bluuebunny/crossref_metadata_2025 huggingface dataset:
One-step hydrothermal synthesis of Fe3O4@C nanoparticles with great performance in biomedicine
Authors: Mao Gui-Yun , Yang Wen-Jing , Bu Fan-Xing , Jiang Dong-Mei , Zhao Zhen-Jie , Zhang Qing-Hong , Fang Qi-Chen , Jiang Ji-Sen
Published: May 2014

Core@shell structured Fe3O4@C nanoparticles synthesized by one-pot hydrothermal method show good pH-response drug release property and magneto-thermal performance.
Highly reliable AgNW/PEDOT:PSS hybrid films: efficient methods for enhancing transparency and lowering resistance and haziness
Authors: Kim Seyul , Kim So Yeon , Kim Jeonghun , Kim Jung Hyun
Published: May 2014

Multi-layer coated AgNW/PEDOT:PSS films show excellent electrical standard deviation and enhanced optical properties without any further process. Furthermore, introduction of PEDOT:PSS could reduce the standard deviation to below 2.
Structural and enzymatic insights into Lambda glutathione transferases from Populus trichocarpa, monomeric enzymes constituting an early divergent class specific to terrestrial plants
Authors: Lallement Pierre-Alexandre , Meux Edgar , Gualberto José M. , Prosper Pascalita , Didierjean Claude , Saul Frederick , Haouz Ahmed , Rouhier Nicolas , Hecker Arnaud
Published: May 2014

GSTs represent a superfamily of multifunctional proteins which play crucial roles in detoxification processes and secondary metabolism. Instead of promoting the conjugation of glutathione to acceptor molecules as do most GSTs, members of the Lambda class (GSTLs) catalyse deglutathionylation reactions via a catalytic cysteine residue. Three GSTL genes (Pt-GSTL1, Pt-GSTL2 and Pt-GSTL3) are present in Populus trichocarpa, but two transcripts, differing in their 5′ extremities, were identified for Pt-GSTL3. Transcripts for these genes were primarily found in flowers, fruits, petioles and buds, but not in leaves and roots, suggesting roles associated with secondary metabolism in these organs. The expression of GFP-fusion proteins in tobacco showed that Pt-GSTL1 is localized in plastids, whereas Pt-GSTL2 and Pt-GSTL3A and Pt-GSTL3B are found in both the cytoplasm and the nucleus. The resolution of Pt-GSTL1 and Pt-GSTL3 structures by X-ray crystallography indicated that, although these proteins adopt a canonical GST fold quite similar to that found in dimeric Omega GSTs, their non-plant counterparts, they are strictly monomeric. This might explain some differences in the enzymatic properties of both enzyme types. Finally, from competition experiments between aromatic substrates and a fluorescent probe, we determined that the recognition of glutathionylated substrates is favoured over non-glutathionylated forms.
Robust and decentralised output regulation of switched non‐linear systems with switched internal model
Authors: Long Lijun , Zhao Jun
Published: May 2014

This study investigates the global robust output regulation problem for a class of switched non‐linear systems with stabilisable and unstabilisable subsystems. First, this study proposes a new concept, namely switched internal model, as an extension of the concept of non‐switched internal model, which provides a tool for solving the output regulation problem of switched non‐linear systems. Also, the authors show that the problem of output regulation boils down to a global robust regulation problem of an appropriately switched augmented system via a switched internal model. Then, the global robust regulation problem under a class of switching signals with average dwell time is solved by using the average dwell time method, which leads to the solution of the problem of global robust output regulation. Further, the authors apply this type of switched internal models above to solve the global decentralised output regulation problem for a class of large‐scale switched non‐linear systems with stabilisable and unstabilisable subsystems. An example is provided to demonstrate the effectiveness of the proposed approach.
Control and diagnosis of temperature, density, and uniformity in x-ray heated iron/magnesium samples for opacity measurements
Authors: Nagayama T. , Bailey J. E. , Loisel G. , Hansen S. B. , Rochau G. A. , Mancini R. C. , MacFarlane J. J. , Golovkin I.
Published: May 2014

Experimental tests are in progress to evaluate the accuracy of the modeled iron opacity at solar interior conditions, in particular to better constrain the solar abundance problem [S. Basu and H. M. Antia, Phys. Rep. 457, 217 (2008)]. Here, we describe measurements addressing three of the key requirements for reliable opacity experiments: control of sample conditions, independent sample condition diagnostics, and verification of sample condition uniformity. The opacity samples consist of iron/magnesium layers tamped by plastic. By changing the plastic thicknesses, we have controlled the iron plasma conditions to reach (1) Te = 167 ± 3 eV and ne = (7.1 ± 1.5)× 1021 cm−3, (2) Te = 170 ± 2 eV and ne = (2.0 ± 0.2) × 1022 cm−3, and (3) Te = 196 ± 6 eV and ne = (3.8 ± 0.8) × 1022 cm−3, which were measured by magnesium tracer K-shell spectroscopy. The opacity sample non-uniformity was directly measured by a separate experiment where Al is mixed into the side of the sample facing the radiation source and Mg into the other side. The iron condition was confirmed to be uniform within their measurement uncertainties by Al and Mg K-shell spectroscopy. The conditions are suitable for testing opacity calculations needed for modeling the solar interior, other stars, and high energy density plasmas.
Structure and dynamics of water inside endohedrally functionalized carbon nanotubes
Authors: Paul Sanjib , Abi T. G. , Taraphder Srabani
Published: May 2014

We have carried out classical molecular dynamics simulations on the formation of extended water chains inside single-walled carbon nanotubes (SWCNTs) in water in the presence of selected functional groups covalently attached to the inner wall of the tube. Analogues of polar amino acid sidechains have been chosen to carry out the endohedral functionalization of SWCNTs. Our results show a spontaneous and asymmetric filling of the nanotube with dynamical water chains in all the cases studied. The presence of Asp- and Glu-like sidechains is found to result in the formation of well-ordered water chains across the tube having the maximum number of water molecules being retained within the core with the largest residence times. The presence of methyl or methylene groups along the suspended chain is observed to disrupt the formation of water chains with higher length and/or longer residence times. The importance of hydrogen bonding in forming these water chains is assessed in terms of the relaxations of different hydrogen bond correlation functions. For a given dimension of the hydrophobic nanopore, we thus obtain a scale comparing the ability of carboxylic, alcohol, and imidazole groups in controlling the structure and dynamics of water in it. Our results also suggest that SWCNTs of varying lengths, endohedrally functionalized with Asp- and Glu-like sidechains, may be used as design templates in CNT-based water storage devices.
Region of validity of the finite–temperature Thomas–Fermi model with respect to quantum and exchange corrections
Authors: Dyachkov Sergey , Levashov Pavel
Published: May 2014

We determine the region of applicability of the finite–temperature Thomas–Fermi model and its thermal part with respect to quantum and exchange corrections. Very high accuracy of computations has been achieved by using a special approach for the solution of the boundary problem and numerical integration. We show that the thermal part of the model can be applied at lower temperatures than the full model. Also we offer simple approximations of the boundaries of validity for practical applications.
Exciton-dominant electroluminescence from a diode of monolayer MoS2
Authors: Ye Yu , Ye Ziliang , Gharghi Majid , Zhu Hanyu , Zhao Mervin , Wang Yuan , Yin Xiaobo , Zhang Xiang
Published: May 2014

In two-dimensional monolayer MoS2, excitons dominate the absorption and emission properties. However, the low electroluminescent efficiency and signal-to-noise ratio limit our understanding of the excitonic behavior of electroluminescence. Here, we study the microscopic origin of the electroluminescence from a diode of monolayer MoS2 fabricated on a heavily p-type doped silicon substrate. Direct and bound-exciton related recombination processes are identified from the electroluminescence. At a high electron-hole pair injection rate, Auger recombination of the exciton-exciton annihilation of the bound exciton emission is observed at room temperature. Moreover, the efficient electrical injection demonstrated here allows for the observation of a higher energy exciton peak of 2.255 eV in the monolayer MoS2 diode, attributed to the excited exciton state of a direct-exciton transition.
A ladder of polariton branches formed by coupling an organic semiconductor exciton to a series of closely spaced cavity-photon modes
Authors: Coles David M. , Lidzey David G.
Published: May 2014

We construct a microcavity in which the extended optical path length of the cavity (5.9 μm) permits a series of closely spaced optical modes to be supported. By placing a J-aggregated cyanine dye into the cavity, we reach the strong-coupling regime and evidence a simultaneous optical hybridization between the organic-exciton and a number of the confined cavity modes, forming an effective ladder of polariton branches. We explore the emission from such cavities and evidence a polariton-population on adjacent polariton branches around k∥ = 0.
Maintenance Work and the Performativity of Urban Inscriptions: The Case of Paris Subway Signs
Authors: Denis Jérôme , Pontille David
Published: May 2014

Urban inscriptions are performative devices that play a crucial part in urban assemblages. They mark sites, give places a name, designate directions. This paper questions such performativity by investigating the design and maintenance of subway signs in Paris. Studying backstage activities rather than user tactics, it shows that the semiotic production of space is mainly played out in standardization processes that are both oriented towards signs immutability and fueled by a daily consideration for their vulnerability. Such a posture allows us to take full account of the ontological variations of signs (which can be, for example, stable or unstable, consistent or fragile, immutable or mutable). Maintenance work, through which the agency of urban inscriptions is partially shaped, ensures the articulation of such a multiplicity.
Networks, Interfaces, and Computer-Generated Images: Learning from Digital Visualisations of Urban Redevelopment Projects
Authors: Rose Gillian , Degen Monica , Melhuish Clare
Published: May 2014

Over the past five years, computer-generated images (CGIs) have become commonplace as a means to market urban redevelopments. To date, however, they have been given relatively little attention as a new form of visualising the urban. In this paper we argue that these CGIs deserve more attention, and attention of a particular kind. We argue that, instead of approaching them as images situated in urban space, their digitality invites us to understand them as interfaces circulating through a software-supported network space. We use an actor-network theory understanding of ‘network’ and argue that the action done on and with CGIs as they are created takes place at a series of interfaces. These interfaces—between and among humans, software, and hardware—are where work is done both to create the CGI and to create the conditions for their circulation. These claims are explored in relation to the CGIs made for a large urban redevelopment project in Doha, Qatar. We conclude by suggesting that geographers need to reconsider their understanding of digital images and be as attentive to the interfaces embedded in the image as to the CGI's visual content.
Micro-encapsulated sodium butyrate attenuates oxidative stress induced by corticosterone exposure and modulates apoptosis in intestinal mucosa of broiler chickens
Authors: Jiang Y. , Zhang W. H. , Gao F. , Zhou G. H.
Published: May 2014

The aim of the present study was to investigate the effects of micro-encapsulated sodium butyrate (MSB) on oxidative stress and apoptosis induced by dietary corticosterone (CORT) in the intestinal mucosa of broiler chickens. In total, 120 1-day-old male broilers (Arbor Acres) were randomly allocated to two treatment groups and were fed on a control diet (without MSB) or 0.4 g MSB/kg diet. Each treatment had six replicates with five chickens each. From 7 days of age onward, 50% of the chickens in each dietary treatment were subjected to CORT treatment (30 mg/kg of diet). The experimental period was 21 days. The results showed that CORT administration decreased (P < 0.001) feed intake and bodyweight gain and increased (P < 0.001) feed to gain ratio (F : G) of broiler chickens. The dietary MSB supplementation decreased (P < 0.01) F : G and there was an interaction between MSB and CORT on F : G (P < 0.05). Moreover, the activities of superoxide dismutase, glutathione peroxidase and catalase in intestinal mucosa were decreased (P < 0.01 or P < 0.001), and the concentrations of malondialdehyde in the intestinal mucosa were elevated (P < 0.01) by CORT administration. In contrast, treatment of MSB increased (P < 0.01) the catalase activities in duodenal and jejunal mucosa and decreased (P < 0.01) the malondialdehyde concentrations in duodenal mucosa. Higher apoptosis index and lower mRNA expressions of bcl-2 in intestinal epithelial cells were induced (P < 0.05) by CORT treatment. However, MSB decreased (P < 0.05) the apoptosis index and increased the bcl-2 expression. These results suggest that dietary MSB can partially attenuate oxidative stress induced by CORT treatment and inhibit apoptosis of intestinal epithelial cells in broiler chickens.
Crown Ether Derivatised Pyromellitic Diimides
Authors: Sandanayake Saman , Langford Steven J.
Published: May 2014

Pyromellitic diimide functionalised on the aromatic core with azacrown ethers have been synthesised and characterised by analytical methods including X-ray crystallography. Changes in their UV-vis spectra by the addition of metal salts have been investigated.
Effects of grazing on crop crown temperature: implications for phenology
Authors: Harrison Matthew T. , Kelman Walter M. , Virgona Jim M.
Published: May 2014

In many regions, livestock are allowed to graze grain crops during their vegetative development, before grain is harvested at crop maturity. Little is known of the effects of grazing on crop microclimate, particularly the effects of defoliation on crown temperatures. Knowledge of such effects is important because temperature is the main factor underpinning crop ontogeny, and ontogeny drives dry matter allocation, leaf appearance rates and the timing of anthesis, which are key determinants of grain yield. The primary aim of this study was to examine the influence of grazing intensity and duration on the crown temperatures of winter wheat crops grown at Canberra, Australia. A secondary aim was to examine the association between crown temperature and phenology. In 2007, wheat cv. Mackellar was grazed at intensity–duration combinations of low–short (LS, 33 sheep/ha for 31 days), heavy–short (HS, 67 sheep/ha for 31 days) or low–long (LL, 33 sheep/ha for 62 days). In 2008, cvv. Mackellar and Naparoo were grazed at the HS intensity-duration. Cubic smoothing splines were fitted to crown temperature data measured between the end of grazing and anthesis to facilitate identification of long-term trends and statistical differences caused by the effects of defoliation on crown temperature. Grazing treatments with greater intensity or longer duration significantly elevated maximum daily crown temperature; differences of 6–7°C were common in the month following grazing. Cubic-spline analysis showed that long-term trends in maximum crown temperature of the HS and LL treatments were significantly greater than corresponding temperatures of controls for the entire post-grazing duration. By contrast, effects of grazing on minimum diurnal crown temperature were small. Increasing biomass removal significantly delayed stem elongation and anthesis. We demonstrate that although initial phenological delays caused by defoliation are large, greater diurnal crown temperature fluctuation in grazed crops leads to greater growing degree-day accumulation between the end of grazing and anthesis. This increases the rate of thermal time accumulation during the post-grazing–anthesis period and is likely prominent in driving greater development rates of grazed crops. We further demonstrate that delays in phenology associated with grazing can be largely accounted for by a thermal time constant, with the LS, HS and LL treatments delaying stem elongation by ~52, 141 and 214 degree-days, respectively, above a base temperature of 0°C. Results from these experiments and interpretations herein will be of use in designing crop-grazing regimes, and in studies examining implications of defoliation on vegetative microclimate and on physiological feedback effects caused by elevated temperature.
De-coupling seasonal changes in water content and dry matter to predict live conifer foliar moisture content
Authors: Jolly W. Matt , Hadlow Ann M. , Huguet Kathleen
Published: May 2014

Live foliar moisture content (LFMC) significantly influences wildland fire behaviour. However, characterising variations in LFMC is difficult because both foliar mass and dry mass can change throughout the season. Here we quantify the seasonal changes in both plant water status and dry matter partitioning. We collected new and old foliar samples from Pinus contorta for two growing seasons and quantified their LFMC, relative water content (RWC) and dry matter chemistry. LFMC quantifies the amount of water per unit fuel dry weight whereas RWC quantifies the amount of water in the fuel relative to how much water the fuel can hold at saturation. RWC is generally a better indicator of water stress than is LFMC. We separated water mass from dry mass for each sample and we attempted to best explain the seasonal variations in each using our measured physiochemical variables. We found that RWC explained 59% of variation in foliar water mass. Additionally, foliar starch, sugar and crude fat content explained 87% of the variation in seasonal dry mass changes. These two models combined explained 85% of the seasonal variations in LFMC. These results demonstrate that changes to dry matter exert a stronger control on seasonal LFMC dynamics than actual changes in water content, and they challenge the assumption that LFMC variations are strongly related to water stress. This methodology could be applied across a range of plant functional types to better understand the factors that drive seasonal changes in LFMC and live fuel flammability.
Expression and functional analyses of Krüppel-like factor 3 in chicken adipose tissue
Authors: Zhang Zhi-Wei , Wu Chun-Yan , Li Hui , Wang Ning
Published: May 2014

Studies in mammalian species showed that Krüppel-like factor 3 (KLF3) regulated adipose tissue development. However, it was not reported in chicken. In the current study, we found that during the growth and development of abdominal fat tissue, chicken KLF3 (Gallus gallus KLF3, gKLF3) was consecutively expressed, and its transcripts were higher at 7 weeks of age and lower at 10 weeks of age in lean broilers than in fat broilers. In addition, gKLF3 overexpression suppressed chicken CCAAT/enhancer binding protein alpha (C/EBPα), fatty acid binding protein 4 (FABP4), fatty acid synthase (FASN), and lipoprotein lipase (LPL) promoter activities, but increased chicken peroxisome proliferator-activated receptor gamma (PPARγ) promoter activity. Additionally, point mutagenesis analysis showed that the substitution of Asp by Gly within the Pro-Val-Asp-Leu-Thr (PVDLT) motif of gKLF3 significantly reduced the ability of gKLF3 to regulate the promoter activities of FABP4, FASN, LPL, C/EBPα, and PPARγ.
Salmonella typhimurium with γ-radiation induced H2AX phosphorylation and apoptosis in melanoma
Authors: Yoon Won Suck , Kim Sinyeon , Seo Sungchul , Park Yongkeun
Published: May 2014

To investigate the combinatorial effects using Salmonella and γ-radiation, the Salmonella typhimurium infection in combination with γ-radiation was investigated on melanoma. We showed that ROS expression and H2AX phosphorylation increased during stress by γ-radiation irrespective of Salmonella infection, inducing apoptosis by caspase-3 and bcl2 in tumor cells. In addition, tumor growth was suppressed by this combinatory therapy suggesting candidates for radiation therapy against melanoma.
Glycogen synthase kinase-3 is involved in regulation of ribosome biogenesis in yeast
Authors: Yabuki Yukari , Kodama Yushi , Katayama Masako , Sakamoto Akiko , Kanemaru Hirofumi , Wan Kun , Mizuta Keiko
Published: May 2014

Secretory defects cause transcriptional repression of both ribosomal proteins and ribosomal RNA genes in Saccharomyces cerevisiae. Rrs1, a trans-acting factor that participates in ribosome biogenesis, is involved in the signaling pathway induced by secretory defects. Here, we found that Rrs1 interacts with two homologs of the glycogen synthase kinase-3 (GSK-3), Rim11, and Mrk1. Rrs1 possesses a repetitive consensus amino acid sequence for phosphorylation by GSK-3, and mutation of this sequence abolished the interaction of Rrs1 with Rim11 and Mrk1. Although this mutation did not affect vegetative cell growth or secretory response, disruption of all four genes encoding GSK-3 homologs, especially Mck1, diminished the transcriptional repression of ribosomal protein genes in response to secretory defects. Among the four GSK-3 kinases, Mck1 appears to be the primary mediator of this response, while the other GSK-3 kinases contribute redundantly.
Contributions of tryptophan 2,3-dioxygenase and indoleamine 2,3-dioxygenase to the conversion of d-tryptophan to nicotinamide analyzed by using tryptophan 2,3-dioxygenase-knockout mice
Authors: Maeta Akihiro , Sano Mitsue , Fukuwatari Tsutomu , Funakoshi Hiroshi , Nakamura Toshikazu , Shibata Katsumi
Published: May 2014

We investigated the contribution percentage of tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO) to the conversion of d-tryptophan to nicotinamide in TDO-knockout mice. The calculated percentage conversions indicated that TDO and IDO oxidized 70 and 30%, respectively, of the dietary l-tryptophan. These results indicate that both TDO and IDO biosynthesize nicotinamide from d-tryptophan and l-tryptophan in mice.
Effects of low molecular weight soybean peptide on mRNA and protein expression levels of differentiation markers in normal human epidermal keratinocytes
Authors: Tokudome Yoshihiro , Nakamura Kyosuke , Hashimoto Fumie
Published: May 2014

Low molecular weight soybean peptide (LSP) was applied to normal human epidermal keratinocytes, and the results showed a significant increase in the gene expression levels of involucrin, transglutaminase, and profilaggrin. Filaggrin protein levels were also significantly higher. It is possible that LSP has an epidermal cell differentiation-promoting effect and may be able to regulate metabolism of the epidermis.
Effectiveness of Common Healthcare Disinfectants against H1N1 Influenza Virus on Reusable Elastomeric Respirators
Authors: Subhash Shobha S. , Cavaiuolo Maria , Radonovich Lewis J. , Eagan Aaron , Lee Martin L. , Campbell Sheldon , Martinello Richard A.
Published: May 2014

This study evaluated the efficacy of 3 common hospital disinfectants to inactivate influenza virus on elastomeric respirators. Quaternary ammonium/isopropyl alcohol and bleach detergent wipes eliminated live virus, whereas 70% isopropyl alcohol alone was ineffective.

Infect Control Hosp Epidemiol 2014;35(7):894–897
Complex symmetry of composition operators induced by involutive ball automorphisms
Authors: Noor S. Waleed
Published: May 2014

Suppose

H

\mathcal {H}

is a weighted Hardy space of analytic functions on the unit ball

B

n

⊂

C

n

\mathbb {B}_n\subset \mathbb {C}^n

such that the composition operator

C
ψ

C_\psi

defined by

C

ψ

f
=
f
∘
ψ

C_{\psi }f=f\circ \psi

is bounded on

H

\mathcal {H}

whenever

ψ
\psi

is a linear fractional self-map of

B

n

\mathbb {B}_n

. If

φ
\varphi

is an involutive Moebius automorphism of

B

n

\mathbb {B}_n

, we find a conjugation operator

J

\mathcal {J}

on

H

\mathcal {H}

such that

C

φ

=

J

C

φ

∗

J

C_{\varphi }=\mathcal {J} C^*_{\varphi }\mathcal {J}

. The case

n
=
1

n=1

answers a question of Garcia and Hammond.
GRP78 is a novel receptor initiating a vascular barrier protective response to oxidized phospholipids
Authors: Birukova Anna A. , Singleton Patrick A. , Gawlak Grzegorz , Tian Xinyong , Mirzapoiazova Tamara , Mambetsariev Bolot , Dubrovskyi Oleksii , Oskolkova Olga V. , Bochkov Valery N. , Birukov Konstantin G.
Published: May 2014

Vascular integrity and the maintenance of blood vessel continuity are fundamental features of the circulatory system maintained through endothelial cell–cell junctions. Defects in the endothelial barrier become an initiating factor in several pathologies, including ischemia/reperfusion, tumor angiogenesis, pulmonary edema, sepsis, and acute lung injury. Better understanding of mechanisms stimulating endothelial barrier enhancement may provide novel therapeutic strategies. We previously reported that oxidized phospholipids (oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine [OxPAPC]) promote endothelial cell (EC) barrier enhancement both in vitro and in vivo. This study examines the initiating mechanistic events triggered by OxPAPC to increase vascular integrity. Our data demonstrate that OxPAPC directly binds the cell membrane–localized chaperone protein, GRP78, associated with its cofactor, HTJ-1. OxPAPC binding to plasma membrane–localized GRP78 leads to GRP78 trafficking to caveolin-enriched microdomains (CEMs) on the cell surface and consequent activation of sphingosine 1-phosphate receptor 1, Src and Fyn tyrosine kinases, and Rac1 GTPase, processes essential for cytoskeletal reorganization and EC barrier enhancement. Using animal models of acute lung injury with vascular hyperpermeability, we observed that HTJ-1 knockdown blocked OxPAPC protection from interleukin-6 and ventilator-induced lung injury. Our data indicate for the first time an essential role of GRP78 and HTJ-1 in OxPAPC-mediated CEM dynamics and enhancement of vascular integrity.
The perturbation of electromagnetic fields at distances that are large compared with the object's size
Authors: Ledger Paul D , Lionheart William R B
Published: May 2014

We rigorously derive the leading-order terms in asymptotic expansions for the scattered electric and magnetic fields in the presence of a small object at distances that are large compared with its size. Our expansions hold for fixed wavenumber when the scatterer is a (lossy) homogeneous dielectric object with constant material parameters or a perfect conductor. We also derive the corresponding leading-order terms in expansions for the fields for a low-frequency problem when the scatterer is a non-lossy homogeneous dielectric object with constant material parameters or a perfect conductor. In each case, we express our results in terms of polarization tensors.
Buckling of regular, chiral and hierarchical honeycombs under a general macroscopic stress state
Authors: Haghpanah Babak , Papadopoulos Jim , Mousanezhad Davood , Nayeb-Hashemi Hamid , Vaziri Ashkan
Published: May 2014

An approach to obtain analytical closed-form expressions for the macroscopic ‘buckling strength’ of various two-dimensional cellular structures is presented. The method is based on classical beam-column end-moment behaviour expressed in a matrix form. It is applied to sample honeycombs with square, triangular and hexagonal unit cells to determine their buckling strength under a general macroscopic in-plane stress state. The results were verified using finite-element Eigenvalue analysis.
Lack of antibody response in pigs immunized with the transmembrane envelope protein of porcine endogenous retroviruses
Authors: Keller Martina , Petersen Björn , Niemann Heiner , Denner Joachim
Published: May 2014

Recently, we immunized different mammalian species (goats, mice, rats, rabbits, guinea pigs and hamsters) with the recombinant ectodomain of the transmembrane envelope (TM) protein p15E of porcine endogenous retrovirus (PERV). In all cases, neutralizing immune sera were induced, which recognized epitopes in the fusion peptide proximal region and the membrane proximal external region of p15E. In order to analyse whether pigs are also able to produce such antibodies, and whether such antibodies can be used to study the involvement of the TM protein in placental development (as was shown for endogenous retroviruses of other species), German landrace pigs were immunized with PERV p15E. No binding and neutralizing antibodies were produced as shown in three Western blot analyses and in a neutralization assay, indicating that pigs are tolerant to their endogenous retroviruses, at least for the ectodomain of the TM protein.
Increased susceptibility of transgenic mice expressing human PrP to experimental sheep bovine spongiform encephalopathy is not due to increased agent titre in sheep brain tissue
Authors: Plinston Chris , Hart Patricia , Hunter Nora , Manson Jean C. , Barron Rona M.
Published: May 2014

Bovine spongiform encephalopathy (BSE) in cattle and variant Creutzfeldt–Jakob disease in humans have previously been shown to be caused by the same strain of transmissible spongiform encephalopathy agent. It is hypothesized that the agent spread to humans following consumption of food products prepared from infected cattle. Despite evidence supporting zoonotic transmission, mouse models expressing human prion protein (HuTg) have consistently shown poor transmission rates when inoculated with cattle BSE. Higher rates of transmission have however been observed when these mice are exposed to BSE that has been experimentally transmitted through sheep or goats, indicating that humans may potentially be more susceptible to BSE from small ruminants. Here we demonstrate that increased transmissibility of small ruminant BSE to HuTg mice was not due to replication of higher levels of infectivity in sheep brain tissue, and is instead due to other specific changes in the infectious agent.
Comparative studies on the genetic, antigenic and pathogenic characteristics of Bokeloh bat lyssavirus
Authors: Nolden Tobias , Banyard Ashley C. , Finke Stefan , Fooks Anthony R. , Hanke Dennis , Höper Dirk , Horton Daniel L. , Mettenleiter Thomas C. , Müller Thomas , Teifke Jens P. , Freuling Conrad M.
Published: May 2014

Bokeloh bat lyssavirus (BBLV), a novel lyssavirus, was isolated from a Natterer’s bat (Myotis nattererii), a chiropteran species with a widespread and abundant distribution across Europe. As a novel lyssavirus, the risks of BBLV to animal and human health are unknown and as such characterization both in vitro and in vivo was required to assess pathogenicity and vaccine protection. Full genome sequence analysis and antigenic cartography demonstrated that the German BBLV isolates are most closely related to European bat lyssavirus type 2 (EBLV-2) and Khujand virus and can be characterized within phylogroup I. In vivo characterization demonstrated that BBLV was pathogenic in mice when inoculated peripherally causing clinical signs typical for rabies encephalitis, with higher pathogenicity observed in juvenile mice. A limited vaccination-challenge experiment in mice was conducted and suggested that current vaccines would afford some protection against BBLV although further studies are warranted to determine a serological cut-off for protection.
Collecting reward to defend homeostasis: A homeostatic reinforcement learning theory
Authors: Keramati Mehdi , Gutkin Boris
Published: May 2014

Efficient regulation of internal homeostasis and defending it against perturbations requires complex behavioral strategies. However, the computational principles mediating brain’s homeostatic regulation of reward and associative learning remain undefined. Here we use a definition of primary rewards, as outcomes fulfilling physiological needs, to build a normative theory showing how learning motivated behavior is modulated by the internal state of the animal. The theory proves that seeking rewards is equivalent to the fundamental objective of physiological stability, defining the notion of physiological rationality of behavior. We further give a formal basis for temporal discounting of reward. It also explains how animals learn to act predictively to preclude prospective homeostatic challenges, and attributes a normative computational role to the modulation of midbrain dopaminergic activity by hypothalamic signals.
A new insight for the screening of potential β-lactamase inhibitors
Authors: Singh Vijai , Chaudhary Dharmendra Kumar
Published: May 2014

The β-lactamase produces byAeromonas hydrophilawhich enables to hydrolyze and inactivate β- lactam ring of antibiotics. The homology modeling was used to generate the 3-D model of β-lactamase by using known template 3-D structure. The stereochemical quality and torsion angle of 3-D model were validated. Total eleven effective drugs have been selected and targeted the active amino acid residues in β-lactamase. The drugs were derivative of β-lactam ring antibiotics and screening was made by docking. Out of 11 drugs, 3 drugs (Ampicillin, Astreonam and Sultamicillin) were found to be more potent on the basis of robust binding energy between protein-drug interactions. Additionally, homology of β-lactamase ofA. hydrophilaresembled with other pathogenic bacteria that used for phylogeny analysis. These findings suggest a new insight for better understanding and useful for designing of novel potent drugs.
Roles of SLX1–SLX4, MUS81–EME1, and GEN1 in avoiding genome instability and mitotic catastrophe
Authors: Sarbajna Shriparna , Davies Derek , West Stephen C.
Published: May 2014

The resolution of recombination intermediates containing Holliday junctions (HJs) is critical for genome maintenance and proper chromosome segregation. Three pathways for HJ processing exist in human cells and involve the following enzymes/complexes: BLM–TopoIIIα–RMI1–RMI2 (BTR complex), SLX1–SLX4–MUS81–EME1 (SLX–MUS complex), and GEN1. Cycling cells preferentially use the BTR complex for the removal of double HJs in S phase, with SLX–MUS and GEN1 acting at temporally distinct phases of the cell cycle. Cells lacking SLX–MUS and GEN1 exhibit chromosome missegregation, micronucleus formation, and elevated levels of 53BP1-positive G1 nuclear bodies, suggesting that defects in chromosome segregation lead to the transmission of extensive DNA damage to daughter cells. In addition, however, we found that the effects of SLX4, MUS81, and GEN1 depletion extend beyond mitosis, since genome instability is observed throughout all phases of the cell cycle. This is exemplified in the form of impaired replication fork movement and S-phase progression, endogenous checkpoint activation, chromosome segmentation, and multinucleation. In contrast to SLX4, SLX1, the nuclease subunit of the SLX1–SLX4 structure-selective nuclease, plays no role in the replication-related phenotypes associated with SLX4/MUS81 and GEN1 depletion. These observations demonstrate that the SLX1–SLX4 nuclease and the SLX4 scaffold play divergent roles in the maintenance of genome integrity in human cells.
Higher chromatin mobility supports totipotency and precedes pluripotency in vivo
Authors: Bošković Ana , Eid André , Pontabry Julien , Ishiuchi Takashi , Spiegelhalter Coralie , Raghu Ram Edupuganti V.S. , Meshorer Eran , Torres-Padilla Maria-Elena
Published: May 2014

The fusion of the gametes upon fertilization results in the formation of a totipotent cell. Embryonic chromatin is expected to be able to support a large degree of plasticity. However, whether this plasticity relies on a particular conformation of the embryonic chromatin is unknown. Moreover, whether chromatin plasticity is functionally linked to cellular potency has not been addressed. Here, we adapted fluorescence recovery after photobleaching (FRAP) in the developing mouse embryo and show that mobility of the core histones H2A, H3.1, and H3.2 is unusually high in two-cell stage embryos and decreases as development proceeds. The transition toward pluripotency is accompanied by a decrease in histone mobility, and, upon lineage allocation, pluripotent cells retain higher mobility than the differentiated trophectoderm. Importantly, totipotent two-cell-like embryonic stem cells also display high core histone mobility, implying that reprogramming toward totipotency entails changes in chromatin mobility. Our data suggest that changes in chromatin dynamics underlie the transitions in cellular plasticity and that higher chromatin mobility is at the nuclear foundations of totipotency.
E3 ligase Hei10: a multifaceted structure-based signaling molecule with roles within and beyond meiosis
Authors: De Muyt Arnaud , Zhang Liangran , Piolot Tristan , Kleckner Nancy , Espagne Eric , Zickler Denise
Published: May 2014

Human enhancer of invasion-10 (Hei10) mediates meiotic recombination and also plays roles in cell proliferation. Here we explore Hei10’s roles throughout the sexual cycle of the fungus Sordaria with respect to localization and effects of null, RING-binding, and putative cyclin-binding (RXL) domain mutations. Hei10 makes three successive types of foci. Early foci form along synaptonemal complex (SC) central regions. At some of these positions, depending on its RING and RXL domains, Hei10 mediates development and turnover of two sequential types of recombination complexes, each demarked by characteristic amplified Hei10 foci. Integration with ultrastructural data for recombination nodules further reveals that recombination complexes differentiate into three types, one of which corresponds to crossover recombination events during or prior to SC formation. Finally, Hei10 positively and negatively modulates SUMO localization along SCs by its RING and RXL domains, respectively. The presented findings suggest that Hei10 integrates signals from the SC, associated recombination complexes, and the cell cycle to mediate both the development and programmed turnover/evolution of recombination complexes via SUMOylation/ubiquitination. Analogous cell cycle-linked assembly/disassembly switching could underlie localization and roles for Hei10 in centrosome/spindle pole body dynamics and associated nuclear trafficking. We suggest that Hei10 is a unique type of structure-based signal transduction protein.
Development of a microsecond X-ray protein footprinting facility at the Advanced Light Source
Authors: Gupta Sayan , Celestre Richard , Petzold Christopher J. , Chance Mark R. , Ralston Corie
Published: May 2014

X-ray footprinting (XF) is an important structural biology tool used to determine macromolecular conformations and dynamics of both nucleic acids and proteins in solution on a wide range of timescales. With the impending shut-down of the National Synchrotron Light Source, it is ever more important that this tool continues to be developed at other synchrotron facilities to accommodate XF users. Toward this end, a collaborative XF program has been initiated at the Advanced Light Source using the white-light bending-magnet beamlines 5.3.1 and 3.2.1. Accessibility of the microsecond time regime for protein footprinting is demonstrated at beamline 5.3.1 using the high flux density provided by a focusing mirror in combination with a micro-capillary flow cell. It is further reported that, by saturating samples with nitrous oxide, the radiolytic labeling efficiency is increased and the imprints of boundversusbulk water can be distinguished. These results both demonstrate the suitability of the Advanced Light Source as a second home for the XF experiment, and pave the way for obtaining high-quality structural data on complex protein samples and dynamics information on the microsecond timescale.
Quantitative evaluation of a single-distance phase-retrieval method applied on in-line phase-contrast images of a mouse lung
Authors: Mohammadi Sara , Larsson Emanuel , Alves Frauke , Dal Monego Simeone , Biffi Stefania , Garrovo Chiara , Lorenzon Andrea , Tromba Giuliana , Dullin Christian
Published: May 2014

Propagation-based X-ray phase-contrast computed tomography (PBI) has already proven its potential in a great variety of soft-tissue-related applications including lung imaging. However, the strong edge enhancement, caused by the phase effects, often hampers image segmentation and therefore the quantitative analysis of data sets. Here, the benefits of applying single-distance phase retrieval prior to the three-dimensional reconstruction (PhR) are discussed and quantified compared with three-dimensional reconstructions of conventional PBI data sets in terms of contrast-to-noise ratio (CNR) and preservation of image features. The PhR data sets show more than a tenfold higher CNR and only minor blurring of the edges when compared with PBI in a predominately absorption-based set-up. Accordingly, phase retrieval increases the sensitivity and provides more functionality in computed tomography imaging.
Comparative Urbanism and the ‘Asian City': Implications for Research and Theory
Authors: Ren Julie , Luger Jason
Published: May 2014

While voices in the comparative urbanism literature call for researchers to approach comparison with more experimental and critical methodologies, there remains no consensus on how to design and realize these studies. This essay examines the implications of comparative urbanism for researching the ‘Asian City'. Given the critique of existing modes of comparison embedded in recent calls for a new comparative urbanism, researchers are faced with a number of pressing questions: How do we approach this ‘regional' topic in a way that both resists categorizing the ‘Asian City' as an exotic ‘other', elevating it onto a mythical pedestal, yet appreciates its differences, localisms and unique ‘cosmopolitan vernacular' (Clifford, 1997; Werbner and Modood, 1997)? This essay thus highlights the multiple challenges of applying the comparative lens to the ‘Asian City', arguing that broader conceptualizations of the ‘Asian City' help to address the dangers in isolating Asian research into its own canon of parochial urban theory and offering a greater diversity of possibilities for justifying case selection in comparative approaches. In doing so, we hope that this essay responds to the comparative turn by illuminating to some extent its inherent complexity and methodological challenges.
Gestation‐specific D‐dimer reference ranges: a cross‐sectional study
Authors: Murphy N , Broadhurst DI , Khashan AS , Gilligan O , Kenny LC , O'Donoghue K
Published: May 2014

Objective

To establish a gestation‐specific reference range for D‐dimer in healthy pregnant women with a singleton pregnancy using the Auto‐Dimer assay.

Design

Cross‐sectional study

Setting

Cork University Maternity Hospital, Ireland.

Population

Healthy pregnant women attending for routine antenatal care.

Methods

Simultaneous‐quantile regression was performed to construct a median, 5th percentile, and 95th percentile, model of normal pregnancy D‐dimer concentration versus gestational week, ranging from week 6 to 42. Additionally, pair‐wise Mann–Whitney U‐tests were performed to compare distributions of D‐dimer concentrations for each of the four discrete gestational sampling windows with the distribution of D‐dimer concentrations 48 hours postpartum.

Main outcome measures

D‐dimer concentrations (ng/ml) during normal gestation (approximately week 6 to week 42).

Results

Seven hundred and sixty healthy pregnant women were investigated between gestational age week 5 and 48 hours postpartum. There was a clear steady increase in median D‐dimer concentrations over the complete gestational period. Additionally, the 95th centile estimates for all gestational time‐points were above the accepted non‐pregnancy normal cut‐off concentration (224 ng/ml). The results of the Mann–Whitney U‐tests suggested that the long‐term postnatal return to normal D‐dimer concentrations begins in the immediate postpartum period.

Conclusions

We found that there is a continuous increase in D‐dimer concentrations across all gestations. This research is potentially beneficial to future diagnosis of venous thromboembolism (VTE) in pregnancy using the new recommended 95th centile potential cut‐offs. Possible further investigation involves an observational study comparing D‐dimer concentrations in women with proven DVT with those that don't, generating likelihood ratios.
Attitudes and self‐efficacy of pre‐service teachers towards inclusion in Pakistan
Authors: Sharma Umesh , Shaukat Sadia , Furlonger Brett
Published: May 2014

This study sought to determine the attitudes and teaching self‐efficacy of pre‐service teachers towards the inclusion of students with disabilities into regular classrooms. A questionnaire was administered to 194 pre‐service Pakistani teachers (male 73, female 121) enrolled in a 1‐year teacher education programme at a government university in Pakistan. Overall, male pre‐service teachers expressed more positive attitudes than their female counterparts regarding the inclusion of students with disabilities in regular classrooms. Surprisingly, those pre‐service teachers majoring in special education did not express more positive attitudes towards inclusion than their counterparts who were preparing to teach in mainstream schools. However, participants with training in special education, knowledge of disability legislation, teaching experience and personal experience with a disability reported higher levels of self‐efficacy towards teaching within inclusive settings. The findings of the study are discussed with possible implications for policy‐makers and teacher educators in Pakistan and other countries in the South Asian region.
Underlying liver disease influences volumetric changes in the spared hemiliver after selective internal radiation therapy with 90Y in patients with hepatocellular carcinoma
Authors: Teo Jin Yao , Goh Brian Kim Poh , Cheah Foong Koon , Allen John Carson , Lo Richard Hoau Gong , Ng David Chee Eng , Goh Anthony Soon Whatt , Khor Andrew Yu Keat , Sim Hui Shan , Ng Jia Jun , Chow Pierce Kah‐Hoe
Published: May 2014

Objective

Hypertrophy of the contralateral liver lobe after treatment with yttrium‐90 (90Y) microspheres has recently been reported. This study aimed to quantify left hepatic lobe hypertrophy after right‐sided radioembolization for hepatocellular carcinoma (HCC) and to identify pretreatment predictive factors of hypertrophy in an Asian population.

Methods

A retrospective review of patients with inoperable HCC undergoing selective internal radiation treatment (SIRT) with 90Y microspheres at a single institution from January 2008 to January 2012 was performed. Only patients who had treatment delivered via the right hepatic artery alone were included.

Results

In all, 17 patients fulfilling the study criteria were identified. The mean percentage of left‐lobe hypertrophy was 34.2% ± 34.9% (range 19.0–106.5%) during a median of 5‐month follow‐up. Patients with hepatitis B were found to experience a significantly greater degree of hypertrophy than those with hepatitis C or alcoholic liver cirrhosis. There were no cases of acute liver failure after the administration of SIRT in this study and none of the patients developed disease in the contralateral lobe over the study period.

Conclusions

Administration of unilobar SIRT to the right liver lobe in patients with HCC resulted in a significant degree of contralateral left lobe hypertrophy. Patients with hepatitis B experienced a greater degree of hypertrophy than those with hepatitis C or alcoholic liver cirrhosis.