bluuebunny/crossref_metadata_2025 huggingface dataset:
Beyond Surface Similarities: Telecommunications Industry Structure Evolution in Finland and New Zealand
Authors: Howell Bronwyn , Sangekar Manisha
Published: May 2009

Finland and New Zealand share many geographic, demographic and economic similarities. Their telecommunications markets also demonstrate many similarities; but behind these superficial similarities lie important structural differences that influence market performance. By tracing the evolutionary path of each market from the nineteenth century, this paper identifies how ownership and control structures in the very early stages of market development have influenced the shape of each market today. The paper concludes that an appreciation of the different economic histories and cultures in each country’s telecommunications market is helpful for understanding subsequent industry responses to changes in regulatory processes and government policies.
E‐commerce and SMEs—The Need for Caution
Authors: Hashim Noor
                      Azuan
Published: May 2009

Much has been written about e‐commerce. Many authors seem certain that e‐commerce conveys undisputed benefits. Yet, e‐commerce is not being adopted readily by SMEs. The disinclination of SMEs to adopt and use e‐commerce deserves serious attention, given the role that SMEs play in all economies. This paper looks critically at the issue. It highlights findings from a large‐scale survey of SMEs and interviews with SME managers across Malaysia. Results show online payment and online buying are not common. Websites are used for little more than providing contact details of the company and information about the company’s goods and services. While there may be good, logical reasons for SME managers having websites, many are clearly just boys with toys.
Reverse Salients at the Meta‐System Level: The Case of Containerization
Authors: Sawhney Harmeet , Wang Xiaofei
Published: May 2009

The power of Hughes’ concept of reverse salients is evident in its widespread adoption and use in areas as diverse as water distribution, metals production, and mobile music businesses. In all these studies the reverse salient concept has been mainly applied to internal problems in the development of a large‐scale system. We focus not only on reverse salients within a system but also at the meta‐system level, wherein different systems come together to create a system of systems. We draw on the experience with containerization, which is a particularly interesting case study because it developed in response to the reverse salients at the meta‐system level—the bottlenecks at the interfaces between motor carriers, railroads, and water carriers, the three systems that together form the overall surface transportation system. We examine the processes both within each system and also at the meta‐system level and expand our understanding of reverse salients as a system development phenomenon.
Clone Detection in Sensor Networks with Ad Hoc and Grid Topologies
Authors: Brooks R. R. , Govindaraju P. Y. , Pirretti M. , Vijaykrishnan N. , Kandemir M.
Published: May 2009

In cloning attacks, an adversary captures a sensor node, reprograms it, makes multiple copies, and inserts these copies, into the network. Cloned nodes subvert sensor network processing from within. In a companion paper [ 2 ], we show how to detect and remove clones from sensor networks using random key predistribution security measures. Keys that are present on the cloned nodes are detected by using authentication statistics based on key usage frequency. For consistency with existing random key predistribution literature, and ease of explanation, the network in that paper used an Erdos-Renyi topology. In the Erdos-Renyi topology, the probability of connection between any two nodes in the network is uniform. Since the communications ranges of sensor nodes are limited, this topology is flawed. This article applies the clone detection approach from [ 2 ] to more realistic network topologies. Grid and ad hoc topologies reflect the node connectivity patterns of networks of nodes with range limits. We provide analytical methods for choosing detection thresholds that accurately detect clones. We use simulations to verify our method. In particular we find the limitations of this approach, such as the number of nodes that can be inserted without being detected.
Coding categorical and coordinate spatial relations in visual–spatial short-term memory
Authors: Dent Kevin
Published: May 2009

Four experiments explored the coding of categorical and coordinate spatial relations in visual–spatial short-term memory (VSSTM). Participants judged whether two stimuli presented successively on a computer screen were the same or different. On positional change trials the two stimuli differed in the position of one element. Positional changes were of two types, coordinate and categorical. On coordinate trials the position of one element changed by a small amount, but retained the categorical relationships (above, below, left of, right of) to all other elements. On categorical trials one element moved by the same amount but additionally changed its categorical relationship to one of the other elements (e.g., changed from below to above). Participants detected categorical changes more accurately than coordinate changes when the elements were independent locations marked by squares, indicating that the categorical relationships amongst the squares were encoded in memory. Furthermore, this categorical advantage was unmodulated by either the suppression of articulation (Experiment 2) or by the requirement to retain either colour–position associations or positions only (Experiment 3). When the elements to be remembered were the vertices of simple outline polygons (Experiment 4) there was no categorical advantage, establishing the effect as spatial in nature. Contrary to predictions derived from Postma and De Haan (1996), the employment of categorical relations appears not to be specifically linked to either verbal coding or to the requirement to associate objects with positions. The results suggest that the categorical relations are an intrinsic property of the representation of spatial configurations.
Crucial challenges to global and oil-rentier economies
Authors: Al-Saadi Sabri Zire
Published: May 2009

This article highlights the limitation of the traditional macroeconomic policies related to oil-rent crucial issues and suggests remedies for the current global financial and economic crises in view of free market efficiency principles as advocated by contemporary economic doctrines: Keynesian and Monetarism. It also reasserts the long-term alternative strategy for the liberalization of the oilhostage rentier economies. The given analysis is based on the experience of the oilrentier countries, as well as the fiscal and monetary policies applied in the advanced economies; especially the United States, Britain and the European Union for dealing with the current global financial crisis and economic recession. The general aim of the analysis is to establish the bases for the required confidence in market efficiency and the benefits of the globalization thrust that are not consistent with the applied remedies. It suggests that for both advanced and oil-rentier economies, heavy investment in modernizing and the expansion of the physical, social, and environmental infrastructure projects are, at this stage, essential. However, for the oil-rentier economies, more emphasis should be given to the role of the state until the objectives of the required economic diversification strategy are achieved. As the credibility and trust of the banks and financial institutions, the policy-makers, fiscal and monetary authorities and regulators are very low, it is essential to retain the confidence of business communities and consumers in the financial and economic systems by undertaking unbiased assessment of the causes, impact, and remedies of the crises for different economies.
PUMA Promotes Bax Translocation by Both Directly Interacting with Bax and by Competitive Binding to Bcl-XL during UV-induced Apoptosis
Authors: Zhang Yingjie , Xing Da , Liu Lei
Published: May 2009

Cell apoptosis induced by UV irradiation is a highly complex process in which different molecular signaling pathways are involved. p53 up-regulated modulator of apoptosis (PUMA) has been proposed as an important regulator in UV irradiation-induced apoptosis. However, the molecular mechanism through which PUMA regulates apoptosis, especially how PUMA activates Bcl-2-associated X protein (Bax) in response to UV irradiation is still controversial. In this study, by using real-time single-cell analysis and fluorescence resonance energy transfer, we investigated the tripartite nexus among PUMA, Bax, and Bcl-XL in living human lung adenocarcinoma cells (ASTC-a-1) to illustrate how PUMA promotes Bax translocation to initiate apoptosis. Our results show that the interaction between PUMA and Bax increased gradually, with Bax translocating to mitochondria and colocalizing with PUMA after UV irradiation, indicating PUMA promotes Bax translocation directly. Simultaneously, the interaction increased markedly between PUMA and Bcl-XL and decreased significantly between Bcl-XL and Bax after UV treatment, suggesting PUMA competitively binds to Bcl-XL to activate Bax indirectly. The above-mentioned results were further confirmed by coimmunoprecipitation experiments. In addition, pifithrin-α (a p53 inhibitor) and cycloheximide (a protein synthesis inhibitor) could inhibit PUMA-mediated Bax translocation and cell apoptosis. Together, these studies create an important conclusion that PUMA promotes Bax translocation by both by directly interacting with Bax and by competitive binding to Bcl-XL in UV-induced apoptosis.
Robust synthetic biology design: stochastic game theory approach
Authors: Chen Bor-Sen , Chang Chia-Hung , Lee Hsiao-Ching
Published: May 2009

Motivation: Synthetic biology is to engineer artificial biological systems to investigate natural biological phenomena and for a variety of applications. However, the development of synthetic gene networks is still difficult and most newly created gene networks are non-functioning due to uncertain initial conditions and disturbances of extra-cellular environments on the host cell. At present, how to design a robust synthetic gene network to work properly under these uncertain factors is the most important topic of synthetic biology.

Results: A robust regulation design is proposed for a stochastic synthetic gene network to achieve the prescribed steady states under these uncertain factors from the minimax regulation perspective. This minimax regulation design problem can be transformed to an equivalent stochastic game problem. Since it is not easy to solve the robust regulation design problem of synthetic gene networks by non-linear stochastic game method directly, the Takagi–Sugeno (T–S) fuzzy model is proposed to approximate the non-linear synthetic gene network via the linear matrix inequality (LMI) technique through the Robust Control Toolbox in Matlab. Finally, an in silico example is given to illustrate the design procedure and to confirm the efficiency and efficacy of the proposed robust gene design method.

Availability:  http://www.ee.nthu.edu.tw/bschen/SyntheticBioDesign_supplement.pdf

Contact:  bschen@ee.nthu.edu.tw

Supplementary information:  Supplementary data are available at Bioinformatics online.
Complex discovery from weighted PPI networks
Authors: Liu Guimei , Wong Limsoon , Chua Hon Nian
Published: May 2009

Motivation: Protein complexes are important for understanding principles of cellular organization and function. High-throughput experimental techniques have produced a large amount of protein interactions, which makes it possible to predict protein complexes from protein–protein interaction (PPI) networks. However, protein interaction data produced by high-throughput experiments are often associated with high false positive and false negative rates, which makes it difficult to predict complexes accurately.

Results: We use an iterative scoring method to assign weight to protein pairs, and the weight of a protein pair indicates the reliability of the interaction between the two proteins. We develop an algorithm called CMC (clustering-based on maximal cliques) to discover complexes from the weighted PPI network. CMC first generates all the maximal cliques from the PPI networks, and then removes or merges highly overlapped clusters based on their interconnectivity. We studied the performance of CMC and the impact of our iterative scoring method on CMC. Our results show that: (i) the iterative scoring method can improve the performance of CMC considerably; (ii) the iterative scoring method can effectively reduce the impact of random noise on the performance of CMC; (iii) the iterative scoring method can also improve the performance of other protein complex prediction methods and reduce the impact of random noise on their performance; and (iv) CMC is an effective approach to protein complex prediction from protein interaction network.

Contact:  liugm@comp.nus.edu.sg

Supplementary information:  Supplementary data are available at Bioinformatics online.
Climate change and sexual size dimorphism in an Arctic spider
Authors: Høye Toke Thomas , Hammel Jörg U. , Fuchs Thomas , Toft Søren
Published: May 2009

Climate change is advancing the onset of the growing season and this is happening at a particularly fast rate in the High Arctic. However, in most species the relative fitness implications for males and females remain elusive. Here, we present data on 10 successive cohorts of the wolf spider
Pardosa glacialis
from Zackenberg in High-Arctic, northeast Greenland. We found marked inter-annual variation in adult body size (carapace width) and this variation was greater in females than in males. Earlier snowmelt during both years of its biennial maturation resulted in larger adult body sizes and a skew towards positive sexual size dimorphism (females bigger than males). These results illustrate the pervasive influence of climate on key life-history traits and indicate that male and female responses to climate should be investigated separately whenever possible.
TheNGATHADistal Organ Development Genes Are Essential for Style Specification inArabidopsis
Authors: Alvarez John Paul , Goldshmidt Alexander , Efroni Idan , Bowman John L. , Eshed Yuval
Published: May 2009

Floral organ identities are specified by a few transcription factors that act as master regulators. Subsequently, specification of organ axes programs the distribution of distinct tissue types within the organs that themselves develop unique identities. The C-class, AGAMOUS-clade MADS box genes are primary promoters of the gynoecium, which is divided into a distal style and a subtending ovary along the apical-basal axis. We show that members of a clade of B3 domain transcription factors, NGATHA1 (NGA1) to NGA4, are expressed distally in all lateral organs, and all four have a redundant and essential role in style development. Loss of all four genes results in gynoecia where style is replaced by valve-like projections and a reduction in style-specific SHATTERPROOF1 (SHP1) expression. In agreement, floral misexpression of NGA1 promotes ectopic style and SHP1 expression. STYLISH1, an auxin biosynthesis inducer, conditionally activated NGA genes, which in turn promoted distal expression of other STY genes in a putative positive feedback loop. Inhibited auxin transport or lack of YABBY1 gene activities resulted in a basally expanded style domain and broader expression of NGA genes. We speculate that early gynoecium factors delimit NGA gene response to an auxin-based signal, elicited by STY gene activity, to restrict the activation of style program to a late and distal carpel domain.
Size distribution and surface characteristics of silicon nanoparticles
Authors: Britton D. T. , Odo E. A. , Gonfa G. Goro , Jonah E. O. , Härting M.
Published: May 2009

The size distribution and morphology of silicon nanoparticles have been studied using small-angle X-ray scattering (SAXS) and transmission electron microscopy. Quantitative agreement was established between the results of the two methods. The surface characteristics, as well as the size distribution, were found to be independent of the choice of binder material used to prepare printed layers containing the nanoparticles. Intrinsic silicon nanoparticles, produced by laser pyrolysis of silane, have been shown to have a narrow, effectively monodisperse, size distribution and to be roughly spherical in shape. SAXS measurements indicate that the particles have a regular geometry and a smooth surface. There is, however, a thin disordered region at the surface of the particles. Particles produced by milling of bulk silicon have surface fractal characteristics and a high dispersivity resulting from the milling process, in which the particles become smoother as they are milled to smaller size or for longer periods. The size dispersion, but not the median size, is similarly reduced by milling for longer periods
HATODAS II – heavy-atom database system with potentiality scoring
Authors: Sugahara Michihiro , Asada Yukuhiko , Shimada Hiroki , Taka Hideyuki , Kunishima Naoki
Published: May 2009

HATODAS II is the second version of HATODAS (the Heavy-Atom Database System), which suggests potential heavy-atom reagents for the derivatization of protein crystals. The present expanded database contains 3103 heavy-atom binding sites, which is four times more than the previous version. HATODAS II has three new criteria to evaluate the feasibility of the search results: (1) potentiality scoring for the predicted heavy-atom reagents, (2) exclusion of the disordered amino acid residues based on the secondary structure prediction and (3) consideration of the solvent accessibility of amino acid residues from a homology model. In the point mutation option, HATODAS II suggests possible mutation sites into reactive amino acid residues such as Met, Cys and His, on the basis of multiple sequence alignments of homologous proteins. These new features allow the user to make a well informed decision as to the possible heavy-atom derivatization experiments of protein crystals.
The pseudo-single-crystal method: a third approach to crystal structure determination
Authors: Kimura Tsunehisa , Chang Chengkang , Kimura Fumiko , Maeyama Masataka
Published: May 2009

A novel method that enables single-crystal diffraction data to be obtained from a powder sample is presented. A suspension of LiCoPO4microrods was subjected to a frequency-modulated dynamic elliptical magnetic field to align the microrods; the alignment achieved was consolidated by photopolymerization of the suspending UV-curable monomer. The composite thus obtained (referred to as a pseudo single crystal) gave rise to X-ray diffraction data from which the crystal structure was solved using the standard method for single-crystal X-ray analyses. The structure determined was in good agreement with that reported using a conventional single crystal.
Determination of the degree of preferred orientation within the March–Dollase approach
Authors: Zolotoyabko Emil
Published: May 2009

An analytic expression has been derived connecting the degree of preferred orientation in a polycrystalline material to the March parameter. The latter defines the spread of angular distribution of crystallite inclinations in the March–Dollase approach [March (1932).Z. Kristallogr.81, 285–297; Dollase (1986).J. Appl. Cryst.19, 267–272]. In turn, the March parameter can be extracted from experimental data using either the Rietveld refinement of the entire diffraction pattern or the measurement of two diffraction intensities originating in the selected crystallographic planes. Working examples taken with two different types of samples are presented.
Preferred orientation of ettringite in concrete fractures
Authors: Wenk Hans-Rudolf , Monteiro Paulo J. M. , Kunz Martin , Chen Kai , Tamura Nobumichi , Lutterotti Luca , Del Arroz John
Published: May 2009

Sulfate attack and the accompanying crystallization of fibrous ettringite [Ca6Al2(OH)12(SO4)3·26H2O] cause cracking and loss of strength in concrete structures. Hard synchrotron X-ray microdiffraction is used to quantify the orientation distribution of ettringite crystals. Diffraction images are analyzed using the Rietveld method to obtain information on textures. The analysis reveals that thecaxes of the trigonal crystallites are preferentially oriented perpendicular to the fracture surfaces. By averaging single-crystal elastic properties over the orientation distribution, it is possible to estimate the elastic anisotropy of ettringite aggregates.
N-Acetyl-N-{2-[(Z)-2-chloro-3,3,3-trifluoroprop-1-enyl]phenyl}acetamide
Authors: Niu Jia-Jia , Li Zhi-Gang , Xu Jing-Wei
Published: May 2009

The title compound, C13H11ClF3NO2, adopts aZconformation. Halogen...oxygen interactions [Cl...O = 2.967 (3) Å] in the crystal packing lead to the formation of a dimer joined by two Cl...O bonds.
cis-Cyclohexane-1,4-dicarboxylic acid
Authors: Wang Yan-Qin , Weng Jia-Bao
Published: May 2009

In the title compound, C8H12O4, the two carboxyl groups are on the same side of the cyclohexane ring and the ring adopts a chair conformation. Adjacent molecules related by an inversion centre are linked by pairs of O—H...O hydrogen bonds, forming a zigzag chain along [1\overline{1}\overline{1}].
Methyl 2-(5-iodo-7-methyl-3-methylsulfinyl-1-benzofuran-2-yl)acetate
Authors: Choi Hong Dae , Seo Pil Ja , Son Byeng Wha , Lee Uk
Published: May 2009

There are two symmetry-independent molecules in the asymmetric unit of the title compound, C13H13IO4S. In each molecule, the O atom and the methyl group of the methylsulfinyl substituent lie on opposite sides of the plane of the benzofuran fragment. The crystal structure is stabilized by aromatic π–π interactions between the benzene and furan ring [centroid–centroid distance = 3.866 (7) Å], and by intermolecular C—H...π interactions and a sulfinyl–sulfinyl interaction [S...O = 3.025 (4) Å]. The crystal structure also exhibits weak intermolecular C—H...O hydrogen bonds and two different I...O halogen bonds.
2,2′-{1,1′-[Pentane-1,5-diylbis(oxynitrilo)]diethylidyne}di-1-naphthol
Authors: Sun Yin-Xia , Wu Jian-Chao , Dong Wen-Kui , Gong Shang-sheng , Tong Jun-Feng
Published: May 2009

The title compound, C29H30N2O4, adopts a distortedZconfiguration with respect to the oxime group, which is almost coplanar with the adjacent naphthalene ring [dihedral angle = 4.11 (2)°]. There is one half-molecule in the asymmetric unit, with a crystallographic twofold rotation axis passing through the central C atom of the –CH=N—O-(CH)5—O—N=CH– bridge. Within the molecule, the dihedral angle formed by the two naphthalene rings is 79.08 (3)°, and there are two intramolecular O—H...N hydrogen bonds.
1,3-Dihydroxy-2-(hydroxymethyl)propan-2-aminium 2,2-dichloroacetate
Authors: Yu Yan-Hong , Qian Kun
Published: May 2009

The title compound, C4H12NO3+·C2HCl2O2−, was obtained from dichloroacetic acid and 2-amino-2-(hydroxymethyl)propane-1,3-diol. In the crystal structure, the cations and anions are connected by intermolecular N—H...O and O—H...O hydrogen bonding, forming a two-dimensional array parallel to (001). The crystal used for analysis was a merohedral twin, as indicated by the Flack parameter of 0.67 (6).
Pr5Si3N9
Authors: Lupart Saskia , Schnick Wolfgang
Published: May 2009

Single crystals of Pr5Si3N9, pentapraseodymium trisilicon nonanitride, were obtained by the reaction of elemental praseodymium with silicon diimide in a radio-frequency furnace at 1873 K. The crystal structure consists of a chain-like Si—N substructure of corner-sharing SiN4tetrahedra. An additionalQ1-type [SiN4] unit is attached to every second tetrahedron directed alternately in opposite directions. The resulting branched chains interlock with each other, building up a three-dimensional structure. The central atoms of theQ1-type [SiN4] unit and of its attached tetrahedron are situated on a mirror plane, as are two of the four crystallographically unique Pr3+ions. The latter are coordinated by six to ten N atoms, with Pr—N distances similar to those of other rare earth nitridosilicates.
catena-Poly[[tetraaquanickel(II)]-μ3-benzene-1,3,5-tricarboxylato-3′:1:2-κ4O1:O3,O3′:O5-[tetraaquanickel(II)]-μ2-benzene-1,3,5-tricarboxylato-2:3κ2O1:O3-[tetraaquanickel(II)]]
Authors: Hsu Shih-Chen , Chiang Pei-Hsuan , Chang Chih-Hsien , Lin Chia-Her
Published: May 2009

The microwave solvothermal reaction of nickel nitrate with trimesic acid provided the title compound, [Ni3(BTC)2(H2O)12]n(BTC = benzene-1,3,5-tricarboxylate anion, C9H3O6), which is a metal coordination polymer composed of one-dimensional zigzag chains. The crystal under investigation was ramecically twinned with an approximate twin domain ratio of 1:1. In the asymmetric unit, there are two types of Ni atoms. One of the NiO6groups (2 symmetry) is coordinated to only one carboxylate group and thus terminal, the other is bridging, forming the coordination polymer. The extended chains are connected by the organic BTC anionsvia μ2-linkages. O—H...O hydrogen bonds and π–π interactions between the chains [centroid–centroid distance 3.58 (1) Å] induce the complex to mimic a three-dimensional structure.
N,N′-Bis[(E)-(6-methyl-2-pyridyl)methylene]hexane-1,6-diamine
Authors: Ramos Silva Manuela , Silva Joana A. , Matos Beja Ana , Sobral Abilio J. F.N.
Published: May 2009

The title compound, C20H26N4, is composed of two (6-methyl-2-pyridyl)methylene units linked by a 1,6-diamine hexane chain. The molecule hasCisymmetry with the inversion center situated at the mid-point of the central C—C bond. The alkyl chain has an all-transconformation, with all the non-H atoms sharing the same plane [maximum deviation 0.004 (3) Å]. The pyridylmethylene groups are also planar [maximum deviation 0.009 (3) Å], making an angle of 53.78 (19)° with the hexane chain plane. In the crystal, the molecules assemble in layers, stacking along theaaxis. The stacks are hold together by attractive interactions between π electron systems.
Methyl 3-[3-(ethoxycarbonyl)thioureido]-1H-pyrazole-5-carboxylate
Authors: Huang Buwen , Kung Pei-Pei , Rheingold Arnold L. , DiPasquale Antonio , Yanovsky Alex
Published: May 2009

The title compound, C9H12N4O4S, was proven to be the product of the reaction of methyl 5-amino-1H-pyrazole-3-carboxylate with ethyl isothiocyanatocarbonate. All non-H atoms of the molecule are planar, the mean deviation from the least squares plane being 0.048 Å. The intramolecular N—H...O bond involving the NH-group, which links the thiourea and pyrazole fragments, closes a six-membered pseudo-heterocyclic ring, and two more hydrogen bonds (N—H...O with the participation of the pyrazole NH group and N—H...S involving the second thiourea NH group) link the molecules into infinite chains running along [1\overline{2}0].
(E)-3-[4-(Pentyloxy)phenyl]-1-phenylprop-2-en-1-one
Authors: Abbas Asghar , Khawar Rauf M. , Bolte Michael , Hasan Aurangzeb
Published: May 2009

The title compound, C20H22O2, crystallizes with two independent molecules in the asymmetric unit. In each molecule, all the non-H atoms lie in a common plane (r.m.s. deviations of 0.098 and 0.079 Å). There is a π–π stacking interaction in the crystal structure. The central aromatic rings of the two molecules, which are stacked head-to-tail one above the other, are separated by centroid-to-centroid distances of 3.872 (13) and 3.999 (10) Å.
1,2-Dibenzoylhydrazine–dimethylformamide (3/1)
Authors: He Qing-Peng , Li Hong-Gang , Wang Guang-Bo , Fu Feng-Lian , Liu Ming-Shi
Published: May 2009

The title compound, 3C14H12N2O2·C3H7NO, was synthesized by reaction of benzoyl chloride with hydrazine hydrate under microwave irradition. The asymmetric unit comprises three 1,2-dibenzoylhydrazine molecules and one dimethylformamide molecule. The 1,2-dibenzoylhydrazine molecules are linked by pairs of N—H...O hydrogen bonds into chains propagating along [010].
1-Benzyl-5-methyl-1H-1,2,3-triazole-4-carboxylic acid monohydrate
Authors: Zhao Hong
Published: May 2009

In the title compound, C11H11N3O2·H2O, the planes of the triazole and phenyl rings are almost perpendicular to each other [dihedral angle 89.5 (3)°]. The crystal packing is stabilized by strong intermolecular O—H...O and O—H...N hydrogen bonds involving the water molecule as both donor and acceptor.
trans-Bis(5-carboxy-2-methyl-1H-imidazole-4-carboxylato-κ2N3,O4)copper(II)
Authors: Guo Xin , Li Yi Liang , Wang Ju Xian , Wang Yu Cheng
Published: May 2009

In the title compound, [Cu(C6H5N2O4)2], the copper(II) atom lies on an inversion centre and is in an N2O2four-coordinate environment with a nearly regular square-planar geometry. An extended network of intramolecular O—H...O and intermolecular N—H...O and C—H...O hydrogen bonds stabilizes the crystal structure.
Tris{2-methoxy-6-[(4-methylphenyl)iminiomethyl]phenolato-κ2O,O′}tris(thiocyanato-κN)cerium(III)
Authors: Liu Jian-Feng , Xian Hui-Duo , Zhao Guo-Liang
Published: May 2009

The asymmetric unit of the title compound, [Ce(NCS)3(C15H15NO2)3], contains three Schiff base 2-methoxy-6-[(4-methylphenyl)iminomethyl]phenol (HL) ligands and three independent thiocyanate ions that coordinate the cerium ionviatheir N atoms. The protonated imine N atoms are involved in an intramolecular hydrogen bond with the respective phenoxide group. The Ce(III) ion exhibits a coordination number of nine.
trans-Diaquabis[(E)-3-(dimethylamino)-1-(2-pyridyl)prop-2-en-1-one-κ2N1,O]cobalt(II) dinitrate dihydrate
Authors: Bi Jian-Hong
Published: May 2009

In the title compound, [Co(C10H12N2O)2(H2O)2](NO3)2·2H2O, the CoIIion, located on an inversion center, istrans-coordinated by twoN,O-bidentate chelating (E)-3-(dimethylamino)-1-(2-pyridyl)prop-2-en-1-one ligands and by two water molecules in a slightly distorted octahedral geometry. Intermolecular O—H...O hydrogen bonds link the cations, anions and water molecules into layers parallel to theacplane. The crystal packing also exhibits weak intermolecular C—H...O hydrogen bonds.
4,6-Dimethyl-2-thioxo-1,2-dihydropyrimidin-3-ium chloride–thiourea (1/1)
Authors: Gaye Papa Aly , Barry Aliou Hamady , Gaye Mohamed , Sarr Aminata Diasse , Sall Abdou Salam
Published: May 2009

In the title compound, C6H9N2S+·Cl−·CH4N2S, the 4,6-dimethyl-2-thioxo-1,2-dihydropyrimidin-3-ium cation is protonated at one of the pyrimidine N atoms. The cations are bridged by the chloride anions through a pair of N—H...Cl hydrogen bonds. The amino groups of each thiourea adduct interact with the chloride anions through a pair of N—H...Cl hydrogen bonds and the S atom of another thiourea adduct through a pair of N—H...S hydrogen bonds. These interactions result in a layered hydrogen-bonded network propagating parallel to thebcplane. Except for two H atoms, all atoms are on special positions.
4,4′-Di-3-pyridyl-2,2′-dithiodipyrimidine
Authors: Ji Jun-Feng , Li Lei , Zhu Hai-Bin
Published: May 2009

The asymmetric unit of the title compound, C18H12N6S2, contains one half-molecule situated on a twofold rotational axis that passes through the mid-point of the S—S bond. In the molecule, the C—S—S—C torsion angle is 81.33 (7)°. The crystal packing exhibits no significantly short intermolecular contacts.
3-(2-Pyridylaminocarbonyl)propanoic acid
Authors: Wang Cheng-Feng
Published: May 2009

In the crystal structure of the title compound, C9H10N2O3, the molecules are linked by intermolecular O—H...N and N—H...O hydrogen bonds, resulting in chains propagating in [010]. Weak intramolecular and intermolecular C—H...O interactions are also observed.
Poly[[μ4-tartrato-cadmium(II)] 0.167-hydrate]
Authors: Zhao Li-Zhen , Li Ping , Cao Bao-Liang , Ng Seik Weng
Published: May 2009

The title compound, {[Cd(C4H4O6)]·0.167H2O}n, adopts a three-dimensional network structure in which each CdIIion is chelated by two pairs of carboxylate and hydroxyl O atoms from two tartrate anions, and is additionally linked to two O atoms of two carboxylate groups that are not involved in chelation. The asymmetric unit has four independent cadmium atoms, two of which lie on special positions of 2 site symmetry. The tartrate anions all lie on general positions. All hydroxyl groups are engaged in O—H...O hydrogen-bonds, one of which is also bifurcated. The non-coordinating water molecule is situated on a site with half-occupation.
S-5-Amino-2-(dimethylammonio)phenyl sulfothioate
Authors: Pavlović Gordana , Racané Livio , Tralić-Kulenović Vesna
Published: May 2009

The title compound, C8H12N2O3S2, has been isolated as a by-product in the synthesis of methylene blue dye. The compound crystallizes with four independent molecules in the unit cell (Z′= 4). The zwitterionic form of the molecule was established on the basis of the hydrogen atom located at the dimethylamino group. The crystal structure is dominated by intermolecular hydrogen bonds of the N—H...O type formed between amino and ammonio N—H groups and O atoms from the sulfothioate group. There are in addition two weak intermolecular N—H...N interactions and some non-conventional C—H...O hydrogen bonds.
Poly[(μ2-azido-κ2N1:N1)[μ2-5-(8-quinolyloxymethyl)tetrazolato-κ4N1,O,N5:N4]zinc(II)]
Authors: Cai Hong-ling
Published: May 2009

In the title compound, [Zn(C11H8N5O)(N3)]n, the Zn atom is hexacoordinated by five N atoms and one O atom in a distorted octahedral geometry. The chelating 5-(8-quinolyloxymethyl)tetrazolate ligands are approximately planar, with a dihedral angle of 3.6 (2)° between the quinoline and tetrazole planes. Adjacent Zn atoms are linked by two bridging azide ligands across a centre of inversion, and further coordination by one N atom of an adjacent tetrazole unit forms two-dimensional frameworks in (100). C—H...N interactions exist between ligands in neighbouring layers.
1-(4-tert-Butylbenzyl)-3-phenyl-1H-pyrazole-5-carboxylic acid
Authors: Tang Zheng , Ding Xiao-Ling , Xie Yong-Sheng , Zhao Bao-Xiang
Published: May 2009

In the title compound, C21H22N2O2, the mean plane of the pyrazole ring makes dihedral angles of 18.80 (12) and 77.13 (5)°, respectively, with the mean planes of the phenyl andtert-butylbenzyl rings. The carboxylate group is inclined at 8.51 (14)° with respect to the pyrazole ring. The crystal structure displays intermolecular O—H...O hydrogen bonding, generating centrosymmetric dimers.
Low-temperature redetermination of benzofurazan 1-oxide
Authors: Ng Seik Weng
Published: May 2009

In the six-membered ring of the low-temperature crystal structure of benzofurazan 1-oxide, C6H4N2O2, the two C atoms adjacent to the N atoms are linked by a delocalized aromatic bond [1.402 (2) Å]; each is connected to its neighbour by a longer, more localized, bond [1.420 (2), 1.430 (2) Å]. However, the next two bonds in the ring approximate double bonds [1.357 (2), 1.366 (2) Å]. As such, the six-membered ring is better described as a cyclohexadiene system, in contrast to the description in the room-temperature structure reported by Britton & Olson (1979) [Acta Cryst.B35, 3076–3078].
trans-Diaquabis(6-methoxycarbonylpyridazine-3-carboxylato-κ2N,O)zinc(II) dihydrate
Authors: Starosta Wojciech , Leciejewicz Janusz
Published: May 2009

In the title centrosymmetric complex, [Zn(C7H5N2O4)2(H2O)2]·2H2O, the ZnIIion is coordinated in atransmode by two symmetry-related bis-chelating 6-methoxycarbonylpyridazine-3-carboxylate ligandsviaN and O atoms, and by two aqua ligand O atoms in axial positions, in a slightly distorted octahedral environment. In the crystal structure, complex molecules are linked by intermolecular O—H...O hydrogen bonds between coordinated and solvent water molecules and carboxylate O atoms, forming molecular ribbons propagating along theaaxis.
Tetra-μ-acetato-κ8O:O′-bis[(N2,N2-dimethylpyrazin-2-amine-κN4)copper(II)]
Authors: Meng Lin , Yang Lin Yan , Shi Jing Min
Published: May 2009

The title binuclear complex, [Cu2(C2H3O2)4(C6H9N3)2], lies on an inversion center with four acetate ligands bridging two CuIIions and two monodentateN,N-dimethylpyrazine-2-amine ligands coordinating each CuIIionviaN atoms, forming slightly distorted square-pyramidal environments.
Methyl 3β-methoxycarbonyloxy-4,4-dimethyl-17-oxo-16α-(3-oxobutyl)-16β-carboxylate
Authors: Yan Xin , Xu Shiqing , Wang Jingmei , Chen Ying , Xia Peng
Published: May 2009

The title steroid, C29H44O7, is a new androgen derivative and a key intermediate for synthesizing novel anti-HIV steroid agents. There are fourtrans-fused rings in the structure. The three six-membered rings exhibit chair conformations, while the five-membered ring adopts an envelope conformation.
Poly[[tetraaquabis(μ-hydroxyacetato-κ4O1,O2:O1,O1′)-μ2-sulfato-κ2O:O′-dicadmium(II)] monohydrate]
Authors: Rychlewska Urszula , Warzajtis Beata , Dimitrijević Mirjana Dj. , Draskovic Nenad S. , Djuran Miloš I.
Published: May 2009

The title compound, {[Cd2(C2H3O3)2(SO4)(H2O)4]·H2O}n, was obtained unintentionally in a transmetallation reaction. The crystal structure contains a two-dimensional metal–organic framework based on CdII–(μ-hydroxyacetato-κ4O1,O2:O1,O1′)–CdIIzigzag chains joined together by bridging SO4anions. The resulting layers are shifted with respect to each other and are stacked along thecaxis. Their construction is supported by hydrogen bonds between water molecules and between water molecules and carboxylate or sulfate groups. Neighbouring layers are bridged by hydrogen bonds between the hydroxyl substituent and a sulfate anion. The sulfate anion and solvent water molecule are located on twofold axes. The results demonstrate that care must be taken when preparing ethylenediaminetetraacetic acid-type complexes by transmetallation, in order to avoid precipitation of metal complexes with the α-hydroxyacetate ligand.
4-Fluoro-2-[(E)-2-pyridyliminomethyl]phenol
Authors: Cui Ping , Shi Lei
Published: May 2009

In the title compound, C12H9FN2O, the dihedral angle between the benzene ring and the pyridine ring is 4.35 (16)°. The molecular conformation is stabilized by an intramolecular O—H...N hydrogen bond.
Redetermination ofL-tryptophan hydrobromide
Authors: Stewart Kirsty
Published: May 2009

The redetermined crystal structure of the title compound, C11H13N2O2+·Br−, is reported. Data collection at 100 K about three crystallographic axes resulted in a crystal structure with significantly higher precision in comparison to the two-dimensional data collected at 176 K [Takigawaet al.[(1966)Bull. Chem. Soc. Jpn,39, 2369–2378]. The carboxyl group and indole ring system are planar, with maximum deviations of 0.002 (2) and 0.007 (2) Å, respectively, and make an angle of 70.17 (1)° with each other. The molecules are arranged in double layers of carboxyl and amino groups parallel to theabplane, stabilized by an extensive network of N—H...Br and O—H...Br hydrogen bonds. The polar layer is held together by a network of three N—H...Br hydrogen bonds and one O—H...Br hydrogen bond. In the non-polar layer, the indole rings are linked mainly by electrostatic N—H...C interactions between the polarized bond N—H (H is δ+) of the pyrrole unit and two of the ring C atoms (δ−) of the benzene rings of adjacent molecules. The distances of these electrostatic interactions are 2.57 and 2.68 Å, respectively. C—H...O and C—H...π interactions are also present.
7,7′,8,8′-Tetramethoxy-4,4′-dimethyl-3,3′-bicoumarin
Authors: Fun Hoong-Kun , Jebas Samuel Robinson , Parveen Mehtab , Khanam Zakia , Ghalib Raza Murad
Published: May 2009

In the crystal structure, the title compound, C24H22O8, lies on a twofold rotation axis and the asymmetric unit comprises one half-molecule. The dihedral angle formed by the coumarin unit with the symmetry-related part is 74.78 (14)°. One of the methoxy groups attached to the coumarin unit is considerably twisted, making an angle of 87.17 (17)° with respect to the coumarin unit; the other is twisted by 0.66 (19)°. No classical hydrogen bonds are found in the sturcture; only a weak C—H...π interaction and short intramolecular O...O contacts [2.683 (2)–2.701 (2) Å] are observed.
Methyltrans-(±)-1-oxo-2-phenethyl-3-(thiophen-2-yl)-1,2,3,4-tetrahydroisoquinoline-4-carboxylate
Authors: Akkurt Mehmet , Karaca Selvi , Bogdanov Milen G. , Kandinska Meglena I. , Büyükgüngör Orhan
Published: May 2009

In the title compound, C23H21NO3S, the piperidine ring of the tetrahydroisoquinolinone unit adopts a screw-boat conformation. The thiophene ring is disordered in a 0.700 (3):0.300 (3) ratio by an approximate 180° rotation of the ring around the C—C bond linking the ring to the tetrahydroisoquinolinone unit. The benzene ring of the tetrahydroisoquinolinone unit makes dihedral angles of 83.1 (2) and 62.38 (11)° with the major occupancy thiophene ring and the phenyl ring, respectively. The dihedral angle between the phenyl ring and the thiophene ring is 71.0 (2)°. In the crystal structure, molecules are linked together by intermolecular C—H...O and C—H...π interactions.
N′-{2-[2-(3-Methoxyphenyl)ethenyl]phenyl}acetamide
Authors: Ahmad Kartini , Thomas Noel F. , Nafiah Mohd Azlan , Awang Khalijah , Ng Seik Weng
Published: May 2009

In the title compound, C17H17NO2, the phenylene rings are bent with respect to the carbon–carbon double bond [dihedral angle between rings = 39.6 (1)°]. The acetamido group is twisted out of the plane of the aromatic ring [dihedral angle = 44.2 (1)°] in order to form an N–H...O hydrogen bond to the acetamido group of an adjacent molecule, generating a zigzag chain running along thecaxis.
2-{4-[(2,2-Dimethyl-4,6-dioxo-1,3-dioxan-5-ylidene)methylamino]phenyl}acetonitrile
Authors: Li Rui , Ding Zhen-Yu , Wei Yu-Quan , Ding Jian
Published: May 2009

The title compound, C15H14N2O4, is approximately planar, with a dihedral angle of 6.48 (4)° between the aminomethylene unit and the planar five-atom part of the dioxane ring, and a dihedral angle of 2.40 (4)° between aminomethylene unit and the phenylene ring. The dioxane ring is envelope shaped, with the dimethyl-substituted C atom that represents the flap 0.535 (8) Å out of the plane. The molecule has an intramolecular N—H...O hydrogen bond.
(E)-3-[4-(Hexyloxy)phenyl]-1-(2-hydroxyphenyl)prop-2-en-1-one
Authors: Ngaini Zainab , Fadzillah Siti Muhaini Haris , Hussain Hasnain , Razak Ibrahim Abdul , Fun Hoong-Kun
Published: May 2009

In the title compound, C21H24O3, the conformation of the enone group iss–cis. The benzene rings are inclined at an angle of 7.9 (1)°. The alkoxy tail is planar, with a maximum deviation from the least-squares plane of 0.009 (2) Å, and adopts atransconformation throughout. An intramolecular O—H...O interaction between the keto and hydroxy groups formsS(6) ring motifs. In the crystal, molecules are arranged in a head-to-tail manner down theaaxis and are subsequently stacked along thebaxis, forming molecular sheets parallel to theabplane. The crystal structure is further stabilized by weak C—H...π interactions and short C...O [3.376 (2) Å] contacts.
Diaquabis[4-(dimethylamino)benzoato](isonicotinamide)zinc(II)
Authors: Hökelek Tuncer , Dal Hakan , Tercan Barış , Aybirdi Özgür , Necefoğlu Hacali
Published: May 2009

The molecule of the title ZnIIcomplex, [Zn(C9H10NO2)2(C6H6N2O)(H2O)2], contains two 4-(dimethylamino)benzoate (DMAB) ligands, one isonicotinamide (INA) ligand and two water molecules; one of the DMAB ions acts as a bidentate ligand while the other and INA are monodentate ligands. The four O atoms in the equatorial plane around the Zn atom form a distorted square-planar arrangement, while the distorted octahedral coordination is completed by the N atom of the INA ligand and the O atom of the water molecule in the axial positions. Intramolecular C—H...O hydrogen bonding results in the formation of a six-membered ring adopting an envelope conformation. The dihedral angle between the carboxyl groups and the adjacent benzene rings are 4.87 (16) and 2.2 (2)°, while the two benzene rings are oriented at a dihedral angle of 65.13 (8)°. The dihedral angle between the benzene and pyridine rings are 11.47 (7) and 74.83 (8)°, respectively. In the crystal structure, intermolecular O—H...O, O—H...N and N—H...O hydrogen bonds link the molecules into a supramolecular structure. π–π contacts between the pyridine and benzene rings and between the benzene rings [centroid–centroid distances = 3.695 (1) and 3.841 (1) Å, respectively] further stabilize the structure. Weak intermolecular C—H...π interactions are also present.
Expression and regulation of the NALP3 inflammasome complex in periodontal diseases
Authors: Bostanci N , Emingil G , Saygan B , Turkoglu O , Atilla G , Curtis M A , Belibasakis G N
Published: May 2009

Periodontitis is an infectious process characterized by inflammation affecting the supporting structures of the teeth. Porphyromonas gingivalis is a major oral bacterial species implicated in the pathogenesis of periodontitis. Processing of interleukin (IL)-1 family cytokines is regulated by an intracellular innate immune response system, known as the NALP3 [nacht domain-, leucine-rich repeat-, and pyrin domain (PYD)-containing protein 3] inflammasome complex. The aim of the present study was to investigate by quantitative real-time polymerase chain reaction (PCR) the mRNA expression of NALP3, its effector molecule apoptosis associated speck-like protein (ASC), its putative antagonist NLRP2 (NLR family, PYD-containing protein 2), IL-1β and IL-18 (i) in gingival tissues from patients with gingivitis (n = 10), chronic periodontitis (n = 18), generalized aggressive periodontitis (n = 20), as well as in healthy subjects (n = 20), (ii) in vitro in a human monocytic cell line (Mono-Mac-6), in response to P. gingivalis challenge for 6 h. The clinical data indicate that NALP3 and NLRP2, but not ASC, are expressed at significantly higher levels in the three forms of inflammatory periodontal disease compared to health. Furthermore, a positive correlation was revealed between NALP3 and IL-1β or IL-18 expression levels in these tissues. The in vitro data demonstrate that P. gingivalis deregulates the NALP3 inflammasome complex in Mono-Mac-6 cells by enhancing NALP3 and down-regulating NLRP2 and ASC expression. In conclusion, this study reveals a role for the NALP3 inflammasome complex in inflammatory periodontal disease, and provides a mechanistic insight to the host immune responses involved in the pathogenesis of the disease by demonstrating the modulation of this cytokine-signalling pathway by bacterial challenge.
The treatment of CIN: what are the risks?
Authors: Prendiville W.
Published: May 2009

The treatment of squamous cervical intraepithelial neoplasia is to remove or destroy the transformation zone (TZ). It is likely that no method of treatment is superior to another if it is performed properly and the limited available evidence supports this view. The significant advantages of excision (simplicity, cost, outpatient procedure, histological examination of the entire TZ) mean that treatment thresholds may have lowered over the last decade. Long‐term pregnancy‐related morbidity associated with excision has been reported recently. The evidence would suggest that this increase equates to a genuine increase in serious adverse outcome for cone biopsy but not large loop excision of the transformation zone (LLETZ). The available data also point to an increase in both incomplete excision and premature labour associated with the excision of large endocervical TZs. The clinical implications arising from this are firstly that women with large type 2 and 3 TZs need appropriate counselling before treatment and that the threshold for treating young women with mild abnormalities needs review.
Pan‐glacial—a third state in the climate system
Authors: Hoffman Paul F.
Published: May 2009

Radiative energy‐balance models reveal that Earth could exist in any one of three discrete climate states—‘non‐glacial’ (no continental ice‐sheets), ‘glacial‐interglacial’ (high‐latitude ice‐sheets) or ‘pan‐glacial’ (ice‐sheets at all latitudes)—yet only the first two were represented in Phanerozoic time. There is mounting evidence that pan‐glacial states existed at least twice in the Cryogenian (roughly 750–635 Ma), the penultimate period of the Neoproterozoic. Consensus is lacking on whether the world ocean was fully glaciated (‘snowball’ model) or largely unglaciated (‘slushball’ model). The first appearances of multicellular animal fossils (diapause eggs and embryos in China, and sponge‐specific biomarkers in Oman), being closely associated with the last pan‐glacial state, revive speculation that environmental forces had a hand in the origin of metazoa.