bluuebunny/crossref_metadata_2025 huggingface dataset:
Viscoelastic modeling of nanoindentation experiments: A multicurve method
Authors: Zhai Meiyu , McKenna Gregory B.
Published: March 2014

Nanoindentation is an increasingly used method of extracting surface mechanical properties of viscoelastic materials, especially polymers. Recently, Hutcheson and McKenna used a viscoelastic contact mechanics model to analyze the contact problem between a nanosphere and polystyrene surface. In nanoindentation experiments, the ramp loading test is a similar problem to the particle embedment experiment except that the indentation load function differs. The motivation in this work is to expand the Hutcheson and McKenna analysis to the nanoindentation problem. In particular, we illustrate the limitations of analyzing only a single load‐indentation curve, which does not provide enough information to determine the full range of the viscoelastic response of a polymer, and we show that performing a test sequence that includes multiple loading rates or indentation rates spanning two or more orders of magnitude greatly improves the extracted viscoelastic properties. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 633–639
Structure–activity study of macropin, a novel antimicrobial peptide from the venom of solitary bee Macropis fulvipes (Hymenoptera: Melittidae)
Authors: Monincová Lenka , Veverka Václav , Slaninová Jiřina , Buděšínský Miloš , Fučík Vladimír , Bednárová Lucie , Straka Jakub , Čeřovský Václav
Published: March 2014

A novel antimicrobial peptide, designated macropin (MAC‐1) with sequence Gly‐Phe‐Gly‐Met‐Ala‐Leu‐Lys‐Leu‐Leu‐Lys‐Lys‐Val‐Leu‐NH2, was isolated from the venom of the solitary bee Macropis fulvipes. MAC‐1 exhibited antimicrobial activity against both Gram‐positive and Gram‐negative bacteria, antifungal activity, and moderate hemolytic activity against human red blood cells. A series of macropin analogs were prepared to further evaluate the effect of structural alterations on antimicrobial and hemolytic activities and stability in human serum. The antimicrobial activities of several analogs against pathogenic Pseudomonas aeruginosa were significantly increased while their toxicity against human red blood cells was decreased. The activity enhancement is related to the introduction of either l‐ or d‐lysine in selected positions. Furthermore, all‐d analog and analogs with d‐amino acid residues introduced at the N‐terminal part of the peptide chain exhibited better serum stability than did natural macropin. Data obtained by CD spectroscopy suggest a propensity of the peptide to adopt an amphipathic α‐helical secondary structure in the presence of trifluoroethanol or membrane‐mimicking sodium dodecyl sulfate. In addition, the study elucidates the structure–activity relationship for the effect of d‐amino acid substitutions in MAC‐1 using NMR spectroscopy. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.
A spin glass perspective on ferroic glasses
Authors: Sherrington David
Published: March 2014

A range of ferroic glasses, magnetic, polar, relaxor and strain glasses, are considered together from the perspective of spin glasses. Simple mathematical modelling is shown to provide a possible conceptual unification to back similarities of experimental observations, without considering all possible complexities and alternatives.
Prenatal exposure to PFOS caused mitochondia‐mediated apoptosis in heart of weaned rat
Authors: Zeng Huai‐cai , He Qing‐zhi , Li Yuan‐yuan , Wu Cheng‐qiu , Wu Yi‐mou , Xu Shun‐qing
Published: March 2014

Perfluorooctanyl sulfonate (PFOS), a cardiac toxicity compound, has been widely detected in the environment and in organisms. However, the toxic mechanism is not clear. Our previous study indicated that prenatal PFOS exposure led to swollen mitochondrial with vacuolar structure and loss of cristae in offsping's heart. The purpose of this study was to investigate the effect of PFOS on the apoptosis in developing heart and mitochondria‐mediated apoptosis pathway. Pregnant Sprague‐Dawley (SD) rats were exposed to PFOS at doses of 0.1, 0.6, and 2.0 mg/kg‐d and 0.05% Tween 80 as control by gavage from gestation day 2 (GD 2) to GD 21. Apoptosis, as well as expression of apoptosis related genes associated with mitochondrial‐mediated apoptosis pathway, including p53, bcl‐2, bax, cytochrome c, caspase‐9, and caspase‐3 were analyzed in heart tissues from weaned (postnatal day 21, PND 21) offspring. The results showed that prenatal PFOS exposure resulted in apoptosis in the offspring's heart. The mRNA and protein expression levels of p53, bax, cytochrome c, caspase‐9, and caspase‐3 in the offspring's heart were enhanced in various PFOS‐treated groups, meanwhile, the bcl‐2 expression levels were decreased. Our results indicated that prenatal PFOS exposure induced the apoptosis of weaned offspring rat heart tissue via mitochondria‐mediated apoptotic pathway. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1082–1090, 2015.
Molecular mechanisms of silk gland damage caused by phoxim exposure and protection of phoxim‐induced damage by cerium chloride in Bombyx mori
Authors: Li Bing , Sun Qingqing , Yu Xiaohong , Xie Yi , Hong Jie , Zhao Xiaoyang , Sang Xuezi , Shen Weide , Hong Fashui
Published: March 2014

It is known that exposure to organophosphorus pesticides (OP) including phoxim can produce oxidative stress, neurotoxicity, and greatly attenuate cocooning rate in the silkworm, Bombyx mori. Cerium treatment has been demonstrated to relieve phoxim‐induced toxicity in B. mori; however, very little is known about the molecular mechanisms of silk gland injury due to OP exposure and protection of gland damage due to cerium pretreatment. The aim of this study was to evaluate silk gland damage and its molecular mechanisms in phoxim‐induced silkworm toxicity and the protective mechanisms of cerium following exposure to phoxim. The results showed that phoxim exposure resulted in severe gland damage, reductions in protein synthesis and the cocooning rate of silkworms. Cerium (Ce) attenuated gland damage caused by phoxim, promoted protein synthesis, increased the antioxidant capacity of the gland and increased the cocooning rate of B. mori. Furthermore, digital gene expression data suggested that phoxim exposure led to significant up‐regulation of 714 genes and down‐regulation of 120 genes. Of these genes, 122 were related to protein metabolism, specifically, the down‐regulated Ser2, Ser3, Fib‐L, P25, and CYP450. Ce pretreatment resulted in up‐regulation of 162 genes, and down‐regulation of 141 genes, importantly, Ser2, Ser3, Fib‐L, P25, and CYP333B8 were up‐regulated. Treatment with CeCl3 + phoxim resulted in higher levels of Fib‐L, P25, Ser2, Ser3, CAT, TPx, and CYP333B8 expression in the silk gland of silkworms. These findings indicated that Ce increased cocooning rate via the promotion of silk protein synthesis‐related gene expression in the gland under phoxim‐induced toxicity. These findings may expand the application of rare earths in sericulture. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1102–1111, 2015.
Range‐wide population size of the lesser prairie‐chicken: 2012 and 2013
Authors: McDonald Lyman , Beauprez Grant , Gardner Grant , Griswold Jim , Hagen Christian , Hornsby Fawn , Klute David , Kyle Sean , Pitman James , Rintz Troy , Schoeling Doug , Van Pelt Bill
Published: March 2014

We flew aerial line‐transect surveys to estimate the range‐wide population size of lesser prairie‐chickens (Tympanuchus pallidicinctus) in the Great Plains, United States in 2012 and 2013. We also estimated the number of lesser prairie‐chicken leks, the number of mixed‐species leks that contained both lesser and greater prairie‐chickens (T. cupido) and the number of hybrid lesser–greater prairie‐chickens where these species' ranges overlap. The study area included the 2011 estimated occupied lesser prairie‐chicken range in 5 states and was divided into 4 ecoregions. We created a sampling frame over the study area, consisting of 536 15‐ × 15‐km grid cells. We flew 512 transects within a probabilistic sample of 256 cells totaling 7,680 km in 2012 and 566 transects within a probabilistic sample of 283 cells totaling 8,490 km in 2013. We estimated a total of 34,440 individual lesser prairie‐chickens in 2012 (17,615 in 2013) and 350 hybrid lesser–greater prairie‐chickens in 2012 (342 in 2013) in the study area. We estimated a total of 2,930 lesser prairie‐chicken leks in 2012 (2,037 in 2013) and 453 lesser and greater prairie‐chicken mixed leks in 2012 (356 in 2013) in the study area. We discuss the implications of alternative sampling designs with regard to conservation questions to be addressed. © 2014 The Wildlife Society.
The Operating Room During a Severe Earthquake: Lessons From the 2011 Great East Japan Earthquake
Authors: Suzuki Yasuyuki , Fukuda Ikuo , Nakaji Shigeyuki
Published: March 2014

Objective

The Great East Japan Earthquake occurred at 14:46 on March 11, 2011, producing serious and widespread damage. To assess damages in hospital operating departments during and after the earthquake, we surveyed hospitals in this region.

Methods

Questionnaires were sent to 415 acute care hospitals in Tohoku and east Kanto areas. The questionnaires elicited the number of perioperative patients when the earthquake hit, obstacles to continuing surgery, structural and nonstructural damage to the operating department, and the effect on routine surgery after the earthquake.

Results

Of the 213 hospitals (51%) that completed questionnaires, 474 patients were undergoing operations during the earthquake, and 222 operations were canceled afterward. Risk factors for continuing operations, as reported by 102 hospitals, were tremors and electrical blackouts (odds ratio [OR]: 79.3 and 110.5; P < .01). In 154 hospitals, difficulties in performing operations after the earthquake were reported. Significant obstacles to the management of operations after the earthquake were characterized by infrastructure disorder scores, seismic intensity, disruption of electrical power and air conditioning, and damage to out-of-hospital telecommunications (OR, 0.46; P = .04).

Conclusions

Tremors and electrical blackouts were important risk factors for performing operations. Nonstructural damage, especially to out-of-hospital telecommunications, affected the management of the operating rooms. Hospital logistics are very important to achieve appropriate disaster management. (Disaster Med Public Health Preparedness. 2014;0:1–7)
A NONSEPARABLE AMENABLE OPERATOR ALGEBRA WHICH IS NOT ISOMORPHIC TO A -ALGEBRA
Authors: CHOI YEMON , FARAH ILIJAS , OZAWA NARUTAKA
Published: March 2014

It has been a long-standing question whether every amenable operator algebra is isomorphic to a (necessarily nuclear) $\mathrm{C}^*$-algebra. In this note, we give a nonseparable counterexample. Finding out whether a separable counterexample exists remains an open problem. We also initiate a general study of unitarizability of representations of amenable groups in $\mathrm{C}^*$-algebras and show that our method cannot produce a separable counterexample.
Inertial particle trapping in an open vortical flow
Authors: Angilella Jean-Régis , Vilela Rafael D. , Motter Adilson E.
Published: March 2014

Recent numerical results on advection dynamics have shown that particles denser than the fluid can remain trapped indefinitely in a bounded region of an open fluid flow. Here, we investigate this counterintuitive phenomenon both numerically and analytically to establish the conditions under which the underlying particle-trapping attractors can form. We focus on a two-dimensional open flow composed of a pair of vortices and its specular image, which is a system we represent as a vortex pair plus a wall along the symmetry line. Considering particles that are much denser than the fluid, referred to as heavy particles, we show that two attractors form in the neighbourhood of the vortex pair provided that the particle Stokes number is smaller than a critical value of order unity. In the absence of the wall, the attractors are fixed points in the frame rotating with the vortex pair, and the boundaries of their basins of attraction are smooth. When the wall is present, the point attractors describe counter-rotating ellipses in this frame, with a period equal to half the period of one isolated vortex pair. The basin boundaries remain smooth if the distance from the vortex pair to the wall is large. However, these boundaries are shown to become fractal if the distance to the wall is smaller than a critical distance that scales with the inverse square root of the Stokes number. This transformation is related to the breakdown of a separatrix that gives rise to a heteroclinic tangle close to the vortices, which we describe using a Melnikov function. For an even smaller distance to the wall, we demonstrate that a second separatrix breaks down and a new heteroclinic tangle forms farther away from the vortices, at the boundary between the open and closed streamlines. Particles released in the open part of the flow can approach the attractors and be trapped permanently provided that they cross the two separatrices, which can occur under the effect of flow unsteadiness. Furthermore, the trapping of heavy particles from the open flow is shown to be robust to the presence of viscosity, noise and gravity. Navier–Stokes simulations for large flow Reynolds numbers show that viscosity does not destroy the attracting points until vortex merging takes place, while simulation of thermal noise shows that particle trapping persists for extended periods provided that the Péclet number is large. The presence of a gravitational field does not alter the permanent trapping by the attracting points if the settling velocities are not too large. For larger settling velocities, however, gravity can also give rise to a limit-cycle attractor next to the external separatrix and to a new form of trapping from the open flow that is not mediated by a heteroclinic tangle.
Astrometric Observations of X-ray Binaries Using Very Long Baseline Interferometry
Authors: Miller-Jones James C. A.
Published: March 2014

I review the astrophysical insights arising from high-precision astrometric observations of X-ray binary systems, focussing primarily (but not exclusively) on recent results with very long baseline interferometry. Accurate, model-independent distances from geometric parallax measurements can help determine physical parameters of the host binary system and constrain black hole spins via broadband X-ray spectral modelling. Long-term proper motion studies, combined with binary evolution calculations, can provide observational constraints on the formation mechanism of black holes. Finally, the astrometric residuals from parallax and proper motion fits can provide information on orbital sizes and jet physics. I end by discussing prospects for future progress in this field.
Pivotality and Turnout: Evidence from a Field Experiment in the Aftermath of a Tied Election
Authors: Enos Ryan D. , Fowler Anthony
Published: March 2014

Many citizens abstain from the political process, and the reasons for this abstention are of great interest and importance. Most scholars and pundits assume that greater electoral competition and the increased chance of pivotality will motivate citizens to participate. We test this hypothesis through a large-scale field experiment that exploits the rare opportunity of a tied election for major political office. Informing citizens that an upcoming election will be close has little mobilizing effect. Any effect that we do detect is concentrated among a small set of frequent voters. The evidence suggests that increased pivotality is not a solution to low turnout and the predominant models of turnout focusing on pivotality are of little practical use.
The 1903 Human Pavilion: Colonial Realities and Subaltern Subjectivities in Twentieth-Century Japan
Authors: Ziomek Kirsten L.
Published: March 2014

This article discusses the 1903 Human Pavilion's Ainu Fushine Kōzō, who advanced a notion of imperial subjecthood, where one could be Ainu and a loyal subject of the Japanese empire. Fushine urged that the Ainu be treated equitably not because all races were equal, a rather modern and Western notion, but because he viewed imperial subjecthood as predicated upon military conscription and being children of the emperor. I examine the removal of the Okinawan women, Nakamura Kame and Uehara Ushi, from the display, amidst a larger debate where competing visions of imperial subjecthood and what it meant to be civilized were tied up with the charge that the pavilion was a humanitarian concern (jindō mondai). The Human Pavilion became a nexus between colonial and imperial subjects, which, rather than reifying distinctions between the two, called into question the coherence of civilizational taxonomies in Japan and the world.
Factors affecting duration of gastrostomy tube retention in survivors following treatment for head and neck cancer
Authors: Blanchford H , Hamilton D , Bowe I , Welch S , Kumar R , Moor J W , Welch A R , Paleri V
Published: March 2014

Background:

Many patients treated for head and neck cancer require nutritional support, which is often delivered using a gastrostomy tube. It is difficult to predict which patients will retain their gastrostomy tube in the long term. This study aimed to identify the factors which affect the duration of gastrostomy tube retention.

Method:

In this retrospective study, 151 consecutive patients from one centre were audited. All patients had a mucosal tumour of the head and neck, and underwent gastrostomy tube insertion between 2003 and 2007.

Results:

There were near-complete data sets for 132 patients. The gastrostomy tube was retained in survivors (n = 66) for a mean of 21.3 months and in non-survivors (n = 66) for 11.9 months. Univariate analysis showed that co-morbidity was the only factor which significantly increased duration of gastrostomy tube retention in survivors (p = 0.041).

Conclusion:

Co-morbidity alone was associated with a significant increase in gastrostomy tube retention. It is suggested that co-morbidity be included as a variable in future relevant research. Co-morbidity should also be considered when counselling patients about their long-term function following cancer treatment. Gastrostomy tube retention is likely to be affected by many factors, with few single variables having importance independently.
Inventory of organisms interfering with transmission of a marine trematode
Authors: Welsh Jennifer E. , van der Meer Jaap , Brussaard Corina P.D. , Thieltges David W.
Published: March 2014

It has increasingly been recognized that organisms can interfere with parasitic free-living stages, preventing them from infecting their specified host and thus reducing infection levels. This common phenomenon in freshwater and terrestrial systems has been termed the ‘dilution effect’ and, so far, is poorly studied in marine systems. Ten common intertidal organisms found in the Dutch Wadden Sea (North Sea) were tested to establish their effects on the free-living cercarial stages of the trematode parasite Himasthla elongata. Most species tested resulted in a significant reduction in cercariae over a 3 hr time period. The amphipod Gammarus marinus removed 100% of the cercariae, while other effective diluters were Crangon crangon (93%), Sargassum muticum (87%), Semibalanus balanoides (71%), Crassostrea gigas (67%), Hemigrapsus takanoi (>54%), Crassostrea gigas shells (44%) and Idotea balthica (24%). In contrast, mixed shells (Cerastoderma edule, Mytilus edulis, Ensis americanus and Littorina littorea) and Fucus versiculosus had no significant effect. These results suggest that dilution effects are widespread in the trematode of H. elongata, with potentially strong effects on its population dynamics.
Description of a new species ofAbyssoninoe(Polychaeta: Lumbrineridae) from north-east Sicily (central Mediterranean Sea)
Authors: D'Alessandro Michela , Cosentino Andrea , Giacobbe Salvatore , Andaloro Franco , Romeo Teresa
Published: March 2014

A new species ofAbyssoninoe(Polychaeta: Lumbrineridae) has been found on sublittoral soft bottoms in the Gulf of Milazzo (central Mediterranean Sea). The description is based on eleven specimens recorded in six grab samples carried out by Van Veen grab from 20 to 50 m depth.Abyssoninoe bidentatasp. nov. differs from the six hitherto known species ofAbyssoninoeby having the maxillae III with two subequal teeth instead of one, the shape of the parapodial lobes and chaetal distribution.
Empirical evidence for discrete neurocognitive subgroups in bipolar disorder: clinical implications
Authors: Burdick K. E. , Russo M. , Frangou S. , Mahon K. , Braga R. J. , Shanahan M. , Malhotra A. K.
Published: March 2014

Background

Recent data suggest trait-like neurocognitive impairments in bipolar disorder (BPD), with deficits about 1 s.d.below average, less severe than deficits noted in schizophrenia. The frequency of significant impairment in BPD is approximately 60%, with 40% of patients characterized as cognitively spared. This contrasts with a more homogeneous presentation in schizophrenia. It is not understood why some BPD patients develop deficits while others do not.

Method

A total of 136 patients with BPD completed the MATRICS Consensus Cognitive Battery and data were entered into hierarchical cluster analyses to: (1) determine the optimal number of clusters (subgroups) that fit the sample; and (2) assign subjects to a specific cluster based on individual profiles. We then compared subgroups on several clinical factors and real-world community functioning.

Results

Three distinct neurocognitive subgroups were found: (1) an intact group with performance comparable with healthy controls on all domains but with superior social cognition; (2) a selective impairment group with moderate deficits on processing speed, attention, verbal learning and social cognition and normal functioning in other domains; and (3) a global impairment group with severe deficits across all cognitive domains comparable with deficits in schizophrenia.

Conclusions

These results suggest the presence of multiple cognitive subgroups in BPD with unique profiles and begin to address the relationships between these subgroups, several clinical factors and functional outcome. Next steps will include using these data to help guide future efforts to target these disabling symptoms with treatment.
Quantitative Electrochemical Measurements Using In Situ ec-S/TEM Devices
Authors: Unocic Raymond R. , Sacci Robert L. , Brown Gilbert M. , Veith Gabriel M. , Dudney Nancy J. , More Karren L. , Walden Franklin S. , Gardiner Daniel S. , Damiano John , Nackashi David P.
Published: March 2014

Insight into dynamic electrochemical processes can be obtained with in situ electrochemical-scanning/transmission electron microscopy (ec-S/TEM), a technique that utilizes microfluidic electrochemical cells to characterize electrochemical processes with S/TEM imaging, diffraction, or spectroscopy. The microfluidic electrochemical cell is composed of microfabricated devices with glassy carbon and platinum microband electrodes in a three-electrode cell configuration. To establish the validity of this method for quantitative in situ electrochemistry research, cyclic voltammetry (CV), choronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) were performed using a standard one electron transfer redox couple [Fe(CN)6]3−/4−-based electrolyte. Established relationships of the electrode geometry and microfluidic conditions were fitted with CV and chronoamperometic measurements of analyte diffusion coefficients and were found to agree with well-accepted values that are on the order of 10−5 cm2/s. Influence of the electron beam on electrochemical measurements was found to be negligible during CV scans where the current profile varied only within a few nA with the electron beam on and off, which is well within the hysteresis between multiple CV scans. The combination of experimental results provides a validation that quantitative electrochemistry experiments can be performed with these small-scale microfluidic electrochemical cells provided that accurate geometrical electrode configurations, diffusion boundary layers, and microfluidic conditions are accounted for.
The Simple Rules of Social Contagion
Authors: Hodas Nathan O. , Lerman Kristina
Published: March 2014

It is commonly believed that information spreads between individuals like a pathogen, with each exposure by an informed friend potentially resulting in a naive individual becoming infected. However, empirical studies of social media suggest that individual response to repeated exposure to information is far more complex. As a proxy for intervention experiments, we compare user responses to multiple exposures on two different social media sites, Twitter and Digg. We show that the position of exposing messages on the user-interface strongly affects social contagion. Accounting for this visibility significantly simplifies the dynamics of social contagion. The likelihood an individual will spread information increases monotonically with exposure, while explicit feedback about how many friends have previously spread it increases the likelihood of a response. We provide a framework for unifying information visibility, divided attention and explicit social feedback to predict the temporal dynamics of user behavior.
Strengthening N⋯X halogen bonding via nitrogen substitution in the aromatic framework of halogen-substituted arylpyrazinamides
Authors: Khavasi Hamid Reza , Hosseini Mahdieh , Tehrani Alireza Azhdari , Naderi Soheila
Published: March 2014

The importance of N⋯X halogen bonding in a series of N-(5-halo-2-pyridinyl)pyrazine-2-carboxamides has been investigated by different methods.
Metal–organic frameworks as solid catalysts for the synthesis of nitrogen-containing heterocycles
Authors: Dhakshinamoorthy Amarajothi , Garcia Hermenegildo
Published: March 2014

This Critical Review summarizes the recent developments in the use of metal–organic frameworks as catalysts for the synthesis of nitrogen-containing heterocycles.
Exploration of new second-order nonlinear optical materials of the Cs–Hg–Br–I system
Authors: Wu Qi , Huang Yin , Meng Xianggao , Zhong Cheng , Chen Xingguo , Qin Jingui
Published: March 2014

A new compound, Cs2Hg2Br2I4·H2O, was synthesized to achieve a better balance between nonlinear optical properties and its band gap.
The one pot synthesis of heterobimetallic complexes from a homoditopic pyrimidine–hydrazone ligand
Authors: Hutchinson Daniel J. , Hanton Lyall R. , Moratti Stephen C.
Published: March 2014

Three new heterobimetallic complexes have been synthesised facilely in high yield and purity from a symmetric homoditopic pyrimidine-hydrazone ligand in a one-pot, two step reaction.
Probing the 2D-to-3D structural transition in gold clusters with a single sulfur atom: AuxS0,±1 (x = 1–10)
Authors: Wen Hui , Liu Yi-Rong , Xu Kang-Ming , Huang Teng , Hu Chang-Jin , Zhang Wei-Jun , Huang Wei
Published: March 2014

Gold sulfur clusters have received much attention because of the dramatic effect that the gold–sulfide interaction produces in thiol-passivated gold nanoparticles.
Simple click reactions on polymer surfaces leading to antimicrobial behavior
Authors: Pearson Heather A. , Urban Marek W.
Published: March 2014

Microwave plasma and click chemistry on polymeric substrates.
Fused H-shaped tetrathiafulvalene–oligothiophenes as charge transport materials for OFETs and OPVs
Authors: Wright Iain A. , Findlay Neil J. , Arumugam Sasikumar , Inigo Anto R. , Kanibolotsky Alexander L. , Zassowski Pawel , Domagala Wojciech , Skabara Peter J.
Published: March 2014

Complex multi-redox-active organic semiconductors have been made incorporating tetrathiafulvalene as a fused bridge between oligothiophene chains.
Development of a particle-settling tolerant transmission Raman scheme for analysis of suspension samples
Authors: Shin Kayeong , Duy Pham Khac , Park Sijun , Woo Young-Ah , Chung Hoeil
Published: March 2014

We have demonstrated a simple and effective strategy, the so-called axial illumination scheme, that is able to obtain representative Raman spectra of suspension samples with minimal influence from internal particle settling.
CotA laccase: high-throughput manipulation and analysis of recombinant enzyme libraries expressed in E. coli using droplet-based microfluidics
Authors: Beneyton Thomas , Coldren Faith , Baret Jean-Christophe , Griffiths Andrew D. , Taly Valérie
Published: March 2014

A high-throughput cell analysis and sorting platform using droplet-based microfluidics is introduced for directed evolution of recombinant CotA laccase expressed in E. coli.
Non-relaxor responses of highly ordered Pb(Sc1/2Nb1/2)O3 crystals
Authors: Wang Zujian , Long Xifa
Published: March 2014

Pb(Sc1/2Nb1/2)O3 crystals have been grown by the top seeded solid solution technique and present a pure rhombohedral perovskite structure.
Controlled synthesis of Au–Fe3O4 hybrid hollow spheres with excellent SERS activity and catalytic properties
Authors: Gao Qian , Zhao Aiwu , Guo Hongyan , Chen Xucheng , Gan Zibao , Tao Wenyu , Zhang Maofeng , Wu Rong , Li Zhenxin
Published: March 2014

Here demonstrated a facile one-pot hydrothermal method for the controlled synthesis of porous Au–Fe3O4 hybrid hollow spheres. The obtained spheres exhibit superior SERS sensitivity and excellent catalytic activity.
Dynamics in next-generation solar cells: time-resolved surface photovoltage measurements of quantum dots chemically linked to ZnO (101̄0)
Authors: Spencer Ben F. , Cliffe Matthew J. , Graham Darren M. , Hardman Samantha J. O. , Seddon Elaine A. , Syres Karen L. , Thomas Andrew G. , Sirotti Fausto , Silly Mathieu G. , Akhtar Javeed , O'Brien Paul , Fairclough Simon M. , Smith Jason M. , Chattopadhyay Swapan , Flavell Wendy R.
Published: March 2014

The charge dynamics at the surface of the transparent conducting oxide and photoanode material ZnO are investigated in the presence and absence of light-harvesting colloidal quantum dots (QDs). The time-resolved change in surface potential upon photoexcitation has been measured in them-plane ZnO (101̄0) using a laser pump-synchrotron X-ray probe methodology. By varying the oxygen annealing conditions, and hence the oxygen vacancy concentration of the sample, we find that dark carrier lifetimes at the ZnO surface vary from hundreds of μs to ms timescales,i.e.a persistent photoconductivity (PPC) is observed. The highly-controlled nature of our experiments under ultra-high vacuum (UHV), and the use of band-gap and sub-band-gap photoexcitation, allow us to demonstrate that defect statesca.340 meV above the valence band edge are directly associated with the PPC, and that the PPC mediated by these defects dominates over the oxygen photodesorption mechanism. These observations are consistent with the hypothesis that ionized oxygen vacancy states are responsible for the PPC in ZnO. The effect of chemically linking two colloidal QD systems (type I PbS and type II CdS–ZnSe) to the surface has also been investigated. Upon deposition of the QDs onto the surface, the dark carrier lifetime and the surface photovoltage are reduced, suggesting a direct injection of charge carriers into the ZnO conduction band. The results are discussed in the context of the development of next-generation solar cells.
A divergent approach to the synthesis of iGb3 sugar and lipid analogues via a lactosyl 2-azido-sphingosine intermediate
Authors: Cheng Janice M. H. , Dangerfield Emma M. , Timmer Mattie S. M. , Stocker Bridget L.
Published: March 2014

Isoglobotrihexosylceramide (iGb3, 1) is an immunomodulatory glycolipid that binds to CD1d and is presented to the T-cell receptor (TCR) of invariant natural killer T (iNKT) cells.
Enhanced performance for organic bulk heterojunction solar cells by cooperative assembly of ter(ethylene oxide) pendants
Authors: Chen Lie , Tian Shaojie , Chen Yiwang
Published: March 2014

A ter(ethylene oxide) functionalized donor and acceptor are explored to manipulate the self-assembly morphology of the photoactive layer in polymer solar cells.
Nitroxide-mediated microemulsion polymerization of n-butyl acrylate: decoupling of target molecular weight and particle size
Authors: Li W. S. Jennifer , Cunningham Michael F.
Published: March 2014

Independent control of molecular weight and particle size can be achieved in nitroxide mediatedn-butyl acrylate microemulsion polymerization.
Spatial and temporal control of drug release through pH and alternating magnetic field induced breakage of Schiff base bonds
Authors: Dunn Alexander E. , Dunn Douglas J. , Macmillan Alexander , Whan Renee , Stait-Gardner Tim , Price William S. , Lim May , Boyer Cyrille
Published: March 2014

A novel theranostic controlled drug delivery platform that binds the drug to the nanocarrier by utilising Schiff base bonds to achieve high spatial and temporal control over drug release.
Controllable preparation of graphene oxide/metal nanoparticle hybrids as surface-enhanced Raman scattering substrates for 6-mercaptopurine detection
Authors: Fu Wen Liang , Zhen Shu Jun , Huang Cheng Zhi
Published: March 2014

In this contribution, a new simple and cost-effective strategy for the preparation of hybrids of graphene oxide (GO) and metal nanoparticles (MNPs) through the mediation of polyethyleneimine (PEI) molecules was reported.
Bioactive norditerpenoids from Flickingeria fimbriata
Authors: Chen Jin-Long , Zhao Zhi-Min , Xue Xue , Tang Gui-Hua , Zhu Long-Ping , Yang De-Po , Jiang Lin
Published: March 2014

11 new diterpenoids determined by NMR, X-ray diffraction, calculated ECD and CD exciton chirality methods were isolated from Flickingeria fimbriata.
One-pot production of hydrocarbon oil from poly(3-hydroxybutyrate)
Authors: Kang Shimin , Yu Jian
Published: March 2014

Decarboxylation of poly(3-hydroxybutyrate) (PHB) in a H3PO4 solution generates a renewable hydrocarbon oil.
Enhanced ‘in situ’ catalysis via microwave selective heating: catalytic chain transfer polymerisation
Authors: Adlington Kevin , McSweeney Robert , Dimitrakis Georgios , Kingman Samuel W. , Robinson John P. , Irvine Derek J.
Published: March 2014

The formation of a CCTP active catalyst, which is promoted by adopting microwave heating and an “in situ” synthesis methodology.
Green synthesis of a silver nanoparticle–graphene oxide composite and its application for As(iii) detection
Authors: Dar Riyaz Ahmad , Khare Ninad G. , Cole Daniel P. , Karna Shashi P. , Srivastava Ashwini Kumar
Published: March 2014

We report a facile and green synthetic approach to synthesize a silver nanoparticle (AgNPs)–graphene oxide (GO) composite using beta cyclodextrin as a stabilizing agent and ascorbic acid as a reducing agent.
Stimuli-responsive protoporphyrin IX silica-based nanoparticles for photodynamic therapy in vitro
Authors: Vivero-Escoto Juan L. , Vega Daniel L.
Published: March 2014

Redox-responsive silica nanoparticles, which selectively release photosensitizers inside cancer cells, enhance the photodynamic therapy efficacy in vitro.
Predicted crystal energy landscapes of porous organic cages
Authors: Pyzer-Knapp Edward O. , Thompson Hugh P. G. , Schiffmann Florian , Jelfs Kim E. , Chong Samantha Y. , Little Marc A. , Cooper Andrew I. , Day Graeme M.
Published: March 2014

Computational methods predict the crystal packing of porous organic cage molecules, allowing crystal structure and porosity to be predicted starting from the chemical diagram alone.
A mitochondrion-targeting copper complex exhibits potent cytotoxicity against cisplatin-resistant tumor cells through multiple mechanisms of action
Authors: Zhou Wen , Wang Xiaoyong , Hu Ming , Zhu Chengcheng , Guo Zijian
Published: March 2014

A cationic copper complex with triphenylphosphine as a targeting group preferentially accumulates in mitochondria of tumor cells and strongly inhibits their proliferation.
A general approach for construction of asymmetric modification membranes for gated flow nanochannels
Authors: Ma Shuanhong , Liu Jianxi , Ye Qian , Wang Daoai , Liang Yongmin , Zhou Feng
Published: March 2014

Double hydrophilic, double responsive, hydrophilic/hydrophobic polymer brushes asymmetrically-modified anodic aluminum oxide (AAO) nanochannel arrays were prepared by asymmetrical polymerization strategies.
Macroporous metal–organic framework microparticles with improved liquid phase separation
Authors: Ahmed Adham , Hodgson Nicola , Barrow Michael , Clowes Rob , Robertson Craig M. , Steiner Alexander , McKeown Paul , Bradshaw Darren , Myers Peter , Zhang Haifei
Published: March 2014

Macroporous HKUST-1 crystalline particles are prepared by solvothermal modification and exhibit improved liquid chromatographic separation.
Covalent-organic frameworks: potential host materials for sulfur impregnation in lithium–sulfur batteries
Authors: Liao Huaping , Ding Huimin , Li Bijian , Ai Xinping , Wang Cheng
Published: March 2014

We report, for the first time, construction of a sulfur electrode in a lithium–sulfur battery by using covalent-organic frameworks (COFs) as a host.
Polymer microcapsules loaded with Ag nanocatalyst as active microreactors
Authors: Horecha Marta , Kaul Elisabeth , Horechyy Andriy , Stamm Manfred
Published: March 2014

Silica-supported silver nanoparticles (Ag/SiO2) encapsulated inside the PNIPAM-based microcapsules (MC) were proved to be an efficient and easy-to-handle catalyst. Due to the hydrophilic nature of MCs, they act as microreactors in a mixed organic–aqueous environment. It was demonstrated that the catalytic activity of encapsulated Ag/SiO2 substantially exceeds that of freely dispersed catalyst.
Occurrence and subcellular distribution of the NAD(P)HX repair system in mammals
Authors: Marbaix Alexandre Y. , Tyteca Donatienne , Niehaus Tom D. , Hanson Andrew D. , Linster Carole L. , Van Schaftingen Emile
Published: March 2014

Hydration of NAD(P)H to NAD(P)HX, which inhibits several dehydrogenases, is corrected by an ATP-dependent dehydratase and an epimerase recently identified as the products of the vertebrate Carkd (carbohydrate kinase domain) and Aibp (apolipoprotein AI-binding protein) genes respectively. The purpose of the present study was to assess the presence of these enzymes in mammalian tissues and determine their subcellular localization. The Carkd gene encodes proteins with a predicted mitochondrial propeptide (mCARKD), a signal peptide (spCARKD) or neither of them (cCARKD). Confocal microscopy analysis of transfected CHO (Chinese-hamster ovary) cells indicated that cCARKD remains in the cytosol, whereas mCARKD and spCARKD are targeted to the mitochondria and the endoplasmic reticulum respectively. Unlike the other two forms, spCARKD is N-glycosylated, supporting its targeting to the endoplasmic reticulum. The Aibp gene encodes two different proteins, which we show to be targeted to the mitochondria (mAIBP) and the cytosol (cAIBP). Quantification of the NAD(P)HX dehydratase and epimerase activities in rat tissues, performed after partial purification, indicated that both enzymes are widely distributed, with total activities of ≈3–10 nmol/min per g of tissue. Liver fractionation by differential centrifugation confirmed the presence of the dehydratase and the epimerase in the cytosol and in mitochondria. These data support the notion that NAD(P)HX repair is extremely widespread.
Pharmacological inhibition of DDAH1 improves survival, haemodynamics and organ function in experimental septic shock
Authors: Wang Zhen , Lambden Simon , Taylor Valerie , Sujkovic Elizabeth , Nandi Manasi , Tomlinson James , Dyson Alex , McDonald Neil , Caddick Stephen , Singer Mervyn , Leiper James
Published: March 2014

The aim of the present study was to investigate the therapeutic effects of pharmacological inhibition of DDAH1 (dimethylarginine dimethylaminohydrolase 1), an enzyme that metabolizes endogenously produced nitric oxide synthase inhibitors, principally ADMA (asymmetric dimethylarginine). The present study employs a series of rodent models to evaluate the effectiveness a DDAH1-selective inhibitor (L-257). Short-term models involved the development of endotoxaemia using lipopolysaccharide and long-term models involved the intraperitoneal administration of faecal slurry. In order to generate the most relevant model possible, following induction of severe sepsis, animals received appropriate fluid resuscitation and in some models vasopressor therapy. The effects of L-257 on survival, haemodynamics and organ function were subsequently assessed. Survival was significantly longer in all L-257 treatment groups (P<0.01) and no adverse effects on haemodynamics and organ function were observed following L-257 administration to either animals with sepsis or naïve animals. Haemodynamic performance was preserved and the noradrenaline dose required to maintain target blood pressure was reduced in the treated animals (P<0.01). Animals receiving L-257 had significantly increased plasma ADMA concentrations. Plasma nitrite/nitrate was reduced as was severity of sepsis-associated renal dysfunction. The degree of tachycardia was improved as were indices of tissue and microvascular perfusion. The results of the present study show that the selective DDAH-1 inhibitor L-257 improved haemodynamics, provided catecholamine sparing and prolonged survival in experimental sepsis. Further studies will determine its potential utility in human septic shock.
Joint phase noise estimation and data detection in coded multi‐input–multi‐output systems
Authors: Isikman Arif O. , Mehrpouyan Hani , Nasir Ali A. , Amat Alexandre G. , Kennedy Rodney. A.
Published: March 2014

The problem of joint oscillator phase noise (PHN) estimation and data detection for multi‐input multi‐output (MIMO) systems using bit‐interleaved‐coded modulation is analysed. A new MIMO receiver that iterates between the estimator and the detector, based on the expectation‐maximisation (EM) framework, is proposed. It is shown that at high signal‐to‐noise ratios, a maximum a posteriori (MAP) estimator can be used to carry out the maximisation step of the EM algorithm. Moreover, to reduce the computational complexity of the proposed EM algorithm, a soft decision‐directed extended Kalman filter‐smoother (EKFS) is applied instead of the MAP estimator to track the PHN parameters. The numerical results show that by combining the proposed EKFS‐based approach with an iterative detector that employs low‐density parity check codes, PHN can be accurately tracked. The simulations also demonstrate that compared to the existing algorithms, the proposed iterative receiver can significantly enhance the performance of MIMO systems in the presence of PHN.
Performance assessment of a wideband code‐division multiple access‐based radio‐over‐fibre system with near–far effect: downlink scenario
Authors: Baghersalimi Gholamreza
Published: March 2014

The impact of a radio‐over‐fibre subsystem on the total degradation (TD) performance of downlink wideband code‐division multiple access with near–far effect is evaluated. The study investigates the use of pilot‐aided channel estimation to compensate for the optical subsystem non‐linearities for different channel conditions, estimation intervals, load factors (LFs) and near–far factors (NFFs). The results show that pilot‐aided channel estimation is an effective method for compensating the composite impairments of the optical subsystem and the radio frequency channel. It is found that there is always a suitable quiescent point that optimises the system performance regardless of aforementioned conditions, however, the optimum achievable performance depends on the LF, spreading factor (SF) and NFF. Also, LF has more impact on the system performance in comparison to SF. Further, the optimum TD performance is only slightly affected by a decrease in the estimation interval over the optimum output backoff range.
High current sensitivity and large magnetoelectric effect in magnetostrictive–piezoelectric concentric ring
Authors: Ming Leung Chung , Wing Or Siu , Ho S. L.
Published: March 2014

A magnetostrictive–piezoelectric concentric ring (MPCR) is fabricated, and its current sensitivity and magnetoelectric effect are studied theoretically and experimentally. The MPCR has an inner Tb0.3Dy0.7Fe1.92/NdFeB/epoxy magnetostrictive composite ring with a circumferential magnetization and an internal magnetic biasing bonded concentrically to an outer Pb(Zr, Ti)O3 piezoelectric ceramic ring with a wall-thickness polarization. The current sensing in the MPCR is based on the direct coupling of vortex magnetic fields generated by current-carrying cables with the magnetoelectric effect in the MPCR structure. The MPCR shows high and linear current sensitivities and magnetoelectric voltage coefficients of 15–17 mV/A and 22–26 mV/Oe in the nonresonance frequency range of 1 Hz–50 kHz, and of 185 mV/A and 277 mV/Oe at the fundamental shape resonance of 96 kHz, for current and vortex magnetic field levels of up to 10 A and 6.7 Oe, respectively.
Discharging fused silica optics occluded by an electrostatic drive
Authors: Ugolini D. , Fitzgerald C. , Rothbarth I. , Wang J.
Published: March 2014

Charge accumulation on test masses is a potentially limiting noise source for gravitational-wave interferometers, and may occur due to exposure to an electrostatic drive (ESD) in modern test mass suspensions. We verify that an ESD can cause charge accumulation on a fused silica test mass at a rate of 8 × 10−16 C/cm2/h. We also demonstrate a charge mitigation system consisting of a stream of nitrogen ionized by copper feedthrough pins at 3750 VAC. We demonstrate that the system can neutralize positive and negative charge from 10−11 C/cm2 to 3 × 10−14 C/cm2 in under 2 h.
Electrostatics of proteins in dielectric solvent continua. I. An accurate and efficient reaction field description
Authors: Bauer Sebastian , Mathias Gerald , Tavan Paul
Published: March 2014

We present a reaction field (RF) method which accurately solves the Poisson equation for proteins embedded in dielectric solvent continua at a computational effort comparable to that of an electrostatics calculation with polarizable molecular mechanics (MM) force fields. The method combines an approach originally suggested by Egwolf and Tavan [J. Chem. Phys. 118, 2039 (2003)] with concepts generalizing the Born solution [Z. Phys. 1, 45 (1920)] for a solvated ion. First, we derive an exact representation according to which the sources of the RF potential and energy are inducible atomic anti-polarization densities and atomic shielding charge distributions. Modeling these atomic densities by Gaussians leads to an approximate representation. Here, the strengths of the Gaussian shielding charge distributions are directly given in terms of the static partial charges as defined, e.g., by standard MM force fields for the various atom types, whereas the strengths of the Gaussian anti-polarization densities are calculated by a self-consistency iteration. The atomic volumes are also described by Gaussians. To account for covalently overlapping atoms, their effective volumes are calculated by another self-consistency procedure, which guarantees that the dielectric function ε(r) is close to one everywhere inside the protein. The Gaussian widths σi of the atoms i are parameters of the RF approximation. The remarkable accuracy of the method is demonstrated by comparison with Kirkwood's analytical solution for a spherical protein [J. Chem. Phys. 2, 351 (1934)] and with computationally expensive grid-based numerical solutions for simple model systems in dielectric continua including a di-peptide (Ac-Ala-NHMe) as modeled by a standard MM force field. The latter example shows how weakly the RF conformational free energy landscape depends on the parameters σi. A summarizing discussion highlights the achievements of the new theory and of its approximate solution particularly by comparison with so-called generalized Born methods. A follow-up paper describes how the method enables Hamiltonian, efficient, and accurate MM molecular dynamics simulations of proteins in dielectric solvent continua.