bluuebunny/crossref_metadata_2025 huggingface dataset:
Beyond pairwise additivity in London dispersion interactions
Authors: Dobson John F.
Published: February 2014

The simplest way to predict London dispersion energies involving complex multiatom objects is to add separate contributions from each pair of atoms. Semiempirical, and even certain less empirical, ways to do this can be very efficient computationally and have recently been developed to a high level of sophistication, with considerable success. There are, however, effects that are not captured in this way, including surprising dependences of the dispersion energy on the number N of atoms and on separation D. Higher level quantum chemical, perturbative, and random‐phase approximation (RPA)‐like theories can capture these beyond pairwise effects, but at a high computational cost. Very recent simplified RPA‐like approaches based on localized oscillators account for the unusual N dependence in a computationally efficient way. To proceed further, the present work proposes three physically distinct categories of nonpairwise effects (types A, B, and C) against which the performance of existing and future theories can be assessed. © 2014 Wiley Periodicals, Inc.
Psychosocial Stressors of Sickle Cell Disease on Adult Patients in Cameroon
Authors: Wonkam Ambroise , Mba Caryl Zameyo , Mbanya Dora , Ngogang Jeanne , Ramesar Raj , Angwafo Fru F.
Published: February 2014

Sickle Cell Disease (SCD) is a debilitating illness that affects quality of life. Studies of the psychosocial burden of SCD on patients have been rarely reported in Africa. We used a quantitative method, with face‐to‐face administered questionnaires, to study indices of psychosocial stressors on adult SCD patients in Cameroon. The questionnaire included a 36‐item stress factors scale evaluating general perceptions of stress and five main stressors’ domain: disease factors, hospital factors, financial factors, family factors and quality of personal‐life factors. Items pertaining to psychosocial stressors involved four response options with increasing severity: 0, 1, 2 or 3. Non‐parametric tests were used for analysis. The majority of the 83 participants were urban dwellers, female, 20–30 years old, single, unemployed, with at least a secondary or tertiary education. Median age at diagnosis was 100 months; 47.8 % had >3 painful vaso‐oclusive crises annually. Only 4.8 % had been treated with hydroxyurea. The majority reported moderate to severe difficulty coping with SCD. The “degree of clinical severity” category displayed the highest median score (2.0), while familial stressors showed the lowest (0.8). Being female, married, with low education level, an additional affected sibling and low direct income were significantly associated with specific stressors’ categories. In Cameroon, there is an urgent need to implement policies that ensure affordable access to health‐care and practices to reduce SCD morbidity and improve patients’ quality of life.
Hot spots in apolipoprotein A‐II misfolding and amyloidosis in mice and men
Authors: Gursky Olga
Published: February 2014

ApoA‐II is the second‐major protein of high‐density lipoproteins. C‐terminal extension in human apoA‐II or point substitutions in murine apoA‐II cause amyloidosis. The molecular mechanism of apolipoprotein misfolding, from the native predominantly α‐helical conformation to cross‐β‐sheet in amyloid, is unknown. We used 12 sequence‐based prediction algorithms to identify two ten‐residue segments in apoA‐II that probably initiate β‐aggregation. Previous studies of apoA‐II fragments experimentally verify this prediction. Together, experimental and bioinformatics studies explain why the C‐terminal extension in human apoA‐II causes amyloidosis and why, unlike murine apoA‐II, human apoA‐II normally does not cause amyloidosis despite its unusually high sequence propensity for β‐aggregation.
Splicing inhibition induces gene expression through canonical NF‐κB pathway and extracellular signal‐related kinase activation
Authors: Khan Khalid , Schneider-Poetsch Tilman , Ishfaq Muhammad , Ito Akihiro , Yoshimoto Rei , Mukaida Naofumi , Yoshida Minoru
Published: February 2014

Splicing, a process for mRNA maturation, is essential for correct gene expression after transcription. However, recent studies also suggest that splicing affects transcription, but its mechanism remains elusive. We previously reported that treatment with spliceostatin A (SSA), a specific splicing inhibitor targeting the splicing factor SF3b, leads to transcriptional activation of a small subset of genes. To investigate the underlying mechanism we utilized luciferase reporters driven by the Interleukin 8 (IL‐8) and cytomegalovirus (CMV) promoters, as both recruit a similar set of transcription factors. We also found that SSA treatment led to increased extracellular signal‐regulated protein kinase (ERK) activity and that chemical inhibition of ERK also led to decreased promoter activation. Systematic deletion studies suggested that NF‐κB activation is mainly responsible for SSA‐induced promoters activation.
Characterization of the effects of phosphorylation by CK2 on the structure and binding properties of human HP1β
Authors: Munari Francesca , Gajda Michal Jan , Hiragami-Hamada Kyoko , Fischle Wolfgang , Zweckstetter Markus
Published: February 2014

Proteins of the Heterochromatin Protein 1 (HP1) family are regulators of chromatin structure and genome function in eukaryotes. Post‐translational modifications expand the repertoire of the chemical diversity of HP1 proteins and regulate their activity. Here, we investigated the effect of phosphorylation by Casein kinase 2 (CK2) on the structure, dynamics and binding activity of human HP1β. We show that Ser89 in the hinge region is the most effective substrate, followed by Ser175 at the C‐terminal tail. Phosphorylation at these sites results in localized conformational changes in HP1β that do not compromise the ability of the protein to bind chromatin.
A hIAPP‐derived all‐d‐amino‐acid inhibits hIAPP fibrillation efficiently at membrane surface by targeting α‐helical oligomeric intermediates
Authors: Wang Li , Lei Liyan , Li Yang , Wang Liping , Li Fei
Published: February 2014

A variety of peptides and peptide derivatives have been constructed using the “β‐sheet core segment” of amyloid proteins as inhibitors of amyloidogenic fibrillation. A novel all‐d‐amino‐acid from hIAPP β‐sheet core segment (hIAPP 22–27) is demonstrated to inhibit hIAPP fibril formation efficiently both at the phospholipid membrane and in bulk solution. The inhibitor terminates hIAPP aggregation to the α‐helical oligomeric intermediates at the membrane surface, whereas it stops the aggregation at the stage of β‐sheet oligomeric intermediates in bulk solution. This is the first evidence that the inhibition mechanism of the inhibitor at membrane surface is significantly different from that in bulk solution.
Bonds of Belonging: Subjecthood and the British Empire
Authors: Muller Hannah Weiss
Published: February 2014

In the 1760s and 1770s, rancorous struggles over the rights of French Catholic subjects threatened the political and economic stability of Grenada and Quebec, both formerly French colonies ceded to Britain at the close of the Seven Years' War (1756–63). This article analyzes claims of subject status made during those decades, focusing on petitions in which numerous inhabitants made demands for privileges they believed to be their due. These memorials reveal the fundamental role that “new” and “adopted” subjects played in shaping the boundaries of “British” subjecthood, as well as highlight key characteristics that made subjecthood an organizing principle of the mid-eighteenth-century British Empire. Indeed, the bonds between subject and sovereign, the ones articulated and performed each time subjects approached their monarch or his representatives, operated at a symbolic and functional level to integrate an empire that had become increasingly diverse by the 1760s.
The Iceberg and the Cathedral: Encounter, Entanglement, and Isuma in Inuit London
Authors: Thrush Coll
Published: February 2014

In 1772, entrepreneur George Cartwright brought five Inuit people to England from Nunatsiavut (Labrador). Most of their time was spent in London, where they encountered many of the city's sights and experienced its social divisions and environmental conditions. This article explores their voyage, challenging the notion that “primitives” such as the Inuit visitors were necessarily awed into submission by the urban landscape. Rather, they understood it according to their own cultural logics and even articulated critiques of the city. Illustrating the entanglement of urban and Inuit spaces and places across the Atlantic, and ending by telling the story of the death of four of the five visitors from smallpox in 1773, the article argues for a new kind of scholarship that shows connections between Indigenous and urban histories at the transoceanic and imperial levels.
The Trouble with Convicts: From Transportation to Penal Servitude, 1840–67
Authors: Harling Philip
Published: February 2014

This article makes three points about the death throes of convict transportation. First, the quarrel over transportation shows the double-edged nature of the moral critique of empire in the early Victorian era. Metropolitan criticism of transportation had its roots in the same effort to moralize the empire that was seen in the almost contemporaneous assault on slavery. But transportation was deemed too convenient a means of getting rid of criminals for Britons safely to do without it. Second, the Whig government of 1846–52 sought to save transportation by moralizing the convict before shipping him off. By this point, however, the moral objections to transportation in eastern Australia had become so strong as to make the plan untenable. Third, colonial opposition to transportation ultimately left the British government with no choice but to replace it with penal servitude at home, and the debate over crime and punishment that played out over the next decade revealed a waning of faith in convict rehabilitation that manifested itself in a harsher prison regime. In necessitating the rise of penal servitude, the end of transportation makes it clear that the empire mattered very much indeed to the reshaping of British penal policy in the mid-Victorian era.
Citizenship from the Margins: Vernacular Theories of Rights and the State from the Interwar Caribbean
Authors: Putnam Lara
Published: February 2014

This essay explores debates over political membership and rights within empire from the interwar British Caribbean. Although no formal status of imperial, British, or colonial citizenship existed in this era, British Caribbeans routinely hailed each other as meritorious local “citizens,” demanded political rights due them as “British citizens,” and decried rulers' failure to treat colored colonials equally with other “citizens” of the empire. In the same years, the hundreds of thousands of British West Indians who labored in circum-Caribbean republics like the United States, Panama, Cuba, Venezuela, and Costa Rica experienced firsthand the international consolidation of formal citizenship as a state-issued credential ensuring mobility and abode. This convergence pushed British Caribbeans at home and abroad to question the costs of political disfranchisement and the place of race within empire. The vernacular political philosophy they developed in response importantly complements the influential theories of citizenship and rights developed by European thinkers of the same generation, such as T. H. Marshall and Hannah Arendt.
Linearized oscillations of a vortex column: the singular eigenfunctions
Authors: Roy Anubhab , Subramanian Ganesh
Published: February 2014

In 1880 Lord Kelvin analysed the linearized inviscid oscillations of a Rankine vortex as part of a theory of vortex atoms. These eponymously named neutrally stable modes are, however, exceptional regular oscillations that make up the discrete spectrum of the Rankine vortex. In this paper, we examine the singular oscillations that make up the continuous spectrum (CS) and span the entire base state range of frequencies. In two dimensions, the CS eigenfunctions have a twin-vortex-sheet structure similar to that known from earlier investigations of parallel flows with piecewise linear velocity profiles. The vortex sheets are cylindrical, being threaded by axial lines, with one sheet at the edge of the core and the other at the critical radius in the irrotational exterior; the latter refers to the radial location at which the fluid co-rotates with the eigenmode. In three dimensions, the CS eigenfunctions have core vorticity and may be classified into two families based on the singularity at the critical radius. For the first family, the singularity is a cylindrical vortex sheet threaded by helical vortex lines, while for the second family it has a localized dipole structure with radial vorticity. The presence of perturbation vorticity in the otherwise irrotational exterior implies that the CS modes, unlike the Kelvin modes, offer a modal interpretation for the (linearized) interaction of the Rankine vortex with an external vortical disturbance. It is shown that an arbitrary initial distribution of perturbation vorticity, both in two and three dimensions, may be evolved as a superposition over the discrete and CS modes; this modal representation being equivalent to a solution of the corresponding initial value problem. For the restricted case of an initial axial vorticity distribution in two dimensions, the modal representation may be generalized to a smooth vortex. Finally, for the three-dimensional case, the analogy between rotational flows and stratified shear flows, and the known analytical solution for stratified Couette flow, are used to clarify the singular manner in which the modal superposition for a smooth vortex approaches the Rankine limit.
Analyst Disagreement and Aggregate Volatility Risk
Authors: Barinov Alexander
Published: February 2014

The paper explains why firms with high dispersion of analyst forecasts earn low future returns. These firms beat the capital asset pricing model in periods of increasing aggregate volatility and thereby provide a hedge against aggregate volatility risk. The aggregate volatility risk factor can explain the abnormal return differential between high- and low-disagreement firms. This return differential is higher for firms with abundant real options, and this fact can be explained by aggregate volatility risk. Aggregate volatility risk can also explain why the link between analyst disagreement and future returns is stronger for firms with high short-sale constraints.
Accidental button battery ingestion presenting as croup
Authors: Gohil R , Culshaw J , Jackson P , Singh S
Published: February 2014

Objectives:

To report a case of misdiagnosis of an impacted oesophageal button battery in a child, and to describe the associated risk factors for impaction and the management of such cases.

Case report:

An 18-month-old, otherwise fit and well child with stridulous respiration was initially treated for croup. Medical treatment over the course of three months failed, and appropriate imaging subsequently demonstrated an impacted button battery in the upper oesophagus. This was promptly removed. There were no signs of damage on direct visualisation, or on a follow-up contrast swallow image.

Conclusion:

This case highlights the difficulty of diagnosing oesophageal foreign bodies. We also discuss the characteristics of button batteries which confer a greater risk of impaction, and the associated sequelae and complications.
High and low doses of clarithromycin treatment are associated with different clinical efficacies and immunomodulatory properties in chronic rhinosinusitis
Authors: Fan Y , Xu R , Hong H , Luo Q , Xia W , Ding M , Shi J , Lv M , Li H
Published: February 2014

Background:

Low-dose clarithromycin has been recommended for the treatment of chronic rhinosinusitis without nasal polyps. However, it is uncertain whether a high dose of clarithromycin is more effective than a low dose.

Methods:

Forty-three chronic rhinosinusitis patients were randomised to low-dose or high-dose clarithromycin groups, and clinical efficacy was evaluated. Pre- and post-treatment measures included: nasal symptom assessment, endoscopic inspection (Lund–Kennedy system), a quality of life questionnaire (the Sino-Nasal Outcome Test 20) and examination of cytokine levels (interleukin-5 and -8) in nasal secretions.

Results:

The high dose of clarithromycin was significantly better in terms of clinical efficacy than the low dose for the treatment of chronic rhinosinusitis (p < 0.025). Significant differences in nasal cytokine levels (interleukin-5 and -8) were also observed between the low-dose and high-dose groups after short-term clarithromycin treatment (p < 0.025).

Conclusion:

Short-term, high-dose clarithromycin appears to be more effective for the treatment of chronic rhinosinusitis than low-dose clarithromycin.
Partitioning the etiology of hoarding and obsessive–compulsive symptoms
Authors: Mathews C. A. , Delucchi K. , Cath D. C. , Willemsen G. , Boomsma D. I.
Published: February 2014

Background

Until recently, hoarding was considered an obsessive–compulsive symptom (OCS). However, current evidence suggests that these two phenotypes may be clinically, and perhaps etiologically, distinct. Both hoarding and OCS have a genetic etiology, but the degree of unique and shared genetic contributions to these phenotypes has not been well studied.

Method

Prevalence rates were assessed for hoarding and OCS in a sample of adult twin pairs (n = 7906 twins) and their family members from the Netherlands Twin Register (total sample = 15 914). Using Mplus, genetic analyses using liability threshold models were conducted for both phenotypes, for their co-morbidity, and for specific hoarding symptoms (cluttering, discarding and acquiring).

Results

Of the total sample, 6.7% met criteria for clinically significant hoarding; endorsement of all three hoarding symptoms was ⩾79%. Men had slightly higher rates than women. Also, 5.7% met criteria for clinically significant OCS; rates were similar in males and females. Genetic factors accounted for 36% of the variance for hoarding and 40% of the variance for OCS. The genetic correlation between hoarding and OCS was 0.10. There was no evidence of sex-specific genetic contributions for hoarding or OCS. There was evidence for a genetic contribution to all hoarding symptom subtypes. Only cluttering showed evidence of a contribution from the shared environment.

Conclusions

OCS and hoarding are common in this population-based sample, have prevalence rates similar to those previously reported, and show significant heritability. Genetic factors contributed to the co-morbidity of both traits, although the genetic correlation between them was low.
Mammalian herbivores in Australia transport nutrients from terrestrial to marine ecosystems via mangroves
Authors: Reef Ruth , Feller Ilka C. , Lovelock Catherine E.
Published: February 2014

Nutrient subsidies from one ecosystem to another serve a critical link among ecosystems. The transfer of materials across the terrestrial-to-marine boundary is considered to be driven by hydrological connectivity, but animal movement can provide another pathway for nutrient transfers. In two separate studies we assessed the role mammals (bats and kangaroos) play in alleviating nutrient limitation in mangrove forests in Australia. At Lizard Island, we measured tree growth and foliar elemental and isotopic composition of trees growing within and outside a large flying fox roost. In Western Australia, we measured foliar elemental and isotopic composition of trees within two forests frequented by kangaroos that feed in spinifex grasslands and shelter in the shade of the mangroves. We compared those with mangroves from adjacent forests that are not frequented by kangaroos. We show that at both locations, the mangrove forest receives terrestrial nutrient subsidies through animal movement. At Lizard Island dominant mangrove species were significantly enriched in nitrogen within the bat roost, as evidenced by higher foliar N concentrations (by up to 150%), N:P and N:C ratios in trees within the roost compared with trees outside the roost. The isotopic signature of foliar N was significantly enriched in 15N by 1–3‰ within the roost, further suggesting that the source of the N enrichment was the bat roost. Growth rates of mangroves within the roost were nearly six times higher than trees outside the roost. In the arid coast of Western Australia, we show elevated foliar 15N abundance of up to 3‰ in mangroves where kangaroos shelter relative to trees where they do not. Thus, this study presents two examples for mammalian herbivore mediated localized transport of nutrients from terrestrial to marine ecosystems, consequently affecting mangrove tree growth, productivity and forest structure.
On Loewy lengths of blocks
Authors: KOSHITANI SHIGEO , KÜLSHAMMER BURKHARD , SAMBALE BENJAMIN
Published: February 2014

We give a lower bound on the Loewy length of a p-block of a finite group in terms of its defect. We then discuss blocks with small Loewy length. Since blocks with Loewy length at most 3 are known, we focus on blocks of Loewy length 4 and provide a relatively short list of possible defect groups. It turns out that p-solvable groups can only admit blocks of Loewy length 4 if p=2. However, we find (principal) blocks of simple groups with Loewy length 4 and defect 1 for all p ≡ 1 (mod 3). We also consider sporadic, symmetric and simple groups of Lie type in defining characteristic. Finally, we give stronger conditions on the Loewy length of a block with cyclic defect group in terms of its Brauer tree.
Potential effect of virus interference on influenza vaccine effectiveness estimates in test-negative designs
Authors: SUZUKI M. , CAMACHO A. , ARIYOSHI K.
Published: February 2014

A hypothetical influenza infection-induced non-specific immunity may reduce the risk of subsequent non-influenza respiratory virus (NIRV) infection and bias the influenza vaccine effectiveness (VE) estimates in test-negative designs (TNDs). We conducted a simulation study using a simple TND model and explored the degree of bias in the VE estimates. The bias was marginal during the usual seasons and most of the time during pandemics; the bias only became large when the influenza infection attack rate increased to pandemic levels (>50%), the true VE was low to moderate, and the non-specific immunity almost completely protected from NIRV infections and lasted at least half the influenza season.
Distribution and specificity of S-cone (“blue cone”) signals in subcortical visual pathways
Authors: MARTIN PAUL R. , LEE BARRY B.
Published: February 2014

We review here the distribution of S-cone signals and properties of S-cone recipient receptive fields in subcortical pathways. Nearly everything we know about S-cone signals in the subcortical visual system comes from the study of visual systems in cats and primates (monkeys); in this review, we concentrate on results from macaque and marmoset monkeys. We discuss segregation of S-cone recipient (blue-on and blue-off) receptive fields in the dorsal lateral geniculate nucleus and describe their receptive field properties. We treat in some detail the question of detecting weak S-cone signals as an introduction for newcomers to the field. Finally, we briefly consider the question on how S-cone signals are distributed among nongeniculate targets.
Patient-centred assessment and management of pain for older adults with dementia in care home and acute settings
Authors: Newton P , Reeves R , West E , Schofield P
Published: February 2014

Evidence suggests that there is a greater prevalence of pain, particularly chronic pain, in the older than in the younger population. This review looks at how dementia affects older people's ability to report pain, and indicates that pain is poorly assessed and managed in people living with dementia, in particular in care and acute settings. The review also reports findings from two recent studies looking at ways of improving the assessment and management of pain in acute settings. Multi-dimensional, patient-centred approaches to assessing and managing pain in those living with dementia are required, and future research should focus on innovative and practical approaches that can be applied in care home and acute settings.
Bridging the gap in pension participation: how much can universal tax-deferred pension coverage hope to achieve?
Authors: KARAMCHEVA NADIA S. , SANZENBACHER GEOFFREY
Published: February 2014

In light of the declining pension coverage of low-income workers, policy makers have discussed requiring all employers to offer individual retirement accounts, similar to defined contribution plans. How likely to participate are workers who currently do not have access to a pension plan? We address this question by using plausibly exogenous variation in pension-plan availability to estimate the determinants of participation in a standard selection on unobservables model. We find that currently uncovered low-income workers are fairly likely to participate in a newly offered plan, yet they are much less likely to do so than currently covered workers.
Phylogenetic distribution of three pathways for propionate production within the human gut microbiota
Authors: Reichardt Nicole , Duncan Sylvia H , Young Pauline , Belenguer Alvaro , McWilliam Leitch Carol , Scott Karen P , Flint Harry J , Louis Petra
Published: February 2014

Propionate is produced in the human large intestine by microbial fermentation and may help maintain human health. We have examined the distribution of three different pathways used by bacteria for propionate formation using genomic and metagenomic analysis of the human gut microbiota and by designing degenerate primer sets for the detection of diagnostic genes for these pathways. Degenerate primers for the acrylate pathway (detecting the lcdA gene, encoding lactoyl-CoA dehydratase) together with metagenomic mining revealed that this pathway is restricted to only a few human colonic species within the Lachnospiraceae and Negativicutes. The operation of this pathway for lactate utilisation in Coprococcus catus (Lachnospiraceae) was confirmed using stable isotope labelling. The propanediol pathway that processes deoxy sugars such as fucose and rhamnose was more abundant within the Lachnospiraceae (based on the pduP gene, which encodes propionaldehyde dehydrogenase), occurring in relatives of Ruminococcus obeum and in Roseburia inulinivorans. The dominant source of propionate from hexose sugars, however, was concluded to be the succinate pathway, as indicated by the widespread distribution of the mmdA gene that encodes methylmalonyl-CoA decarboxylase in the Bacteroidetes and in many Negativicutes. In general, the capacity to produce propionate or butyrate from hexose sugars resided in different species, although two species of Lachnospiraceae (C. catus and R. inulinivorans) are now known to be able to switch from butyrate to propionate production on different substrates. A better understanding of the microbial ecology of short-chain fatty acid formation may allow modulation of propionate formation by the human gut microbiota.
Taxonomical and functional microbial community selection in soybean rhizosphere
Authors: Mendes Lucas W , Kuramae Eiko E , Navarrete Acácio A , van Veen Johannes A , Tsai Siu M
Published: February 2014

This study addressed the selection of the rhizospheric microbial community from the bulk soil reservoir under agricultural management of soybean in Amazon forest soils. We used a shotgun metagenomics approach to investigate the taxonomic and functional diversities of microbial communities in the bulk soil and in the rhizosphere of soybean plants and tested the validity of neutral and niche theories to explain the rhizosphere community assembly processes. Our results showed a clear selection at both taxonomic and functional levels operating in the assembly of the soybean rhizosphere community. The taxonomic analysis revealed that the rhizosphere community is a subset of the bulk soil community. Species abundance in rhizosphere fits the log-normal distribution model, which is an indicator of the occurrence of niche-based processes. In addition, the data indicate that the rhizosphere community is selected based on functional cores related to the metabolisms of nitrogen, iron, phosphorus and potassium, which are related to benefits to the plant, such as growth promotion and nutrition. The network analysis including bacterial groups and functions was less complex in rhizosphere, suggesting the specialization of some specific metabolic pathways. We conclude that the assembly of the microbial community in the rhizosphere is based on niche-based processes as a result of the selection power of the plant and other environmental factors.
Flow injection chemiluminescence immunosensor for the determination of clenbuterol by immobilizing coating-antigen on carboxylic resin beads
Authors: Song Jingjing , Xu Mingxia , Zhao Kang , Deng Anping , Li Jianguo
Published: February 2014

A flow-injection chemiluminescence immunoassay based on a transparent immunoaffinity reactor for the detection of clenbuterol.
Dinuclear metal catalysts: improved performance of heterodinuclear mixed catalysts for CO2–epoxide copolymerization
Authors: Saini P. K. , Romain C. , Williams C. K.
Published: February 2014

A catalyst system comprising homo- and heteronuclear Zn–Mg complexes shows excellent polymerization control and exhibits higher activity than the homodinuclear catalysts for CO2–epoxide copolymerization.
Oligo(phenylenevinylene) hybrids and self-assemblies: versatile materials for excitation energy transfer
Authors: Praveen Vakayil K. , Ranjith Choorikkat , Bandini Elisa , Ajayaghosh Ayyappanpillai , Armaroli Nicola
Published: February 2014

The engineering of the nanostructure of OPV based self-assemblies allows control of photoinduced energy transfer processes, leading to materials exhibiting tunable luminescence colours, including white.
Dehydration, dehydrogenation, and condensation of alcohols on supported oxide catalysts based on cyclic (WO3)3and (MoO3)3clusters
Authors: Rousseau Roger , Dixon David A. , Kay Bruce D. , Dohnálek Zdenek
Published: February 2014

The review summarizes recent synthesis and reactivity studies of model oxide catalysts prepared by the deposition of gas phase cyclic (WO3)3and (MoO3)3clusters.
Direct oxidation of methane to methanol on Fe–O modified graphene
Authors: Impeng Sarawoot , Khongpracha Pipat , Warakulwit Chompunuch , Jansang Bavornpon , Sirijaraensre Jakkapan , Ehara Masahiro , Limtrakul Jumras
Published: February 2014

The reaction mechanisms of the partial oxidation of methane to methanol over FeO/graphene are unraveled using an advanced DFT approach.
Single-molecule magnet engineering: building-block approaches
Authors: Pedersen Kasper S. , Bendix Jesper , Clérac Rodolphe
Published: February 2014

This Feature article focuses on the use ofbuilding-blocksto direct structure and properties of complexes exhibiting single-molecule magnet behavior.
Characterization of biometal profiles in neurological disorders
Authors: Pfaender Stefanie , Grabrucker Andreas M.
Published: February 2014

This review summarizes the findings on dysregulation of metal ions in neurological diseases and tries to develop and predict specific biometal profiles.
Stimuli responsive triblock copolymers by chain-growth polymerization from telechelic macroinitiators prepared via a step-growth polymerization
Authors: Dan Krishna , Ghosh Suhrit
Published: February 2014

The synthesis of stimuli-responsive ABA tri-block copolymers using a step-growth polmerization followed by a chain-growth polymerization.
MOR zeolite supported Brønsted acidic ionic liquid: an efficient and recyclable heterogeneous catalyst for ketalization
Authors: Li Zhang-Min , Zhou Yan , Tao Duan-Jian , Huang Wei , Chen Xiang-Shu , Yang Zhen
Published: February 2014

In order to widen the application of ionic liquids as efficient and renewable heterogeneous catalysts, supported ionic liquids (SILs) have received considerable attention.
Morphological changes of gold nanoparticles due to adsorption onto silicon substrate and oxygen plasma treatment
Authors: Winkler Katarzyna , Wojciechowski Tomasz , Liszewska Malwina , Górecka Ewa , Fiałkowski Marcin
Published: February 2014

We present comprehensive studies of the morphological evolution that gold nanoparticles undergo during their adsorption on a solid substrate and subsequent oxygen plasma treatment.
Anti-HSV activity and mode of action study of α-pyrone carboxamides
Authors: Karampuri Srinivas , Ojha Durbadal , Bag Paromita , Chakravarty Harapriya , Bal Chandralata , Chattopadhyay Debprasad , Sharon Ashoke
Published: February 2014

Potential anti-HSV lead candidate3d(EC50= 9.8 μg ml−1) and its possible binding mode to utilize cavity-A and cavity-B of viral enzyme HSV polymerase.
Novel flower-like titanium phosphate microstructures and their application in lead ion removal from drinking water
Authors: Wang Xueyun , Yang Xiulin , Cai Jianhua , Miao Tingting , Li Lihua , Li Gen , Deng Dingrong , Jiang Li , Wang Chunru
Published: February 2014

Flower-like titanium phosphate microstructures were formed via hierarchical nucleation and growth and showed excellent adsorption capacity for lead ion removal.
Parallel deblocking filter for HEVC on many‐core processor
Authors: Yan Chenggang , Zhang Yongdong , Dai Feng , Wang Xi , Li Liang , Dai Qionghai
Published: February 2014

High‐efficiency video coding (HEVC) is the next generation standard of video coding. The deblocking filter (DF) constitutes a significant part of the HEVC decoder complexity. A three‐step parallel framework (TPF) is proposed for the H.264/AVC DF, which is also suitable for HEVC except the third step. The third step of the TPF is replaced with a directed acyclic graph‐based order. Experiments show that the proposed method dramatically accelerates more than the state‐of‐the‐art parallel method.
Dual‐hop amplify‐and‐forward cooperative relaying in the presence of Tx and Rx in‐phase and quadrature‐phase imbalance
Authors: Qi Jian , Aissa Sonia , Alouini Mohamed‐Slim
Published: February 2014

In this study, dual‐hop channel state information‐assisted amplify‐and‐forward (AF) cooperative systems in the presence of in‐phase and quadrature‐phase (I/Q) imbalance, which refers to the mismatch between components in the I and Q branches, are investigated. First, the authors analyse the performance of the considered AF cooperative protocol without compensation for the I/Q imbalance as the benchmark. Then, a compensation algorithm for the I/Q imbalance is proposed, which makes use of the received signals at the destination, from the source and the relay nodes, together with their conjugations to detect the transmitted signal. Moreover, the authors study the considered AF cooperative system implemented with the opportunistic relay selection and the proposed compensation mechanism for the I/Q imbalance. The performance of the AF cooperative system under study is evaluated in terms of average symbol error probability, which is derived by considering transmission in a Rayleigh fading environment. Numerical results are provided and show that the proposed compensation algorithm can efficiently mitigate the effect of the I/Q imbalance. On the other hand, it is observed that the AF cooperative system with opportunistic relay selection acquires a performance gain beyond that without relay selection.
Event‐triggered dynamic output feedback control for networked control systems
Authors: Zhang Xian‐Ming , Han Qing‐Long
Published: February 2014

This study is concerned with the event‐triggered control for networked control systems via dynamic output feedback controllers (DOFCs). The output measurement signals of the physical plant are sampled periodically. An output‐based discrete event‐triggering mechanism is introduced to choose those only necessary sampled‐data packets to be transmitted through a communication network for controller design. Under this event‐triggering mechanism, the resultant closed‐loop system is first modelled as a linear system with an interval time‐varying delay. Then a novel stability criterion is established by employing the Lyapunov–Krasovskii functional approach. Based on this stability criterion, a new sufficient condition is derived to co‐design both the desired DOFCs and the event‐triggering parameters. Finally, a satellite control system is taken to show the effectiveness of the proposed method.
On adaptive loop transfer recovery using Kalman filter‐based disturbance accommodating control
Authors: George Jemin
Published: February 2014

An adaptive loop transfer recovery (LTR) approach for uncertain systems using the Kalman filter‐based disturbance accommodating control scheme is presented. This study shows that the full LTR property of disturbance accommodating control is invariant to system uncertainties and external disturbances acting on the system. Also presented here is an adaptive LTR scheme, where the system process noise intensity matrix is updated online to achieve full LTR. Numerical simulations are presented to verify the superiority of the approach compared to the traditional linear quadratic regulator/LTR.
Design and performance evaluation of a mature FM/DAB/DVB‐T multi‐illuminator passive radar system
Authors: Edrich Michael , Schroeder Alexander , Meyer Fabienne
Published: February 2014

Passive radar (PR) systems use the target illumination by third‐party transmitters, for example, from broadcast or cellular base stations, for target detection and localisation. Since PR does not use an own transmitter, it can be installed and operated at low cost and it is hard to detect and jam. These advantages and the increasing maturity of PR technology has led to growing interest in these systems over the last years. However, until now most PR systems have been rather experimental set‐ups tailored to a single frequency band or implemented as laboratory test devices. This study in contrast describes the design, implementation and performance evaluation of a multi‐band, multi‐illuminator PR system developed at near‐production stage. Starting out from a FM‐broadcast‐based approach, the step to DAB‐based and DVB‐T‐based operation has already been made. As a result, a fully mobile FM/DAB/DVB‐T multi‐band PR system is now available, offering maximum flexibility for measurement campaigns with air, ground and sea targets. Experiments with a great variety of third‐party transmitters and arbitrary transmitter‐target‐receiver geometries have been conducted. The design considerations and the resulting PR system concept are described, and the results of representative measurement campaigns with different types of ground and aerial targets are presented.
Wideband antenna array for Digital Video Broadcast Terrestrial‐based passive bistatic radar applications
Authors: O'Hagan Daniel W. , Schröder Martin , Basavarajappa Vedaprabhu , Knott Peter , Kuschel Heiner , Simeoni Massimilano
Published: February 2014

A Digital Video Broadcast Terrestrial (DVB‐T)‐based passive radar requires the development of a dedicated antenna array that performs satisfactorily over the entire DVB‐T band. The array should require no mechanical adjustments to the inter‐element spacing to correspond to the DVB‐T carrier frequency used for any particular measurement. This study describes the challenges involved in designing an ultra high frequency (UHF) antenna array with a bandwidth of 450 MHz. The design procedure is discussed and a number of simulated array configurations are demonstrated. The final configuration of the array will be shown along with the simulations of the expected performance over the desired frequency span. Finally, the actual array is characterised to evaluate its performance based on data from anechoic chamber measurements.
Mitigating interference via spatial and spectral nulling
Authors: Higgins Thomas , Webster Tegan , Shackelford Aaron K.
Published: February 2014

Phase‐only transmit nulling may help the next generation of radar systems operate in an over‐crowded radio frequency spectrum. The reiterative uniform weight optimisation (RUWO) algorithm generates constant modulus radar waveforms with spatial, frequency or space–frequency nulls for multiple‐input multiple‐output (MIMO) transmit arrays by utilising the maximum signal‐to‐interference plus noise ratio framework in a reiterative fashion. This study presents loop‐back and open air experimental results, obtained using an eight‐channel X‐band coherent MIMO radar test bed, that demonstrate the use of RUWO to generate constant modulus waveforms that possess spatial and/or frequency nulls. The RUWO algorithm is first used to deterministically generate phase‐only weights that produce spatial, frequency or space–frequency nulls at baseband in a loop‐back configuration. The algorithm is then utilised to generate weights to produce spatial nulls, both deterministically and adaptively, for the full eight‐channel test bed in an open air configuration. The deterministic and adaptive strategies are compared; results demonstrate that RUWO can be used to create spatial nulls and highlight the need for careful calibration of both the transmitter and the receiver.
Synthesis of novel CuSn10‐graphite nanocomposite powders by mechanical alloying
Authors: Canakci A. , Varol T. , Cuvalci H. , Erdemir F. , Ozkaya S. , Yalcın E.D.
Published: February 2014

CuSn10‐Gr nanocomposite powders were successfully synthesised by mechanical alloying of the powder mixtures of CuSn10 and Gr (1, 3 and 5 wt%, respectively, of Gr). The effects of increasing the graphite particles weight percentage and milling time on the morphology, the particle size and the microstructure of the CuSn10‐Gr nanocomposite powders were investigated. The CuSn10‐Gr nanocomposite powders were characterised using a scanning electron microscope, a laser particle‐size analyser, X‐ray diffraction analysis and energy dispersive X‐ray analysis. The results show that the addition of the graphite particles as the reinforcement and the milling time has an important effect on the particle size, the morphology and the yield of the powder. The electron microscopy studies showed the formation of the equiaxed grains with a wide size distribution ranging from 50 to 250 nm. It was found that the particle size decreased until the creation of a balance between the rate of welding and fracturing. Moreover, the powder yield dropped drastically with the increasing milling time and the decreasing graphite content.
The behaviour of niobium and molybdenum during uni-axial strain loading
Authors: Millett J. C. F. , Cotton M. , Bourne N. K. , Park N. T. , Whiteman G.
Published: February 2014

The mechanical response of niobium and molybdenum during one dimensional shock loading in the weak shock regime is investigated in terms of the Hugoniot elastic limit (dynamic yield) and spall (tensile) strengths. Results indicate that although both metals have high elastic limits of ca. 2 GPa, their responses are very different. Deformation in the weak shock regime in niobium is controlled by both the motion and generation of dislocations, resulting in high spall (dynamic tensile) strengths and ductility. In contrast, molybdenum has low spall strength and ductility, which suggests lower dislocation mobility in this metal. We have also shown that the strain-rate in the rising part of the shock front is related to the stress amplitude by the fourth power, as first shown by Swegle and Grady. Although we have not been able to elucidate further on the power relation, we believe that the scaling factor A is related to a materials ability to accommodate shock imposed plasticity via slip and dislocation generation. Overall, we have used arguments about the Peierls stress in body centred cubic metals to explain these results, with niobium (low Peierls stress) having a high dislocation mobility, resulting in behaviour showing some similarities to face centred cubic metals. Molybdenum, with its much higher Peierls stress has a much lower dislocation mobility, and hence lower spall strengths and ductility.
Hard magnetic properties observed in bulk Mn1−xGax
Authors: Brown Daniel R. , Han Ke , Siegrist Theo
Published: February 2014

Mn-Ga binary alloys have shown promising magnetic properties, even though these alloys contain no rare-earth metals. Both theoretical predictions and experimental work have indicated that nanoscaled Mn-Ga samples (thin films) possess remarkable magnetic properties. Whether the same properties occur in macroscale ingots, however, require the investigation and production of bulk materials, which are needed for majority of the applications that require a strong magnetic field. We have used mechanically milling followed by heat treatment to produce bulk Mn1−xGax alloys. In this paper, we report annealed Mn1−xGax bulk composites that exhibit coercivity up to 18.8 kOe.
Taylor dispersion in heterogeneous porous media: Extended method of moments, theory, and modelling with two-relaxation-times lattice Boltzmann scheme
Authors: Vikhansky Alexander , Ginzburg Irina
Published: February 2014

This article describes a generalization of the method of moments, called extended method of moments (EMM), for dispersion in periodic structures composed of impermeable or permeable porous inclusions. Prescribing pre-computed steady state velocity field in a single periodic cell, the EMM sequentially solves specific linear stationary advection-diffusion equations and restores any-order moments of the resident time distribution or the averaged concentration distribution. Like the pioneering Brenner's method, the EMM recovers mean seepage velocity and Taylor dispersion coefficient as the first two terms of the perturbative expansion. We consider two types of dispersion: spatial dispersion, i.e., spread of initially narrow pulse of concentration, and temporal dispersion, where different portions of the solute have different residence times inside the system. While the first (mean velocity) and the second (Taylor dispersion coefficient) moments coincide for both problems, the higher moments are different. Our perturbative approach allows to link them through simple analytical expressions. Although the relative importance of the higher moments decays downstream, they manifest the non-Gaussian behaviour of the breakthrough curves, especially if the solute can diffuse into less porous phase. The EMM quantifies two principal effects of bi-modality, as the appearance of sharp peaks and elongated tails of the distributions. In addition, the moments can be used for the numerical reconstruction of the corresponding distribution, avoiding time-consuming computations of solute transition through heterogeneous media. As illustration, solutions for Taylor dispersion, skewness, and kurtosis in Poiseuille flow and open/impermeable stratified systems, both in rectangular and cylindrical channels, power-law duct flows, shallow channels, and Darcy flow in parallel porous layers are obtained in closed analytical form for the entire range of Péclet numbers. The high-order moments and reconstructed profiles are compared to their predictions from the advection-diffusion equation for averaged concentration, based on the same averaged seepage velocity and Taylor dispersion coefficient. In parallel, we construct Lattice-Boltzmann equation (LBE) two-relaxation-times scheme to simulate transport of a passive scalar directly in heterogeneous media specified by discontinuous porosity distribution. We focus our numerical analysis and assessment on (i) truncation corrections, because of their impact on the moments, (ii) stability, since we show that stable Darcy velocity amplitude reduces with the porosity, and (iii) interface accuracy which is found to play the crucial role. The task is twofold: the LBE supports the EMM predictions, while the EMM provides non-trivial benchmarks for the numerical schemes.