bluuebunny/crossref_metadata_2025 huggingface dataset:
Using standard calibrated geometries to characterize a coaxial high purity germanium gamma detector for Monte Carlo simulations
Authors: van der Graaf E. R. , Dendooven P. , Brandenburg S.
Published: June 2014

A detector model optimization procedure based on matching Monte Carlo simulations with measurements for two experimentally calibrated sample geometries which are frequently used in radioactivity measurement laboratories results in relative agreement within 5% between simulated and measured efficiencies for a high purity germanium detector. The optimization procedure indicated that the increase in dead layer thickness is largely responsible for a detector efficiency decrease in time. The optimized detector model allows Monte Carlo efficiency calibration for all other samples of which the geometry and bulk composition is known. The presented method is a competitive and economic alternative to more elaborate detector scanning methods and results in a comparable accuracy.
Intrinsic carrier mobility of a single-layer graphene covalently bonded with single-walled carbon nanotubes
Authors: Li Dian , Shao Zhi-Gang , Hao Qing , Zhao Hongbo
Published: June 2014

We report intrinsic carrier mobility calculations of a two-dimensional nanostructure that consists of porous single layer graphene covalently bonded with single-walled carbon nanotubes on both sides. We used first-principles calculation and found that the deformation potential of such system is about 25% of that of graphene, and the carrier mobility is about 5 × 104 cm2 V−1 s−1 for both electrons and holes, about one order of magnitude lower than that of graphene. This nanostructure and its three-dimensional stacking could serve as novel organic electronic materials.
Interface-dependent magnetotransport properties for thin Pt films on ferrimagnetic Y3Fe5O12
Authors: Shiomi Y. , Ohtani T. , Iguchi S. , Sasaki T. , Qiu Z. , Nakayama H. , Uchida K. , Saitoh E.
Published: June 2014

We have studied magnetoresistance and Hall effects for 1.8-nm-thick Pt films grown on a ferrimagnetic insulator Y3Fe5O12 in a wide temperature (0.46–300 K) and magnetic-field (−15 to 15 T) region. In the low-temperature regime where quantum corrections to conductivity are observed, weak antilocalization behavior observed in Pt films is critically suppressed when the film is attached to Y3Fe5O12. Hall resistance in the Pt film is also affected by Y3Fe5O12, and it exhibits logarithmic temperature dependence in a broad temperature range. The magnetotransport properties in the high-field range are significantly influenced by the interface between Pt and Y3Fe5O12.
Coupled-cavity terahertz quantum cascade lasers for single mode operation
Authors: Li H. , Manceau J. M. , Andronico A. , Jagtap V. , Sirtori C. , Li L. H. , Linfield E. H. , Davies A. G. , Barbieri S.
Published: June 2014

We demonstrate the operation of coupled-cavity terahertz frequency quantum-cascade lasers composed of two sub-cavities separated by an air gap realized by optical lithography and dry etching. This geometry allows stable, single mode operation with typical side mode suppression ratios in the 30–40 dB range. We employ a transfer matrix method to model the mode selection mechanism. The obtained results are in good agreement with the measurements and allow prediction of the operating frequency.
Remarkable reduction in the threshold voltage of pentacene-based thin film transistors with pentacene/CuPc sandwich configuration
Authors: Li Yi , Liu Qi , Cai Jing , Li Yun , Shi Yi , Wang Xizhang , Hu Zheng
Published: June 2014

This study investigates the remarkable reduction in the threshold voltage (VT) of pentacene-based thin film transistors with pentacene/copper phthalocyanine (CuPc) sandwich configuration. This reduction is accompanied by increased mobility and lowered sub-threshold slope (S). Sandwich devices coated with a 5 nm layer of CuPc layer are compared with conventional top-contact devices, and results indicate that VT decreased significantly from −20.4 V to −0.2 V, that mobility increased from 0.18 cm2/Vs to 0.51 cm2/Vs, and that S was reduced from 4.1 V/dec to 2.9 V/dec. However, the on/off current ratio remains at 105. This enhanced performance could be attributed to the reduction in charge trap density by the incorporated CuPc layer. Results suggest that this method is simple and effectively generates pentacene-based organic thin film transistors with high mobility and low VT.
Tilted post arrays for separating long DNA
Authors: Thomas Joel D. P. , Dorfman Kevin D.
Published: June 2014

Recent simulations by Chen and Dorfman [Electrophoresis 35, 405–411 (2014)] suggested that “tilting” the electric field with respect to the lattice vectors of a hexagonal post array would lead to a substantial improvement in electrophoretic DNA separations therein. We constructed such an array where the electric field is applied at an angle equidistant between the two lattice vectors. This tilted array leads to (i) baseline resolution of 20 kbp DNA and λ DNA (48.5 kbp) in a 4 mm channel and (ii) measurable separation resolutions for electric fields up to 50 V/cm, both of which are improvements over untilted post arrays of the same post density. The predicted time required to reach a resolution of unity is approximately 5 min, independent of electric field. The separations are more reproducible at higher fields.
Cytochrome P450-generated metabolites derived from ω-3 fatty acids attenuate neovascularization
Authors: Yanai Ryoji , Mulki Lama , Hasegawa Eiichi , Takeuchi Kimio , Sweigard Harry , Suzuki Jun , Gaissert Philipp , Vavvas Demetrios G. , Sonoda Koh-Hei , Rothe Michael , Schunck Wolf-Hagen , Miller Joan W. , Connor Kip M.
Published: June 2014

Significance

The ω-3 long-chain polyunsaturated fatty acids are a class of dietary lipids that are highly enriched in the central nervous system and the retina. We demonstrate that dietary enrichment with ω-3s suppresses choroidal neovascularization in a mouse model of age-related macular degeneration (AMD), a leading cause of blindness. The ω-3s have anti-inflammatory properties and compete with ω-6s for downstream lipid metabolite synthesis at the cytochrome P450 (CYP) level. Specifically, 17,18- epoxyeicosatetraenoic acid and 19,20- epoxydocosapentaenoic acid derived from the CYP pathway were identified by liquid chromatography-tandem MS and found to confer protection. Systemic immune-cell recruitment and adhesion-molecule regulation were dampened significantly in mice receiving ω-3s. These findings provide a unique mechanism whereby specific CYP-derived lipid metabolites regulate angiogenesis in a mouse model of AMD.
Multiscale simulation reveals a multifaceted mechanism of proton permeation through the influenza A M2 proton channel
Authors: Liang Ruibin , Li Hui , Swanson Jessica M. J. , Voth Gregory A.
Published: June 2014

Significance

The M2 channel in the influenza A virus is one of three commonly targeted proteins in the viral membrane. Proton permeation across the M2 channel acidifies the virion, releasing the viral RNA and core proteins. This work constitutes, to our knowledge, the first complete characterization of this process by multiscale computer simulation, and the results are in quantitative agreement with prior experimental measurements. The simulations confirm that the mechanism involves a “shuttling” of protons through the His37 tetrad and that the rate-limiting step is histidine deprotonation. The results also reveal several important features, including a large barrier for protons to reach the His37 tetrad and increased conductance for lower pH values due to channel broadening and increased solvent dynamics despite larger charge repulsion.
Climate change underlies global demographic, genetic, and cultural transitions in pre-Columbian southern Peru
Authors: Fehren-Schmitz Lars , Haak Wolfgang , Mächtle Bertil , Masch Florian , Llamas Bastien , Tomasto Cagigao Elsa , Sossna Volker , Schittek Karsten , Isla Cuadrado Johny , Eitel Bernhard , Reindel Markus
Published: June 2014

Significance

It has long been assumed that climate played a major role in the population history of the Central Andes. Although adaptations of the Andean populations to climatic changes such as the intensification of agriculture have been inferred from the archaeological record, evidence for demographic adaptations such as migration is missing so far. In this paper, ancient DNA data from populations that lived in southern Peru between 840 BC and 1450 AD provide evidence for two large-scale migrations in the Central Andes coincident with episodes of drought and increased climatic variability. These migrations led to a successive genetic homogenization of southern Peruvian populations generally attributed to intrusions by the late pre-Columbian highland empires such as the Wari, Tiwanaku, or Inca.
Inhibition of Ninjurin 1 restores erectile function through dual angiogenic and neurotrophic effects in the diabetic mouse
Authors: Yin Guo Nan , Choi Min Ji , Kim Woo Jean , Kwon Mi-Hye , Song Kang-Moon , Park Jin-Mi , Das Nando Dulal , Kwon Ki-Dong , Batbold Dulguun , Oh Goo Taeg , Koh Gou Young , Kim Kyu-Won , Ryu Ji-Kan , Suh Jun-Kyu
Published: June 2014

Significance

Curative treatment modalities for erectile dysfunction (ED) are not available. Penile erection is a neurovascular phenomenon, and ED is caused mainly by vascular and neurologic disturbances. Here we demonstrate that inhibition of nerve injury-induced protein 1 promotes penile angiogenesis and neural regeneration through angiopoietin-1–Tie2 signaling and rescues erectile function in diabetic mice. Our preclinical work shed light on the application of therapeutic angiogenesis and neural regeneration for the treatment of human ED.
RETRACTED: Identification of gene ontologies linked to prefrontal–hippocampal functional coupling in the human brain
Authors: Dixson Luanna , Walter Henrik , Schneider Michael , Erk Susanne , Schäfer Axel , Haddad Leila , Grimm Oliver , Mattheisen Manuel , Nöthen Markus M. , Cichon Sven , Witt Stephanie H. , Rietschel Marcella , Mohnke Sebastian , Seiferth Nina , Heinz Andreas , Tost Heike , Meyer-Lindenberg Andreas
Published: June 2014

Functional interactions between the dorsolateral prefrontal cortex and hippocampus during working memory have been studied extensively as an intermediate phenotype for schizophrenia. Coupling abnormalities have been found in patients, their unaffected siblings, and carriers of common genetic variants associated with schizophrenia, but the global genetic architecture of this imaging phenotype is unclear. To achieve genome-wide hypothesis-free identification of genes and pathways associated with prefrontal–hippocampal interactions, we combined gene set enrichment analysis with whole-genome genotyping and functional magnetic resonance imaging data from 269 healthy German volunteers. We found significant enrichment of the synapse organization and biogenesis gene set. This gene set included known schizophrenia risk genes, such as neural cell adhesion molecule (
NRCAM
) and calcium channel, voltage-dependent, beta 2 subunit (
CACNB2
), as well as genes with well-defined roles in neurodevelopmental and plasticity processes that are dysfunctional in schizophrenia and have mechanistic links to prefrontal–hippocampal functional interactions. Our results demonstrate a readily generalizable approach that can be used to identify the neurogenetic basis of systems-level phenotypes. Moreover, our findings identify gene sets in which genetic variation may contribute to disease risk through altered prefrontal–hippocampal functional interactions and suggest a link to both ongoing and developmental synaptic plasticity.
Dopamine transporters govern diurnal variation in extracellular dopamine tone
Authors: Ferris Mark J. , España Rodrigo A. , Locke Jason L. , Konstantopoulos Joanne K. , Rose Jamie H. , Chen Rong , Jones Sara R.
Published: June 2014

Significance

The mechanism for diurnal (i.e., light/dark) oscillations in extracellular dopamine tone in mesolimbic and nigrostriatal systems is unknown. This is because, unlike other neurotransmitter systems, variation in dopamine tone does not correlate with variation in dopamine cell firing. The current research pinpoints the dopamine transporter as a critical governor of diurnal variation in both extracellular dopamine tone and the intracellular availability of releasable dopamine. These data describe shifts in the function of the dopamine system over time, which may have implications for diurnal effects on dopamine-dependent learning, sleep/wake behavior, locomotor activity, reward, and drug addiction.
Synthesis and photophysical studies of self-assembled multicomponent supramolecular coordination prisms bearing porphyrin faces
Authors: Shi Yanhui , Sánchez-Molina Irene , Cao Changsheng , Cook Timothy R. , Stang Peter J.
Published: June 2014

Significance

Sunlight is an attractive energy source because it is available in amounts that far exceed current and future global demands. Its use, however, requires materials that can efficiently absorb visible wavelength photons. Nature has evolved light-harvesting complexes comprising many pigment molecules to act as antennae, inspiring synthetic designs that similarly organize many chromophores. One method for constructing multiple-pigment ensembles is to use coordination-driven self-assembly. Porphyrin molecules are excellent candidates for both light harvesting and self-assembly, owing to their photophysical properties and rigid framework that allows for directional bonding. Here, we describe the construction of porphyrin prisms using multicomponent self-assembly, wherein 14 total building blocks organize into well-defined metallacages in a single step.
Role of diacylglycerol activation of PKCθ in lipid-induced muscle insulin resistance in humans
Authors: Szendroedi Julia , Yoshimura Toru , Phielix Esther , Koliaki Chrysi , Marcucci Mellissa , Zhang Dongyan , Jelenik Tomas , Müller Janette , Herder Christian , Nowotny Peter , Shulman Gerald I. , Roden Michael
Published: June 2014

Significance

Muscle insulin resistance is a major factor in the pathogenesis of type 2 diabetes, but the underlying cellular mechanisms are yet unclear. This study found that muscle diacylglycerol content was temporally associated with protein kinase Cθ activation and impairment of insulin signaling in human skeletal muscle. A similar relationship between muscle diacylglycerol content and protein kinase Cθ activation was observed in insulin-resistant obese and type 2 diabetic individuals. In contrast, we observed no relationship between other putative mediators of muscle insulin resistance including ceramides, acylcarnitines, or circulating adipocytokines. These data support the hypothesis that diacylglycerol activation of protein kinase Cθ and subsequent impairment of insulin signaling plays a major role in the pathogenesis of muscle insulin resistance in humans.
Hydrogen/deuterium exchange of cross-linkable α-amino acid derivatives in deuterated triflic acid
Authors: Wang Lei , Murai Yuta , Yoshida Takuma , Okamoto Masashi , Masuda Katsuyoshi , Sakihama Yasuko , Hashidoko Yasuyuki , Hatanaka Yasumaru , Hashimoto Makoto
Published: June 2014

In this paper we report here a hydrogen/deuterium exchange (H/D exchange) of cross-linkable α-amino acid derivatives with deuterated trifluoromethanesulfonic acid (TfOD). H/D exchange with TfOD was easily applied to o-catechol containing phenylalanine (DOPA) within an hour. A partial H/D exchange was observed for trifluoromethyldiazirinyl (TFMD) phenylalanine derivatives. N-Acetyl-protected natural aromatic α-amino acids (Tyr and Trp) were more effective in H/D exchange than unprotected ones. The N-acetylated TFMD phenylalanine derivative afforded slightly higher H/D exchange than unprotected derivatives. An effective post-deuteration method for cross-linkable α-amino acid derivatives will be useful for the analysis of biological functions of bioactive peptides and proteins by mass spectrometry.
A novel self-lipid antigen targets human T cells against CD1c+ leukemias
Authors: Lepore Marco , de Lalla Claudia , Gundimeda S. Ramanjaneyulu , Gsellinger Heiko , Consonni Michela , Garavaglia Claudio , Sansano Sebastiano , Piccolo Francesco , Scelfo Andrea , Häussinger Daniel , Montagna Daniela , Locatelli Franco , Bonini Chiara , Bondanza Attilio , Forcina Alessandra , Li Zhiyuan , Ni Guanghui , Ciceri Fabio , Jenö Paul , Xia Chengfeng , Mori Lucia , Dellabona Paolo , Casorati Giulia , De Libero Gennaro
Published: June 2014

T cells that recognize self-lipids presented by CD1c are frequent in the peripheral blood of healthy individuals and kill transformed hematopoietic cells, but little is known about their antigen specificity and potential antileukemia effects. We report that CD1c self-reactive T cells recognize a novel class of self-lipids, identified as methyl-lysophosphatidic acids (mLPAs), which are accumulated in leukemia cells. Primary acute myeloid and B cell acute leukemia blasts express CD1 molecules. mLPA-specific T cells efficiently kill CD1c+ acute leukemia cells, poorly recognize nontransformed CD1c-expressing cells, and protect immunodeficient mice against CD1c+ human leukemia cells. The identification of immunogenic self-lipid antigens accumulated in leukemia cells and the observed leukemia control by lipid-specific T cells in vivo provide a new conceptual framework for leukemia immune surveillance and possible immunotherapy.
Screening, Assessment, and Diagnosis of Mood and Anxiety Disorders During Pregnancy and the Postpartum Period
Authors: Hart Kimberly J. , Flynn Heather A.
Published: June 2014

Mood and anxiety disorders are highly prevalent in perinatal samples, affecting as many as 20% of childbearing women (Gavin et al., 2005). In an effort to prevent adverse outcomes associated with perinatal mood and anxiety disorders, researchers and clinicians have advocated routine screening during the perinatal period (NRC, 2009). Although, there are several screening measures for depression, many of which have been used or validated in perinatal populations, few screening tools have been developed specifically for or validated in perinatal samples for bipolar disorder or anxiety disorders. Despite the ongoing need for brief, accurate, and easily administered screening measures, it seems clear that perinatal mood and anxiety screening is associated with substantial improvement in rate of detection (Georgiopoulous et al., 1999; Georgiopoulos, Bryan, Wollan, and Yawn, 2001; Gilbody, Sheldon, and House, 2008). However, in the absence of systematic protocols to ensure further assessment, treatment, and follow-up, screening is unlikely to have a positive impact on depression-associated morbidity (Gjerdingen, Katon, and Rich, 2008; Gilbody et al., 2008; Miller et al., 2012; NRC, 2009). Preliminary evidence suggests that screening for perinatal mood and anxiety disorders, when embedded within larger systems to ensure comprehensive assessment, connection to treatment, and regular monitoring, has the potential to improve outcomes for women and their families. The question of whether screening programs can ultimately decrease depression-associated morbidity and prevent adverse outcomes cannot be answered given the existing research base (Myers et al., 2013). Although much is left to be understood about perinatal screening for mood and anxiety disorders, the impact of this research lies in potential for reducing negative maternal outcomes as well as for prevention of the negative impact of perinatal depression on the health and well-being of babies born to depressed or anxious mothers.
The Power of Political Communication
Authors: Tesler Michael , Zaller John
Published: June 2014

Most scholars agree that the effects of mass communication are more than minimal. We find, however, that most communication effects are short-lived, involve mainly weakly held attitudes, and produce no political consequences. Party cues conveyed in mass communication can change attitudes, but usually weakly held ones; when individuals hold strong views, they often change parties rather than change attitudes. Non-partisan communication may not durably change any attitudes, even weakly held ones. These conclusions, derived from field studies rather than laboratory experiments, raise the old minimal effects question in a new form: How politically important are the effects of mass communication? Our answer is that it depends on context. Short-term communication effects can be quite consequential if they occur close to a relevant political decision, such as an election or congressional vote. Communication that continues over a long period of time, such as messages carrying the value of racial equality, may also be important. Short-term or episodic communication that aims to produce a generally informed citizenry, independent of any political decision, may have little importance.
Political Advertising
Authors: Fallis Timothy W.
Published: June 2014

Within the field of political communication, the study of political advertising has attempted to relate its content to posited effects. Most of this inquiry has been conducted using one or some combination of three methods: survey, experiment, and content analysis. As a result, a picture of what political advertising does and why and how it does it has emerged. This chapter synthesizes findings by suggesting that differences in spending on political advertising can affect vote choice; that advertising’s effect on vote choice are mediated by factors that include party affiliation, political knowledge and involvement, and media exposure; and that such advertising has a significant effect on the political process. “Negative” advertising is a messaging structure that affects the political process for ill and for good; it can both decrease and increase voter turnout but is misunderstood when conflated with informative “attack” and “contrast” advertising.
Disagreement in Political Discussion
Authors: Nir Lilach
Published: June 2014

Normative theory extols the virtues of disagreement to democracy, but evidence to support these suppositions is somewhat mixed. This chapter reviews the empirical literature on exposure to disagreement that occurs in ordinary political conversations among citizens. After outlining conceptual distinctions and operational definitions in the literature, the main section highlights both the agreed-upon and contested findings on the consequences of disagreement, including opinion quality, political tolerance, attitudinal ambivalence, knowledge gains, polarization, and participatory outcomes. The concluding section points to unanswered questions and proposes several directions for future research on disagreement. These include exploring factors that shape receptivity to disagreement, such as individual differences, situational cues, the content of verbal exchanges, and cross-national differences in political institutions, media systems, or cultural preference for outspokenness.
On the generation of nonlinear travelling waves in confined geometries using electric fields
Authors: Cimpeanu R , Papageorgiou D. T
Published: June 2014

We investigate electrostatically induced interfacial instabilities and subsequent generation of nonlinear coherent structures in immiscible, viscous, dielectric multi-layer stratified flows confined in small-scale channels. Vertical electric fields are imposed across the channel to produce interfacial instabilities that would normally be absent in such flows. In situations when the imposed vertical fields are constant, interfacial instabilities emerge due to the presence of electrostatic forces, and we follow the nonlinear dynamics via direct numerical simulations. We also propose and illustrate a novel pumping mechanism in microfluidic devices that does not use moving parts. This is achieved by first inducing interfacial instabilities using constant background electric fields to obtain fully nonlinear deformations. The second step involves the manipulation of the imposed voltage on the lower electrode (channel wall) to produce a spatio-temporally varying voltage there, in the form of a travelling wave with pre-determined properties. Such travelling wave dielectrophoresis methods are shown to generate intricate fluid–surface–structure interactions that can be of practical value since they produce net mass flux along the channel and thus are candidates for microfluidic pumps without moving parts. We show via extensive direct numerical simulations that this pumping phenomenon is a result of an externally induced nonlinear travelling wave that forms at the fluid–fluid interface and study the characteristics of the generated velocity field inside the channel.
2-[2,6-Bis(propan-2-yl)phenyl]-1,3-dicyclohexylguanidine
Authors: Chlupatý Tomáš , Padělková Zdeňka
Published: June 2014

In the title asymmetric dicyclohexylphenylguanidine, C25H41N3, the central guanidine C atom deviates by only 0.004 (2) Å from the central plane defined by the three N atoms. The benzene and the cyclohexyl rings are rotated out of the central plane of the N3C unit by 85.63 (12)° (benzene) and 51.52 (9) and 49.37 (12)° (cyclohexyl). The crystal packing features only by van der Waals interactions.
Ethyl 6-amino-5-cyano-4-phenyl-2,4-dihydropyrano[2,3-c]pyrazole-3-carboxylate dimethyl sulfoxide monosolvate
Authors: Sharma Naresh , Brahmachari Goutam , Banerjee Bubun , Kant Rajni , Gupta Vivek K.
Published: June 2014

In the asymmetric unit of the title compound, C16H14N4O3·C2H6OS, there are two independent main molecules (AandB) and two dimethyl sulfoxide solvent molecules. In moleculeA, the pyran ring is in a flattened sofa conformation, with thesp3-hydridized C atom forming the flap. In moleculeB, the pyran ring is in a flattened boat conformation, with thesp3-hydridized C atom and the O atom deviating by 0.073 (3) and 0.055 (3) Å, respectively, from the plane of the other four atoms. The mean planes the pyrazole and phenyl rings form dihedral angles of 84.4 (2) and 84.9 (2)°, respectively, for moleculesAandB. In the crystal, N—H...O and N—H...N hydrogen bonds link the components of the structure into chains along [010]. In both solvent molecules, the S atoms are disordered over two sites, with occupancy ratios of 0.679 (4):0.321 (4) and 0.546 (6):0.454 (6).
Poly[tris(μ-4,4′-bipyridine-κ2N:N′)bis(dimethyl sulfoxide-κO)tetrakis(thiocyanato-κN)dicobalt(II)]
Authors: Kaenket Surasak , Phuengphai Pongthipun , Pakawatchai Chaveng , Youngme Sujittra
Published: June 2014

The asymmetric unit of the title compound, [Co2(NCS)4(C10H8N2)3(C2H6OS)2]n, consists of one CoIIatom, two thiocyanate anions, one dimethyl sulfoxide molecule and one and a half 4,4′-bipyridine molecules. The half-molecule is completed by inversion symmetry. The CoIIatom is coordinated in a distorted octahedral geometry by two N atoms from two thiocyanate anions, one O atom from dimethyl sulfoxide as a terminal ligand and three N atoms from three 4,4′-bipyridine molecules as bridging ligands linking the cations, with a Co...Co separation of 11.5964 (5) Å. This generates a two-dimensional structure parallel to (-103). A C—H...S hydrogen bond links the layers into a three-dimensional supramolecular framework. The layers are stacked in anABCfashion preventing the occurrence of interlayer void space and hence leading to the absence of lattice solvent and/or organic guest molecules in the structure.
(E)-4-Methoxy-N′-[(6-methyl-4-oxo-4H-chromen-3-yl)methylidene]benzohydrazide monohydrate
Authors: Ishikawa Yoshinobu , Watanabe Kohzoh
Published: June 2014

In the title hydrate, C19H16N2O4·H2O, the 4H-chromen-4-one segment is slightly twisted, with a dihedral angle between the two six-membered rings of 3.30 (5)°. The dihedral angles between the plane of the pyranone ring and the hydrazide plane and between the planes of the pyranone ring and the benzene ring of thep-methoxybenzene unit are 26.69 (4) and 2.23 (3)°, respectively. The molecule is connected to the solvent water molecule by an N—H...O hydrogen bond. In the crystal, there are π–π stacking interactions between centrosymmetrically related pyranone rings [centroid–centroid distance = 3.5394 (9) Å], as well as bridges formed by the water moleculesviaO—H...O hydrogen bonds.
2,3-Dimethylquinazolin-4(3H)-one
Authors: Saitkulov Fozil E. , Tashniyazov Azamat A. , Mamadrahimov Azimjon A. , Shakhidoyatov Kh. M.
Published: June 2014

The non-H atoms of the title molecule, C10H10N2O, are essentially coplanar, with a maximum deviation of 0.046 (4) Å for the O atom. In the crystal, molecules are linked by weak C—H...O hydrogen bonds, forming chains along [010]. In addtion, weak C—H...π interactions and π–π stacking interactions between benzene and pyrimidine rings, with a centroid–centroid distance of 3.730 (3) Å, link the chains, forming a two-dimensional network parallel to (001).
Expression, purification and crystallization of the phosphate-binding PstS protein fromPseudomonas aeruginosa
Authors: Neznansky Avi , Opatowsky Yarden
Published: June 2014

Pseudomonas aeruginosa(PA) infections pose a serious threat to human health. PA is a leading cause of fatal lung infections in cystic fibrosis and immune-suppressed patients, of sepsis in burn victims and of nosocomial infections. An important element in PA virulence is its ability to establish biofilms that evade suppression by the host's immune system and antibiotics. PstS, a periplasmic subunit of the Pst phosphate-transport system of PA, plays a critical role in the establishment of biofilms. In some drug-resistant PA strains, PstS is secreted in large quantities from the bacteria, where it participates in the assembly of adhesion fibres that enhance bacterial virulence. In order to understand the dual function of PstS in biofilm formation and phosphate transport, the crystal structure of PA PstS was determined. Here, the overexpression inEscherichia coliand purification of PA PstS in the presence of phosphate are described. Two crystal forms were obtained using the vapour-diffusion method at 20°C and X-ray diffraction data were collected. The first crystal form belonged to the centred orthorhombic space groupC2221, with unit-cell parametersa= 67.5,b= 151.3,c= 108.9 Å. Assuming the presence of a dimer in the asymmetric unit gives a crystal volume per protein weight (VM) of 2.09 Å3 Da−1and a solvent content of 41%. The second crystal form belonged to the primitive orthorhombic space groupP212121, with unit-cell parametersa= 35.4,b= 148.3,c= 216.7 Å. Assuming the presence of a tetramer in the asymmetric unit gives a crystal volume per protein weight (VM) of 2.14 Å3 Da−1and a solvent content of 42.65%. A pseudo-translational symmetry is present in theP212121crystal form which is consistent with a filamentous arrangement of PstS in the crystal lattice.
Crystallization and preliminary crystallographic studies of the complement 1qA globular domain from zebrafish,Dare-C1qAgD
Authors: Yuan Hongyu , Chen Rong , Liu Yanjie , Tariq Mansoor , Sun Yaping , Xia Chun
Published: June 2014

Complement 1q (C1q) is the first component of the complement system which can initiate the classical complement pathway. In human, C1q is composed of 18 polypeptide chains: six C1qA chains, six C1qB chains and six C1qC chains. Each chain has a signal peptide and is comprised of a collagen-like region and a C-terminal C1q globular domain (C1qgD), which is organized as a heterotrimer. C1qgD can recognize antigen–antibody complexes containing IgG and IgM or can bind directly to the C-reactive protein. Although the classical complement pathway is found from fish to mammals, only the human C1qgD structure has been determined. Compared with that of mammals, fish C1q exhibits similar immune functions and genome arrangement. In order to illustrate the structure of C1qgD in fish, zebrafish (Danio rerio) C1qA globular domain (Dare-C1qAgD) was expressed, purified and crystallized. X-ray diffraction data were collected from a crystal to a resolution of 2.05 Å; the crystal belonged to the orthorhombic space groupP212121, with unit-cell parametersa= 50.347,b= 85.059,c= 95.560 Å. It contained three molecules in the asymmetric unit. The Matthews coefficient valueVMwas 2.31 Å3 Da−1, with a calculated solvent content of 46.7%. The data will help to give insight into the structural basis of C1qA in fish species.
Structure of d(CCCCGGTACCGGGG)2at 1.65 Å resolution
Authors: Purushothaman Monica , Varghese Anna , Mandal Pradeep Kumar , Gautham Namasivayam
Published: June 2014

The crystal structure of the tetradecanucleotide d(CCCCGGTACCGGGG)2has previously been reported as an A-type double helix at a resolution of 2.5 Å in space groupP41. Here, the structure of this sequence was determined at a significantly higher resolution of 1.65 Å in space groupP41212. The differences in crystal packing between the former and latter are described. The crystallographic asymmetric unit consists of one tetradecanucleotide duplex that spans more than one full turn of the A-helix. This structure allowed the unambiguous identification of solvent interactions.
Structure ofD-tagatose 3-epimerase-like protein fromMethanocaldococcus jannaschii
Authors: Uechi Keiko , Takata Goro , Yoneda Kazunari , Ohshima Toshihisa , Sakuraba Haruhiko
Published: June 2014

The crystal structure of a D-tagatose 3-epimerase-like protein (MJ1311p) encoded by a hypothetical open reading frame, MJ1311, in the genome of the hyperthermophilic archaeonMethanocaldococcus jannaschiiwas determined at a resolution of 2.64 Å. The asymmetric unit contained two homologous subunits, and the dimer was generated by twofold symmetry. The overall fold of the subunit proved to be similar to those of the D-tagatose 3-epimerase fromPseudomonas cichoriiand the D-psicose 3-epimerases fromAgrobacterium tumefaciensandClostridium cellulolyticum. However, the situation at the subunit–subunit interface differed substantially from that in D-tagatose 3-epimerase family enzymes. In MJ1311p, Glu125, Leu126 and Trp127 from one subunit were found to be located over the metal-ion-binding site of the other subunit and appeared to contribute to the active site, narrowing the substrate-binding cleft. Moreover, the nine residues comprising a trinuclear zinc centre in endonuclease IV were found to be strictly conserved in MJ1311p, although a distinct groove involved in DNA binding was not present. These findings indicate that the active-site architecture of MJ1311p is quite unique and is substantially different from those of D-tagatose 3-epimerase family enzymes and endonuclease IV.
Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of glyceraldehyde-3-phosphate dehydrogenase fromStreptococcus agalactiaeNEM316
Authors: Nagarajan Revathi , Ponnuraj Karthe
Published: June 2014

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is an essential enzyme involved in glycolysis. Despite lacking the secretory signal sequence, this cytosolic enzyme has been found localized at the surface of several bacteria and fungi. As a surface protein, GAPDH exhibits various adhesive functions, thereby facilitating colonization and invasion of host tissues.Streptococcus agalactiae, also known as group B streptococcus (GBS), binds onto the host using its surface adhesins and causes sepsis and pneumonia in neonates. GAPDH is one of the surface adhesins of GBS binding to human plasminogen and is a virulent factor associated with host colonization. Although the surface-associated GAPDH has been shown to bind to a variety of host extracellular matrix (ECM) molecules in various bacteria, the molecular mechanism underlying their interaction is not fully understood. To investigate this, structural studies on GAPDH ofS. agalactiaewere initiated. ThegapCgene ofS. agalactiaeNEM316 encoding GAPDH protein was cloned into pET-28a vector, overexpressed inEscherichia coliBL21(DE3) cells and purified to homogeneity. The purified protein was crystallized using the hanging-drop vapour-diffusion method. The GAPDH crystals obtained in two different crystallization conditions diffracted to 2.8 and 2.6 Å resolution, belonging to two different space groupsP21andP212121, respectively. The structure was solved by molecular replacement and structure refinement is now in progress.
Vocational students’ perspective on organizational factors enhancing workplace learning
Authors: Metso Sari
Published: June 2014

Purpose

– The purpose of this paper is to identify organizational factors that enhance the vocational students’ development of professional skills during workplace learning and, furthermore, to examine the effects of the factors identified on the development.

Design/methodology/approach

– The results were based on 285 Finnish graduating vocational students’ responses. The confirmatory factor analysis and structural equations were conducted by using Lisrel.

Findings

– The students’ development of professional skills was enhanced by three organizational factors: an innovative climate, guidance, and interactions with seniors. Furthermore, the results emphasized that other employees have a central role in enhancing the students’ professional skills development.

Research limitations/implications

– The study used the students’ self-appraisal of the examined factors because it seems to be a common approach. However, future research should consider managers’ and seniors’ viewpoints.

Practical implications

– Managers should map present and future skills requirements set by the organization and create a detailed plan for the students’ workplace learning. A practical tool to engage and support employees to enhance the students’ professional skills is to make a process with explicit descriptions of each organizational factor and the actors’ responsibilities.

Originality/value

– The study provides empirical evidence supporting the substantial influence of organizations on the students’ development of professional skills.
A mechanisms-driven theory of business incubation
Authors: Junaid Ahmad Ali
Published: June 2014

Purpose

– Following recommendations by scholars for further research on the business incubation process, the purpose of this paper is to build new theory on incubation using the social mechanisms approach – a well-developed body of theory on social processes.

Design/methodology/approach

– A critical review of dominant theoretical approaches in the area highlighted that researchers in the past have not studied incubation as a social “process.” In order to study a social process such as incubation, a case is made for the value of social mechanisms theory. In order to study incubation as a social mechanism, an inductive-qualitative research design based on ethnography was used. Data were collected over six months each at two Dublin-Ireland-based business incubators.

Findings

– Results highlight the significant role of a positive relational bond between the incubator manager and client entrepreneurs. Incubation is triggered in a sophisticated normative environment under the prevalence of ground rules, subtle signals and the interplay of personal histories. These contribute to the incubation mechanism's non-linearity, thereby, making the prediction of outcomes difficult.

Originality/value

– A contribution of this research comes in the form of a new conceptualization of incubation based in mechanisms reasoning. The mechanisms approach was found to be versatile and helped in extending the work of previous researchers who proposed advancements in the area based on dyadic theory, social capital theory and social network theory. Further, a new, and it is argued, more fruitful direction for incubation process-related research is also highlighted; one which takes on board the often glossed over idiosyncrasies of incubation as a social mechanism for promoting early stage entrepreneurship.
The practical implications of the unification of the real estate registration system in Korea
Authors: Han Zonghie
Published: June 2014

Purpose

– This paper aims to show the practical conditions of the unification of real estate register system in Korea.

Design/methodology/approach

– Literature research.

Findings

– Although some information improvements and benefits in transaction can be expected through the elimination of discordances between dualized registry/registration books, the unification process should consider some legal and institutional factors which have been stabilized in the Korean society.

Research limitations/implications

– The socioeconomic effect of unification of real estate register system, such as cost-benefit consideration, is not included in this study. As for methodology, the conceptional framework is not based on an established theory, but on the simple thumb rule.

Practical implications

– The unification of registry and registration system of real estate in Korea could be implemented in a way of mild delegation of tasks, without a radical restructuring of the system. The practical guideline could be found in the system of family registry.

Originality/value

– The possibility of implementation of unification of the real estate register system is analyzed in aspects of social institutions and legal considerations.
ABCD open source software for managing ETD repositories
Authors: Namdev Dhamdhere Sangeeta , De Smet Egbert , Lihitkar Ramdas
Published: June 2014

Purpose

– The purpose of this paper is to give technical information about the application of ABCD open source software for managing institutional repository of electronic theses and dissertations (ETDs) at various levels with illustrations.

Design/methodology/approach

– Practical method and programming in the ABCD software for building ETD repository and its management

Findings

– ABCD software is an excellent tool for creating institutional repository (IR) and manages it at various levels and to create ETD portal.

Practical implications

– The paper describes using ABCD software how one can create database of ETDs, how to submit ETDs in full text or abstract, how to search, how to implement it in open archive environment and simplicity of making union catalogue of ETD repositories on one platform of ABCD portal.

Social implications

– The process of ETD management and IR building using ABCD open source software will be useful to all the new institutions, colleges, universities, national libraries, international organizations who want to initiate the process of building ETD repository.

Originality/value

– The development team of ABCD software is still in process of releasing 2.0 versions and to develop tool for IR and ETD management. In this paper attempt has been made to describe with illustrations that how the software is making progress towards ETD management or building IR. One of the author is main project leader of ABCD open source software.
A longitudinal assessment of early childhood education with integrated speech therapy for children with significant language impairment in Germany
Authors: Ullrich Dieter , Ullrich Katja , Marten Magret
Published: June 2014

Background

In Lower Saxony, Germany, pre‐school children with language‐ and speech‐deficits have the opportunity to access kindergartens with integrated language‐/speech therapy prior to attending primary school, both regular or with integrated speech therapy. It is unknown whether these early childhood education treatments are helpful and effective.

Aims

To determine the value of early language‐/speech therapy treatment in combination with support of personality traits during the pre‐school and primary school period on the long‐term social and academic development of children with significant language‐/speech delay.

Methods & Procedures

We conducted prospective longitudinal case series, following the academic progress of 71 children after they had been discharged from a speech therapy kindergarten (STK) up to 19 years previously. Data collection included details on language/speech impairment, socio‐economic factors, psycho‐social skills and intelligence quotient.

Results & Implications

At the end of the follow‐up period, 58 children were attending secondary schools: 44 (76%) children attended a regular secondary school, whereas 14 (24%) children were enrolled in a school with special needs education. The results suggest that self‐awareness and intelligence quotient in this study cohort correlated with later academic achievements.

Conclusion & Implications

Kindergartens and primary schools which support curriculum‐integrated language‐/speech therapy and allow for different personality traits appear to improve longterm development and academic outcome of children with language‐/speech impairment or delay.
RANZCR Body Systems Framework of diagnostic imaging examination descriptors
Authors: Pitman Alexander G. , Penlington Lisa , Doromal Darren , Slater Gregory , Vukolova Natalia
Published: June 2014

Introduction

A unified and logical system of descriptors for diagnostic imaging examinations and procedures is a desirable resource for radiology in Australia and New Zealand and is needed to support core activities of RANZCR. Existing descriptor systems available in Australia and New Zealand (including the Medicare DIST and the ACC Schedule) have significant limitations and are inappropriate for broader clinical application.

Methods

An anatomically based grid was constructed, with anatomical structures arranged in rows and diagnostic imaging modalities arranged in columns (including nuclear medicine and positron emission tomography). The grid was segregated into five body systems. The cells at the intersection of an anatomical structure row and an imaging modality column were populated with short, formulaic descriptors of the applicable diagnostic imaging examinations. Clinically illogical or physically impossible combinations were ‘greyed out’. Where the same examination applied to different anatomical structures, the descriptor was kept identical for the purposes of streamlining.

Results

The resulting Body Systems Framework of diagnostic imaging examination descriptors lists all the reasonably common diagnostic imaging examinations currently performed in Australia and New Zealand using a unified grid structure allowing navigation by both referrers and radiologists. The Framework has been placed on the RANZCR website and is available for access free of charge by registered users.

Conclusion

The Body Systems Framework of diagnostic imaging examination descriptors is a system of descriptors based on relationships between anatomical structures and imaging modalities. The Framework is now available as a resource and reference point for the radiology profession and to support core College activities.