bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient soft demodulation scheme for Digital Video Broadcasting via Satellite – Second Generation system
Authors: Zhang Meixiang , Kim Sooyoung
Published: November 2013

In this study, the authors propose a compact soft demodulation method for M‐ary modulation schemes defined in the Digital Video Broadcasting via Satellite – Second Generation (DVB‐S2) system. They first derive a conventional soft demodulation method for quadrature phase shift keying and 8‐ary phase shift keying with a linear order of complexity, and apply this to the modulation schemes defined in DVB‐S2. In particular, they propose a new constellation for 32‐ary amplitude and phase shift keying (32‐APSK), which provides better performance, regardless of the soft demodulation scheme. In addition, the proposed constellation enables us to apply a very simple and efficient soft demodulation method. The proposed soft demodulation method estimates the soft information by simple distance calculation, and greatly reduces the computational complexity, compared with maximum‐log‐likelihood detection. They demonstrate the bit error rate (BER) performance of various soft demodulation methods, combined with the low density parity check codes specified in DVB‐S2. The BER simulation results reveal that the proposed constellation for 32‐APSK can achieve better performance than the conventional one, regardless of the soft demodulation method. In addition, the proposed soft demodulation method can highly reduce the computational complexity, with reasonable performance degradation.
Robust local stereo matching under varying radiometric conditions
Authors: Qu Yufu , Jiang Jixiang , Deng Xiangjin , Zheng Yanhong
Published: November 2013

The authors present a local stereo matching algorithm whose performance is insensitive to changes in radiometric conditions between the input images. First, a prior on the disparities is built by combining the DAISY descriptor and Census filtering. Then, a Census‐based cost aggregation with a self‐adaptive window is performed. Finally, the maximum a‐posteriori estimation is carried out to compute the disparity. The authors’ algorithm is compared with both local and global stereo matching algorithms (NLCA, ELAS, ANCC, AdaptWeight and CSBP) by using Middlebury datasets. The results show that the proposed algorithm achieves high‐accuracy dense disparity estimations and is more robust to radiometric differences between input images than other algorithms.
Application of synchronised phasor measurements to wide‐area fault diagnosis and location
Authors: Salehi‐Dobakhshari Ahmad , Ranjbar Ali Mohammad
Published: November 2013

This study introduces a novel approach to power system fault diagnosis by synchronised phasor measurements. Conventionally, faults are diagnosed through the status of protective relays and circuit breakers which are activated following a fault. However, the hidden failures of the protection system has itself often been among the main suspects of partial or widespread blackouts. This study proposes an alternative fault diagnosis approach independent of the function of the protection system. An analytical method is introduced for power system fault diagnosis using dispersed synchronised measurements and bus impedance matrix (Zbus). Fault inception is first detected by local phasor measurement units (PMUs). Fault diagnosis is then carried out in a hierarchical manner so that first the faulted zone of the system is diagnosed, next the faulted line in the faulted zone is diagnosed and finally the fault point along the diagnosed line is located by gradient descent. The proposed method is applied to the WSCC 9‐bus, where fault incidents on all of the transmission lines are examined. Moreover, the proposed method is successfully applied to the IEEE 118‐bus test system consisting of 28 PMUs, which demonstrates successful fault diagnosis and location for a large‐scale power system despite the limited coverage of PMUs.
Effects of driving behaviour on vehicle cluster formation and its application
Authors: Lan Kun‐chan , Chou Chien‐Ming , Li Cheng‐Yuan
Published: November 2013

Node mobility in a vehicular network is strongly affected by driving behaviour, such as the choice of route. Although various route choice models have been studied in the transportation community, the effects of preferred routes on vehicular networks have not been discussed much in the networking literature. In this work, we set out to understand the effects of different parameters, such as route choice, traffic lights and the locations of road‐side units, on the formation of vehicle clusters. We also show how the dynamics of vehicle clusters change over time using real‐world vehicle trace data. Furthermore, inspired by the observation that the existence of vehicle clusters provides an opportunity to share Internet bandwidth among neighbouring cars, we propose an architecture that allows a car to utilise the unused Internet links of neighbouring nodes by stripping the data across multiple paths through its neighbours. We design a protocol, called enhancements for transmission control protocol (TCP) on a multi‐homed environment (ETOM), to improve the performance of TCP in such an architecture without the need to modify the end points. We evaluate the performance of ETOM by comparing it with the concurrent multi‐path transfer stream control transmission protocol (SCTP), and show that it can achieve similar or better performance.
Inverted‐E shaped monopole on high‐permittivity substrate for application in industrial, scientific, medical, high‐performance radio local area network, unlicensed National information infrastructure, and worldwide interoperability for microwave access
Authors: Chen Yih‐Chien , Hsu Chih‐Hao
Published: November 2013

In this study, the simulation and measured results of coplanar waveguide (CPW)‐fed inverted‐E shaped monopole for application in industrial, scientific, medical (ISM), high‐performance radio local area network (HIPERLAN), unlicensed National information infrastructure (UNII), and worldwide interoperability for microwave access (WiMAX) bands are presented. The CPW‐fed inverted‐E shaped monopole is fabricated on a high‐permittivity substrate. The lower band is associated with the longer strips of the inverted‐E shaped monopole whereas the higher band is associated with the middle and shorter strips of the inverted‐E shaped monopole. The proposed antenna has good agreement between the measured and the simulation results. The proposed antenna has a 10 dB return loss with bandwidth 644 MHz (2033–2677 MHz) in the lower band and 1913 MHz (4815–6728 MHz) in the higher band. The proposed dual‐band CPW‐fed inverted‐E shaped monopole covered the ISM, HIPERLAN, UNII and WiMAX bands.
Compact slot antenna for ultra‐wide band applications
Authors: Gong Bing , Ren Xue Shi , Zeng Ying Yin , Su Lin Hua , Zheng Qiu Rong
Published: November 2013

A novel compact ultra‐wide band antenna with L‐shaped slot is presented. The printed antenna is fed by a microstrip feed line to achieve impedance matching for the SMA connector. The proposed antenna offers 118% bandwidth when printed on a substrate of dielectric constant 4.4 and has an overall dimension of 23.7 × 23.7 × 0.8 mm3. The simulated and measured reflection characteristics of the antenna with the variation of key‐parameters along with radiation patterns of the final antenna are presented and discussed. In addition, by decreasing the dimension of radiating patch, band‐notched properties in the lower wireless local area network (WLAN) (5.15–5.35 GHz) or higher WLAN (5.725–5.825 GHz) bands are achieved. With the compact size and broadband, this antenna is very suitable for using in a trade‐off which has to be taken account for a design of miniaturisation.
Printed Newton's egg curved monopole antenna for ultrawideband applications
Authors: Verma Sudhanshu , Kumar Preetam
Published: November 2013

The edge curve of a planar antenna significantly influences its radiation properties. In this study, a novel egg curve‐based design of printed monopole antenna of size 40 × 40 mm2 is proposed for ultrawideband (UWB) applications. The egg shape of the proposed antennas is obtained by Newton's diverging parabolas curve referred in this study as Newton's egg curve. The design equations of the proposed antenna are developed. The variation in impedance bandwidth (BW) with various parametric variations of design curve is studied. The proposed Newton's egg curved monopole antenna (NECMA) is designed, fabricated and measured to validate the theoretical design. Good agreement between the simulated results and the measured ones is observed. An empirical formula is also proposed to approximately determine the frequency corresponding to the lower edge of −10 dB operating BW. The results show that the proposed NECMA can obtain the measured BW of 116.55% (2.9–11.0 GHz) along with stable gain of about 2.2–2.9 dBi. The proposed antenna exhibits almost omnidirectional radiation patterns with low cross polarisation in all directions and consistent group delay over the entire UWB bandwidth (3.1–10.6 GHz).
Complementary metal‐oxide semiconductor Doherty power amplifier based on voltage combining method
Authors: Zhao Chenxi , Park Byungjoon , Kim Bumman
Published: November 2013

A 1.75 GHz Doherty power amplifier (PA) is designed and implemented in a 0.18‐µm complementary metal‐oxide semiconductor (CMOS) process. This Doherty PA uses a voltage combining transformer to combine the output power and realise the load modulation which is different from conventional current combining Doherty amplifiers. The prototype has a power‐added efficiency (PAE) of 31.6% at a maximum output power of 28.6 dBm from 3.4 V supply voltage. The PAE at 6 dB back‐off is still high, about 25%. It shows clearly the efficiency enhancement at the power back‐off point because of the Doherty operation. This is the first use of voltage combining techniques in CMOS Doherty PA design.
Three‐dimensional folded antenna with ultra‐wideband performance, directional radiation and compact size
Authors: Mobashsher Ahmed Toaha , Abbosh Amin
Published: November 2013

A compact ultra‐wideband (UWB) antenna with directional radiation is presented. The antenna has a low profile and does not need a large ground for its performance. The antenna is based on using a three‐dimensional folded structure that is modified using semi‐circular slots on bowtie‐shaped elements. The antenna's mechanism, its design guidelines and its optimisation are described thoroughly. A prototype of the antenna is fabricated and measured for performance verification. The prototype shows 77% fractional bandwidth (centred at 2 GHz) based on 10 dB return loss reference. The equivalent overall size of the prototype is (λeff/3) × (λeff/4) × 0.07λeff (λeff = effective wavelength at the lowest resonant frequency), which proves the compactness of the antenna. The antenna shows unidirectional radiation pattern with around 15 dB front‐to‐back ratio, −20 dB cross‐polarisation in the two principle planes and around 5 dBi gain. The antenna is prescribed for compact UWB applications that use the low 1–3 GHz frequency band.
Design, microfabrication and measurement of cooling arm for fusion energy source application
Authors: Jiang Shui‐Dong , Liu Jing‐Quan , Yang Bin , Zhu Hong‐Ying , Yang Chun‐Sheng
Published: November 2013

The novel cooling arm plays an important role in thermal transfer in the production process of fusion energy. Its structure is designed and simulated by a finite element method. The result shows that the structure with two branches can obtain a temperature difference less than 1 mK among the grip surfaces of all the fingers. A (111) crystal orientation silicon is deployed to fabricate the cooling arm, because of its isotropic Young's modulus. The thermal conductivity of this material is measured by a Gifford‐McMahon (GM) cooler. The result shows it has large thermal conductivity at cryogenic temperature, which excellently contributes to heat transfer. The cooling arm is obtained by a microfabrication process. With a uniform pattern width mask and optimised deep reactive ion etching process recipe, a nearly 90° vertical sidewall is obtained. The temperature distribution of the cooling arm is also measured by a GM cooler, and the result shows that the maximum temperature deviation is 0.48 mK among the 16 fingers. There is a good agreement between finite element analysis and the experimental result.
Stretchable cell culture platforms using micropneumatic actuators
Authors: Heo Yun Jung , Kan Tetsuo , Iwase Eiji , Matsumoto Kiyoshi , Shimoyama Isao
Published: November 2013

A stretchable cell culture platform in which elastic micropneumatic actuators are embedded has been developed. By using the softlithography of polydimethylsiloxane (PDMS), the platform can be fabricated to any size and shape. It also permits cell culture by using the same standard methods that one would use with a Petri dish and it is transparent, permitting optical inspection of the cells. Thus, the platform is promising for studying cell responses because of mechanical stimulus. In this reported work, cells were cultured on a PDMS diaphragm of the micropneumatic actuators. Owing to input pressure, the micropneumatic actuators swell like a balloon, thereby stretching the cell membranes on the PDMS. The design flexibility of the presented approach is demonstrated by developing two kinds of stretchable platforms with diaphragm diameters of 558 and 24.8 μm to stretch whole and local cell membranes, respectively. Then, the cell membranes attached on the PDMS diaphragms are stretched by applying pressure on the pneumatic actuators. The applied stress causes an increase in the intracellular calcium ion concentration that is a fast cellular mechanotransduction. Therefore, it is concluded that the method for stretching cell membranes can stimulate either whole or local cell membranes, thus showing the potential to be used in in vitro studies of cellular mechanotransduction.
Electrochemical detection of methanol by platinum/carbon nanotubes nanocomposites synthesised via hydrogen plasma reduction process
Authors: Xu Jielin , Wang Shenggao , Du Zurong , Zhu Jinlong , Liu Yi , Zhang Wei , Wang Jianhua
Published: November 2013

Platinum (Pt)/carbon nanotube (CNTs) nanocomposites were fabricated on the basis of Pt precursors reduced by hydrogen plasma generated by microwave process. The Pt nanoparticles were uniformly dispersed on multi‐walled CNTs. Such nanocomposites exhibit remarkable catalytic performance towards the oxidation of methanol. The concentration of methanol was determined by a chronoamperometric method by using the Pt/CNTs modified glass carbon electrode (Pt/CNTs/GCE) at an oxidation potential of 0.7 V against the saturated calomel electrode. The Pt/CNTs/GCE showed a good performance for detecting methanol because of the unique properties of CNTs which increased the active surface area of the electrode and accelerated the electro transfer. The linear detection range of methanol was determined to be from 2.0 × 10−4 to 10.0 M in two slopes with a detection limit 5 × 10−5M at a signal‐to‐noise ratio of 3. The performance of the Pt/CNTs/GCE in terms of stability, linear range and detection limit shows its potential application for methanol detection.
Approaching the utopia of a global brand
Authors: Pérez Hernández Lorena
Published: November 2013

Increasingly global markets impose strains on the branding industry for the design of trademarks with a worldwide appeal. This paper explores the potential benefits of the exploitation of embodied schemata for this purpose. A corpus of international automobile brands is analyzed in search of the image schemas at work in the conceptualization of different car categories (i.e. minis, family cars, sports cars, and off-road 4 × 4s). Our findings evince that, together with other well-known strategies (i.e. sound symbolism), multimodal image schemas can be added to the inventory of branding tools which help to imbue brands with a globally comprehensible semantics. In the context of branding, it is also attested that the structure of the general schemas is fleshed out through their interaction with the most salient attributes of the target product/service named by a particular brand, rather than in relation to other contextual or cultural facts.
Multimodality in Conversational Humor
Authors: Attardo Salvatore , Pickering Lucy , Lomotey Fofo , Menjo Shigehito
Published: November 2013

The paper presents the analysis of the humor found in four dyadic conversations. The results of the conversational data match those of previous studies (Pickering et al., 2009): no differences were found in volume or speech-rate between humorous pause units and non-humorous ones. Similarly, pauses were not found to mark humorous turns. However, the result that punch-lines showed lower pitch than non-humorous parts of the text was not replicated: humorous pause units showed no significant differences in pitch from non-humorous ones. Smiling is found to mark humor only in a general sense of “setting the frame” and is not integrated (i.e., co-extensive) with the humor.
Genetic resources and conservation challenges under the threat of climate change.
Authors: Ford-Lloyd B. , Engels J. M. M. , Jackson M.
Published: November 2013

This chapter describes and discusses some of the initiatives and developments that make the world better prepared to respond to climate change in terms of plant genetic resources (PGRs). A broad overview is provided of important issues concerning conservation and use of PGRs, including conservation approaches, strategies and responses that become more relevant under the threat of climate change. An enormous amount of crop germplasm and wild relatives is conserved in genebanks around the world, as well as in situ. Although not all this conserved germplasm is equally characterized and evaluated, there is sufficient documented germplasm available to plant breeders that can be used to tackle the growing threat of global climate change.
Climate projections.
Authors: Betts R. A. , Hawkins E.
Published: November 2013

This chapter discusses the following topics: the concept and drivers of climate change and variability; climate models for estimating future climate variations and changes; long-term climate projections (temperature, precipitation, different patterns of regional climate change at specific global warming levels, implications of uncertainties in CO2 concentrations for a given level of global warming, changes in weather extremes); near-term climate projections; and emerging research on the AR4 Projections.
International mechanisms for conservation and use of genetic resources.
Authors: Moore G. , Hawtin G.
Published: November 2013

This chapter explores briefly the various international mechanisms for the conservation and use of genetic resources and how they have developed. Then it looks more closely at the Treaty (International Treaty on Plant Genetic Resources for Food and Agriculture) and explore ways in which its Contracting Parties, acting through the Governing Body of the Treaty, may be able to improve its implementation.
Poverty, livestock and food security in developing countries.
Authors: Turk J. M.
Published: November 2013

Poverty, livestock and food security are linked directly and indirectly. Insufficient capital to purchase enough food is a direct linkage, but even wealthy people can be poorly nourished if the nutritional quality of foods they consume is unbalanced. The most recent FAO State of Food Insecurity in the World report highlights that between 2010 and 2012 chronic undernourishment affected nearly 870 million people in the developing countries or 12.5% of the global population, the majority of whom live in developing countries. However, poverty is not necessarily equated with the level of malnutrition, especially that of children. There is a likelihood that higher levels of malnutrition among children would be found in lower income countries, but proportions of malnourishment may not always be associated with a country's economic status. Malnutrition is caused by a lack of sufficient calories and proteins from animal source foods (ASFs) and other sources, as well as micronutrient (vitamin and mineral) deficiency. Malnutrition and undernutrition severely affect children's physical and intellectual development. In developing countries, both urban and rural populations keep livestock for many reasons. Livestock value is measured economically, socioculturally, environmentally and nutritionally. ASFs contain some of the most important micronutrients needed by humans, and diverse diets that include ASF contain greater energy and higher protein digestibility than plants. For example, ASF protein digestibility is approximately 94%, whereas digestibility of bean protein is 78% and that of whole wheat 86%. However, rural populations that produce livestock do not necessarily benefit from adequate ASF consumption.
Genetic robustness and functional evolution of gene duplicates
Authors: Plata Germán , Vitkup Dennis
Published: November 2013

Gene duplications are a major source of evolutionary innovations. Understanding the functional divergence of duplicates and their role in genetic robustness is an important challenge in biology. Previously, analyses of genetic robustness were primarily focused on duplicates essentiality and epistasis in several laboratory conditions. In this study, we use several quantitative data sets to understand compensatory interactions between Saccharomyces cerevisiae duplicates that are likely to be relevant in natural biological populations. We find that, owing to their high functional load, close duplicates are unlikely to provide substantial backup in the context of large natural populations. Interestingly, as duplicates diverge from each other, their overall functional load is reduced. At intermediate divergence distances the quantitative decrease in fitness due to removal of one duplicate becomes smaller. At these distances, yeast duplicates display more balanced functional loads and their transcriptional control becomes significantly more complex. As yeast duplicates diverge beyond 70% sequence identity, their ability to compensate for each other becomes similar to that of random pairs of singletons.
Establishment of active chromatin structure at enhancer elements by mixed-lineage leukemia 1 to initiate estrogen-dependent gene expression
Authors: Jeong Kwang Won , Andreu-Vieyra Claudia , You Jueng Soo , Jones Peter A. , Stallcup Michael R.
Published: November 2013

A number of genome-wide analyses have revealed that estrogen receptor α binding to and regulation of its target genes correlate with binding of FOXA1, a pioneer factor, to nearby DNA sites in MCF-7 breast cancer cells. The enhancer element-specific histone H3K4me1/2 mark is enriched at the specific FOXA1/ERα recruitment sites in chromatin, but the mechanism by which these enhancer marks are established in chromatin before hormone treatment is unclear. Here, we show that mixed-lineage leukemia 1 (MLL1) protein is a key determinant that maintains permissive chromatin structure of the TFF1 enhancer region. MLL1 occupies the TFF1 enhancer region and methylates H3K4 before hormone stimulation. In vitro, MLL1 binds directly to the CpG-rich region of the TFF1 enhancer, and its binding is dependent on hypomethylation of DNA. Furthermore, the depletion of MLL1 in MCF-7 cells results in a dramatic decrease of chromatin accessibility and recruitment of FOXA1 and ERα to the enhancer element. Our study defines the mechanism by which MLL1 nucleates histone H3K4 methylation marks in CpG-enriched regions to maintain permissive chromatin architecture and allow FOXA1 and estrogen receptor α binding to transcriptional regulatory sites in breast cancer cells.
Intramolecular binding mode of the C-terminus ofEscherichia colisingle-stranded DNA binding protein determined by nuclear magnetic resonance spectroscopy
Authors: Shishmarev Dmitry , Wang Yao , Mason Claire E. , Su Xun-Cheng , Oakley Aaron J. , Graham Bim , Huber Thomas , Dixon Nicholas E. , Otting Gottfried
Published: November 2013

Single-stranded DNA (ssDNA) binding protein (SSB) is an essential protein to protect ssDNA and recruit specific ssDNA-processing proteins. Escherichia coli SSB forms a tetramer at neutral pH, comprising a structurally well-defined ssDNA binding domain (OB-domain) and a disordered C-terminal domain (C-domain) of ∼64 amino acid residues. The C-terminal eight-residue segment of SSB (C-peptide) has been shown to interact with the OB-domain, but crystal structures failed to reveal any electron density of the C-peptide. Here we show that SSB forms a monomer at pH 3.4, which is suitable for studies by high-resolution nuclear magnetic resonance (NMR) spectroscopy. The OB-domain retains its 3D structure in the monomer, and the C-peptide is shown by nuclear Overhauser effects and lanthanide-induced pseudocontact shifts to bind to the OB-domain at a site that harbors ssDNA in the crystal structure of the SSB–ssDNA complex. 15N relaxation data demonstrate high flexibility of the polypeptide segment linking the C-peptide to the OB-domain and somewhat increased flexibility of the C-peptide compared with the OB-domain, suggesting that the C-peptide either retains high mobility in the bound state or is in a fast equilibrium with an unbound state.
Quantifying the role of steric constraints in nucleosome positioning
Authors: Rube H. Tomas , Song Jun S.
Published: November 2013

Statistical positioning, the localization of nucleosomes packed against a fixed barrier, is conjectured to explain the array of well-positioned nucleosomes at the 5′ end of genes, but the extent and precise implications of statistical positioning in vivo are unclear. We examine this hypothesis quantitatively and generalize the idea to include moving barriers as well as nucleosomes actively packed against a barrier. Early experiments noted a similarity between the nucleosome profile aligned and averaged across genes and that predicted by statistical positioning; however, we demonstrate that aligning random nucleosomes also generates the same profile, calling the previous interpretation into question. New rigorous results reformulate statistical positioning as predictions on the variance structure of nucleosome locations in individual genes. In particular, a quantity termed the variance gradient, describing the change in variance between adjacent nucleosomes, is tested against recent high-throughput nucleosome sequencing data. Constant variance gradients provide support for generalized statistical positioning in ∼50% of long genes. Genes that deviate from predictions have high nucleosome turnover and cell-to-cell gene expression variability. The observed variance gradient suggests an effective nucleosome size of 158 bp, instead of the commonly perceived 147 bp. Our analyses thus clarify the role of statistical positioning in vivo.
Bioavailability of the anti-clostridial bacteriocin thuricin CD in gastrointestinal tract
Authors: Rea Mary C. , Alemayehu Debebe , Casey Pat G. , O’Connor Paula M. , Lawlor Peadar G. , Walsh Maria , Shanahan Fergus , Kiely Barry , Ross R. Paul , Hill Colin
Published: November 2013

Thuricin CD is a two component narrow spectrum bacteriocin comprising two peptides with targeted activity against Clostridium difficile. This study examined the bioavailability of thuricin with a view to developing it as an effective antimicrobial against intestinal infection. One of the peptides, Trn-β, was found to be degraded by the gastric enzymes pepsin and α-chymotrypsin both in vitro and in vivo, whereas Trn-α was resistant to digestion by these enzymes and hence was detected in the intestinal porcine digesta following oral ingestion by pigs. In order to determine if spores of the producing organism Bacillus thuringiensis DPC 6431 could be used to deliver the bacteriocin to the gut, spores were fed to 30 mice (approx. 108–2×108 per animal) and their germination, growth and production of thuricin in the gastrointestinal tract (GIT) of the animals was monitored. Almost 99 % of the spores delivered to the GIT were excreted in the first 24 h and neither Trn-α nor Trn-β was detected in the gut or faecal samples of the test mice, indicating that ingestion of B.
thuringiensis spores may not be a suitable vehicle for the delivery of thuricin CD. When thuricin CD was delivered rectally to mice (n = 40) and C. difficile shedding monitored at 1, 6, 12 and 24 h post-treatment, there was a >95 % (>1.5 log units) reduction of C. difficile 027 in the colon contents of infected mice (n = 10) 1 h post-treatment compared with the control group (n = 10; P<0.001). Furthermore, 6 h post-treatment there was a further 1.5 log reduction in C. difficile numbers (n = 10) relative to the control group (n = 10; P<0.05). These results would suggest that rectal administration of thuricin may be a promising mode of delivery of thuricin CD to the colon.
Isolation, pharmacological activity and structure determination of physalin B and 5β,6β-epoxyphysalin B isolated from CongolesePhysalis angulataL.
Authors: Mangwala Kimpende Peter , Lusakibanza Mariano , Mesia Kahunu , Tona Lutete , Tits Monique , Angenot Luc , Frédérich Michel , Van Meervelt Luc
Published: November 2013

Physalis angulataL., an annual herb from the Solanaceae family, is widely used in popular medicine in tropical countries to treat a variety of diseases. Two products, (X) and (Y), were isolated from a crude CH2Cl2extract of dried CongolesePhysalis angulataL. plants and crystallized from acetone for structure elucidation. Compound (X) corresponds to a physalin B dimer acetone solvate hydrate (2C28H30O9·C3H6O·0.22H2O), while compound (Y) crystallizes as a mixed crystal containing two physalin B molecules which overlap with 5β,6β-epoxyphysalin B, also known as physalin F, and one acetone molecule in the asymmetric unit (1.332C28H30O9·0.668C28H30O10·C3H6O). Antiplasmodial activity, cytotoxic activity and selectivity indices were determined for crude extracts and the two isolated products (X) and (Y).
Supramolecular architecture of metal–organic frameworks involving dinuclear copper paddle-wheel complexes
Authors: Gomathi Sundaramoorthy , Muthiah Packianathan Thomas
Published: November 2013

The two centrosymmetric dinuclear copper paddle-wheel complexes tetrakis(μ-4-hydroxybenzoato-κ2O:O′)bis[aquacopper(II)] dimethylformamide disolvate dihydrate, [Cu2(C7H5O3)4(H2O)2]·2C3H7NO·2H2O, (I), and tetrakis(μ-4-methoxybenzoato-κ2O:O′)bis[(dimethylformamide-κO)copper(II)], [Cu2(C8H7O3)4(C3H7NO)2], (II), crystallize with half of the dinuclear paddle-wheel cage unit in the asymmetric unit and, in addition, complex (I) has one dimethylformamide (DMF) and one water solvent molecule in the asymmetric unit. In both (I) and (II), two CuIIions are bridged by foursyn,syn-η1:η1:μ carboxylate groups, showing a paddle-wheel cage-type structure with a square-pyramidal coordination geometry. The equatorial positions of (I) and (II) are occupied by the carboxylate groups of 4-hydroxy- and 4-methoxybenzoate ligands, and the axial positions are occupied by aqua and DMF ligands, respectively. The three-dimensional supramolecular metal–organic framework of (I) consists of three differentR22(20) and anR44(36) ring motif formedviaO—H...O and OW—HW...O hydrogen bonds. Complex (II) simply packs as molecular species.
(3aR,8bR)-3a,8b-Dihydroxy-1-(4-methoxyphenyl)-2-methylsulfanyl-3-nitro-1,8b-dihydroindeno[1,2-b]pyrrol-4(3aH)-one
Authors: Nagalakshmi R. A. , Suresh J. , Jeyachandran V. , Kumar R. Ranjith , Lakshman P. L. Nilantha
Published: November 2013

In the title compound, C19H16N2O6S, the pyrrolidine ring adopts a twisted conformation with puckering parametersq2= 0.088 (3) Å and Φ2= 61.5 (14)°. The cyclopentane ring adopts a twisted conformation with puckering parametersq2= 0.099 (2) Å and Φ2= 242.8 (14)°. A weak intramolecular O—H...O interaction occurs. In the crystal, pairs of C—H...O interactions generate dimers with graph-set motifR22(24) and they are interconnected by pairs of O—H...O hydrogen bonds, which link the molecules into inversion dimers with graph-set motifR22(10).
2-[(Quinolin-8-yloxy)methyl]-1H-benzimidazole monohydrate
Authors: Tang Lin , Zhang Yue , Wen Yonghong
Published: November 2013

In the title hydrate, C17H13N3O·H2O, the dihedral angle between the quinoline and benzimidazole ring systems is 6.22 (7)°. The water molecule is linked to the main molecule by N—H...O and O—H...N hydrogen bonds. Further O—H...N hydrogen bonds link the organic molecules intoC(6) chains running parallel to thebaxis.
(S)-(+)-cis-4′-Benzyloxypraziquantel
Authors: Cedillo-Cruz Alberto , Aguilar María Isabel , Jung-Cook Helgi
Published: November 2013

The asymmetric unit of the title compound, C26H30N2O3{systematic name (S)-(+)-2-[cis-4-(benzyloxy)cyclohexanecarbonyl]-1,2,3,6,7,11b-hexahydro-4H-pyrazino[2,1-a]isoquinolin-4-one}, consists of two independent molecules in which the O= Camidegroup issynto the N—C(C=Olactam) moiety, making dihedral angles of 2.0 (8) and 3.7 (8)°. The conformation of the 1,4-disubstituted cyclohexane ring iscisin each independent molecule, with the carbonyl group occupying an equatorial position and the benzyloxy group an axial position. In one molecule, two C and one O atom of the benzyloxy group are disordered over two sets of sites, with a refined occupancy ratio of 0.772 (8):0.228 (8). In the crystal, molecules are linked by C—H...O interactions, forming ribbons parallel to theb-axis direction.
{4-Chloro-N′-[(2-oxidonaphthalen-1-yl-κO)methylidene]benzohydrazidato-κ2N′,O}dimethyltin(IV)
Authors: Cui Jichun , Qiao Yanling , Wang Fei
Published: November 2013

In the title complex, [Sn(CH3)2(C18H11ClN2O2)], the SnIVion is coordinated by two O atoms and an N atom from a 4-chloro-N′-[(2-oxidonaphthalen-1-yl)methylidene]benzohydrazidate ligand and two C atoms from two methyl ligands in a distorted trigonal–bipyramidal geometry [Sn—O = 2.092 (3) and 2.144 (3) Å; Sn—N = 2.160 (4) Å]. The dihedral angle between the naphthalene ring system and the benzene ring is 8.6 (2)°. In the crystal, adjacent molecules are linked by weak C—H...O hydrogen bonds, forming a chain along theb-axis direction.
catena-Poly[[tetra-μ-formato-κ8O:O′-dicopper(II)]-μ-hexamethylenetetramine-κ2N1:N5]
Authors: Cao Jianfang , Huang Ziping , Cao Changnian , Cheng Chunchun , Sun Chunyan
Published: November 2013

In the title polymeric compound, [Cu2(HCO2)4(C6H12N4)]n, the CuIIatom is five-coordinated in a square-pyramidal geometry that is defined by four O atoms from four formate ligands and one N atom from a hexamethylenetetramine ligand. The two CuIIatoms are separated by 2.6850 (7) Å, and together with the four formate ligands they form a paddle-wheel unit. The hexamine ligand uses only two of its four N atoms to link Cu2cluster units, affording a zigzag chain running along theb-axis direction. The hexamine ligand lies on a mirror plane.
Ethyl 6-(4-chlorophenyl)-4-(4-fluorophenyl)-2-oxocyclohex-3-ene-1-carboxylate
Authors: Sapnakumari M. , Narayana B. , Yathirajan H.S. , Jasinski Jerry P. , Butcher Ray J.
Published: November 2013

The asymmetric unit of the title compound, C21H18ClFO3, contains two independent molecules. In one molecule (A), the 4-chlorophenyl, oxocyclohex-3-ene, carboxylate, and ethyl groups were refined as disordered over two sets of sites with a 0.684 (5):0.316 (5) ratio. The cyclohexene ring in the disordered molecule is in a slightly distorted envelope conformation for the major component (with the C atom bound to the carboxylate group being the flap atom) and in a screw-boat conformation for the minor component. In the ordered molecule (B), the cyclohexene ring is in a half-chair conformation. The dihedral angles between the mean planes of the fluoro- and chloro-substituted benzene rings are 89.9 (7) (only the major component is considered forA) and 76.4 (7)° (B). In the crystal, inversion dimers are observed along with weak C—H...O hydrogen bonds, which form chains along [100].
N-(2-Oxo-2,3,4,5,6,7-hexahydro-1H-azepin-3-yl)cyclohexanecarboxamide
Authors: Chunjuan Shi , Zhao Yang
Published: November 2013

In the title compound, C13H22N2O2, both the six-membered ring and the seven-membered lactam ring adopt chair conformations. In the crystal, molecules are linked by pairs of N—H...O hydrogen bonds between inversion-related lactam rings into centrosymmetric dimers with anR22(8) graph-set motif. Further N—H...O hydrogen bonds link the molecules into [100] chains.
Na3Co2(As0.52P0.48)O4(As0.95P0.05)2O7
Authors: Ben Smida Youssef , Guesmi Abderrahmen , Zid Mohamed Faouzi , Driss Ahmed
Published: November 2013

The title compound, trisodium dicobalt(II) (arsenate/phosphate) (diarsenate/diphosphate), was prepared by a solid-state reaction. It is isostructural with Na3Co2AsO4As2O7. The framework shows the presence of CoX22O12(X2 is statistically disordered with As0.95P0.05) units formed by sharing corners between Co1O6octahedra andX22O7groups. These units form layers perpendicular to [010]. Co2O6octahedra andX1O4(X1 = As0.54P0.46) tetrahedra form Co2X1O8chains parallel to [001]. Cohesion between layers and chains is ensured by theX22O7groups, giving rise to a three-dimensional framework with broad tunnels, running along thea- andc-axis directions, in which the Na+ions reside. The two Co2+cations, theX1 site and three of the seven O atoms lie on special positions, with site symmetries 2 andmfor the Co,mfor theX1, and 2 andm(× 2) for the O sites. One of two Na atoms is disordered over three special positions [occupancy ratios 0.877 (10):0.110 (13):0.066 (9)] and the other is in a general position with full occupancy. A comparison between structures such as K2CdP2O7, α-NaTiP2O7and K2MoO2P2O7is made. The proposed structural model is supported by charge-distribution (CHARDI) analysis and bond-valence-sum (BVS) calculations. The distortion of the coordination polyhedra is analyzed by means of the effective coordination number.
Dimethyl (2Z)-2-[4-((1Z)-1-{2-[(2Z,5Z)-5-(2-methoxy-2-oxoethylidene)-4-oxo-3-phenyl-1,3-thiazolidin-2-ylidene]hydrazin-1-ylidene}ethyl)anilino]but-2-enedioate
Authors: Mohamed Shaaban K. , Akkurt Mehmet , Mague Joel T. , Hassan Alaa A. , Albayati Mustafa R.
Published: November 2013

The molecule of the title compound, C26H24N4O7S, adopts atransconformation about the central N—N bond, presumably to minimize steric between the substituents on these two atoms. An intramolecular N—H...O hydrogen bond occurs. The phenyl ring is disordered over two sets of sites, with an occupancy ratio of 0.624 (8):0.376 (8). The azolidine ring is essentially planar [maximum deviation = 0.008 (5) Å] and makes a dihedral angle of 4.3 (2)° with the benzene ring and dihedral angles of 74.1 (3) and 69.1 (5)°, respectively, with the mean planes of the major and minor components of the disordered phenyl ring. The packing in the crystal is aided by the formation of several weak C—H...O and C—H...N interactions.
4-Chlorophenyl quinoline-2-carboxylate
Authors: Fazal E. , Kaur Manpreet , Sudha B. S. , Nagarajan S. , Jasinski Jerry P.
Published: November 2013

In the title compound, C16H10ClNO2, the dihedral angle between the quinoline ring system and the benzene ring is 14.7 (5)°. The carboxylate group is twisted from the mean planes of the quinoline ring system and the benzene ring by 17.7 (5) and 32.1 (4)°, respectively. In the crystal, inversion dimers are formed with the molecules linked by pairs of weak C—H...O interactions arising from an activated aromatic C atom adjacent to the C—Cl bond, generatingR22(14) loops.
μ-Hexathiometadiphosphato-bis[(1,4,7,10,13,16-hexaoxacyclooctadecane-κ6O)rubidium] acetonitrile disolvate
Authors: Gjikaj Mimoza , Pook Niels-Patrick , Qarri Flora
Published: November 2013

The asymmetric unit of the title compound, [Rb2(P2S6)(C12H24O6)2]·2CH3CN, contains one half of an [Rb(18-crown-6)2]2[P2S6] unit and one acetonitrile solvent molecule. The [Rb(18-crown-6)]2[P2S6] unit is completed by inversion symmetry. Its Rb+ion is situated near the centre of the macrocyclic cavity, but is displaced by 0.8972 (1) Å from the O atoms of the crown in the direction of the [P2S6]2−moiety. The overall coordination number of the cation is eight, defined by the six crown ether O atoms and by two terminal S atoms of the [P2S6]2−anion. The hexathiometadiphosphate anion is built up from two tetrahedral PS4units joined together by a common edge. The crystal structure is characterized by alternating layers of [Rb(18-crown-6)]2[P2S6] and acetonitrile solvent molecules stacked along [010].
Di-μ-oxido-bis[bis(diisopropylacetamidinato)-κN;κ2N,N′-germanium(IV)]
Authors: Syre Ronny , Frenzel Nancy , Hrib Cristian G. , Burte Edmund P. , Jones Peter G. , Edelmann Frank T.
Published: November 2013

The title compound, [Ge2(C8H17N2)4O2], crystallizes with imposed twofold symmetry, which allows the monodentate amidinate ligands to be arranged in acisoidfashion. The independent Ge—O distances within the central Ge2O2ring, which is essentially planar (r.m.s. deviation = 0.039 Å), are 1.7797 (8) and 1.8568 (8) Å. The germanium centres adopt a distorted trigonal–bipyramidal geometry, being coordinated by the two O atoms and by one bidentate and one monodentate amidinate ligand (three N atoms). OneN-isopropyl group is disordered over two positions; these are mutually exclusive because of `collisions' between symmetry-equivalent methyl groups and thus each has 0.5 occupancy.
2-Methylaspartic acid monohydrate
Authors: Brewer Greg , Burton Aaron S. , Dworkin Jason P. , Butcher Ray J.
Published: November 2013

The title compound, C5H9NO4·H2O, is an isomer of the α-amino acid glutamic acid that crystallizes from water in its zwitterionic form as a monohydrate. It is not one of the 20 proteinogenic α-amino acids that are used in living systems and differs from the natural amino acids in that it has an α-methyl group rather than an α-H atom. In the crystal, an O—H...O hydrogen bond is present between the acid and water molecules while extensive N—H...O and O—H...O hydrogen bonds link the components into a three-dimensional array.
4-Hydroxy-3-methoxybenzaldehyde thiosemicarbazone
Authors: Oliveira Adriano Bof de , Feitosa Bárbara Regina Santos , Näther Christian , Jess Inke
Published: November 2013

In the title compound, C9H11N3S, there is an intramolecular O—H...O hydrogen bond involving the OH group and the adjacent methoxy O atom. The molecule is essentially planar, with the maximum deviation from the mean plane of the non-H atoms being 0.1127 (14) Å for the methyl C atom. In the crystal, molecules are connectedviacentrosymmetric pairs of N—H...S and O—H...O hydrogen bonds into a two-dimensional network parallel to (10-3).
Phylogenetically related and ecologically similar carnivores harbour similar parasite assemblages
Authors: Huang Shan , Bininda‐Emonds Olaf R. P. , Stephens Patrick R. , Gittleman John L. , Altizer Sonia
Published: November 2013

Most parasites infect multiple hosts, but what factors determine the range of hosts a given parasite can infect? Understanding the broad scale determinants of parasite distributions across host lineages is important for predicting pathogen emergence in new hosts and for estimating pathogen diversity in understudied host species.

In this study, we used a new data set on 793 parasite species reported from free‐ranging populations of 64 carnivore species to examine the factors that influence parasite sharing between host species.

Our results showed that parasites are more commonly shared between phylogenetically related host species pairs. Additionally, host species with higher similarity in biological traits and greater geographic range overlap were also more likely to share parasite species.

Of three measures of phylogenetic relatedness considered here, the number divergence events that separated host species pairs most strongly influenced the likelihood of parasite sharing. We also showed that viruses and helminths tend to infect carnivore hosts within more restricted phylogenetic ranges than expected by chance.

Overall, our results underscore the importance of host evolutionary history in determining parasite host range, even when simultaneously considering other factors such as host ecology and geographic distribution.
Towards an energetic landscape: broad‐scale accelerometry in woodland caribou
Authors: Mosser Anna A. , Avgar Tal , Brown Glen S. , Walker C. Spencer , Fryxell John M.
Published: November 2013

Energetic balance is a central driver of individual survival and population change, yet estimating energetic costs in free‐ and wide‐ranging animals presents a significant challenge. Animal‐borne activity monitors (using accelerometer technology) present a promising method of meeting this challenge and open new avenues for exploring energetics in natural settings.

To determine the behaviours and estimated energetic costs associated with a given activity level, three captive reindeer (Rangifer tarandus tarandus) at the Toronto Zoo were fitted with collars and observed for 53 h. Activity patterns were then measured over 13 months for 131 free‐ranging woodland caribou (R. t. caribou) spanning 450 000 km2 in northern Ontario. The captive study revealed a positive but decelerating relationship between activity level and energetic costs inferred from previous behavioural studies.

Field‐based measures of activity were modelled against individual displacement, vegetation abundance (Normalized Difference Vegetation Index), snow depth and temperature, and the best fit model included all parameters and explained over half of the variation in the data. Individual displacement was positively related to activity levels, suggesting that broad differences in energetic demands are influenced by variation in movement rates. After accounting for displacement, activity was highest at intermediate levels of vegetation abundance, presumably due to foraging behaviour. Snow depth, probably associated with digging for winter forage, moderately increased activity. Activity levels increased significantly at the coldest winter temperatures, suggesting the use of behavioural thermoregulation by caribou. These interpretations of proximate causal factors should be regarded as hypotheses subject to validation under normal field conditions.

These results illustrate the landscape characteristics that increase energetic demands for caribou and confirm the great potential for the use of accelerometry in studies of animal energetics.
Natural malaria infection reduces starvation resistance of nutritionally stressed mosquitoes
Authors: Lalubin Fabrice , Delédevant Aline , Glaizot Olivier , Christe Philippe
Published: November 2013

In disease ecology, there is growing evidence that environmental quality interacts with parasite and host to determine host susceptibility to an infection. Most studies of malaria parasites have focused on the infection costs incurred by the hosts, and few have investigated the costs on mosquito vectors. The interplay between the environment, the vector and the parasite has therefore mostly been ignored and often relied on unnatural or allopatricPlasmodium/vector associations.

Here, we investigated the effects of natural avian malaria infection on both fecundity and survival of field‐caught femaleCulex pipiensmosquitoes, individually maintained in laboratory conditions. We manipulated environmental quality by providing mosquitoes with different concentrations of glucose‐feeding solution prior to submitting them to a starvation challenge. We used molecular‐based methods to assess mosquitoes’ infection status.

We found that mosquitoes infected withPlasmodiumhad lower starvation resistance than uninfected ones only under low nutritional conditions. The effect of nutritional stress varied with time, with the difference of starvation resistance between optimally and suboptimally fed mosquitoes increasing from spring to summer, as shown by a significant interaction between diet treatment and months of capture. Infected and uninfected mosquitoes had similar clutch size, indicating no effect of infection on fecundity.

Overall, this study suggests that avian malaria vectors may sufferPlasmodiuminfection costs in their natural habitat, under certain environmental conditions. This may have major implications for disease transmission in the wild.