Layman C.A. , Arrington D.A. , Jepsen D.B.
Published: September 2006

Abstract –  In this study we examine trends in body condition of three Cichla species native to the Cinaruco River, Venezuela. Specifically, we characterise the potential subsidy provided by migratory Semaprochilodus kneri to Cichla by comparing condition among species, hydrologic seasons and different size‐classes (based on the ability to consume S. kneri assuming gape‐limitation). All three species had lowest body condition during the rising‐water season (following the reproduction period). Only Cichla temensis had greater body condition during the falling‐water season than low‐water season. During the falling‐water season, C. temensis >300 mm SL had significantly greater condition than smaller conspecifics. Annual migration of S. kneri into the river during the falling‐water season provides a resource subsidy to large C. temensis. Transfer of whitewater production into nutrient‐poor rivers by migratory fishes appears to be a general phenomenon in the major Neotropical river basins and may partially account for high standing stocks of large piscivores in these unproductive ecosystems.
Follicular rash during therapy with erlotinib (Tarceva®)
Authors: Gerdes Sascha , Mrowietz Ulrich
Published: September 2006

Erlotinib is a small‐molecule tyrosine kinase inhibitor of the EGF receptor which has become an important oncological agent, used primarily in treating non‐small‐cell lung cancer. The most common side effects of this class of EGF receptor antagonists are cutaneous rashes. The severity of the skin rash seems to be correlated to clinical response and should be a motivating factor to continue therapy. We report a case of a patient who developed a follicular rash during therapy with erlotinib.